NAME¶
POE::Component::Server::HTTP - Foundation of a POE HTTP Daemon
SYNOPSIS¶
use POE::Component::Server::HTTP;
use HTTP::Status;
my $aliases = POE::Component::Server::HTTP->new(
Port => 8000,
ContentHandler => {
'/' => \&handler1,
'/dir/' => sub { ... },
'/file' => sub { ... }
},
Headers => { Server => 'My Server' },
);
sub handler {
my ($request, $response) = @_;
$response->code(RC_OK);
$response->content("Hi, you fetched ". $request->uri);
return RC_OK;
}
POE::Kernel->call($aliases->{httpd}, "shutdown");
# next line isn't really needed
POE::Kernel->call($aliases->{tcp}, "shutdown");
DESCRIPTION¶
POE::Component::Server::HTTP (PoCo::HTTPD) is a framework for building custom
HTTP servers based on POE. It is loosely modeled on the ideas of apache and
the mod_perl/Apache module.
It is built alot on work done by Gisle Aas on HTTP::* modules and the URI module
which are subclassed.
PoCo::HTTPD lets you register different handler, stacked by directory that will
be run during the cause of the request.
Handlers
Handlers are put on a stack in fifo order. The path /foo/bar/baz/honk.txt will
first push the handlers of / then of /foo/ then of /foo/bar/, then of
/foo/bar/baz/, and lastly /foo/bar/baz/honk.txt. Pay attention to directories!
A request for /honk will not match /honk/ as you are used to with apache. If
you want /honk to act like a directory, you should have a handler for /honk
which redirects to /honk/.
However, there can be only one ContentHandler and if any handler installs a
ContentHandler that will override the old ContentHandler.
If no handler installs a ContentHandler it will find the closest one directory
wise and use it.
There is also a special StreamHandler which is a coderef that gets invoked if
you have turned on streaming by doing $response->
streaming(1);
Handlers take the $request and $response objects as arguments.
- RC_OK
- Everything is ok, please continue processing.
- RC_DENY
- If it is a TransHandler, stop translation handling and carry on with a
PreHandler, if it is a PostHandler do nothing, else return denied to the
client.
- RC_WAIT
- This is a special handler that suspends the execution of the handlers.
They will be suspended until $response-> continue() is called,
this is usefull if you want to do a long request and not blocck.
The following handlers are available.
- TransHandler
- TransHandlers are run before the URI has been resolved, giving them a
chance to change the URI. They can therefore not be registred per
directory.
new(TransHandler => [ sub {return RC_OK} ]);
A TransHandler can stop the dispatching of TransHandlers and jump to the
next handler type by specifing RC_DENY;
- PreHandler
- PreHandlers are stacked by directory and run after TransHandler but before
the ContentHandler. They can change ContentHandler (but beware, other
PreHandlers might also change it) and push on PostHandlers.
new(PreHandler => { '/' => [sub {}], '/foo/' => [\&foo]});
- ContentHandler
- The handler that is supposed to give the content. When this handler
returns it will send the response object to the client. It will
automaticly add Content-Length and Date if these are not set. If the
response is streaming it will make sure the correct headers are set. It
will also expand any cookies which have been pushed onto the response
object.
new(ContentHandler => { '/' => sub {}, '/foo/' => \&foo});
- ErrorHandler
- This handler is called when there is a read or write error on the socket.
This is most likely caused by the remote side closing the connection.
$resquest->is_error and $response->is_error will return true. Note
that "PostHanlder" will still called, but
"TransHandler" and "PreHandler" won't be. It is a map
to coderefs just like ContentHandler is.
- PostHandler
- These handlers are run after the socket has been flushed.
new(PostHandler => { '/' => [sub {}], '/foo/' => [\&foo]});
- StreamHandler
- If you turn on streaming in any other handler, the request is placed in
streaming mode. This handler is called, with the usual parameters, when
streaming mode is first entered, and subsequently when each block of data
is flushed to the client.
Streaming mode is turned on via the $response object:
$response->streaming(1);
You deactivate streaming mode with the same object:
$response->close;
Content is also sent to the client via the $response object:
$response->send($somedata);
The output filter is set to POE::Filter::Stream, which passes the data
through unchanged. If you are doing a multipart/mixed response, you will
have to set up your own headers.
Example:
sub new {
.....
POE::Component::Filter::HTTP->new(
ContentHandler => { '/someurl' => sub { $self->someurl(@_) },
StreamHandler => sub { $self->stream(@_),
);
}
sub someurl {
my($self, $resquest, $response)=@_;
$self->{todo} = [ .... ];
$response->streaming(1);
$response->code(RC_OK); # you must set up your response header
$response->content_type(...);
return RC_OK;
}
sub stream {
my($self, $resquest, $response)=@_;
if( @{$self->{todo}} ) {
$response->send(shift @{$self->{todo}});
}
else {
$response->close;
}
}
Another example can be found in t/30_stream.t. The parts dealing with
multipart/mixed are well documented and at the end of the file.
NOTE: Changes in streaming mode are only verified when StreamHandler exits.
So you must either turn streaming off in your StreamHandler, or make sure
that the StreamHandler will be called again. This last is done by sending
data to the client. If for some reason you have no data to send, you can
get the same result with "continue". Remember that this will
also cause the StreamHandler to be called one more time.
my $aliases=POE::Component::Filter::HTTP->new( ....);
# and then, when the end of the stream in met
$response->close;
$response->continue;
NOTE: even when the stream ends, the client connection will be held open if
Keepalive is active. To force the connection closed, set the
Connection header to close:
$resquest->header(Connection => 'close');
This might be a bug. Are there any cases where we'd want to keep the
connection open after a stream?
Events¶
The "shutdown" event may be sent to the component indicating that it
should shut down. The event may be sent using the return value of the
new() method (which is a session id) by either
post()ing or
call()ing.
I've experienced some problems with the session not receiving the event when it
gets
post()ed so
call() is advised.
See Also¶
Please also take a look at HTTP::Response, HTTP::Request, URI, POE and
POE::Filter::HTTPD
TODO¶
- Document Connection Response and Request objects.
- Write more tests
- Add a PoCo::Server::HTTP::Session that matches a http session against poe
session using cookies or other state system
- Add more options to streaming
- Figure out why post()ed "shutdown" events don't get
received.
- Probably lots of other API changes
AUTHOR¶
Arthur Bergman, arthur@contiller.se
Additional hacking by Philip Gwyn, poe-at-pied.nu
Released under the same terms as POE.