POE::Filter::HTTPD(3) User Contributed Perl DocumentationPOE::Filter::HTTPD(3)NAMEPOE::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")) {
my $response = $request;
$request = $response->request;
warn "ERROR: ", $request->message if $request;
$_[HEAP]{client}->put($response);
$_[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);
$_[KERNEL]->yield("shutdown");
}
);
print "Aim your browser at port 8088 of this host.\n";
POE::Kernel->run();
exit;
DESCRIPTIONPOE::Filter::HTTPD interprets input streams as HTTP 0.9, 1.0 or 1.1
requests. It returns a HTTP::Request objects upon successfully parsing
a request.
On failure, it returns an HTTP::Response object describing the failure.
The intention is that application code will notice the HTTP::Response
and send it back without further processing. The erroneous request
object is sometimes available via the "$r->request" in HTTP::Response
method. 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 METHODSPOE::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:
NOTE: Using this test with libwww-perl/5.834 showed that it added the
proper HTTP/1.1 data! We're not sure which version of LWP fixed this.
This example is valid for older LWP installations, beware!
use HTTP::Request::Common;
use LWP::UserAgent;
my $ua = LWP::UserAgent->new();
$ua->request(POST 'http://example.com', [ foo => 'bar' ]);
By default, HTTP::Request is HTTP version agnostic. It makes no attempt
to add an HTTP version header unless you specifically declare a
protocol using "$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.
Upon handling a request error, it is most expedient and reliable to
respond with the error and shut down the connection. Invalid HTTP
requests may corrupt the request stream. For example, the absence of a
Content-Length header signals that a request has no content. Requests
with content but not that header will be broken into a content-less
request and invalid data. The invalid data may also appear to be a
request! Hilarity will ensue, possibly repeatedly, until the filter
can find the next valid request. By shutting down the connection on
the first sign of error, the client can retry its request with a clean
connection and filter.
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 & COPYRIGHTSPOE::Filter::HTTPD was contributed by Artur Bergman. Documentation is
provided by Rocco Caputo.
Please see POE for more information about authors and contributors.
perl v5.14.2 2011-12-15 POE::Filter::HTTPD(3)
