Provided by: nghttp2-proxy_1.59.0-1ubuntu0.2_amd64 bug

NAME

       nghttpx - HTTP/2 proxy

SYNOPSIS

       nghttpx [OPTIONS]... [<PRIVATE_KEY> <CERT>]

DESCRIPTION

       A reverse proxy for HTTP/3, HTTP/2, and HTTP/1.

       <PRIVATE_KEY>
              Set   path  to  server's private  key.   Required  unless "no-tls" parameter is used in --frontend
              option.

       <CERT> Set  path   to   server's   certificate.    Required   unless  "no-tls"   parameter  is   used  in
              --frontend option.   To make OCSP stapling work, this must be an absolute path.

OPTIONS

       The options are categorized into several groups.

   Connections
       -b, --backend=(<HOST>,<PORT>|unix:<PATH>)[;[<PATTERN>[:...]][[;<PARAM>]...]
              Set  backend  host  and   port.   The  multiple  backend addresses are  accepted by repeating this
              option.   UNIX  domain  socket   can  be   specified  by  prefixing  path name with "unix:" (e.g.,
              unix:/var/run/backend.sock).

              Optionally, if <PATTERN>s are given, the backend address is  only  used  if  request matches   the
              pattern.    The  pattern   matching is  closely  designed  to ServeMux  in net/http package of  Go
              programming language.  <PATTERN> consists of  path, host +  path or just  host.    The  path  must
              start  with "/".  If  it ends with "/",  it matches all  request path  in  its subtree.   To  deal
              with   the request  to the  directory without  trailing slash,  the path which ends  with "/" also
              matches  the request path which  only  lacks  trailing  '/'  (e.g.,  path  "/foo/" matches request
              path  "/foo").  If it does  not end with "/", it  performs exact match against  the request  path.
              If   host   is given,  it  performs  a match  against  the request host.   For a  request received
              on  the frontend listener with  "sni-fwd" parameter enabled,  SNI   host  is  used  instead  of  a
              request  host.   If  host alone is given, "/" is  appended to it,  so that it matches  all request
              paths  under the  host  (e.g., specifying  "nghttp2.org"  equals   to  "nghttp2.org/").    CONNECT
              method   is  treated  specially.   It   does  not  have  path, and we  don't allow empty path.  To
              workaround  this, we assume that CONNECT method has "/" as path.

              Patterns with  host take  precedence over  patterns with just path.   Then, longer  patterns  take
              precedence over shorter ones.

              Host   can   include  "*"  in  the  left most  position  to indicate  wildcard match  (only suffix
              match is  done).  The "*" must match  at  least  one  character.   For  example,  host     pattern
              "*.nghttp2.org"     matches     against  "www.nghttp2.org"   and  "git.ngttp2.org", but  does  not
              match  against  "nghttp2.org".   The exact  hosts  match takes precedence over the wildcard  hosts
              match.

              If  path   part  ends  with   "*",  it  is treated  as wildcard path.  The  wildcard path  behaves
              differently  from the normal path.  For normal path,  match is made around the  boundary  of  path
              component   separator,"/".   On the other hand, the wildcard  path does not take  into account the
              path component  separator.  All paths which  include the wildcard  path   without   last   "*"  as
              prefix,   and   are  strictly  longer than wildcard  path without last "*" are matched.  "*"  must
              match  at least one  character.  For example,  the    pattern   "/foo*"   matches    "/foo/"   and
              "/foobar".  But it does not match "/foo", or "/fo".

              If  <PATTERN>  is  omitted  or  empty string, "/" is used as pattern,  which  matches  all request
              paths  (catch-all pattern).  The catch-all backend must be given.

              When doing  a match, nghttpx made  some normalization to pattern, request host and path.  For host
              part, they are converted to lower case.  For  path  part,  percent-encoded  unreserved  characters
              defined  in  RFC  3986   are  decoded,  and  any   dot-segments (".."  and ".")   are resolved and
              removed.

              For   example,   -b'127.0.0.1,8080;nghttp2.org/httpbin/' matches the  request  host  "nghttp2.org"
              and   the  request  path "/httpbin/get", but does not match the request host "nghttp2.org" and the
              request path "/index.html".

              The  multiple  <PATTERN>s   can   be  specified,   delimiting  them             by            ":".
              Specifying  -b'127.0.0.1,8080;nghttp2.org:www.nghttp2.org'   has   the  same   effect   to specify
              -b'127.0.0.1,8080;nghttp2.org' and -b'127.0.0.1,8080;www.nghttp2.org'.

              The backend addresses sharing same <PATTERN> are grouped together forming  load balancing  group.

              Several parameters <PARAM> are accepted after <PATTERN>.  The  parameters are  delimited  by  ";".
              The   available  parameters        are:        "proto=<PROTO>",         "tls",   "sni=<SNI_HOST>",
              "fall=<N>",           "rise=<N>",    "affinity=<METHOD>",       "dns",      "redirect-if-not-tls",
              "upgrade-scheme",                               "mruby=<PATH>",         "read-timeout=<DURATION>",
              "write-timeout=<DURATION>", "group=<GROUP>",  "group-weight=<N>", "weight=<N>",  and "dnf".    The
              parameter   consists   of  keyword,   and optionally followed by "="  and value.  For example, the
              parameter "proto=h2" consists of the keyword "proto" and value "h2".  The parameter "tls" consists
              of the keyword "tls"  without value.   Each parameter  is described  as follows.

              The  backend application protocol  can be specified using optional  "proto"   parameter,  and   in
              the   form  of "proto=<PROTO>".  <PROTO> should be one of the  following  list   without   quotes:
              "h2",  "http/1.1".    The  default value of <PROTO> is  "http/1.1".  Note that usually "h2" refers
              to HTTP/2  over TLS.  But in this  option, it may mean HTTP/2  over cleartext  TCP  unless   "tls"
              keyword is used (see below).

              TLS   can    be   enabled   by   specifying    optional   "tls"  parameter.  TLS is not enabled by
              default.

              With "sni=<SNI_HOST>"  parameter,  it  can  override  the  TLS  SNI   field   value   with   given
              <SNI_HOST>.   This  will default to the backend <HOST> name

              The   feature   to  detect  whether  backend  is online  or offline can be enabled  using optional
              "fall" and "rise" parameters.   Using  "fall=<N>"  parameter,  if  nghttpx cannot  connect   to  a
              this  backend  <N>   times  in   a  row,  this  backend  is  assumed  to be  offline,  and  it  is
              excluded from load balancing.  If <N> is 0, this backend never  be excluded  from load   balancing
              whatever   times  nghttpx  cannot  connect   to  it,  and  this   is  the default.  There is  also
              "rise=<N>" parameter.  After  backend was excluded from load balancing group, nghttpx periodically
              attempts to make a connection to the failed backend, and if the  connection is made   successfully
              <N>  times   in  a  row,  the  backend  is assumed to  be online, and it is now eligible  for load
              balancing target.   If <N>  is 0,  a backend  is permanently  offline,  once   it  goes   in  that
              state, and this is the default behaviour.

              The      session      affinity     is      enabled      using "affinity=<METHOD>"  parameter.   If
              "ip" is  given  in <METHOD>, client  IP based session affinity  is enabled.  If "cookie"  is given
              in <METHOD>,  cookie based session affinity is   enabled.   If   "none"  is  given   in  <METHOD>,
              session  affinity   is  disabled, and this  is the default.  The session  affinity is  enabled per
              <PATTERN>.   If at least  one backend  has   "affinity"   parameter,  and   its  <METHOD>  is  not
              "none",   session affinity is enabled for all backend  servers sharing the same  <PATTERN>.  It is
              advised  to  set  "affinity" parameter  to   all   backend  explicitly  if  session  affinity   is
              desired.   The  session  affinity  may   break  if   one  of  the   backend  gets unreachable,  or
              backend  settings  are   reloaded  or replaced by API.

              If    "affinity=cookie"     is    used,     the     additional   configuration                  is
              required.  "affinity-cookie-name=<NAME>" must be  used to specify a name     of     cookie      to
              use.       Optionally,  "affinity-cookie-path=<PATH>"  can   be  used  to   specify a path   which
              cookie    is   applied.    The   optional "affinity-cookie-secure=<SECURE>"  controls  the  Secure
              attribute of a cookie.  The default value is "auto", and the Secure attribute is  determined by  a
              request  scheme.  If a request scheme is "https", then Secure attribute is set.  Otherwise, it  is
              not set.  If  <SECURE> is "yes", the  Secure attribute  is  always set.   If  <SECURE>   is  "no",
              the     Secure    attribute   is    always    omitted.   "affinity-cookie-stickiness=<STICKINESS>"
              controls stickiness  of   this  affinity.   If   <STICKINESS>  is "loose", removing  or  adding  a
              backend  server  might  break  the  affinity  and the  request might  be forwarded  to a different
              backend server.   If <STICKINESS> is "strict", removing  the  designated   backend  server  breaks
              affinity,  but  adding   new backend server does  not cause breakage.  If  the designated  backend
              server  becomes unavailable, new backend server is chosen  as if the request  does  not  have   an
              affinity  cookie.   <STICKINESS>  defaults  to "loose".

              By  default,  name  resolution  of  backend  host  name  is  done  at   start   up,   or reloading
              configuration.   If  "dns" parameter   is  given,   name  resolution   takes   place  dynamically.
              This  is  useful   if backend address changes frequently.   If  "dns"  is given,  name  resolution
              of backend   host   name   at  start   up,   or   reloading configuration is skipped.

              If "redirect-if-not-tls" parameter  is  used,  the  matched  backend   requires    that   frontend
              connection    is   TLS  encrypted.   If it isn't, nghttpx responds to the request with 308  status
              code, and  https URI the  client should use instead  is included in Location  header  field.   The
              port  number in  redirect URI is 443 by  default, and can be  changed using  --redirect-https-port
              option.   If at least one  backend has  "redirect-if-not-tls" parameter, this feature  is  enabled
              for  all  backend  servers  sharing  the    same    <PATTERN>.     It     is    advised   to   set
              "redirect-if-no-tls"    parameter   to    all   backends explicitly if this feature is desired.

