Catalyst::Controller::User(Contributed Perl DocumCatalyst::Controller::REST(3)NAMECatalyst::Controller::REST - A RESTful controller
SYNOPSIS
package Foo::Controller::Bar;
use Moose;
use namespace::autoclean;
BEGIN { extends '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
$self->status_ok(
$c,
entity => {
some => 'data',
foo => 'is real bar-y',
},
);
}
# Answer PUT requests to "thing"
sub thing_PUT {
my ( $self, $c ) = @_;
$radiohead = $c->req->data->{radiohead};
$self->status_created(
$c,
location => $c->req->uri,
entity => {
radiohead => $radiohead,
}
);
}
DESCRIPTIONCatalyst::Controller::REST implements a mechanism for building RESTful
services in Catalyst. It does this by extending the normal Catalyst
dispatch mechanism to allow for different subroutines to be called
based on the HTTP Method requested, while also transparently handling
all the serialization/deserialization for you.
This is probably best served by an example. In the above controller,
we have declared a Local Catalyst action on "sub thing", and have used
the ActionClass('REST').
Below, we have declared "thing_GET" and "thing_PUT". Any GET requests
to thing will be dispatched to "thing_GET", while any PUT requests will
be dispatched to "thing_PUT".
Any unimplemented HTTP methods will be met with a "405 Method Not
Allowed" response, automatically containing the proper list of
available methods. You can override this behavior through implementing
a custom "thing_not_implemented" method.
If you do not provide an OPTIONS handler, we will respond to any
OPTIONS requests with a "200 OK", populating the Allowed header
automatically.
Any data included in "$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 "$c->request->body" into the
"$c->request->data" hashref", based on the request's "Content-type"
header. A list of understood serialization formats is below.
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
BEGIN { extends 'Catalyst::Controller::REST' }
CONFIGURATION
See "CONFIGURATION" in Catalyst::Action::Serialize. Note that the
"serialize" key has been deprecated.
SERIALIZATIONCatalyst::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
parameter.
Evaluating the Accept Header
Finally, if the client provided an Accept header, we will evaluate
it and use the best-ranked choice.
AVAILABLE SERIALIZERS
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 its quirks in terms of what sorts of
data structures it will properly handle. Catalyst::Controller::REST
makes no attempt to save 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 usable for Serialization.
· "application/json" => "JSON"
Uses JSON to generate JSON output. It is strongly advised to also
have JSON::XS installed. The "text/x-json" content type is supported
but is deprecated and you will receive warnings in your log.
You can also add a hash in your controller config to pass options to
the json object. For instance, to relax permissions when
deserializing input, add:
__PACKAGE__->config(
json_options => { relaxed => 1 }
)
· "text/javascript" => "JSONP"
If a callback=? parameter is passed, this returns javascript in the
form of: $callback($serializedJSON);
Note - this is disabled by default as it can be a security risk if
you are unaware.
The usual MIME types for this serialization format are:
'text/javascript', 'application/x-javascript',
'application/javascript'.
· "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
output.
· "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 }
· View
Uses a regular Catalyst view. For example, if you wanted to have
your "text/html" and "text/xml" views rendered by TT, set:
__PACKAGE__->config(
map => {
'text/html' => [ 'View', 'TT' ],
'text/xml' => [ 'View', 'XML' ],
}
);
Your views should have a "process" method like this:
sub process {
my ( $self, $c, $stash_key ) = @_;
my $output;
eval {
$output = $self->serialize( $c->stash->{$stash_key} );
};
return $@ if $@;
$c->response->body( $output );
return 1; # important
}
sub serialize {
my ( $self, $data ) = @_;
my $serialized = ... process $data here ...
return $serialized;
}
· Callback
For infinite flexibility, you can provide a callback for the
deserialization/serialization steps.
__PACKAGE__->config(
map => {
'text/xml' => [ 'Callback', { deserialize => \&parse_xml, serialize => \&render_xml } ],
}
);
The "deserialize" callback is passed a string that is the body of the
request and is expected to return a scalar value that results from
the deserialization. The "serialize" callback is passed the data
structure that needs to be serialized and must return a string
suitable for returning in the HTTP response. In addition to
receiving the scalar to act on, both callbacks are passed the
controller object and the context (i.e. $c) as the second and third
arguments.
By default, Catalyst::Controller::REST will return a "415 Unsupported
Media Type" response if an attempt to use an unsupported content-type
is made. You can ensure that something is always returned by setting
the "default" config option:
__PACKAGE__->config(default => 'text/x-yaml');
would make it always fall back to the serializer plugin defined for
"text/x-yaml".
CUSTOM SERIALIZERS
Implementing new Serialization formats is easy! Contributions are most
welcome! If you would like to implement a custom serializer, you
should create two new modules in the Catalyst::Action::Serialize and
Catalyst::Action::Deserialize namespace. Then assign your new class to
the content-type's you want, and you're done.
See Catalyst::Action::Serialize and Catalyst::Action::Deserialize for
more information.
STATUS HELPERS
Since so much of REST is in using HTTP, we provide these Status
Helpers. Using them will ensure that you are responding with the
proper codes, headers, and entities.
