filter.pm

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# 
# /*
#  * *********** WARNING **************
#  * This file generated by ModPerl::WrapXS/0.01
#  * Any changes made here will be lost
#  * ***********************************
#  * 01: lib/ModPerl/Code.pm:708
#  * 02: lib/ModPerl/WrapXS.pm:624
#  * 03: lib/ModPerl/WrapXS.pm:1173
#  * 04: Makefile.PL:423
#  * 05: Makefile.PL:325
#  * 06: Makefile.PL:56
#  */
# 


package Apache2::Filter;

use strict;
use warnings FATAL => 'all';



use Apache2::XSLoader ();
our $VERSION = '2.000002';
Apache2::XSLoader::load __PACKAGE__;



1;
__END__

=head1 NAME

Apache2::Filter - Perl API for Apache 2.0 Filtering




=head1 Synopsis

  use Apache2::Filter ();
  
  # filter attributes
  my $c = $f->c;
  my $r = $f->r;
  my $frec = $f->frec();
  my $next_f = $f->next;
  
  my $ctx = $f->ctx;
  $f->ctx($ctx);
  
  # bucket brigade filtering API
  $rc = $f->next->get_brigade($bb, $mode, $block, $readbytes);
  $rc = $f->next->pass_brigade($bb);
  $rc = $f->fflush($bb);
  
  # streaming filtering API
  while ($filter->read(my $buffer, $wanted)) {
      # transform $buffer here
      $filter->print($buffer);
  }
  if ($f->seen_eos) {
      $filter->print("filter signature");
  }
  
  # filter manipulations
  $r->add_input_filter(\&callback);
  $c->add_input_filter(\&callback);
  $r->add_output_filter(\&callback);
  $c->add_output_filter(\&callback);
  $f->remove;







=head1 Description


C<Apache2::Filter> provides Perl API for Apache 2.0 filtering
framework.

Make sure to read C<the Filtering
tutorial|docs::2.0::user::handlers::filters>.




=head1 Common Filter API

The following methods can be called from any filter handler:




=head2 C<c>

Get the current connection object from a connection or a request
filter:

  $c = $f->c;

=over 4

=item obj: C<$f>
( C<L<Apache2::Filter object|docs::2.0::api::Apache2::Filter>> )

=item ret: C<$c>
( C<L<Apache2::Connection object|docs::2.0::api::Apache2::Connection>> )

=item since: 2.0.00

=back






=head2 C<ctx>

Get/set the filter context data.

  $ctx = $f->ctx;
         $f->ctx($ctx);

=over 4

=item obj: C<$f>
( C<L<Apache2::Filter object|docs::2.0::api::Apache2::Filter>> )

=item opt arg2: C<$ctx> ( SCALAR )

next context

=item ret: C<$ctx> ( SCALAR )

current context

=item since: 2.0.00

=back

A filter context is created before the filter is called for the first
time and it's destroyed at the end of the request. The context is
preserved between filter invocations of the same request. So if a
filter needs to store some data between invocations it should use the
filter context for that.  The filter context is initialized with the
C<undef> value.

The C<ctx> method accepts a single SCALAR argument. Therefore if you
want to store any other perl datastructure you should use a reference
to it.

For example you can store a hash reference:

  $f->ctx({ foo => 'bar' });

and then access it:

  $foo = $f->ctx->{foo};

if you access the context more than once it's more efficient to copy
it's value before using it:

  my $ctx = $f->ctx;
  $foo = $ctx->{foo};

to avoid redundant method calls. As of this writing C<$ctx> is not a
tied variable, so if you modify it need to store it at the end:

  $f->ctx($ctx);

META: later we might make it a TIEd-variable interface, so it'll be
stored automatically.

