Apache2::SubRequest(3) Perl API for Apache subrequests

Synopsis

  use Apache2::SubRequest ();
  
  # run internal redirects at once
  $r->internal_redirect($new_uri);
  $r->internal_redirect_handler($new_uri);
  
  # create internal redirect objects
  $subr = $r->lookup_uri("/foo");
  $subr = $r->lookup_method_uri("GET", "/tmp/bar")
  $subr = $r->lookup_file("/tmp/bar");
  # optionally manipulate the output through main request filters
  $subr = $r->lookup_uri("/foo", $r->output_filters);
  # now run them
  my $rc = $subr->run;

Description

"Apache2::SubRequest" contains API for creating and running of Apache sub-requests.

"Apache2::SubRequest" is a sub-class of "Apache2::RequestRec object".

API

"Apache2::SubRequest" provides the following functions and/or methods:

DESTROY

Free the memory associated with a sub request: 

  undef $subr; # but normally don't do that
obj: $subr ( "Apache2::SubRequest object" )
The sub request to finish
ret: no return value
since: 2.0.00

"DESTROY" is called automatically when $subr goes out of scope.

If you want to free the memory earlier than that (for example if you run several subrequests), you can "undef" the object as: 

  undef $subr;

but never call "DESTROY" explicitly, since it'll result in "ap_destroy_sub_req" being called more than once, resulting in multiple brain injuries and certain hair loss.

internal_redirect

Redirect the current request to some other uri internally 

  $r->internal_redirect($new_uri);
obj: $r ( "Apache2::RequestRec object" )
The current request
arg1: $new_uri ( string )
The URI to replace the current request with
ret: no return value
since: 2.0.00

In case that you want some other request to be served as the top-level request instead of what the client requested directly, call this method from a handler, and then immediately return "Apache2::Const::OK". The client will be unaware the a different request was served to her behind the scenes.

internal_redirect_handler

Identical to "internal_redirect", plus automatically sets "$r->content_type" is of the sub-request to be the same as of the main request, if "$r->handler" is true. 

  $r->internal_redirect_handler($new_uri);
obj: $r ( "Apache2::RequestRec object" )
The current request
arg1: $new_uri ( string )
The URI to replace the current request with.
ret: no return value
since: 2.0.00

This function is designed for things like actions or CGI scripts, when using "AddHandler", and you want to preserve the content type across an internal redirect.

lookup_file

Create a subrequest for the given file. This sub request can be inspected to find information about the requested file 

  $ret = $r->lookup_file($new_file);
  $ret = $r->lookup_file($new_file, $next_filter);
obj: $r ( "Apache2::RequestRec object" )
The current request
arg1: $new_file ( string )
The file to lookup
opt arg2: $next_filter ( "Apache2::Filter" )
See "$r->lookup_uri" for details.
ret: $ret ( "Apache2::SubRequest object" )
The sub request record.
since: 2.0.00

See "$r->lookup_uri" for further discussion.

lookup_method_uri

Create a sub request for the given URI using a specific method. This sub request can be inspected to find information about the requested URI 

  $ret = $r->lookup_method_uri($method, $new_uri);
  $ret = $r->lookup_method_uri($method, $new_uri, $next_filter);
obj: $r ( "Apache2::RequestRec object" )
The current request
arg1: $method ( string )
The method to use in the new sub request (e.g. "GET")
arg2: $new_uri ( string )
The URI to lookup
opt arg3: $next_filter ( "Apache2::Filter object" )
See "$r->lookup_uri" for details.
ret: $ret ( "Apache2::SubRequest object" )
The sub request record.
since: 2.0.00

See "$r->lookup_uri" for further discussion.

lookup_uri

Create a sub request from the given URI. This sub request can be inspected to find information about the requested URI. 

  $ret = $r->lookup_uri($new_uri);
  $ret = $r->lookup_uri($new_uri, $next_filter);
obj: $r ( "Apache2::RequestRec object" )
The current request
arg1: $new_uri ( string )
The URI to lookup
opt arg2: $next_filter ( "Apache2::Filter object" )
The first filter the subrequest should pass the data through. If not specified it defaults to the first connection output filter for the main request "$r->proto_output_filters". So if the subrequest sends any output it will be filtered only once. If for example you desire to apply the main request's output filters to the sub-request output as well pass "$r->output_filters" as an argument.
ret: $ret ( "Apache2::SubRequest object" )
The sub request record
since: 2.0.00

Here is an example of a simple subrequest which serves uri /new_uri: 

  sub handler {
      my $r = shift;
  
      my $subr = $r->lookup_uri("/new_uri");
      $subr->run;
  
      return Apache2::Const::OK;
  }

If let's say you have three request output filters registered to run for the main request: 

  PerlOutputFilterHandler MyApache2::SubReqExample::filterA
  PerlOutputFilterHandler MyApache2::SubReqExample::filterB
  PerlOutputFilterHandler MyApache2::SubReqExample::filterC

and you wish to run them all, the code needs to become: 

      my $subr = $r->lookup_uri("/new_uri", $r->output_filters);

and if you wish to run them all, but the first one ("filterA"), the code needs to be adjusted to be: 

      my $subr = $r->lookup_uri("/new_uri", $r->output_filters->next);

run

Run a sub-request 

  $rc = $subr->run();
obj: $subr ( "Apache2::RequestRec object" )
The sub-request (e.g. returned by "lookup_uri")
ret: $rc ( integer )
The return code of the handler ("Apache2::Const::OK", "Apache2::Const::DECLINED", etc.)
since: 2.0.00

Unsupported API

"Apache2::SubRequest" also provides auto-generated Perl interface for a few other methods which aren't tested at the moment and therefore their API is a subject to change. These methods will be finalized later as a need arises. If you want to rely on any of the following methods please contact the the mod_perl development mailing list so we can help each other take the steps necessary to shift the method to an officially supported API.

internal_fast_redirect

META: Autogenerated - needs to be reviewed/completed

Redirect the current request to a sub_req, merging the pools 

  $r->internal_fast_redirect($sub_req);
obj: $r ( "Apache2::RequestRec object" )
The current request
arg1: $sub_req ( string )
A subrequest created from this request
ret: no return value
since: 2.0.00

META: httpd-2.0/modules/http/http_request.c declares this function as: 

  /* XXX: Is this function is so bogus and fragile that we deep-6 it? */

do we really want to expose it to mod_perl users?

lookup_dirent

META: Autogenerated - needs to be reviewed/completed

Create a sub request for the given apr_dir_read result. This sub request can be inspected to find information about the requested file 

  $lr = $r->lookup_dirent($finfo);
  $lr = $r->lookup_dirent($finfo, $subtype);
  $lr = $r->lookup_dirent($finfo, $subtype, $next_filter);
obj: $r ( "Apache2::RequestRec object" )
The current request
arg1: $finfo ( "APR::Finfo object" )
The apr_dir_read result to lookup
arg2: $subtype ( integer )
What type of subrequest to perform, one of; 

  Apache2::SUBREQ_NO_ARGS     ignore r->args and r->path_info
  Apache2::SUBREQ_MERGE_ARGS  merge  r->args and r->path_info
arg3: $next_filter ( integer )
The first filter the sub_request should use. If this is NULL, it defaults to the first filter for the main request
ret: $lr ( "Apache2::RequestRec object" )
The new request record
since: 2.0.00

META: where do we take the apr_dir_read result from?

See Also

mod_perl 2.0 documentation.

Copyright

mod_perl 2.0 and its core modules are copyrighted under The Apache Software License, Version 2.0.

Authors

The mod_perl development team and numerous contributors.

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