              If "upgrade-scheme"  parameter is used along  with "tls" parameter, HTTP/2 :scheme  pseudo  header
              field  is  changed  to  "https"  from "http" when forwarding a request to this particular backend.
              This is  a workaround for a backend server  which  requires  "https" :scheme  pseudo  header field
              on TLS encrypted connection.

              "mruby=<PATH>"  parameter  specifies  a  path  to  mruby script  file   which   is   invoked  when
              this   pattern   is  matched.   All backends which share the same pattern must have the same mruby
              path.

              "read-timeout=<DURATION>" and "write-timeout=<DURATION>" parameters  specify the  read and   write
              timeout   of the backend connection  when this  pattern is  matched.  All backends which share the
              same pattern must have the same timeouts.  If these timeouts  are entirely omitted for a  pattern,
              --backend-read-timeout           and --backend-write-timeout are used.

              "group=<GROUP>"   parameter  specifies   the  name   of group this backend address belongs to.  By
              default, it belongs to  the unnamed   default  group.    The  name   of  group   is  unique    per
              pattern.   "group-weight=<N>"   parameter specifies the  weight of  the group.  The  higher weight
              gets   more  frequently   selected   by   the  load   balancing  algorithm.  <N> must be  [1, 256]
              inclusive.  The weight 8 has 4 times more weight  than 2.  <N> must be the same for  all addresses
              which  share the  same <GROUP>.   If "group-weight" is  omitted in  an  address,   but  the  other
              address   which   belongs   to   the   same  group  specifies "group-weight",   its    weight   is
              used.     If   no "group-weight"  is  specified  for  all   addresses,   the  weight  of  a  group
              becomes 1.  "group" and "group-weight" are ignored if session affinity is enabled.

              "weight=<N>"  parameter  specifies  the  weight  of  the backend  address  inside  a  group  which
              this   address  belongs   to.   The   higher   weight  gets more  frequently selected by  the load
              balancing algorithm.   <N> must be [1,  256] inclusive.   The  weight 8  has  4 times  more weight
              than weight  2.  If  this parameter  is omitted, weight  becomes  1.   "weight"  is   ignored   if
              session affinity is enabled.

              If  "dnf"  parameter  is   specified,  an incoming request is not forwarded to a backend  and just
              consumed along with the  request body  (actually a  backend server  never be contacted).   It   is
              expected   that  the  HTTP   response  is generated by mruby  script (see "mruby=<PATH>" parameter
              above).  "dnf" is an abbreviation of "do not forward".

              Since ";" and ":" are  used as delimiter, <PATTERN> must not contain  these characters.  In  order
              to  include  ":" in  <PATTERN>,  one  has  to  specify  "%3A"  (which  is percent-encoded  from of
              ":") instead.   Since ";"  has special  meaning  in shell,  the  option  value must  be quoted.

              Default: 127.0.0.1,80

       -f, --frontend=(<HOST>,<PORT>|unix:<PATH>)[[;<PARAM>]...]
              Set  frontend  host and  port.   If  <HOST> is  '*',  it assumes  all addresses   including   both
              IPv4  and   IPv6.   UNIX  domain   socket can  be specified by  prefixing path name  with  "unix:"
              (e.g.,  unix:/var/run/nghttpx.sock).  This  option can  be used  multiple  times   to  listen   to
              multiple addresses.

              This  option   can  take  0 or  more parameters,  which are described  below.   Note   that  "api"
              and  "healthmon" parameters are mutually exclusive.

              Optionally, TLS  can be disabled by  specifying "no-tls" parameter.  TLS is enabled by default.

              If "sni-fwd" parameter is  used, when performing a match to select a  backend  server,   SNI  host
              name received from the client  is used  instead of  the request  host.  See --backend option about
              the pattern match.

              To   make  this   frontend  as   API endpoint,  specify "api" parameter.   This   is  disabled  by
              default.    It  is important  to  limit the  access  to  the API   frontend.   Otherwise,  someone
              may  change   the backend  server, and break your services,  or expose confidential information to
              the outside the world.

              To  make  this  frontend  as  health  monitor  endpoint, specify  "healthmon"   parameter.    This
              is   disabled   by  default.   Any  requests which come through  this address are replied with 200
              HTTP status, without no body.

              To accept  PROXY protocol  version 1   and  2   on  frontend  connection,   specify   "proxyproto"
              parameter.   This  is disabled by default.

              To   receive    HTTP/3  (QUIC)  traffic,   specify  "quic" parameter.  It  makes nghttpx listen on
              UDP port rather than  TCP   port.   UNIX   domain  socket,   "api",  and  "healthmon"   parameters
              cannot   be  used  with  "quic" parameter.

              Default: *,3000

       --backlog=<N>
              Set listen backlog size.

              Default: 65536

       --backend-address-family=(auto|IPv4|IPv6)
              Specify   address  family  of  backend  connections.   If "auto" is given, both IPv4  and IPv6 are
              considered.  If "IPv4" is  given, only  IPv4 address is  considered.  If  "IPv6"  is  given,  only
              IPv6 address is considered.

              Default: auto

       --backend-http-proxy-uri=<URI>
              Specify       proxy        URI       in       the      form http://[<USER>:<PASS>@]<PROXY>:<PORT>.
              If   a   proxy requires  authentication,  specify  <USER>  and  <PASS>.  Note that  they  must  be
              properly   percent-encoded.  This proxy  is used  when the  backend connection  is HTTP/2.  First,
              make  a CONNECT  request  to  the proxy  and  it connects  to the  backend  on behalf  of nghttpx.
              This forms  tunnel.   After  that, nghttpx   performs   SSL/TLS  handshake  with   the  downstream
              through   the   tunnel.   The  timeouts  when  connecting  and   making  CONNECT  request  can  be
              specified    by     --backend-read-timeout    and --backend-write-timeout options.

   Performance
       -n, --workers=<N>
              Set the number of worker threads.

              Default: 1

       --single-thread
              Run everything in one  thread inside the worker process.   This    feature    is    provided   for
              better    debugging  experience,   or   for   the  platforms   which   lack   thread support.   If
              threading  is disabled,  this  option  is always enabled.

       --read-rate=<SIZE>
              Set maximum  average read  rate on  frontend connection.  Setting 0 to this option means read rate
              is unlimited.

              Default: 0

       --read-burst=<SIZE>
              Set  maximum read  burst  size  on frontend  connection.  Setting  0  to this  option  means  read
              burst  size  is unlimited.

              Default: 0

       --write-rate=<SIZE>
              Set maximum  average write rate on  frontend connection.  Setting 0 to  this  option  means  write
              rate is unlimited.

              Default: 0

       --write-burst=<SIZE>
              Set  maximum write  burst size  on frontend  connection.  Setting  0 to  this  option means  write
              burst size  is unlimited.

              Default: 0

       --worker-read-rate=<SIZE>
              Set  maximum  average  read  rate  on  frontend connection per worker.  Setting  0 to  this option
              means read  rate is unlimited.  Not implemented yet.

              Default: 0

       --worker-read-burst=<SIZE>
              Set maximum  read burst size on  frontend connection per worker.  Setting 0 to this  option  means
              read burst size is unlimited.  Not implemented yet.

              Default: 0

       --worker-write-rate=<SIZE>
              Set  maximum   average  write  rate on  frontend connection per worker.  Setting  0 to this option
              means write rate is unlimited.  Not implemented yet.

              Default: 0

       --worker-write-burst=<SIZE>
              Set maximum write burst  size on frontend connection per worker.  Setting 0 to this  option  means
              write burst size is unlimited.  Not implemented yet.

              Default: 0

       --worker-frontend-connections=<N>
              Set maximum number  of simultaneous connections frontend accepts.  Setting 0 means unlimited.

              Default: 0

       --backend-connections-per-host=<N>
              Set   maximum  number   of   backend concurrent  connections (and/or  streams in  case  of HTTP/2)
              per origin  host.  This option  is meaningful when --http2-proxy  option is  used.    The   origin
              host   is   determined   by   authority  portion  of  request URI (or :authority  header field for
              HTTP/2).   To  limit   the    number   of   connections   per  frontend         for        default
              mode,       use --backend-connections-per-frontend.

              Default: 8

       --backend-connections-per-frontend=<N>
              Set   maximum number  of  backend concurrent  connections (and/or streams  in case of HTTP/2)  per
              frontend.  This option  is   only  used  for  default   mode.   0  means unlimited.  To limit  the
              number   of   connections   per  host  with           --http2-proxy          option,           use
              --backend-connections-per-host.

              Default: 0

       --rlimit-nofile=<N>
              Set maximum number of open files (RLIMIT_NOFILE) to <N>.  If 0 is given, nghttpx does not set  the
              limit.

              Default: 0

       --rlimit-memlock=<N>
              Set  maximum  number  of  bytes of memory that may be locked into  RAM.  If  0 is  given,  nghttpx
              does  not set  the limit.

              Default: 0

       --backend-request-buffer=<SIZE>
              Set buffer size used to store backend request.

              Default: 16K

       --backend-response-buffer=<SIZE>
              Set buffer size used to store backend response.

              Default: 128K

       --fastopen=<N>
              Enables  "TCP Fast  Open" for  the listening  socket and limits the  maximum length for the  queue
              of connections that have not yet completed the three-way handshake.  If value is 0 then fast  open
              is disabled.

              Default: 0

       --no-kqueue
              Don't  use   kqueue.   This  option is only  applicable for the platforms  which have kqueue.  For
              other platforms, this option will be simply ignored.

   Timeout
       --frontend-http2-read-timeout=<DURATION>
              Specify read timeout for HTTP/2 frontend connection.

              Default: 3m

       --frontend-http3-read-timeout=<DURATION>
              Specify read timeout for HTTP/3 frontend connection.

              Default: 3m

       --frontend-read-timeout=<DURATION>
              Specify read timeout for HTTP/1.1 frontend connection.

              Default: 1m

       --frontend-write-timeout=<DURATION>
              Specify write timeout for all frontend connections.

              Default: 30s

       --frontend-keep-alive-timeout=<DURATION>
              Specify   keep-alive   timeout   for   frontend   HTTP/1 connection.