Besides its primary purpose of storing context data across multiple
filter invocations, this method is also useful when used as a
flag. For example here is how to ensure that something happens only
once during the filter's life:

  unless ($f->ctx) {
      do_something_once();
      $f->ctx(1);
  }









=head2 C<frec>

Get/set the C<L<Apache2::FilterRec|docs::2.0::api::Apache2::FilterRec>>
(filter record) object.

  $frec = $f->frec();

=over 4

=item obj: C<$f>
( C<L<Apache2::Filter object|docs::2.0::api::Apache2::Filter>> )

=item ret: C<$frec>
( C<L<Apache2::FilterRec object|docs::2.0::api::Apache2::FilterRec>> )

=item since: 2.0.00

=back

For example you can call
C<L<$frec-E<gt>name|docs::2.0::api::Apache2::FilterRec/C_name_>> to get
filter's name.






=head2 C<next>

Return the C<Apache2::Filter> object of the next filter in chain.

  $next_f = $f->next;

=over 4

=item obj: C<$f>
( C<L<Apache2::Filter object|docs::2.0::api::Apache2::Filter>> )

The current filter object

=item ret: C<$next_f>
( C<L<Apache2::Filter object|docs::2.0::api::Apache2::Filter>> )

The next filter object in chain

=item since: 2.0.00

=back

Since Apache inserts several core filters at the end of each chain,
normally this method always returns an object. However if it's not a
mod_perl filter handler, you can call only the following methods on
it: C<L<get_brigade|/C_get_brigade_>>,
C<L<pass_brigade|/C_pass_brigade_>>, C<L<c|/C_c_>>, C<L<r|/C_r_>>,
C<L<frec|/C_frec_>> and C<L<next|/C_next_>>. If you call other methods
the behavior is undefined.

The next filter can be a mod_perl one or not, it's easy to tell which
one is that by calling
C<L<$f-E<gt>frec-E<gt>name|docs::2.0::api::Apache2::FilterRec/C_name_>>.







=head2 C<r>

Inside an HTTP request filter retrieve the current request object:

  $r = $f->r;

=over 4

=item obj: C<$f>
( C<L<Apache2::Filter object|docs::2.0::api::Apache2::Filter>> )

=item ret: C<$r>
( C<L<Apache2::RequestRec object|docs::2.0::api::Apache2::RequestRec>> )

=item since: 2.0.00

=back

If a sub-request adds filters, then that sub-request object is
associated with the filter.








=head2 C<remove>

Remove the current filter from the filter chain (for the current
request or connection).

  $f->remove;

=over 4

=item obj: C<$f>
( C<L<Apache2::Filter object|docs::2.0::api::Apache2::Filter>> )

=item ret: no return value

=item since: 2.0.00

=back

Notice that you should either complete the current filter invocation
normally (by calling C<L<get_brigade|/C_get_brigade_>> or
C<L<pass_brigade|/C_pass_brigade_>> depending on the filter kind) or
if nothing was done, return C<Apache2::Const::DECLINED> and mod_perl will take
care of passing the current bucket brigade through unmodified to the
next filter in chain.

Note: calling remove() on the very top connection filter doesn't
affect the filter chain due to a bug in Apache 2.0 (which may be fixed
in 2.1). So don't use it with connection filters, till it gets fixed
in Apache and then make sure to require the minimum Apache version if
you rely on.

Remember that if the connection is
C<L<$c-E<gt>keepalive|docs::2.0::api::Apache2::Connection/C_keepalive_>>
) and the connection filter is removed, it won't be added until the
connection is closed. Which may happen after many HTTP requests. You
may want to keep the filter in place and pass the data through
unmodified, by returning C<Apache2::Const::DECLINED>. If you need to reset the
whole or parts of the filter context between requests, use the
L<technique based on C<$c-E<gt>keepalives>
counting|docs::2.0::user::handler::filters>.

This method works for native Apache (non-mod_perl) filters too.












=head1 Bucket Brigade Filter API

The following methods can be called from any filter, directly
manipulating bucket brigades:





=head2 C<fflush>

Flush a bucket brigade down the filter stack.

