NAME

POE::Component::Server::REST - publish POE event handlers via REST

SHORT DESCRIPTION

POE::Component::Server::REST is a standalone POE Server which accepts RESTful HTTP requests.
In order to provide a complete solution kit for REST interfaces, this server comes along with
two flavours: YAML and XML. It either unmarshalls/marshalls YAML or XML. This is done by using
XML::Simple or YAML::Tiny. You simply get or reply hash-references on requests/responses, this
module unmarshalls/marshalls them for you.

SYNOPSIS

# This example can be found in the package's examples directory.

use POE;
use POE::Component::Server::REST;

POE::Component::Server::REST->new(
		'ALIAS'         =>      'MyREST',
		'ADDRESS'       =>      'localhost',
		'PORT'          =>      8081,
		'HOSTNAME'      =>      'MyHost.com',
		'CONTENTTYPE'	=>		'text/yaml'		# or 'text/xml'
);

POE::Session->create(
	'inline_states' =>      {
		'_start'        =>      \&start,
		'_stop'         =>      \&stop,
		'GET/things'     =>    \&get_things,
		'POST/thing'    =>     \&add_thing,
		'PUT/thing'      =>    \&upd_thing,
		'DELETE/thing'   =>    \&del_thing,
		'GET/thing'      =>    \&get_thing,
	},
);

$poe_kernel->run;
exit 0;

sub start {
	my ($kernel, $heap) = @_[ KERNEL, HEAP ];

	# Some example preparations
	$heap->{things} = {
		1 => 'Foo',
		2 => 'Bar',
		3 => 'Slow',
		4 => 'Joe',
	};

	# Register each method
	$kernel->alias_set( 'MyServer' );
	$kernel->post( 'MyREST', 'ADDMETHOD', 'MyServer', 'GET/things' );
	$kernel->post( 'MyREST', 'ADDMETHOD', 'MyServer', 'POST/thing' );
	$kernel->post( 'MyREST', 'ADDMETHOD', 'MyServer', 'PUT/thing' );
	$kernel->post( 'MyREST', 'ADDMETHOD', 'MyServer', 'DELETE/thing' );
	$kernel->post( 'MyREST', 'ADDMETHOD', 'MyServer', 'GET/thing' );
}

sub stop {
	my ($kernel) = @_[ KERNEL ];
	# Unregister each method
	$kernel->post( 'MyREST', 'DELMETHOD', 'MyServer', 'GET/things' );
	$kernel->post( 'MyREST', 'DELMETHOD', 'MyServer', 'POST/thing' );
	$kernel->post( 'MyREST', 'DELMETHOD', 'MyServer', 'PUT/thing' );
	$kernel->post( 'MyREST', 'DELMETHOD', 'MyServer', 'DELETE/thing' );
	$kernel->post( 'MyREST', 'DELMETHOD', 'MyServer', 'GET/thing' );
}

# Things
####################

sub get_thing {
	my ($kernel, $heap, $response, $key) = @_[KERNEL, HEAP, ARG0, ARG1];

	# Check if exists
	if( exists($heap->{things}->{$key}) ) {
		  my $val = $heap->{things}->{$key};

		  # Build Repsonse.
		  $response->content({
			'thing' => {
				'id' => $key,
				'name' => $val },
			});
		  $kernel->post( $session, 'DONE', $response, );
		  return;
	} else {
		$kernel->post( $session, 'FAULT', $response, CLIENT_NOTFOUND, "NotFound", "Thing $key does not exists."  );
		return;
	}
}

sub get_things {
	  my ($kernel, $heap, $response, $key) = @_[KERNEL, HEAP, ARG0, ARG1];

	  my $things = [];
	  while( my ($id, $name) = each %{ $heap->{things} }) {
			push(@$things, { id => $id, name => $name } );
	  }
	  $response->content({ things => $things });
	  $kernel->post($session, 'DONE', $response);
	  return;
}

sub add_thing {
	my ($kernel, $heap, $response, $key) = @_[KERNEL, HEAP, ARG0, ARG1];