              Default: 1m

       --stream-read-timeout=<DURATION>
              Specify  read timeout  for HTTP/2  streams.  0  means no timeout.

              Default: 0

       --stream-write-timeout=<DURATION>
              Specify write  timeout for  HTTP/2 streams.  0  means no timeout.

              Default: 1m

       --backend-read-timeout=<DURATION>
              Specify read timeout for backend connection.

              Default: 1m

       --backend-write-timeout=<DURATION>
              Specify write timeout for backend connection.

              Default: 30s

       --backend-connect-timeout=<DURATION>
              Specify  timeout before  establishing TCP  connection to backend.

              Default: 30s

       --backend-keep-alive-timeout=<DURATION>
              Specify   keep-alive   timeout    for   backend   HTTP/1 connection.

              Default: 2s

       --listener-disable-timeout=<DURATION>
              After accepting  connection failed,  connection listener is disabled  for a given  amount of time.
              Specifying 0 disables this feature.

              Default: 30s

       --frontend-http2-setting-timeout=<DURATION>
              Specify  timeout before  SETTINGS ACK  is received  from client.

              Default: 10s

       --backend-http2-settings-timeout=<DURATION>
              Specify  timeout before  SETTINGS ACK  is received  from backend server.

              Default: 10s

       --backend-max-backoff=<DURATION>
              Specify  maximum backoff  interval.  This  is used   when  doing  health   check  against  offline
              backend   (see "fail" parameter  in --backend  option).   It is  also used  to limit  the  maximum
              interval  to  temporarily  disable backend  when  nghttpx   failed  to   connect  to   it.   These
              intervals  are calculated  using exponential backoff, and consecutive failed attempts increase the
              interval.  This option caps its maximum value.

              Default: 2m

   SSL/TLS
       --ciphers=<SUITE>
              Set allowed  cipher list  for frontend  connection.  The format of  the  string  is  described  in
              OpenSSL ciphers(1).  This option  sets cipher suites for  TLSv1.2 or earlier.  Use --tls13-ciphers
              for TLSv1.3.

              Default:
              ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384

       --tls13-ciphers=<SUITE>
              Set  allowed   cipher  list   for  frontend  connection.  The format of the string is described in
              OpenSSL ciphers(1).  This  option  sets   cipher    suites   for   TLSv1.3.    Use  --ciphers  for
              TLSv1.2 or earlier.

              Default: TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256

       --client-ciphers=<SUITE>
              Set   allowed  cipher   list  for   backend connection.   The format of the string is described in
              OpenSSL  ciphers(1).   This  option   sets  cipher  suites   for    TLSv1.2   or   earlier.    Use
              --tls13-client-ciphers for TLSv1.3.

              Default:
              ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384

       --tls13-client-ciphers=<SUITE>
              Set   allowed  cipher   list  for   backend connection.   The format of the string is described in
              OpenSSL   ciphers(1).    This    option    sets    cipher     suites     for     TLSv1.3.      Use
              --tls13-client-ciphers for TLSv1.2 or earlier.

              Default: TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256

       --ecdh-curves=<LIST>
              Set   supported   curve   list   for  frontend  connections.  <LIST> is a  colon separated list of
              curve  NID or names in the preference order.  The supported curves depend on the  linked   OpenSSL
              library.  This  function  requires OpenSSL >= 1.0.2.

              Default: X25519:P-256:P-384:P-521

       -k, --insecure
              Don't  verify backend  server's  certificate  if TLS  is enabled for backend connections.

       --cacert=<PATH>
              Set  path  to  trusted  CA   certificate  file.  It is used in backend  TLS connections  to verify
              peer's  certificate.   It  is  also  used  to   verify  OCSP  response  from  the  script  set  by
              --fetch-ocsp-response-file.   The   file  must  be  in  PEM  format.    It  can  contain  multiple
              certificates.  If the  linked OpenSSL  is configured  to load  system wide certificates, they  are
              loaded at startup  regardless of this option.

       --private-key-passwd-file=<PATH>
              Path  to file  that contains  password for  the server's private key.   If none is  given and  the
              private  key is password protected it'll be requested interactively.

       --subcert=<KEYPATH>:<CERTPATH>[[;<PARAM>]...]
              Specify   additional certificate  and  private key  file.  nghttpx will  choose certificates based
              on  the hostname indicated by client using TLS SNI extension.  If nghttpx is  built with   OpenSSL
              >=  1.0.2,   the  shared   elliptic curves (e.g., P-256) between  client and server are also taken
              into  consideration.  This allows nghttpx  to send ECDSA certificate   to  modern  clients,  while
              sending  RSA  based certificate to older  clients.  This option can be used  multiple  times.   To
              make  OCSP  stapling  work, <CERTPATH> must be absolute path.

              Additional parameter  can be specified in  <PARAM>.  The available <PARAM> is "sct-dir=<DIR>".

              "sct-dir=<DIR>"  specifies the   path  to   directory  which  contains         *.sct         files
              for         TLS  signed_certificate_timestamp  extension  (RFC  6962).   This  feature    requires
              OpenSSL   >=   1.0.2.    See   also --tls-sct-dir option.

       --dh-param-file=<PATH>
              Path to file that contains  DH parameters in PEM format.  Without  this    option,   DHE    cipher
              suites   are  not available.

       --alpn-list=<LIST>
              Comma delimited list of  ALPN protocol identifier sorted in the  order of preference.  That  means
              most  desirable  protocol  comes   first.  The parameter must  be delimited by a single comma only
              and any white spaces are treated as a part of protocol string.

              Default: h2,h2-16,h2-14,http/1.1

       --verify-client
              Require and verify client certificate.

       --verify-client-cacert=<PATH>
              Path  to file  that contains  CA certificates  to verify client certificate.  The file must be  in
              PEM format.  It can contain multiple certificates.

       --verify-client-tolerate-expired
              Accept   expired  client  certificate.   Operator  should handle  the expired  client  certificate
              by some  means (e.g.,  mruby  script).   Otherwise, this  option  might cause a security risk.

       --client-private-key-file=<PATH>
              Path to  file that contains  client private key  used in backend client authentication.

       --client-cert-file=<PATH>
              Path to  file that  contains client certificate  used in backend client authentication.

       --tls-min-proto-version=<VER>
              Specify minimum SSL/TLS protocol.   The name matching is done in   case-insensitive  manner.   The
              versions  between  --tls-min-proto-version  and   --tls-max-proto-version  are  enabled.   If  the
              protocol list advertised by client does not  overlap  this range,  you  will  receive  the   error
              message "unknown protocol".  If a protocol version lower than TLSv1.2 is specified, make sure that
              the  compatible  ciphers  are   included  in  --ciphers  option.    The default cipher  list  only
              includes  ciphers  compatible  with TLSv1.2  or  above.   The  available  versions  are:  TLSv1.3,
              TLSv1.2, TLSv1.1, and TLSv1.0

              Default: TLSv1.2

       --tls-max-proto-version=<VER>
              Specify  maximum  SSL/TLS  protocol.   The name matching is done in  case-insensitive manner.  The
              versions  between  --tls-min-proto-version  and   --tls-max-proto-version  are  enabled.   If  the
              protocol  list  advertised by client does not  overlap  this range,  you  will  receive the  error
              message "unknown protocol".  The available versions are: TLSv1.3, TLSv1.2, TLSv1.1, and TLSv1.0

              Default: TLSv1.3

       --tls-ticket-key-file=<PATH>
              Path to file that  contains   random  data  to  construct  TLS  session  ticket   parameters.   If
              aes-128-cbc  is   given  in  --tls-ticket-key-cipher, the  file must  contain exactly 48    bytes.
              If     aes-256-cbc    is    given    in --tls-ticket-key-cipher, the  file must   contain  exactly
              80  bytes.   This  options  can be  used  repeatedly  to specify  multiple ticket  parameters.  If
              several  files  are  given,  only the  first key is  used to  encrypt TLS session  tickets.  Other
              keys are  accepted but  server will  issue new  session  ticket with   first  key.    This  allows
              session   key  rotation.  Please  note  that  key rotation  does  not  occur automatically.   User
              should rearrange  files or  change options  values and  restart nghttpx gracefully.    If  opening
              or  reading   given  file  fails, all loaded  keys are discarded and  it is treated as if none  of
              this option is given.  If  this option is not given or an error  occurred while opening or reading
              a file,  key is  generated every  1 hour  internally and they are  valid for  12 hours.   This  is
              recommended if ticket  key sharing  between  nghttpx  instances is  not required.

       --tls-ticket-key-memcached=<HOST>,<PORT>[;tls]
              Specify  address   of  memcached   server  to get  TLS ticket keys for  session resumption.   This
              enables  shared TLS ticket key between  multiple nghttpx instances.   nghttpx  does  not  set  TLS
              ticket   key  to memcached.  The external ticket key generator is required.  nghttpx just gets TLS
              ticket  keys  from  memcached, and  use  them,  possibly replacing current set  of keys.  It is up
              to extern TLS ticket  key generator  to  rotate   keys  frequently.    See  "TLS  SESSION   TICKET
              RESUMPTION"  section  in   manual  page  to  know the data format in memcached entry.  Optionally,
              memcached  connection  can  be  encrypted  with  TLS  by specifying "tls" parameter.

       --tls-ticket-key-memcached-address-family=(auto|IPv4|IPv6)
              Specify address  family of memcached connections  to get TLS ticket keys.   If  "auto"  is  given,
              both  IPv4  and  IPv6  are considered.   If "IPv4" is given,  only IPv4 address is considered.  If
              "IPv6" is given, only IPv6 address is considered.

              Default: auto

       --tls-ticket-key-memcached-interval=<DURATION>
              Set interval to get TLS ticket keys from memcached.

              Default: 10m

       --tls-ticket-key-memcached-max-retry=<N>
              Set  maximum   number  of  consecutive   retries  before abandoning TLS ticket key  retrieval.  If
              this number is reached,  the  attempt  is  considered   as   failure,   and  "failure"  count   is
              incremented  by  1,   which  contributed  to            the            value            controlled
              --tls-ticket-key-memcached-max-fail option.

