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Catalyst::Controller::REST - A RESTful controller
package Foo::Controller::Bar;
use base 'Catalyst::Controller::REST';
sub thing : Local : ActionClass('REST') { }
# Answer GET requests to "thing"
sub thing_GET {
my ( $self, $c ) = @_;
# Return a 200 OK, with the data in entity
# serialized in the body
entity => {
some => 'data',
foo => 'is real bar-y',
# Answer PUT requests to "thing"
sub thing_PUT {
.. some action ..
Catalyst::Controller::REST implements a mechanism for building RESTful
services in Catalyst. It does this by extending the normal Catalyst
dispatch mechanism to allow for different subroutines to be called based
on the HTTP Method requested, while also transparently handling all the
serialization/deserialization for you.
This is probably best served by an example. In the above controller, we
have declared a Local Catalyst action on "sub thing", and have used the
Below, we have declared "thing_GET" and "thing_PUT". Any GET requests to
thing will be dispatched to "thing_GET", while any PUT requests will be
dispatched to "thing_PUT".
Any unimplemented HTTP methods will be met with a "405 Method Not
Allowed" response, automatically containing the proper list of available
methods. You can override this behavior through implementing a custom
"thing_not_implemented" method.
If you do not provide an OPTIONS handler, we will respond to any OPTIONS
requests with a "200 OK", populating the Allowed header automatically.
Any data included in "$c->stash->{'rest'}" will be serialized for you.
The serialization format will be selected based on the content-type of
the incoming request. It is probably easier to use the "STATUS HELPERS",
which are described below.
The HTTP POST, PUT, and OPTIONS methods will all automatically
deserialize the contents of $c->request->body based on the requests
content-type header. A list of understood serialization formats is
If we do not have (or cannot run) a serializer for a given content-type,
a 415 "Unsupported Media Type" error is generated.
To make your Controller RESTful, simply have it
use base 'Catalyst::Controller::REST';
Catalyst::Controller::REST will automatically serialize your responses,
and deserialize any POST, PUT or OPTIONS requests. It evaluates which
serializer to use by mapping a content-type to a Serialization module.
We select the content-type based on:
The Content-Type Header
If the incoming HTTP Request had a Content-Type header set, we will
use it.
The content-type Query Parameter
If this is a GET request, you can supply a content-type query
Evaluating the Accept Header
Finally, if the client provided an Accept header, we will evaluate it
and use the best-ranked choice.
A given serialization mechanism is only available if you have the
underlying modules installed. For example, you can't use XML::Simple if
it's not already installed.
In addition, each serializer has it's quirks in terms of what sorts of
data structures it will properly handle. Catalyst::Controller::REST
makes no attempt to svae you from yourself in this regard. :)
"text/x-yaml" => "YAML::Syck"
Returns YAML generated by YAML::Syck.
"text/html" => "YAML::HTML"
This uses YAML::Syck and URI::Find to generate YAML with all URLs
turned to hyperlinks. Only useable for Serialization.
"text/x-json" => "JSON::Syck"
Uses JSON::Syck to generate JSON output
"text/x-data-dumper" => "Data::Serializer"
Uses the Data::Serializer module to generate Data::Dumper output.
"text/x-data-denter" => "Data::Serializer"
Uses the Data::Serializer module to generate Data::Denter output.
"text/x-data-taxi" => "Data::Serializer"
Uses the Data::Serializer module to generate Data::Taxi output.
"application/x-storable" => "Data::Serializer"
Uses the Data::Serializer module to generate Storable output.
"application/x-freezethaw" => "Data::Serializer"
Uses the Data::Serializer module to generate FreezeThaw output.
"text/x-config-general" => "Data::Serializer"
Uses the Data::Serializer module to generate Config::General output.
"text/x-php-serialization" => "Data::Serializer"
Uses the Data::Serializer module to generate PHP::Serialization
"text/xml" => "XML::Simple"
Uses XML::Simple to generate XML output. This is probably not suitable
for any real heavy XML work. Due to XML::Simples requirement that the
data you serialize be a HASHREF, we transform outgoing data to be in
the form of:
{ data => $yourdata }
Uses a regular Catalyst view. For example, if you wanted to have your
"text/html" and "text/xml" views rendered by TT:
'text/html' => [ 'View', 'TT' ],
'text/xml' => [ 'View', 'XML' ],
Will do the trick nicely.
