POE::Filter::HTTPD(3)

NAME
POE::Filter::HTTPD - parse simple HTTP requests, and serialize HTTP::Response

SYNOPSIS
  #!perl

  use warnings;
  use strict;

  use POE qw(Component::Server::TCP Filter::HTTPD);
  use HTTP::Response;

  POE::Component::Server::TCP->new(
    Port         => 8088,
    ClientFilter => 'POE::Filter::HTTPD',  ### <-- HERE WE ARE!

    ClientInput => sub {
      my $request = $_[ARG0];

      # It's a response for the client if there was a problem.
      if ($request->isa("HTTP::Response")) {
        $_[HEAP]{client}->put($request);
        $_[KERNEL]->yield("shutdown");
        return;
      }

      my $request_fields = '';
      $request->headers()->scan(
        sub {
          my ($header, $value) = @_;
          $request_fields .= (
            "<tr><td>$header</td><td>$value</td></tr>"
          );
        }
      );

      my $response = HTTP::Response->new(200);
      $response->push_header( 'Content-type', 'text/html' );
      $response->content(
        "<html><head><title>Your Request</title></head>" .
        "<body>Details about your request:" .
        "<table border='1'>$request_fields</table>" .
        "</body></html>"
      );

      $_[HEAP]{client}->put($response);
      $_[KERNEL]->yield("shutdown");
    }
  );

  print "Aim your browser at port 8088 of this host.\n";
  POE::Kernel->run();
  exit;

DESCRIPTION
POE::Filter::HTTPD interprets input streams as HTTP 0.9 or 1.0 requests. It returns a HTTP::Request objects upon successfully parsing a request. On failure, it returns an HTTP::Response object describing the failure. The intention is that application code will notice the HTTP::Response and send it back without further processing. This is illustrated in the "SYNOPSIS".

For output, POE::Filter::HTTPD accepts HTTP::Response objects and returns their corresponding streams.

Please see HTTP::Request and HTTP::Response for details about how to use these objects.

PUBLIC FILTER METHODS
POE::Filter::HTTPD implements the basic POE::Filter interface.

CAVEATS
Some versions of libwww are known to generate invalid HTTP. For example, this code (adapted from the HTTP::Request::Common documentation) will cause an error in a POE::Filter::HTTPD daemon:

  use HTTP::Request::Common;
  use LWP::UserAgent;

  my $ua = LWP::UserAgent->new();
  $ua->request(POST 'http://some/poe/driven/site', [ foo => 'bar' ]);

By default, HTTP::Request is HTTP version agnostic. It makes no attempt to add an HTTP version header unless you specifically declare a protocol using "$request->protocol('HTTP/1.0')".

According to the HTTP 1.0 RFC (1945), when faced with no HTTP version header, the parser is to default to HTTP/0.9. POE::Filter::HTTPD follows this convention. In the transaction detailed above, the Filter::HTTPD based daemon will return a 400 error since POST is not a valid HTTP/0.9 request type.

Streaming Media
It is possible to use POE::Filter::HTTPD for streaming content, but an application can use it to send headers and then switch to POE::Filter::Stream.

From the input handler (the InputEvent handler if you're using wheels, or the ClientInput handler for POE::Component::Server::TCP):

  my $response = HTTP::Response->new(200);
  $response->push_header('Content-type', 'audio/x-mpeg');
  $_[HEAP]{client}->put($response);
  $_[HEAP]{client}->set_output_filter(POE::Filter::Stream->new());

Then the output-flushed handler (FlushEvent for POE::Wheel::ReadWrite, or ClientFlushed for POE::Component::Server::TCP) can put() chunks of the stream as needed.

  my $bytes_read = sysread(
    $_[HEAP]{file_to_stream}, my $buffer = '', 4096
  );

  if ($bytes_read) {
    $_[HEAP]{client}->put($buffer);
  }
  else {
    delete $_[HEAP]{file_to_stream};
    $_[KERNEL]->yield("shutdown");
  }

SEE ALSO
Please see POE::Filter for documentation regarding the base interface.

The SEE ALSO section in POE contains a table of contents covering the entire POE distribution.

HTTP::Request and HTTP::Response explain all the wonderful things you can do with these classes.

BUGS
Many aspects of HTTP 1.0 and higher are not supported, such as keep-alive. A simple I/O filter can't support keep-alive, for example. A number of more feature-rich POE HTTP servers are on the CPAN. See <http://search.cpan.org/search?query=POE+http+server&mode=dist>

AUTHORS & COPYRIGHTS
POE::Filter::HTTPD was contributed by Artur Bergman. Documentation is provided by Rocco Caputo.

Please see POE for more information about authors and contributors.