              Default: 3

       --tls-ticket-key-memcached-max-fail=<N>
              Set  maximum   number  of  consecutive   failure  before disabling TLS ticket until next scheduled
              key retrieval.

              Default: 2

       --tls-ticket-key-cipher=<CIPHER>
              Specify cipher  to encrypt TLS session  ticket.  Specify either   aes-128-cbc    or   aes-256-cbc.
              By   default, aes-128-cbc is used.

       --tls-ticket-key-memcached-cert-file=<PATH>
              Path to client certificate  for memcached connections to get TLS ticket keys.

       --tls-ticket-key-memcached-private-key-file=<PATH>
              Path to client private  key for memcached connections to get TLS ticket keys.

       --fetch-ocsp-response-file=<PATH>
              Path to  fetch-ocsp-response script file.  It  should be absolute path.

              Default: /usr/local/share/nghttp2/fetch-ocsp-response

       --ocsp-update-interval=<DURATION>
              Set interval to update OCSP response cache.

              Default: 4h

       --ocsp-startup
              Start   accepting connections  after initial  attempts to get OCSP responses  finish.  It does not
              matter some of the  attempts  fail.  This  feature  is  useful if   OCSP  responses    must     be
              available    before   accepting connections.

       --no-verify-ocsp
              nghttpx does not verify OCSP response.

       --no-ocsp
              Disable OCSP stapling.

       --tls-session-cache-memcached=<HOST>,<PORT>[;tls]
              Specify   address of  memcached server  to store  session cache.   This  enables   shared  session
              cache   between  multiple    nghttpx   instances.     Optionally,   memcached  connection  can  be
              encrypted with TLS by specifying "tls" parameter.

       --tls-session-cache-memcached-address-family=(auto|IPv4|IPv6)
              Specify address family of memcached connections to store session cache.  If  "auto" is given, both
              IPv4  and  IPv6 are considered.   If "IPv4" is given,  only IPv4 address is considered.  If "IPv6"
              is given, only IPv6 address is considered.

              Default: auto

       --tls-session-cache-memcached-cert-file=<PATH>
              Path to client certificate  for memcached connections to store session cache.

       --tls-session-cache-memcached-private-key-file=<PATH>
              Path to client private  key for memcached connections to store session cache.

       --tls-dyn-rec-warmup-threshold=<SIZE>
              Specify the  threshold size for TLS  dynamic record size behaviour.  During  a TLS  session, after
              the threshold number of bytes  have been written, the  TLS record size will be  increased  to  the
              maximum  allowed (16K).  The max record size will  continue to be used on  the active TLS session.
              After  --tls-dyn-rec-idle-timeout has elapsed, the record size is reduced  to 1300 bytes.  Specify
              0 to always use  the maximum record size,  regardless of idle period.   This   behaviour   applies
              to  all  TLS  based frontends, and TLS HTTP/2 backends.

              Default: 1M

       --tls-dyn-rec-idle-timeout=<DURATION>
              Specify  TLS  dynamic  record   size  behaviour  timeout.  See --tls-dyn-rec-warmup-threshold  for
              more  information.  This behaviour  applies to all TLS  based frontends, and TLS HTTP/2 backends.

              Default: 1s

       --no-http2-cipher-block-list
              Allow     block     listed      cipher     suite      on      frontend      HTTP/2     connection.
              See  https://tools.ietf.org/html/rfc7540#appendix-A   for  the complete HTTP/2 cipher suites block
              list.

       --client-no-http2-cipher-block-list
              Allow     block     listed      cipher      suite      on      backend      HTTP/2     connection.
              See  https://tools.ietf.org/html/rfc7540#appendix-A   for  the complete HTTP/2 cipher suites block
              list.

       --tls-sct-dir=<DIR>
              Specifies the  directory where  *.sct files  exist.  All *.sct   files   in  <DIR>    are    read,
              and  sent   as extension_data of  TLS signed_certificate_timestamp (RFC 6962)  to  client.   These
              *.sct   files   are   for   the  certificate   specified   in   positional   command-line argument
              <CERT>, or  certificate option in configuration  file.    For    additional   certificates,    use
              --subcert option.  This option requires OpenSSL >= 1.0.2.

       --psk-secrets=<PATH>
              Read  list  of  PSK  identity and secrets from <PATH>.  This is used for frontend connection.  The
              each line of input file  is  formatted  as  <identity>:<hex-secret>,   where  <identity>  is   PSK
              identity, and <hex-secret>  is secret in hex.  An  empty line, and line which  starts with '#' are
              skipped.   The default  enabled cipher list might not contain any PSK cipher suite.  In that case,
              desired PSK cipher suites  must be  enabled using  --ciphers option.   The   desired  PSK   cipher
              suite   may be  block listed  by HTTP/2.   To  use  those   cipher  suites  with  HTTP/2, consider
              to  use  --no-http2-cipher-block-list  option.  But be aware its implications.

       --client-psk-secrets=<PATH>
              Read PSK identity and secrets from <PATH>.  This is used for backend connection.  The  each   line
              of  input  file  is  formatted  as <identity>:<hex-secret>,  where <identity> is PSK identity, and
              <hex-secret>  is secret in hex.  An empty line, and line which  starts with '#' are skipped.   The
              first  identity and  secret pair encountered is used.  The default  enabled cipher  list might not
              contain any PSK  cipher suite.   In  that case,  desired PSK   cipher  suites   must  be   enabled
              using   --client-ciphers option.  The  desired PSK  cipher suite  may be  block listed  by HTTP/2.
              To     use     those      cipher      suites      with      HTTP/2,     consider       to      use
              --client-no-http2-cipher-block-list option.  But be aware its implications.

       --tls-no-postpone-early-data
              By   default,   except  for  QUIC   connections,  nghttpx postpones forwarding  HTTP requests sent
              in  early data, including  those  sent in  partially  in  it, until  TLS handshake  finishes.   If
              all  backend   server  recognizes "Early-Data"  header  field,  using  this  option  makes nghttpx
              not postpone  forwarding request  and get  full potential of 0-RTT data.

       --tls-max-early-data=<SIZE>
              Sets  the  maximum  amount  of 0-RTT  data  that  server accepts.

              Default: 16K

       --tls-ktls
              Enable   ktls.    For   server,  ktls   is    enable    if  --tls-session-cache-memcached  is  not
              configured.

   HTTP/2
       -c, --frontend-http2-max-concurrent-streams=<N>
              Set the maximum number of  the concurrent streams in one frontend HTTP/2 session.

              Default: 100

       --backend-http2-max-concurrent-streams=<N>
              Set  the  maximum  number  of   the concurrent streams in one backend  HTTP/2 session.   This sets
              maximum number  of concurrent opened pushed streams.  The maximum number  of  concurrent  requests
              are set by a remote server.

              Default: 100

       --frontend-http2-window-size=<SIZE>
              Sets  the  per-stream  initial  window  size  of  HTTP/2 frontend connection.

              Default: 65535

       --frontend-http2-connection-window-size=<SIZE>
              Sets the  per-connection window size of  HTTP/2 frontend connection.

              Default: 65535

       --backend-http2-window-size=<SIZE>
              Sets  the   initial  window   size  of   HTTP/2  backend connection.

              Default: 65535

       --backend-http2-connection-window-size=<SIZE>
              Sets the  per-connection window  size of  HTTP/2 backend connection.

              Default: 2147483647

       --http2-no-cookie-crumbling
              Don't crumble cookie header field.

       --padding=<N>
              Add   at most  <N> bytes  to  a HTTP/2  frame payload  as padding.  Specify 0 to  disable padding.
              This option is meant for debugging purpose  and not intended to enhance protocol security.

       --no-server-push
              Disable HTTP/2 server push.  Server push is supported by default mode  and  HTTP/2   frontend  via
              Link  header  field.   It  is  also supported if  both frontend and  backend are HTTP/2 in default
              mode.  In  this case, server push from backend session is relayed  to frontend,  and  server  push
              via Link header field is also supported.

       --frontend-http2-optimize-write-buffer-size
              (Experimental)  Enable  write   buffer size optimization in frontend HTTP/2 TLS  connection.  This
              optimization aims to reduce  write buffer  size so  that it  only contains bytes  which can   send
              immediately.    This  makes   server  more  responsive  to  prioritized  HTTP/2 stream because the
              buffering  of lower  priority stream  is reduced.   This option is only effective on recent  Linux
              platform.

       --frontend-http2-optimize-window-size
              (Experimental)    Automatically   tune    connection   level  window  size of frontend  HTTP/2 TLS
              connection.  If this feature is  enabled,  connection  window  size   starts  with  the    default
              window   size,   65535  bytes.    nghttpx automatically  adjusts connection  window size  based on
              TCP  receiving   window  size.   The  maximum   window  size  is capped      by      the     value
              specified      by --frontend-http2-connection-window-size.     Since   the stream  is  subject  to
              stream level window size, it should be adjusted using --frontend-http2-window-size option as well.
              This option  is only  effective on  recent Linux platform.

       --frontend-http2-encoder-dynamic-table-size=<SIZE>
              Specify  the  maximum dynamic  table size of HPACK encoder in the frontend HTTP/2 connection.  The
              decoder (client) specifies  the maximum  dynamic table  size it   accepts.   Then  the  negotiated
              dynamic table size is the minimum of this option value and the value which client specified.

              Default: 4K

       --frontend-http2-decoder-dynamic-table-size=<SIZE>
              Specify the maximum dynamic  table size of HPACK decoder in the frontend HTTP/2 connection.

              Default: 4K

       --backend-http2-encoder-dynamic-table-size=<SIZE>
              Specify  the  maximum  dynamic  table size of HPACK encoder in the backend HTTP/2 connection.  The
              decoder (backend) specifies  the maximum  dynamic table  size it  accepts.   Then  the  negotiated
              dynamic table size is the minimum of this option value and the value which backend specified.

              Default: 4K

       --backend-http2-decoder-dynamic-table-size=<SIZE>
              Specify the maximum dynamic  table size of HPACK decoder in the backend HTTP/2 connection.

