NAME

       call-handler -  (service-processing program-flow)

PURPOSE

       Call another handler within the same process.

SYNTAX

           call-handler <request path> [ return-value  <return value> ]

DESCRIPTION

       Calls  another  handler  within the same request in the same process. You can call any handler within the
       same application. "Calling a handler" means executing it solely within the context  of  the  top  handler
       currently running; no before-handler or after-handler will execute for the called handler.

       <request  path>  is the request path served by the handler being called. It can be a string variable or a
       constant.

       Use set-param and get-param to pass parameters between the caller and callee handlers.

       You can obtain a <return value> from the called handler <request path> by  using  "return-value"  clause.
       See return-handler on how to return a number value from <request path> handler.

       call-handler  uses  the  same high-performance hash table used by a request to route requests by name; if
       <request path> is a constant string, then a hash table lookup is performed only once for the life of  the
       process and all subsequent calls use a cached address of the request handler.

EXAMPLES

       The  following  example demonstrate calling a call-handler twice, and also using its output inline in the
       caller. An input parameter is passed to it, and an output obtained:

       Copy to file "callsub.golf":

           %% /callsub public
               //
               // First call to call-handler
               //
               // Set input for call-handler
               set-param inp = "some string"
               (( s
               call-handler "/sub/service"
               ))
               // Get output from call-handler
               get-param out type string
               @<<print-out s>> with output [<<print-out out>>]

               //
               // Second call to call-handler
               //
               // Set input for call-handler called as inline code
               set-param inp = "new string"
               (( s
               @Output: <<call-handler "/sub/service">>
               ))
               // Get output from call-handler
               get-param out type string
               @<<print-out s>> with output [<<print-out out>>]
           %%

       And in "sub/service.golf" file (meaning file "service.golf" in subdirectory "sub"):

           %% /sub/service private
               @This is sub!
               get-param inp
               (( out
               @got input: <<print-out inp>>
               ))
               set-param out = out
           %%

       Create and build an application:

           gg -k subhandler
           gg -q

       Run it:

           gg -r --req="/callsub" --exec --silent-header

       The output:

           This is sub! with output [got input: some string]
           Output: This is sub! with output [got input: new string]

SEE ALSO

        Program flow

       break-loop call-handler code-blocks continue-loop do-once exit-handler  if-defined  if-true  quit-process
       return-handler start-loop
        Service processing

       after-handler before-handler begin-handler call-handler See all documentation

$DATE                                               $VERSION                                           GOLF(2gg)