  $rc = $f->fflush($bb);

=over 4

=item obj: C<$f>
( C<L<Apache2::Filter object|docs::2.0::api::Apache2::Filter>> )

The current filter

=item arg1: C<$bb>
( C<L<Apache2::Brigade object|docs::2.0::api::APR::Brigade>> )

The brigade to flush

=item ret:  C<$rc> ( C<L<APR::Const status
constant|docs::2.0::api::APR::Const>> )

Refer to the C<L<pass_brigade()|/C_pass_brigade_>> entry.

=item excpt: C<L<APR::Error|docs::2.0::api::APR::Error>>

Exceptions are thrown only when this function is called in the VOID
context. Refer to the C<L<get_brigade()|/C_get_brigade_>> entry for
details.

=item since: 2.0.00

=back

C<fflush> is a shortcut method. So instead of doing:

  my $b = APR::Bucket::flush_create($f->c->bucket_alloc);
  $bb->insert_tail($b);
  $f->pass_brigade($bb);

one can just write:

  $f->fflush($bb);








=head2 C<get_brigade>

This is a method to use in bucket brigade input filters. It acquires a
bucket brigade from the upstream input filter.

  $rc = $next_f->get_brigade($bb, $mode, $block, $readbytes);
  $rc = $next_f->get_brigade($bb, $mode, $block);
  $rc = $next_f->get_brigade($bb, $mode)
  $rc = $next_f->get_brigade($bb);

=over 4

=item obj: C<$next_f>
( C<L<Apache2::Filter object|docs::2.0::api::Apache2::Filter>> )

The next filter in the filter chain.

Inside L<filter handlers|docs::2.0::user::handlers::filters> it's
usually C<L<$f-E<gt>next|/C_next_>>. Inside L<protocol
handlers|docs::2.0::user::handlers::protocols>:
C<L<$c-E<gt>input_filters|docs::2.0::api::Apache2::Connection/C_input_filters_>>.


=item arg1: C<$bb>
( C<L<APR::Brigade object|docs::2.0::api::APR::Brigade>> )

The original bucket brigade passed to C<get_brigade()>, which must be
empty.

Inside L<input filter
handlers|docs::2.0::user::handlers::filters> it's usually the second
argument to the filter handler.

Otherwise it should be created:

  my $bb = APR::Brigade->new($c->pool, $c->bucket_alloc);

On return it gets populated with the next bucket brigade. That brigade
may contain nothing if there was no more data to read. The return
status tells the outcome.


=item opt arg2: C<$mode> ( C<L<Apache2::Const :input_mode
constant|docs::2.0::api::Apache2::Const/C__input_mode_>> )

The filter mode in which the data should be read.

If inside the filter handler, you should normally pass the same mode
that was passed to the filter handler (the third argument).

At the end of this section the available modes are presented.

If the argument C<$mode> is not passed,
C<L<Apache2::Const::MODE_READBYTES|docs::2.0::api::Apache2::Const/C_Apache2__Const__MODE_READBYTES_>>
is used as a default value.


=item opt arg3: C<$block> ( C<L<APR::Const :read_type
constant|docs::2.0::api::APR::Const/C__input_mode_>> )

You may ask the reading operation to be blocking:
C<L<APR::Const::BLOCK_READ|docs::2.0::api::APR::Const/C_APR__Const__BLOCK_READ_>>,
or nonblocking:
C<L<APR::Const::NONBLOCK_READ|docs::2.0::api::APR::Const/C_APR__Const__NONBLOCK_READ_>>.

If inside the filter handler, you should normally pass the same
blocking mode argument that was passed to the filter handler (the
forth argument).

If the argument C<$block> is not passed,
C<L<APR::Const::BLOCK_READ|docs::2.0::api::APR::Const/C_APR__Const__BLOCK_READ_>> is
used as a default value.


=item opt arg4: C<$readbytes> ( integer )

How many bytes to read from the next filter.