              Default: 4K

   Mode
       (default mode)
              Accept  HTTP/2,  and  HTTP/1.1 over  SSL/TLS.   "no-tls" parameter is  used in  --frontend option,
              accept  HTTP/2  and  HTTP/1.1  over  cleartext   TCP.   The  incoming HTTP/1.1 connection  can  be
              upgraded  to  HTTP/2  through  HTTP Upgrade.

       -s, --http2-proxy
              Like default mode, but enable forward proxy.  This is so called HTTP/2 proxy mode.

   Logging
       -L, --log-level=<LEVEL>
              Set the severity  level of log output.   <LEVEL> must be one of  INFO,  NOTICE,  WARN,  ERROR  and
              FATAL.

              Default: NOTICE

       --accesslog-file=<PATH>
              Set path to write access log.  To reopen file, send USR1 signal to nghttpx.

       --accesslog-syslog
              Send  access log  to syslog.   If this  option is  used, --accesslog-file option is ignored.

       --accesslog-format=<FORMAT>
              Specify   format   string   for  access   log.    The   default  format  is combined format.   The
              following variables are available:

              • $remote_addr: client IP address.

              • $time_local: local time in Common Log format.

              • $time_iso8601: local time in ISO 8601 format.

              • $request: HTTP request line.

              • $status: HTTP response status code.

              • $body_bytes_sent: the  number of bytes sent  to client as response body.

              • $http_<VAR>: value of HTTP  request header <VAR> where '_' in <VAR> is replaced with '-'.

              • $remote_port: client  port.

              • $server_port: server port.

              • $request_time: request processing time in seconds with milliseconds resolution.

              • $pid: PID of the running process.

              • $alpn: ALPN identifier of the protocol which generates the  response.    For  HTTP/1,   ALPN  is
                always http/1.1, regardless of minor version.

              • $tls_cipher: cipher used for SSL/TLS connection.

              • $tls_client_fingerprint_sha256: SHA-256 fingerprint of client certificate.

              • $tls_client_fingerprint_sha1:  SHA-1   fingerprint  of client certificate.

              • $tls_client_subject_name:   subject  name   in  client certificate.

              • $tls_client_issuer_name:   issuer   name   in   client certificate.

              • $tls_client_serial:    serial    number   in    client certificate.

              • $tls_protocol: protocol for SSL/TLS connection.

              • $tls_session_id: session ID for SSL/TLS connection.

              • $tls_session_reused:  "r"   if  SSL/TLS   session  was reused.  Otherwise, "."

              • $tls_sni: SNI server name for SSL/TLS connection.

              • $backend_host:   backend   host    used   to   fulfill  the request.  "-" if backend host is not
                available.

              • $backend_port:  backend  port   used  to  fulfill  the request.  "-"  if  backend  host  is  not
                available.

              • $method: HTTP method

              • $path:  Request  path  including query.   For  CONNECT request, authority is recorded.

              • $path_without_query:   $path    up   to   the   first  '?' character.    For   CONNECT  request,
                authority   is recorded.

              • $protocol_version:   HTTP  version   (e.g.,  HTTP/1.1, HTTP/2)

              The  variable  can  be  enclosed  by  "{"  and  "}"  for disambiguation (e.g., ${remote_addr}).

              Default: $remote_addr  -  -  [$time_local]  "$request"  $status  $body_bytes_sent  "$http_referer"
              "$http_user_agent"

       --accesslog-write-early
              Write   access  log  when   response  header  fields  are received   from  backend   rather   than
              when   request transaction finishes.

       --errorlog-file=<PATH>
              Set path to write error  log.  To reopen file, send USR1 signal  to  nghttpx.    stderr  will   be
              redirected  to the error log file unless --errorlog-syslog is used.

              Default: /dev/stderr

       --errorlog-syslog
              Send  error log  to  syslog.  If  this  option is  used, --errorlog-file option is ignored.

       --syslog-facility=<FACILITY>
              Set syslog facility to <FACILITY>.

              Default: daemon

   HTTP
       --add-x-forwarded-for
              Append  X-Forwarded-For header  field to  the downstream request.

       --strip-incoming-x-forwarded-for
              Strip X-Forwarded-For  header field from  inbound client requests.

       --no-add-x-forwarded-proto
              Don't append  additional X-Forwarded-Proto  header field to  the   backend  request.   If  inbound
              client            sets           X-Forwarded-Proto,                                            and
              --no-strip-incoming-x-forwarded-proto  option  is  used, they are passed to the backend.

       --no-strip-incoming-x-forwarded-proto
              Don't strip X-Forwarded-Proto  header field from inbound client requests.

       --add-forwarded=<LIST>
              Append RFC  7239 Forwarded header field  with parameters specified in comma delimited list <LIST>.
              The supported parameters  are "by",  "for", "host",  and "proto".   By  default,   the  value   of
              "by"   and   "for"  parameters   are  obfuscated      string.      See      --forwarded-by     and
              --forwarded-for options  respectively.   Note  that  nghttpx  does   not   translate  non-standard
              X-Forwarded-*  header fields into Forwarded header field, and vice versa.

       --strip-incoming-forwarded
              Strip  Forwarded   header  field  from   inbound  client requests.

       --forwarded-by=(obfuscated|ip|<VALUE>)
              Specify  the  parameter  value  sent  out  with  "by"  parameter  of Forwarded  header field.   If
              "obfuscated"  is given, the string is randomly generated at startup.   If  "ip"  is  given,    the
              interface    address   of    the  connection, including port number, is  sent with "by" parameter.
              In case of UNIX domain  socket, "localhost" is used instead of address and  port.  User  can  also
              specify  the  static  obfuscated  string.   The  limitation is that it must start with   "_",  and
              only   consists   of  character   set [A-Za-z0-9._-], as described in RFC 7239.

              Default: obfuscated

       --forwarded-for=(obfuscated|ip)
              Specify  the   parameter  value  sent  out   with  "for" parameter of Forwarded header field.   If
              "obfuscated"  is  given, the string is  randomly generated for each client connection.  If "ip" is
              given, the remote client address of  the connection,  without port  number, is   sent  with  "for"
              parameter.   In  case   of  UNIX  domain  socket, "localhost" is used instead of address.

              Default: obfuscated

       --no-via
              Don't append to  Via header field.  If  Via header field is received, it is left unaltered.

       --no-strip-incoming-early-data
              Don't strip Early-Data header  field from inbound client requests.

       --no-location-rewrite
              Don't   rewrite  location   header field  in default  mode.  When --http2-proxy  is used, location
              header  field will not be altered regardless of this option.

       --host-rewrite
              Rewrite  host and  :authority header  fields in  default  mode.   When   --http2-proxy  is   used,
              these  headers will not be altered regardless of this option.

       --altsvc=<PROTOID,PORT[,HOST,[ORIGIN[,PARAMS]]]>
              Specify    protocol   ID,   port,  host   and  origin   of alternative service.  <HOST>,  <ORIGIN>
              and <PARAMS> are optional.   Empty <HOST>  and <ORIGIN>  are allowed  and they   are  treated   as
              nothing  is   specified.   They   are  advertised   in  alt-svc   header  field  only in  HTTP/1.1
              frontend.   This option  can be  used multiple  times to specify  multiple  alternative  services.
              Example: --altsvc="h2,443,,,ma=3600; persist=1"

       --http2-altsvc=<PROTOID,PORT[,HOST,[ORIGIN[,PARAMS]]]>
              Just like --altsvc option, but  this altsvc is only sent in HTTP/2 frontend.

       --add-request-header=<HEADER>
              Specify  additional  header  field  to  add  to  request  header  set.    The field  name must  be
              lowercase.   This option just  appends header  field and  won't  replace   anything  already  set.
              This    option   can  be  used   several  times  to  specify  multiple  header  fields.   Example:
              --add-request-header="foo: bar"

       --add-response-header=<HEADER>
              Specify  additional  header  field to  add  to  response header  set.  The  field  name   must  be
              lowercase.   This  option  just  appends  header field  and  won't  replace anything already  set.
              This  option  can   be  used  several  times  to  specify  multiple   header   fields.    Example:
              --add-response-header="foo: bar"

       --request-header-field-buffer=<SIZE>
              Set  maximum  buffer  size for incoming HTTP request header field list.  This is the sum of header
              name and value in bytes.   If  trailer  fields  exist,  they  are  counted towards this number.

              Default: 64K

       --max-request-header-fields=<N>
              Set  maximum  number  of incoming  HTTP  request  header  fields.    If   trailer   fields  exist,
              they  are  counted towards this number.

              Default: 100

       --response-header-field-buffer=<SIZE>
              Set   maximum   buffer  size for  incoming  HTTP  response header field list.   This is the sum of
              header name and value  in  bytes.  If  trailer  fields  exist,  they   are  counted  towards  this
              number.

              Default: 64K

       --max-response-header-fields=<N>
              Set   maximum  number   of   incoming   HTTP response  header fields.   If  trailer  fields exist,
              they  are  counted towards this number.

              Default: 500

       --error-page=(<CODE>|*)=<PATH>
              Set file path  to custom error page  served when nghttpx originally  generates  HTTP  error status
              code  <CODE>.  <CODE> must be greater than or equal to 400, and at most  599.   If  "*"   is  used
              instead  of  <CODE>,   it  matches  all  HTTP   status  code.  If  error  status  code comes  from
              backend server, the custom error pages are not used.

       --server-name=<NAME>
              Change server response header field value to <NAME>.

              Default: nghttpx

       --no-server-rewrite
              Don't rewrite server header field in default mode.  When --http2-proxy is used, these headers will
              not be altered regardless of this option.

       --redirect-https-port=<PORT>
              Specify the port number which appears in Location header field  when  redirect  to  HTTPS  URI  is
              made  due  to "redirect-if-not-tls" parameter in --backend option.

              Default: 443

       --require-http-scheme
              Always require http or https scheme in HTTP request.  It also  requires that  https  scheme   must
              be   used  for   an encrypted  connection.  Otherwise,  http scheme  must be used.   This   option
              is   recommended  for   a  server deployment which directly faces  clients  and  the  services  it
              provides only require http or https scheme.

   API
       --api-max-request-body=<SIZE>
              Set the maximum size of request body for API request.

