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|
.TH GOLF 2gg $VERSION $DATE Development Tools
.SH NAME
call-handler \- (service-processing
program-flow)
.SH PURPOSE
Call another handler within the same process.
.SH SYNTAX
.RS 4
.EX
call-handler <request path> [ return-value <return value> ]
.EE
.RE
.SH 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 \fBrequest\fP path served by the handler being called. It can be a string variable or a constant.
Use \fBset-param\fP and \fBget-param\fP 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 \fBreturn-handler\fP on how to return a number value from <request path> handler.
call-handler uses the same high-performance hash table used by a \fBrequest\fP 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.
.SH 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":
.RS 4
.EX
%% /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>>]
%%
.EE
.RE
And in "sub/service.golf" file (meaning file "service.golf" in subdirectory "sub"):
.RS 4
.EX
%% /sub/service private
@This is sub!
get-param inp
(( out
@got input: <<print-out inp>>
))
set-param out = out
%%
.EE
.RE
Create and build an application:
.RS 4
.EX
gg -k subhandler
gg -q
.EE
.RE
Run it:
.RS 4
.EX
gg -r --req="/callsub" --exec --silent-header
.EE
.RE
The output:
.RS 4
.EX
This is sub! with output [got input: some string]
Output: This is sub! with output [got input: new string]
.EE
.RE
.SH SEE ALSO
Program flow
\fBbreak-loop\fP
\fBcall-handler\fP
\fBcode-blocks\fP
\fBcontinue-loop\fP
\fBdo-once\fP
\fBexit-handler\fP
\fBif-defined\fP
\fBif-true\fP
\fBquit-process\fP
\fBreturn-handler\fP
\fBstart-loop\fP
Service processing
\fBafter-handler\fP
\fBbefore-handler\fP
\fBbegin-handler\fP
\fBcall-handler\fP
See all
\fBdocumentation\fP
|