	# POE::Component::Server::REST returns undef if there was an error while parsing the request.
	my $content = $response->restbody;
	unless( $content ) {
		$kernel->post( $session, 'FAULT', $response, CLIENT_BADREQUEST, "Bad Request", "Error parsing document structure"  );
		return;
	}

	# Check given ref structure...
	unless( ref($content) eq 'HASH' and exists($content->{thing}) and exists($content->{thing}->{id}) and exists($content->{thing}->{name}) ) {
		$kernel->post( $session, 'FAULT', $response, CLIENT_BADREQUEST, "Bad Request", "Unable to validate structure." );
		return;
	}

	# Check for existence
	if( exists($heap->{things}->{$key}) ) {
		$kernel->post( $session, 'FAULT', $response, CLIENT_BADREQUEST, "Bad Request", "Thing $key exists already." );
		return;
	}

	my $id = $content->{thing}->{id};
	my $name = $content->{thing}->{name};

	# Validate extracted field id
	...

	# Validate extracted field name
	...	

	# Add it
	$heap->{things}->{$id} = $name;

	# Done
	$kernel->post( $session, 'DONE', $response, "Done", "Added thing $id -> $name"  );
	return;

}

sub upd_thing {
	my ($kernel, $heap, $response, $key) = @_[KERNEL, HEAP, ARG0, ARG1];

	# Parse xml
	my $content = $response->restbody;
	unless( $content ) {
		$kernel->post( $session, 'FAULT', $response, CLIENT_BADREQUEST,"Bad Request", "Error parsing document structure."  );
		return;
	}

	# Sheck structure
	unless( exists($content->{thing}) and exists($content->{thing}->{id}) && exists($content->{thing}->{name}) ) {
		$kernel->post( $session, 'FAULT', $response, CLIENT_BADREQUEST, "Bad Request", "Unable to validate structure." );
		return;
	}

	# Only proceed if referenced thing does exist
	unless( exists($heap->{things}->{$key}) ) {
		$kernel->post( $session, 'FAULT', $response, CLIENT_BADREQUEST, "Bad Request", "Thing $key does not exist." );
		return;
	}

	my $id = $content->{thing}->{id};
	my $name = $content->{thing}->{name};

	# Validate extracted field id
	...

	# Validate extracted field name
	...

	# Update thing
	$heap->{things}->{$id} = $name;

	# Done
	$kernel->post( $session, 'DONE', $response, "Done", "Updated thing $id -> $name"  );
	return;

}

sub del_thing {
	my ($kernel, $heap, $response, $key) = @_[KERNEL, HEAP, ARG0, ARG1];

	my $params = $response->restbody;

	# Check if referenced thing does exists
	unless( exists($heap->{things}->{$key}) ) {
			$kernel->post( $session, 'FAULT', $response, CLIENT_BADREQUEST, 'EXISTS', "Thing $key does not exist." );
			return;
	}

	# Delete it 
	delete $heap->{things}->{$key};

	# Done
	$kernel->post( $session, 'DONE', $response, "Done", "Successfully removed ththingg." );
	return;

}

ABSTRACT

An easy to use REST daemon for POE-enabled programs

DESCRIPTION

This module makes serving REST requests a breeze in POE.

The hardest thing to understand in this module is the REST Body. That's it!

The standard way to use this module is to do this:

use POE;
use POE::Component::Server::REST;

POE::Component::Server::REST->new( ... );

POE::Session->create( ... );

POE::Kernel->run();

POE::Component::Server::REST is a bolt-on component that can publish event handlers via REST over HTTP. Currently, this module only supports REST xml or yaml requests. The HTTP server is done via POE::Component::Server::SimpleHTTP.