              Default: 32M

   DNS
       --dns-cache-timeout=<DURATION>
              Set  duration  that  cached  DNS  results remain valid.  Note that nghttpx caches the unsuccessful
              results as well.

              Default: 10s

       --dns-lookup-timeout=<DURATION>
              Set timeout that  DNS server is given to  respond to the initial  DNS  query.  For  the  2nd   and
              later  queries, server is  given time based  on this timeout, and  it is scaled linearly.

              Default: 5s

       --dns-max-try=<N>
              Set the number of DNS query before nghttpx gives up name lookup.

              Default: 2

       --frontend-max-requests=<N>
              The  number   of  requests that single  frontend connection can process.  For HTTP/2, this  is the
              number of streams in  one  HTTP/2 connection.   For  HTTP/1,  this is  the number  of  keep  alive
              requests.  This is hint to nghttpx, and it  may allow additional few  requests.  The default value
              is unlimited.

   Debug
       --frontend-http2-dump-request-header=<PATH>
              Dumps  request headers received by HTTP/2 frontend to the file denoted  in <PATH>.  The  output is
              done  in HTTP/1 header field format and each header block is followed  by  an  empty  line.   This
              option  is not thread safe and MUST NOT be used with option -n<N>, where <N> >= 2.

       --frontend-http2-dump-response-header=<PATH>
              Dumps  response headers sent  from HTTP/2 frontend to the file denoted  in <PATH>.  The  output is
              done  in HTTP/1 header field format and each header block is followed  by  an  empty  line.   This
              option  is not thread safe and MUST NOT be used with option -n<N>, where <N> >= 2.

       -o, --frontend-frame-debug
              Print  HTTP/2  frames  in  frontend to stderr.  This option is  not thread  safe and  MUST NOT  be
              used  with option -n=N, where N >= 2.

   Process
       -D, --daemon
              Run in a background.  If -D is used, the current working directory is changed to '/'.

       --pid-file=<PATH>
              Set path to save PID of this program.

       --user=<USER>
              Run this program as <USER>.   This option is intended to be used to drop root privileges.

       --single-process
              Run this program in a  single process mode for debugging purpose.  Without this  option,   nghttpx
              creates  at  least  2  processes:  main and  worker processes.  If this option is  used, main  and
              worker are  unified  into a  single process.    nghttpx  still   spawns   additional  process   if
              neverbleed  is used.   In the  single process  mode, the signal handling feature is disabled.

       --max-worker-processes=<N>
              The maximum number of  worker processes.  nghttpx spawns new worker  process when  it reloads  its
              configuration.  The previous worker  process enters graceful termination period and will terminate
              when   it   finishes   handling  the  existing     connections.      However,     if     reloading
              configurations  happen   very  frequently,   the  worker processes might be piled up if they  take
              a  bit  long  time  to  finish   the  existing connections.  With  this option, if  the number  of
              worker processes  exceeds the  given value,   the   oldest    worker    process   is    terminated
              immediately.  Specifying 0 means no  limit and it is the default behaviour.

       --worker-process-grace-shutdown-period=<DURATION>
              Maximum   period   for   a    worker   process  to  terminate gracefully.  When  a worker  process
              enters  in graceful shutdown   period  (e.g.,   when  nghttpx   reloads  its  configuration)   and
              it   does  not   finish   handling   the  existing connections in the given  period of time, it is
              immediately terminated.  Specifying 0 means no limit and it is the default behaviour.

   Scripting
       --mruby-file=<PATH>
              Set mruby script file

       --ignore-per-pattern-mruby-error
              Ignore mruby compile error  for per-pattern mruby script file.  If error  occurred, it is  treated
              as  if no mruby file were specified for the pattern.

   HTTP/3 and QUIC
       --frontend-quic-idle-timeout=<DURATION>
              Specify an idle timeout for QUIC connection.

              Default: 30s

       --frontend-quic-debug-log
              Output QUIC debug log to /dev/stderr.

       --quic-bpf-program-file=<PATH>
              Specify  a path to  eBPF program file reuseport_kern.o to direct  an  incoming  QUIC  UDP datagram
              to  a  correct socket.

              Default: /usr/local/lib/nghttp2/reuseport_kern.o

       --frontend-quic-early-data
              Enable early data on frontend QUIC connections.  nghttpx sends  "Early-Data"  header  field  to  a
              backend  server  if  a  request  is  received  in early  data and handshake has not finished.  All
              backend servers should deal with possibly replayed requests.

       --frontend-quic-qlog-dir=<DIR>
              Specify a  directory where  a qlog  file is  written for frontend QUIC  connections.  A qlog  file
              is  created  per each QUIC  connection.  The  file name is  ISO8601 basic format, followed by "-",
              server Source Connection ID and ".sqlog".

       --frontend-quic-require-token
              Require an address validation  token for a frontend QUIC connection.   Server sends  a  token   in
              Retry  packet or NEW_TOKEN frame in the previous connection.

       --frontend-quic-congestion-controller=<CC>
              Specify  a  congestion  controller  algorithm  for  a frontend QUIC  connection.   <CC>  should be
              either  "cubic"  or "bbr".

              Default: cubic

       --frontend-quic-secret-file=<PATH>
              Path to file that contains secure random data to be used as QUIC keying materials.  It is used  to
              derive  keys  for encrypting tokens and Connection IDs.  It is not used to encrypt  QUIC  packets.
              Each  line  of  this file  must contain  exactly  136  bytes  hex-encoded  string   (when  decoded
              the  byte  string  is   68  bytes  long).   The first 2 bits of  decoded byte  string are  used to
              identify the keying material.  An  empty line or a  line which starts '#'  is ignored.   The  file
              can contain  more than  one keying materials.  Because the  identifier is 2 bits, at most 4 keying
              materials  are   read and the remaining data is discarded.  The first keying  material in the file
              is primarily  used for  encryption and  decryption for  new connection.  The other ones  are  used
              to  decrypt  data  for  the  existing connections.   Specifying multiple  keying materials enables
              key rotation.   Please note  that key rotation  does  not   occur  automatically.    User   should
              update   files   or   change   options   values  and  restart nghttpx gracefully.   If opening  or
              reading  given file fails, all loaded keying  materials are discarded and it is treated as if none
              of  this option is given.  If this option is not  given or an error   occurred  while  opening  or
              reading  a  file,  a keying  material  is  generated internally on startup and reload.

       --quic-server-id=<HEXSTRING>
              Specify  server   ID  encoded  in  Connection   ID to identify this  particular  server  instance.
              Connection  ID  is encrypted and  this part is  not visible in  public.  It must be 4  bytes  long
              and must be encoded  in hex string (which is 8  bytes long).  If this option  is omitted, a random
              server  ID   is   generated   on  startup   and configuration reload.

       --frontend-quic-initial-rtt=<DURATION>
              Specify the initial RTT of the frontend QUIC connection.

              Default: 333ms

       --no-quic-bpf
              Disable eBPF.

       --frontend-http3-window-size=<SIZE>
              Sets  the  per-stream  initial  window  size  of  HTTP/3 frontend connection.

              Default: 256K

       --frontend-http3-connection-window-size=<SIZE>
              Sets the  per-connection window size of  HTTP/3 frontend connection.

              Default: 1M

       --frontend-http3-max-window-size=<SIZE>
              Sets  the  maximum  per-stream  window  size  of  HTTP/3 frontend connection.  The window  size is
              adjusted  based  on  the receiving rate of stream data.  The initial value is the  value specified
              by --frontend-http3-window-size and the window size grows up to <SIZE> bytes.

              Default: 6M

       --frontend-http3-max-connection-window-size=<SIZE>
              Sets the  maximum per-connection  window size  of HTTP/3 frontend connection.  The window  size is
              adjusted based  on  the  receiving  rate  of  stream  data.   The  initial  value  is          the
              value         specified          by  --frontend-http3-connection-window-size  and the  window size
              grows up to <SIZE> bytes.

              Default: 8M

       --frontend-http3-max-concurrent-streams=<N>
              Set the maximum number of  the concurrent streams in one frontend HTTP/3 connection.

              Default: 100

   Misc
       --conf=<PATH>
              Load  configuration  from   <PATH>.   Please   note   that  nghttpx  always   tries  to  read  the
              default configuration file if --conf is not given.

              Default: /etc/nghttpx/nghttpx.conf

       --include=<PATH>
              Load  additional  configurations  from  <PATH>.  File <PATH> is  read  when  configuration  parser
              encountered  this option.  This option can be used multiple times, or even recursively.

       -v, --version
              Print version and exit.

       -h, --help
              Print this help and exit.

       The <SIZE> argument is an integer and an optional unit (e.g., 10K is 10 * 1024).  Units are K,  M  and  G
       (powers of 1024).

       The  <DURATION>  argument  is  an  integer  and  an  optional unit (e.g., 1s is 1 second and 500ms is 500
       milliseconds).  Units are h, m, s or ms (hours, minutes, seconds and milliseconds, respectively).   If  a
       unit is omitted, a second is used as unit.

FILES

       /etc/nghttpx/nghttpx.conf
              The  default configuration file path nghttpx searches at startup.  The configuration file path can
              be changed using --conf option.

              Those lines which are staring # are treated as comment.

              The option name in the configuration file is the long command-line option  name  with  leading  --
              stripped  (e.g.,  frontend).   Put  =  between  option name and value.  Don't put extra leading or
              trailing spaces.

              When specifying arguments including characters which have special meaning to a shell,  we  usually
              use  quotes  so  that shell does not interpret them.  When writing this configuration file, quotes
              for this purpose must not be used.  For example, specify additional request header field, do this:

                 add-request-header=foo: bar

              instead of:

                 add-request-header="foo: bar"

              The options which do not take argument in the command-line  take  argument  in  the  configuration
              file.   Specify  yes  as  an  argument  (e.g.,  http2-proxy=yes).  If other string is given, it is
              ignored.

              To specify  private  key  and  certificate  file  which  are  given  as  positional  arguments  in
              command-line, use private-key-file and certificate-file.

              --conf option cannot be used in the configuration file and will be ignored if specified.