If inside the filter handler, you may want the same number of bytes,
as the upstream filter, i.e. the argument that was passed to the
filter handler (the fifth argument).

If the argument C<$block> is not passed, 8192 is used as a default
value.


=item ret: C<$rc> ( C<L<APR::Const status
constant|docs::2.0::api::APR::Const>> )

On success,
C<L<APR::Const::SUCCESS|docs::2.0::api::APR::Const/C_APR__Const__SUCCESS_>> is
returned and C<$bb> is populated (see the C<$bb> entry).

In case of a failure -- a failure code is returned, in which case
normally it should be returned to the caller.

If the bottom-most filter doesn't read from the network, then
C<Apache2::NOBODY_READ> is returned (META: need to add this constant).

Inside L<protocol handlers|docs::2.0::user::handlers::protocols> the
return code can also be C<APR::Const::EOF>, which is success as well.


=item excpt: C<L<APR::Error|docs::2.0::api::APR::Error>>

You don't have to ask for the return value. If this function is called
in the VOID context, e.g.:

  $f->next->get_brigade($bb, $mode, $block, $readbytes);

mod_perl will do the error checking on your behalf, and if the return
code is not
C<L<APR::Const::SUCCESS|docs::2.0::api::APR::Const/C_APR__Const__SUCCESS_>>, an
C<L<APR::Error exception|docs::2.0::api::APR::Error>> will be thrown.
The only time you want to do the error checking yourself, is when
return codes besides
C<L<APR::Const::SUCCESS|docs::2.0::api::APR::Const/C_APR__Const__SUCCESS_>> are
considered as successful and you want to manage them by yourself.

=item since: 2.0.00

=back


Available input filter modes (the optional second argument C<$mode>)
are:

=over

=item * C<L<Apache2::Const::MODE_READBYTES|docs::2.0::api::Apache2::Const/C_Apache2__Const__MODE_READBYTES_>>

The filter should return at most readbytes data

=item * C<L<Apache2::Const::MODE_GETLINE|docs::2.0::api::Apache2::Const/C_Apache2__Const__MODE_GETLINE_>>

The filter should return at most one line of CRLF data.  (If a
potential line is too long or no CRLF is found, the filter may return
partial data).

=item * C<L<Apache2::Const::MODE_EATCRLF|docs::2.0::api::Apache2::Const/C_Apache2__Const__MODE_EATCRLF_>>

The filter should implicitly eat any CRLF pairs that it sees.

=item * C<L<Apache2::Const::MODE_SPECULATIVE|docs::2.0::api::Apache2::Const/C_Apache2__Const__MODE_SPECULATIVE_>>

The filter read should be treated as speculative and any returned data
should be stored for later retrieval in another mode.

=item * C<L<Apache2::Const::MODE_EXHAUSTIVE|docs::2.0::api::Apache2::Const/C_Apache2__Const__MODE_EXHAUSTIVE_>>

The filter read should be exhaustive and read until it can not read
any more. Use this mode with extreme caution.

=item * C<L<Apache2::Const::MODE_INIT|docs::2.0::api::Apache2::Const/C_Apache2__Const__MODE_INIT_>>

The filter should initialize the connection if needed, NNTP or FTP
over SSL for example.

=back

Either compile all these constants with:

  use Apache2::Const -compile => qw(:input_mode);

But it's a bit more efficient to compile only those constants that you
need.

Example:

Here is a fragment of a filter handler, that receives a bucket brigade
from the upstream filter:

  use Apache2::Filter ();
  use APR::Const    -compile => qw(SUCCESS);
  use Apache2::Const -compile => qw(OK);
  sub filter {
      my ($f, $bb, $mode, $block, $readbytes) = @_;
      
      my $rc = $f->next->get_brigade($bb, $mode, $block, $readbytes);
      return $rc unless $rc == APR::Const::SUCCESS;
      
      # ... process $bb