Starting Server::REST

To start Server::REST, just call it's new method:

POE::Component::Server::REST->new(
		'ALIAS'         =>      'MyREST',
		'ADDRESS'       =>      '192.168.1.1',
		'PORT'          =>      11111,
		'HOSTNAME'      =>      'MySite.com',
		'HEADERS'       =>      {},
		'CONTENTTYPE'	=>		'text/yaml',
);

This method will die on error or return success.

ALIAS

This will set the alias Server::REST uses in the POE Kernel. This will default to "RESTServer"

ADDRESS

This value will be passed to POE::Component::Server::SimpleHTTP to bind to.

Examples: ADDRESS => 0 # Bind to all addresses + localhost ADDRESS => 'localhost' # Bind to localhost ADDRESS => '192.168.1.1' # Bindto specified IP

PORT

This value will be passed to POE::Component::Server::SimpleHTTP to bind to.

HOSTNAME

This value is for the HTTP::Request's URI to point to. If this is not supplied, POE::Component::Server::SimpleHTTP will use Sys::Hostname to find it.

HEADERS

This should be a hashref, that will become the default headers on all HTTP::Response objects. You can override this in individual requests by setting it via $response->header( ... )

The default header is: Server => 'POE::Component::Server::REST/' . $VERSION

For more information, consult the HTTP::Headers module.

CONTENTTYPE

Defines in what format request and responses should be unmarshalled/marshalled. Current supported formats are:

text/yaml (default)
text/xml

SIMPLEHTTP

This allows you to pass options to the SimpleHTTP backend. One of the real reasons is to support SSL in Server::REST, yay! To learn how to use SSL, please consult the POE::Component::Server::SimpleHTTP documentation. Of course, you could totally screw up things, just use this with caution :)

You must pass a hash reference as the value, because it will be expanded and put in the Server::SimpleHTTP->new() constructor.

Events

There are only a few ways to communicate with Server::REST.

ADDMETHOD

This event accepts four arguments:
		- The intended session alias
		- The intended session event
		- The public service name       ( not required -> defaults to session alias )
		- The public method name        ( not required -> defaults to session event )

Calling this event will add the method to the registry.

NOTE: This will overwrite the old definition of a method if it exists!

DELMETHOD

This event accepts two arguments:
		- The service name
		- The method name

Calling this event will remove the method from the registry.

NOTE: if the service now contains no methods, it will also be removed.

DELSERVICE

This event accepts one argument:
		- The service name

Calling this event will remove the entire service from the registry.

DONE

This event accepts only one argument: the REST::Response object we sent to the handler.

Calling this event implies that this particular request is done, and will proceed to close the socket.

NOTE: This method automatically sets some parameters:
		- HTTP Status = 200 ( if not defined )
		- HTTP Header value of 'Content-Type' = 'text/xml'

To get greater throughput and response time, do not post() to the DONE event, call() it!
However, this will force your program to block while servicing REST requests...

FAULT

This event accepts five arguments:
		- the HTTP::Response object we sent to the handler
		- REST Fault Code       ( not required -> defaults to 'Server' )
		- REST Fault String     ( not required -> defaults to 'Application Faulted' )
		- REST Fault Detail     ( not required )
		- REST Fault Actor      ( not required )

Again, calling this event implies that this particular request is done, and will proceed to close the socket.

Calling this event will generate a REST Fault and return it to the client.

NOTE: This method automatically sets some parameters:
		- HTTP Status = 500 ( if not defined )
		- HTTP Header value of 'Content-Type' = 'text/xml'
		- HTTP Content = Xml result envelope of the fault ( overwriting anything that was there )

CLOSE

This event accepts only one argument: the REST::Response object we sent to the handler.

Calling this event will proceed to close the socket, not sending any output.

STARTLISTEN

Starts the listening socket, if it was shut down

STOPLISTEN

Simply a wrapper for SHUTDOWN GRACEFUL, but will not shutdown Server::REST if there is no more requests

SHUTDOWN

Without arguments, Server::REST does this:
		Close the listening socket
		Kills all pending requests by closing their sockets
		Removes it's alias

With an argument of 'GRACEFUL', Server::REST does this:
		Close the listening socket
		Waits for all pending requests to come in via DONE/FAULT/CLOSE, then removes it's alias

Processing Requests

if you're new to the world of REST, reading RESTful documentation is recommended!