These helpers try and conform to the HTTP 1.1 Specification. You can
refer to it at: <http://www.w3.org/Protocols/rfc2616/rfc2616.txt>.
These routines are all implemented as regular subroutines, and as such
require you pass the current context ($c) as the first argument.
status_ok
Returns a "200 OK" response. Takes an "entity" to serialize.
Example:
$self->status_ok(
$c,
entity => {
radiohead => "Is a good band!",
}
);
status_created
Returns a "201 CREATED" response. Takes an "entity" to serialize,
and a "location" where the created object can be found.
Example:
$self->status_created(
$c,
location => $c->req->uri,
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.
status_accepted
Returns a "202 ACCEPTED" response. Takes an "entity" to serialize.
Also takes optional "location" for queue type scenarios.
Example:
$self->status_accepted(
$c,
location => $c->req->uri,
entity => {
status => "queued",
}
);
status_no_content
Returns a "204 NO CONTENT" response.
status_multiple_choices
Returns a "300 MULTIPLE CHOICES" response. Takes an "entity" to
serialize, which should provide list of possible locations. Also
takes optional "location" for preferred choice.
status_found
Returns a "302 FOUND" response. Takes an "entity" to serialize.
Also takes optional "location".
status_bad_request
Returns a "400 BAD REQUEST" response. Takes a "message" argument
as a scalar, which will become the value of "error" in the
serialized response.
Example:
$self->status_bad_request(
$c,
message => "Cannot do what you have asked!",
);
status_forbidden
Returns a "403 FORBIDDEN" response. Takes a "message" argument as
a scalar, which will become the value of "error" in the serialized
response.
Example:
$self->status_forbidden(
$c,
message => "access denied",
);
status_not_found
Returns a "404 NOT FOUND" response. Takes a "message" argument as
a scalar, which will become the value of "error" in the serialized
response.
Example:
$self->status_not_found(
$c,
message => "Cannot find what you were looking for!",
);
gone
Returns a "41O GONE" response. Takes a "message" argument as a
scalar, which will become the value of "error" in the serialized
response.
Example:
$self->status_gone(
$c,
message => "The document have been deleted by foo",
);
MANUAL RESPONSES
If you want to construct your responses yourself, all you need to do is
put the object you want serialized in $c->stash->{'rest'}.
IMPLEMENTATION DETAILS
This Controller ties together Catalyst::Action::REST,
Catalyst::Action::Serialize and Catalyst::Action::Deserialize. It
should be suitable for most applications. You should be aware that it:
Configures the Serialization Actions
This class provides a default configuration for Serialization. It
is currently:
__PACKAGE__->config(
'stash_key' => 'rest',
'map' => {
'text/html' => 'YAML::HTML',
'text/xml' => 'XML::Simple',
'text/x-yaml' => 'YAML',
'application/json' => 'JSON',
'text/x-json' => 'JSON',
'text/x-data-dumper' => [ 'Data::Serializer', 'Data::Dumper' ],
'text/x-data-denter' => [ 'Data::Serializer', 'Data::Denter' ],
'text/x-data-taxi' => [ 'Data::Serializer', 'Data::Taxi' ],
'application/x-storable' => [ 'Data::Serializer', 'Storable' ],
'application/x-freezethaw' => [ 'Data::Serializer', 'FreezeThaw' ],
'text/x-config-general' => [ 'Data::Serializer', 'Config::General' ],
'text/x-php-serialization' => [ 'Data::Serializer', 'PHP::Serialization' ],
},
);
You can read the full set of options for this configuration block
in Catalyst::Action::Serialize.
Sets a "begin" and "end" method for you
The "begin" method uses Catalyst::Action::Deserialize. The "end"
method uses Catalyst::Action::Serialize. If you want to override
either behavior, simply implement your own "begin" and "end"
actions and forward to another action with the Serialize and/or
Deserialize action classes:
package Foo::Controller::Monkey;
use Moose;
use namespace::autoclean;
BEGIN { extends 'Catalyst::Controller::REST' }
sub begin : Private {
my ($self, $c) = @_;
... do things before Deserializing ...
$c->forward('deserialize');
... do things after Deserializing ...
}
sub deserialize : ActionClass('Deserialize') {}
sub end :Private {
my ($self, $c) = @_;
... do things before Serializing ...
$c->forward('serialize');
... do things after Serializing ...
}
sub serialize : ActionClass('Serialize') {}
If you need to deserialize multipart requests (i.e. REST data in
one part and file uploads in others) you can do so by using the
Catalyst::Action::DeserializeMultiPart action class.
A MILD WARNING
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 unnecessarily. :)
SEE ALSO
Catalyst::Action::REST, Catalyst::Action::Serialize,
Catalyst::Action::Deserialize
For help with REST in general:
The HTTP 1.1 Spec is required reading.
http://www.w3.org/Protocols/rfc2616/rfc2616.txt
Wikipedia! http://en.wikipedia.org/wiki/Representational_State_Transfer
The REST Wiki: http://rest.blueoxen.net/cgi-bin/wiki.pl?FrontPage
AUTHORS
See Catalyst::Action::REST for authors.
LICENSE
You may distribute this code under the same terms as Perl itself.
perl v5.14.2 2012-07-02 Catalyst::Controller::REST(3)
