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From s...@apache.org
Subject cvs commit: modperl-docs/src/docs/2.0/user/handlers handlers.pod
Date Wed, 19 Jun 2002 19:24:42 GMT
stas        2002/06/19 12:24:42

  Modified:    src/docs/2.0/user/handlers handlers.pod
  Log:
  add PerlOutputFilterHandler example
  
  Revision  Changes    Path
  1.2       +75 -11    modperl-docs/src/docs/2.0/user/handlers/handlers.pod
  
  Index: handlers.pod
  ===================================================================
  RCS file: /home/cvs/modperl-docs/src/docs/2.0/user/handlers/handlers.pod,v
  retrieving revision 1.1
  retrieving revision 1.2
  diff -u -r1.1 -r1.2
  --- handlers.pod	15 Jun 2002 18:26:33 -0000	1.1
  +++ handlers.pod	19 Jun 2002 19:24:42 -0000	1.2
  @@ -483,27 +483,91 @@
   
   =head2 PerlOutputFilterHandler
   
  -This handler registers an stream-orientered output filter (i.e. it
  -works with the response stream). To actually use it the core
  -C<AddOutputFilter> directive must be used.
  +This handler registers and configures a stream-orientered output
  +filter (i.e. it works with the response stream).
   
   This handler is of type C<VOID>.
   
   The handler's configuration scope is C<DIR>.
   
  -Example:
  -
  -In this example the output filter C<Apache::ReverseFilter>
  -
  -The following filter reverts XXX
  +The output filter in the following example reverses every line of the
  +response, preserving the new line characters in their places:
   
  +  file:httpd.conf
  +  ---------------
  +  PerlModule Apache::ReverseFilter
     <Location /reverse>
         SetHandler modperl
  -      PerlOutputFilterHandler TestFilter::reverse
  -      PerlResponseHandler TestFilter::reverse::response
  +      PerlOutputFilterHandler Apache::ReverseFilter::output_filter
  +      PerlResponseHandler     Apache::ReverseFilter::response
     </Location>
   
  -
  +  file:Apache/ReverseFilter.pm
  +  ----------------------------
  +  package Apache::ReverseFilter;
  +  
  +  use strict;
  +  use warnings FATAL => 'all';
  +  
  +  use Apache::RequestRec ();
  +  use Apache::RequestIO ();
  +  use Apache::Filter ();
  +  
  +  use Apache::Const -compile => qw(OK);
  +  
  +  my $clrf = qr/[\r\n]+/;
  +  
  +  sub output_filter {
  +      my $filter = shift;
  +  
  +      my $left_over = '';
  +      while ($filter->read(my $buffer, 2)) {
  +          $buffer = $left_over . $buffer;
  +          $left_over = '';
  +          while ($buffer =~ /([^\r\n]*)([\r\n]*)/g) {
  +              $left_over = $1, last unless $2;
  +              $filter->print(scalar(reverse $1), $2);
  +          }
  +      }
  +      $filter->print(scalar reverse $left_over) if length $left_over;
  +  
  +      Apache::OK;
  +  }
  +  
  +  sub response {
  +      my $r = shift;
  +  
  +      $r->content_type('text/plain');
  +      $r->puts(1..9, "0\n");
  +      $r->puts('a'..'z', "\n");
  +  
  +      Apache::OK;
  +  }
  +  1;
  +
  +
  +In this example when a request to I</reverse> is made, the response
  +handler C<Apache::ReverseFilter::response()> sends:
  +
  +  1234567890
  +  abcdefghijklmnopqrstuvwxyz
  +
  +as a response and the output filter handler
  +C<Apache::ReverseFilter::output_filter> reverses the lines, so the
  +client gets:
  +
  +  0987654321
  +  zyxwvutsrqponmlkjihgfedcba
  +
  +The reversing filter is quite simple: it reads from the output stream
  +in chunks of 1024 characters, and then prints all lines reversed
  +preserving the new line control characters at the end of each
  +line. The special handling of new lines is needed for cases where an
  +input line is longer than the buffer size, (1024 in our example), when
  +this happens we store the reminder of the string in C<$left_over> and
  +prepend it to the buffer when the next chunk is read. At the end we
  +print out the reminder of the input when there is no more data left on
  +the stream.
   
   
   
  
  
  

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