       Error log
              Error  log  is  written  to  stderr  by default.  It can be configured using --errorlog-file.  The
              format of log message is as follows:

              <datetime> <main-pid> <current-pid> <thread-id> <level> (<filename>:<line>) <msg>

              <datetime>
                     It is a combination of date and time when the log is written.  It is in ISO 8601 format.

              <main-pid>
                     It is a main process ID.

              <current-pid>
                     It is a process ID which writes this log.

              <thread-id>
                     It is a thread ID which writes this log.  It would be unique within <current-pid>.

              <filename> and <line>
                     They are source file name, and line number which produce this log.

              <msg>  It is a log message body.

SIGNALS

       SIGQUIT
              Shutdown gracefully.  First accept pending connections and stop accepting connection.   After  all
              connections are handled, nghttpx exits.

       SIGHUP Reload configuration file given in --conf.

       SIGUSR1
              Reopen log files.

       SIGUSR2
          Fork  and  execute  nghttpx.   It  will  execute  the  binary  in the same path with same command-line
          arguments and environment variables.  As of nghttpx version 1.20.0, the new main process sends SIGQUIT
          to the original main process when it is ready to serve requests.  For the earlier versions of nghttpx,
          user has to send SIGQUIT to the original main process.

          The difference between SIGUSR2 (+ SIGQUIT) and SIGHUP is that former is usually used  to  execute  new
          binary,  and  the  main  process  is  newly  spawned.   On  the  other  hand,  the latter just reloads
          configuration file, and the same main process continues to exist.

       NOTE:
          nghttpx consists of multiple processes: one process for processing these signals, and another one  for
          processing requests.  The former spawns the latter.  The former is called main process, and the latter
          is  called  worker  process.   If  neverbleed  is enabled, the worker process spawns neverbleed daemon
          process which does RSA key processing.  The above signal must be sent to the  main  process.   If  the
          other  processes received one of them, it is ignored.  This behaviour of these processes may change in
          the future release.  In other words, in the future release, the processes other than main process  may
          terminate  upon  the  reception  of  these signals.  Therefore these signals should not be sent to the
          processes other than main process.

SERVER PUSH

       nghttpx supports HTTP/2 server push in default mode with Link  header  field.   nghttpx  looks  for  Link
       header field (RFC 5988) in response headers from backend server and extracts URI-reference with parameter
       rel=preload  (see  preload)  and  pushes  those URIs to the frontend client. Here is a sample Link header
       field to initiate server push:

          Link: </fonts/font.woff>; rel=preload
          Link: </css/theme.css>; rel=preload

       Currently, the following restriction is applied for server push:

       1. The associated stream must have method "GET" or "POST".  The associated stream's status code  must  be
          200.

       This limitation may be loosened in the future release.

       nghttpx also supports server push if both frontend and backend are HTTP/2 in default mode.  In this case,
       in  addition  to  server  push  via  Link header field, server push from backend is forwarded to frontend
       HTTP/2 session.

       HTTP/2 server push will be disabled if --http2-proxy is used.

UNIX DOMAIN SOCKET

       nghttpx supports UNIX domain socket with a filename for both frontend and backend connections.

       Please note that current nghttpx implementation does not delete a socket with a filename.  And  on  start
       up, if nghttpx detects that the specified socket already exists in the file system, nghttpx first deletes
       it.   However,  if  SIGUSR2  is  used  to execute new binary and both old and new configurations use same
       filename, new binary does not delete the socket and continues to use it.

OCSP STAPLING

       OCSP query is done using external Python script fetch-ocsp-response, which has been originally  developed
       in Perl as part of h2o project (https://github.com/h2o/h2o), and was translated into Python.

       The script file is usually installed under $(prefix)/share/nghttp2/ directory.  The actual path to script
       can be customized using --fetch-ocsp-response-file option.

       If OCSP query is failed, previous OCSP response, if any, is continued to be used.

       --fetch-ocsp-response-file  option  provides  wide  range of possibility to manage OCSP response.  It can
       take an arbitrary script or executable.  The requirement is that it supports the  command-line  interface
       of  fetch-ocsp-response script, and it must return a valid DER encoded OCSP response on success.  It must
       return exit code 0 on success, and 75 for temporary error, and the other error code for generic  failure.
       For  large  cluster  of  servers,  it  is  not  efficient  for  each  server  to perform OCSP query using
       fetch-ocsp-response.  Instead, you can retrieve OCSP response in some way, and store it in a  disk  or  a
       shared  database.   Then  specify  a program in --fetch-ocsp-response-file to fetch it from those stores.
       This could provide a way to share the OCSP response between fleet of servers, and  also  any  OCSP  query
       strategy can be applied which may be beyond the ability of nghttpx itself or fetch-ocsp-response script.

TLS SESSION RESUMPTION

       nghttpx supports TLS session resumption through both session ID and session ticket.

   SESSION ID RESUMPTION
       By default, session ID is shared by all worker threads.

       If  --tls-session-cache-memcached is given, nghttpx will insert serialized session data to memcached with
       nghttpx:tls-session-cache: + lowercase hex string of session ID as a memcached  entry  key,  with  expiry
       time 12 hours.  Session timeout is set to 12 hours.

       By  default, connections to memcached server are not encrypted.  To enable encryption, use tls keyword in
       --tls-session-cache-memcached option.

   TLS SESSION TICKET RESUMPTION
       By default, session ticket is shared by all worker threads.  The automatic key rotation is  also  enabled
       by  default.   Every  an  hour,  new  encryption  key  is  generated, and previous encryption key becomes
       decryption only key.  We set session timeout to 12 hours, and thus we keep at most 12 keys.

       If --tls-ticket-key-memcached is given, encryption keys are retrieved from memcached.  nghttpx just reads
       keys from memcached; one has to deploy key generator program to update keys  frequently  (e.g.,  every  1
       hour).   The  example  key  generator  tlsticketupdate.go is available under contrib directory in nghttp2
       archive.  The memcached entry key is nghttpx:tls-ticket-key.  The data format stored in memcached is  the
       binary format described below:

          +--------------+-------+----------------+
          | VERSION (4)  |LEN (2)|KEY(48 or 80) ...
          +--------------+-------+----------------+
                         ^                        |
                         |                        |
                         +------------------------+
                         (LEN, KEY) pair can be repeated

       All numbers in the above figure is bytes.  All integer fields are network byte order.

       First  4 bytes integer VERSION field, which must be 1.  The 2 bytes integer LEN field gives the length of
       following KEY field, which contains key.  If --tls-ticket-key-cipher=aes-128-cbc is used, LEN must be 48.
       If --tls-ticket-key-cipher=aes-256-cbc is used, LEN must be  80.   LEN  and  KEY  pair  can  be  repeated
       multiple  times  to  store  multiple  keys.   The  key appeared first is used as encryption key.  All the
       remaining keys are used as decryption only.

       By default, connections to memcached server are not encrypted.  To enable encryption, use tls keyword  in
       --tls-ticket-key-memcached option.

       If  --tls-ticket-key-file  is  given,  encryption key is read from the given file.  In this case, nghttpx
       does not rotate key automatically.  To rotate key, one has to restart nghttpx (see SIGNALS).

CERTIFICATE TRANSPARENCY

       nghttpx supports TLS  signed_certificate_timestamp  extension  (RFC  6962).   The  relevant  options  are
       --tls-sct-dir  and  sct-dir  parameter in --subcert.  They takes a directory, and nghttpx reads all files
       whose extension is .sct under the directory.  The *.sct files are encoded  as  SignedCertificateTimestamp
       struct  described  in  section  3.2  of  RFC  69662.   This  format  is the same one used by nginx-ct and
       mod_ssl_ct.   ct-submit  can  be  used  to  submit  certificates  to  log   servers,   and   obtain   the
       SignedCertificateTimestamp struct which can be used with nghttpx.

MRUBY SCRIPTING

       WARNING:
          The  current  mruby extension API is experimental and not frozen.  The API is subject to change in the
          future release.

       WARNING:
          Almost all string value returned from method, or attribute is a fresh new mruby string, which involves
          memory allocation, and copies.  Therefore, it is strongly recommended to store a  return  value  in  a
          local variable, and use it, instead of calling method or accessing attribute repeatedly.

       nghttpx  allows users to extend its capability using mruby scripts.  nghttpx has 2 hook points to execute
       mruby script: request phase and response phase.  The request phase hook  is  invoked  after  all  request
       header  fields  are  received  from client.  The response phase hook is invoked after all response header
       fields are received from backend server.  These hooks allows users to modify  header  fields,  or  common
       HTTP  variables,  like  authority  or  request  path,  and even return custom response without forwarding
       request to backend servers.

       There are 2 levels of mruby script invocations: global and per-pattern.  The global mruby script  is  set
       by  --mruby-file  option  and is called for all requests.  The per-pattern mruby script is set by "mruby"
       parameter in -b option.  It is invoked for a request which matches the particular pattern.  The order  of
       hook invocation is: global request phase hook, per-pattern request phase hook, per-pattern response phase
       hook,  and  finally  global  response  phase hook.  If a hook returns a response, any later hooks are not
       invoked.  The global request hook is invoked before the pattern matching is  made  and  changing  request
       path may affect the pattern matching.

       Please  note  that  request and response hooks of per-pattern mruby script for a single request might not
       come from the same script.  This might happen after a request hook is executed, backend failed  for  some
       reason, and at the same time, backend configuration is replaced by API request, and then the request uses
       new  configuration  on  retry.   The  response  hook  from new configuration, if it is specified, will be
       invoked.

       The all mruby script will be evaluated once per thread on startup, and it  must  instantiate  object  and
       evaluate  it  as  the  return  value  (e.g.,  App.new).  This object is called app object.  If app object
       defines on_req method, it is called with Nghttpx::Env object on request hook.  Similarly, if  app  object
       defines  on_resp  method,  it  is  called  with  Nghttpx::Env  object  on response hook.  For each method
       invocation, user can can access Nghttpx::Request and Nghttpx::Response objects via  Nghttpx::Env#req  and
       Nghttpx::Env#resp respectively.

       Nghttpx::REQUEST_PHASE
              Constant to represent request phase.

