NAME

POE::Component::Server::REST - a solution kit for REST interfaces.

SHORT DESCRIPTION

POE::Component::Server::REST is a solution kit for REST interfaces.

- Delegates requests to the appropriate hierarchic path's method.
- Unmarshalls/marshalls from/to JSON/XML/YAML
- Delivers request content as hashref to the appropriate method.
- Delivers request keys as string to the appropriate method.

SYNOPSIS

	NOTE: The whole example can be found in the package's examples directory.

	use POE;
	sub POE::Component::Server::REST::DEBUG() { 1 };
	use POE::Component::Server::REST;
	use HTTP::Status qw(:constants);
	use Sys::Hostname;
	use Try::Tiny;

	# This is the POE..REST server
	my $service = 'restservice';
	POE::Component::Server::REST->new(
		'ALIAS'         => $service,
		'ADDRESS'       => '0.0.0.0',
		'PORT'          => 8081,
		'HOSTNAME'      => hostname(),
		'CONTENTTYPE'   => 'text/json',
	);

	# The URI paths mapped to events
	my $methods = {
		'_start'        =>  \&start,
		'_stop'         =>  \&stop,
		'GET/author'     =>  \&get_author,
		'GET/authors'    =>  \&get_authors,
		'GET/author/douglas/adams' => \&get_special,
		'POST/author'    =>  \&add_author,
		'PUT/author'     =>  \&upd_author,
		'DELETE/author'  =>  \&del_author,
	};

	# This is OUR session
	my $name = "library";
	POE::Session->create(
		'inline_states' => $methods
	);

	POE::Kernel->run;
	exit 0;

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

		try {
			# Validate if the request was unmarshalled successfully.
			# Only needed if you are interested in the request body.
			my $body = $response->restbody;
			unless ( $body ) {
				$kernel->post( $service, 'FAULT', $response, HTTP_BAD_REQUEST, "Invalid Request", "Unable to parse your request."  );
				return;
			}

			# Accessing the requests unmarshalled content.
			# This option is optional, be sure to check hash-key  existance before accessing it.
			my $unpopular;
			if ( exists $body->{unpopular} ) {
				$unpopular = $body->{unpopular};
			}

			# If unpopular is true, we inform that we have none.
			if( $unpopular ) {
				$kernel->post( $service, 'FAULT', $response, HTTP_NOT_FOUND, "NotFound", "Sry I dont have any unpopular authors."  );
                return;
			}

			# Build answer
			my $answer = { 
				author => { 
					id => 1, 
					name => FooBar
				}
			};		
		
			# Set answer	
			$response->content($answer);
	
			# Done
			$kernel->post( $service, 'DONE', $response );
			return;
			
		} catch {
			$kernel->post( $service, 'FAULT', $response, HTTP_NOT_FOUND, "Error", $_  );
		};
	}

	sub get_authors { ... }
	sub get_special { ... }
	sub add_author { ... }
	sub upd_author { ... }
	sub del_author { ... }

ABSTRACT

A complete solution kit for REST interfaces.

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 JSON, 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/json',
);

This method will die on error or return success.

ALIAS

This will set the alias for the REST Service Session used in the POE Kernel. This will default to "rest"

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/json (DEFAULT_CONTENT)
text/yaml 
text/xml

Q: Why is JSON supported? I thought this is a pure JavaScript serializing language? A: It's widely spread across web development communities, so alot of stable tools and libraries are available for it. JSON is also the "part" of YAML which is actually used most and therefor the default.

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' = DEFAULT_CONTENT

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 500 )
	- REST Fault String     ( not required -> defaults to 'Fault' )
	- REST Fault Detail     ( not required -> defaults to 'Apllication faulted')
	- REST Fault Actor      ( not required -> defaults to undef)

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' = DEFAULT_CONTENT
	- HTTP Content = marshalled content of whatever type you have instantiated the server with.

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

Ff 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 fromServer::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 REST method that was called
	$response->restbody()                   # The unmarshalled request content, is undef if unmarshalling failed.

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,
}

The only thing left to do is send it off to the DONE event This struct is then beeing marshalled into whatever CONTENTTYPE you have specified.

$kernel->post( 'MyREST', 'DONE', $response );
OR
$kernel->post( 'MyREST', 'DONE', $response, 'Done', 'Successfully terminated your request.' );

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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