By default, Catalyst::Controller::REST will return a "415 Unsupported
Media Type" response if an attempt to use an unsupported content-type is
made. You can ensure that something is always returned by setting the
"default" config option:
__PACKAGE__->config->{'serialize'}->{'default'} = 'text/x-yaml';
Would make it always fall back to the serializer plugin defined for
Implementing new Serialization formats is easy! Contributions are most
welcome! See Catalyst::Action::Serialize and
Catalyst::Action::Deserialize for more information.
If you would like to implement a custom serializer, you should create
two new modules in the Catalyst::Action::Serialize and
Catalyst::Action::Deserialize namespace. Then assign your new class to
the content-type's you want, and you're done.
Since so much of REST is in using HTTP, we provide these Status Helpers.
Using them will ensure that you are responding with the proper codes,
headers, and entities.
These helpers try and conform to the HTTP 1.1 Specification. You can
refer to it at: <>. These
routines are all implemented as regular subroutines, and as such require
you pass the current context ($c) as the first argument.
Returns a "200 OK" response. Takes an "entity" to serialize.
entity => {
radiohead => "Is a good band!",
Returns a "201 CREATED" response. Takes an "entity" to serialize,
and a "location" where the created object can be found.
location => $c->req->uri->as_string,
entity => {
radiohead => "Is a good band!",
In the above example, we use the requested URI as our location. This
is probably what you want for most PUT requests.
Returns a "202 ACCEPTED" response. Takes an "entity" to serialize.
entity => {
status => "queued",
Returns a "400 BAD REQUEST" response. Takes a "message" argument as
a scalar, which will become the value of "error" in the serialized
message => "Cannot do what you have asked!",
Returns a "404 NOT FOUND" response. Takes a "message" argument as a
scalar, which will become the value of "error" in the serialized
message => "Cannot find what you were looking for!",
If you want to construct your responses yourself, all you need to do is
put the object you want serialized in $c->stash->{'rest'}.
This Controller ties together Catalyst::Action::REST,
Catalyst::Action::Serialize and Catalyst::Action::Deserialize. It should
be suitable for most applications. You should be aware that it:
Configures the Serialization Actions
This class provides a default configuration for Serialization. It is
serialize => {
'stash_key' => 'rest',
'map' => {
'text/html' => 'YAML::HTML',
'text/xml' => 'XML::Simple',
'text/x-yaml' => 'YAML',
'text/x-json' => 'JSON',
'text/x-data-dumper' => [ 'Data::Serializer', 'Data::Dumper' ],
'text/x-data-denter' => [ 'Data::Serializer', 'Data::Denter' ],
'text/x-data-taxi' => [ 'Data::Serializer', 'Data::Taxi' ],
'application/x-storable' => [ 'Data::Serializer', 'Storable'
'application/x-freezethaw' => [ 'Data::Serializer', 'FreezeThaw'
'text/x-config-general' => [ 'Data::Serializer', 'Config::General' ]
'text/x-php-serialization' => [ 'Data::Serializer', 'PHP::Serialization' ],
You can read the full set of options for this configuration block in
Sets a "begin" and "end" method for you
The "begin" method uses Catalyst::Action::Deserialize. The "end"
method uses Catalyst::Action::Serialize. If you want to override
either behavior, simply implement your own "begin" and "end" actions
and use NEXT:
my Foo::Controller::Monkey;
use base qw(Catalyst::Controller::REST);
sub begin :Private {
my ($self, $c) = @_;
... do things before Deserializing ...
... do things after Deserializing ...
sub end :Private {
my ($self, $c) = @_;
... do things before Serializing ...
... do things after Serializing ...
I have code in production using Catalyst::Controller::REST. That
said, it is still under development, and it's possible that things
may change between releases. I promise to not break things
unneccesarily. :)
Catalyst::Action::REST, Catalyst::Action::Serialize,
For help with REST in general:
The HTTP 1.1 Spec is required reading.
The REST Wiki:
Adam Jacob <>, with lots of help from mst and
Marchex, Inc. paid me while I developed this module.
You may distribute this code under the same terms as Perl itself.
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