       Nghttpx::RESPONSE_PHASE
              Constant to represent response phase.

       class Nghttpx::Env
              Object to represent current request specific context.

              attribute [R] req
                     Return Request object.

              attribute [R] resp
                     Return Response object.

              attribute [R] ctx
                     Return  Ruby  hash  object.   It persists until request finishes.  So values set in request
                     phase hook can be retrieved in response phase hook.

              attribute [R] phase
                     Return the current phase.

              attribute [R] remote_addr
                     Return IP address of a remote client.  If connection is made via UNIX domain  socket,  this
                     returns the string "localhost".

              attribute [R] server_addr
                     Return address of server that accepted the connection.  This is a string which specified in
                     --frontend  option,  excluding port number, and not a resolved IP address.  For UNIX domain
                     socket, this is a path to UNIX domain socket.

              attribute [R] server_port
                     Return port number of the server frontend which accepted the connection from client.

              attribute [R] tls_used
                     Return true if TLS is used on the connection.

              attribute [R] tls_sni
                     Return the TLS SNI value which client sent in this connection.

              attribute [R] tls_client_fingerprint_sha256
                     Return the SHA-256 fingerprint of a client certificate.

              attribute [R] tls_client_fingerprint_sha1
                     Return the SHA-1 fingerprint of a client certificate.

              attribute [R] tls_client_issuer_name
                     Return the issuer name of a client certificate.

              attribute [R] tls_client_subject_name
                     Return the subject name of a client certificate.

              attribute [R] tls_client_serial
                     Return the serial number of a client certificate.

              attribute [R] tls_client_not_before
                     Return the start date of a client certificate in seconds since the epoch.

              attribute [R] tls_client_not_after
                     Return the end date of a client certificate in seconds since the epoch.

              attribute [R] tls_cipher
                     Return a TLS cipher negotiated in this connection.

              attribute [R] tls_protocol
                     Return a TLS protocol version negotiated in this connection.

              attribute [R] tls_session_id
                     Return a session ID for this connection in hex string.

              attribute [R] tls_session_reused
                     Return true if, and only if a SSL/TLS session is reused.

              attribute [R] alpn
                     Return ALPN identifier negotiated in this connection.

              attribute [R] tls_handshake_finished
                     Return true if SSL/TLS handshake has finished.  If it returns false in  the  request  phase
                     hook,  the request is received in TLSv1.3 early data (0-RTT) and might be vulnerable to the
                     replay attack.  nghttpx will send Early-Data header field to backend  servers  to  indicate
                     this.

       class Nghttpx::Request
              Object  to  represent  request from client.  The modification to Request object is allowed only in
              request phase hook.

              attribute [R] http_version_major
                     Return HTTP major version.

              attribute [R] http_version_minor
                     Return HTTP minor version.

              attribute [R/W] method
                     HTTP method.  On assignment, copy of given value is assigned.  We  don't  accept  arbitrary
                     method  name.  We will document them later, but well known methods, like GET, PUT and POST,
                     are all supported.

              attribute [R/W] authority
                     Authority (i.e., example.org), including optional port component .  On assignment, copy  of
                     given value is assigned.

              attribute [R/W] scheme
                     Scheme (i.e., http, https).  On assignment, copy of given value is assigned.

              attribute [R/W] path
                     Request  path, including query component (i.e., /index.html).  On assignment, copy of given
                     value is assigned.  The path does not include authority component of URI.  This may include
                     query  component.   nghttpx   makes   certain   normalization   for   path.    It   decodes
                     percent-encoding            for            unreserved            characters            (see
                     https://tools.ietf.org/html/rfc3986#section-2.3), and resolves ".." and ".".   But  it  may
                     leave  characters  which should be percent-encoded as is. So be careful when comparing path
                     against desired string.

              attribute [R] headers
                     Return Ruby hash containing copy of request header fields.   Changing  values  in  returned
                     hash  does  not  change  request  header  fields  actually used in request processing.  Use
                     Nghttpx::Request#add_header or Nghttpx::Request#set_header to change request header fields.

              add_header(key, value)
                     Add header entry associated with key.  The value can be single string or array  of  string.
                     It does not replace any existing values associated with key.

              set_header(key, value)
                     Set  header  entry associated with key.  The value can be single string or array of string.
                     It replaces any existing values associated with key.

              clear_headers()
                     Clear all existing request header fields.

              push(uri)
                     Initiate to push resource identified by uri.  Only HTTP/2 protocol supports  this  feature.
                     For  the  other  protocols, this method is noop.  uri can be absolute URI, absolute path or
                     relative path to the current request.  For absolute or relative path, scheme and  authority
                     are  inherited  from  the  current request.  Currently, method is always GET.  nghttpx will
                     issue request to backend servers to fulfill this request.  The request and  response  phase
                     hooks will be called for pushed resource as well.

       class Nghttpx::Response
              Object to represent response from backend server.

              attribute [R] http_version_major
                     Return HTTP major version.

              attribute [R] http_version_minor
                     Return HTTP minor version.

              attribute [R/W] status
                     HTTP  status  code.   It  must be in the range [200, 999], inclusive.  The non-final status
                     code is not supported in mruby scripting at the moment.

              attribute [R] headers
                     Return Ruby hash containing copy of response header fields.  Changing  values  in  returned
                     hash  does  not  change  response  header fields actually used in response processing.  Use
                     Nghttpx::Response#add_header or  Nghttpx::Response#set_header  to  change  response  header
                     fields.

              add_header(key, value)
                     Add  header  entry associated with key.  The value can be single string or array of string.
                     It does not replace any existing values associated with key.

              set_header(key, value)
                     Set header entry associated with key.  The value can be single string or array  of  string.
                     It replaces any existing values associated with key.

              clear_headers()
                     Clear all existing response header fields.

              return(body)
                     Return custom response body to a client.  When this method is called in request phase hook,
                     the  request is not forwarded to the backend, and response phase hook for this request will
                     not be invoked.  When this method is called in response phase hook, response  from  backend
                     server is canceled and discarded.  The status code and response header fields should be set
                     before  using  this  method.   To set status code, use Nghttpx::Response#status.  If status
                     code is not set, 200 is used.  To set response header fields,  Nghttpx::Response#add_header
                     and  Nghttpx::Response#set_header.  When this method is invoked in response phase hook, the
                     response headers are filled with the ones received from backend server.  To send completely
                     custom header fields, first call  Nghttpx::Response#clear_headers  to  erase  all  existing
                     header  fields,  and  then  add required header fields.  It is an error to call this method
                     twice for a given request.

              send_info(status, headers)
                     Send non-final (informational) response to a client.  status must be  in  the  range  [100,
                     199],  inclusive.   headers is a hash containing response header fields.  Its key must be a
                     string, and the associated value must be either string or array of strings.  Since this  is
                     not  a  final  response,  even  if  this method is invoked, request is still forwarded to a
                     backend unless Nghttpx::Response#return is called.  This  method  can  be  called  multiple
                     times.  It cannot be called after Nghttpx::Response#return is called.

   MRUBY EXAMPLES
       Modify request path:

          class App
            def on_req(env)
              env.req.path = "/apps#{env.req.path}"
            end
          end

          App.new

       Don't forget to instantiate and evaluate object at the last line.

       Restrict permission of viewing a content to a specific client addresses:

          class App
            def on_req(env)
              allowed_clients = ["127.0.0.1", "::1"]

              if env.req.path.start_with?("/log/") &&
                 !allowed_clients.include?(env.remote_addr) then
                env.resp.status = 404
                env.resp.return "permission denied"
              end
            end
          end

          App.new

API ENDPOINTS

       nghttpx exposes API endpoints to manipulate it via HTTP based API.  By default, API endpoint is disabled.
       To  enable  it,  add  a  dedicated  frontend  for  API using --frontend option with "api" parameter.  All
       requests which come from this frontend address, will be treated as API request.

       The response is normally JSON dictionary, and at least includes the following keys:

       status The status of the request processing.  The following values are defined:

              Success
                     The request was successful.

              Failure
                     The request was failed.  No change has been made.

       code   HTTP status code

       Additionally, depending on the API endpoint, data key may be present, and  its  value  contains  the  API
       endpoint specific data.

       We  wrote  "normally",  since  nghttpx may return ordinal HTML response in some cases where the error has
       occurred before reaching API endpoint (e.g., header field is too large).

       The following section describes available API endpoints.

   POST /api/v1beta1/backendconfig
       This API replaces the current backend server settings with the requested ones.  The request method should
       be POST, but PUT is also acceptable.  The request body must be nghttpx configuration  file  format.   For
       configuration  file format, see FILES section.  The line separator inside the request body must be single
       LF (0x0A).  Currently, only backend option is parsed, the others are simply ignored.   The  semantics  of
       this  API  is replace the current backend with the backend options in request body.  Describe the desired
       set of backend severs, and nghttpx makes it happen.  If there is no backend option is  found  in  request
       body,  the  current  set  of  backend  is  replaced  with  the  backend  option's default value, which is
       127.0.0.1,80.

       The replacement is done instantly without breaking existing connections or requests.  It also avoids  any
       process creation as is the case with hot swapping with signals.

       The  one  limitation  is  that only numeric IP address is allowed in backend in request body unless "dns"
       parameter is used while non numeric hostname is allowed in command-line or  configuration  file  is  read
       using --conf.

   GET /api/v1beta1/configrevision
       This  API  returns  configuration  revision of the current nghttpx.  The configuration revision is opaque
       string, and it changes after each reloading by SIGHUP.  With this API, an external application knows that
       whether nghttpx has finished reloading its configuration by comparing the configuration revisions between
       before and after reloading.  It is recommended to disable persistent  (keep-alive)  connection  for  this
       purpose  in  order  to  avoid  to  send  a  request using the reused connection which may bound to an old
       process.

       This API returns response including data key.  Its value is JSON object, and it  contains  at  least  the
       following key:

       configRevision
              The configuration revision of the current nghttpx

SEE ALSO

       nghttp(1), nghttpd(1), h2load(1)

AUTHOR

       Tatsuhiro Tsujikawa

COPYRIGHT

       2012, 2015, 2016, Tatsuhiro Tsujikawa

1.59.0                                            Jan 21, 2024                                        NGHTTPX(1)