Now, once you have set up the services/methods, what do you expect from Server::REST? Every request is pretty straightforward, you just get a Server::REST::Response object in ARG0 and an optional KEY identifier in ARG1.

The Server::REST::Response object contains a wealth of information about the specified request:
		- There is the SimpleHTTP::Connection object, which gives you connection information
		- There is the various REST accessors provided via Server::REST::Response
		- There is the HTTP::Request object

Example information you can get:
		$response->connection->remote_ip()      # IP of the client
		$response->restrequest->uri()           # Original URI
		$response->restmethod()                 # The SOAP method that was called
		$response->restbody()                   # The arguments to the method

Simply experiment using Data::Dumper and you'll quickly get the hang of it!

When you're done with the REST request, stuff whatever output you have into the content of the response object by passing it a HASH/ARRAY Reference.

$response->content({ Foo => 1 });

IMPORTANT: I thought it might be smart to use a standard structure for all Responses. Your content ref will be wrapped into a response structure like the following one:

result => {
		short => $short_done_or_fault_msg,
		detail => $detail_done_or_fault_msg,
		content => $your_struct,
}

This struct is then beeing marshalled into XML/YAML.

The only thing left to do is send it off to the DONE event :)

$kernel->post( 'MyREST', 'DONE', $response );

If there's an error, you can send it to the FAULT event, which will convert it into a REST fault.

$kernel->post( 'MyREST', 'FAULT', $response, 'Client.Authentication', 'Invalid password' );

Server::REST Notes

This module is very picky about capitalization and copy&paste errors! and was copied with the authorization of the owner of POE::Component::Server::SOAP :) Thanks!

All of the options are uppercase, to avoid confusion.

You can enable debugging mode by doing this:

sub POE::Component::Server::REST::DEBUG () { 1 }
use POE::Component::Server::REST;

Using SSL

So you want to use SSL in Server::REST? Here's a example on how to do it:

POE::Component::Server::REST->new(
		...
		'SIMPLEHTTP'    =>      {
				'SSLKEYCERT'    =>      [ 'public-key.pem', 'public-cert.pem' ],
		},
);

# And that's it provided you've already created the necessary key + certificate file :)
# EXPERIMENTAL -> See SIMPLEHTTP

SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc POE::Component::Server::REST

Websites

AnnoCPAN: Annotated CPAN documentation

http://annocpan.org/dist/POE-Component-Server-REST

CPAN Ratings

http://cpanratings.perl.org/d/POE-Component-Server-REST

RT: CPAN's request tracker

http://rt.cpan.org/NoAuth/Bugs.html?Dist=POE-Component-Server-REST

Search CPAN

http://search.cpan.org/dist/POE-Component-Server-REST

Bugs

Please report any bugs or feature requests to
"bug-poe-component-server-rest at rt.cpan.org", or through the web
interface at
http://rt.cpan.org/NoAuth/ReportBug.html?Queue=POE-Component-Server-REST
I will be notified, and then you'll automatically be notified of
progress on your bug as I make changes.

AUTHOR

    Jstebens <jstebens@cpan.org>

    I used POE::Server::Component::SOAP as base for this module and documentation.
	There may be still POE::Server::Component::SOAP artifacts spread throught the
	documentation and code. If you find those, please let me know.

	Many thanks to Larwan "Apocalypse" Berke for the approval to use his code as base!

COPYRIGHT AND LICENSE

Copyright 2011 by Jstebens

This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.

To install POE::Component::Server::REST, copy and paste the appropriate command in to your terminal.

cpanm

cpanm POE::Component::Server::REST

CPAN shell

perl -MCPAN -e shell
install POE::Component::Server::REST

For more information on module installation, please visit the detailed CPAN module installation guide.

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