NAME

Plack::Middleware::REST - Route PSGI requests for RESTful web applications

SYNOPSIS

    # $get, $update, $delete, $create, $list, $patch, $app must be PSGI applications
    builder {
        enable 'REST',
            get          => $get,           # GET /{id}
            upsert       => $update,        # PUT /{id}
            delete       => $delete,        # DELETE /{id}
            create       => $create,        # POST /
            list         => $list,          # GET /
            patch        => $patch,         # PATCH /{id}
            head         => 1,              # HEAD /{$id} => $get, HEAD / => $list
            options      => 1,              # support OPTIONS requests
            pass_through => 1,              # pass everything else to $app
            patch_types  => ['text/plain']; # optional accepted patch types
        $app;
    };

DESCRIPTION

Plack::Middleware::REST routes HTTP requests (given in PSGI request format) on the principles of Representational State Transfer (REST). In short, the application manages a set of resources with common base URL, each identified by its URL. One can retrieve, create, update, delete, list, and patch resources based on HTTP request methods.

Let's say an instance of Plack::Middleware::REST is mounted at the base URL http://example.org/item/. The following HTTP request types can be recognized, once they have been assigned:

POST http://example.org/item/: Calls the PSGI application create to create a new resource with URL assigned by the application.
GET http://example.org/item/123: Calls the application get to retrieve an existing resource identified by http://example.org/item/123.
PUT http://example.org/item/123: Calls the PSGI application upsert to either update an existing resource identified by http://example.org/item/123 or to create a new resource with this URL. The application may reject updates and/or creation of new resources, acting like an update or insert method.
DELETE http://example.org/item/123: Calls the PSGI application delete to delete an existing resource identified by http://example.org/item/123.
GET http://example.org/item/: Calls the PSGI application list to get a list of existing resources.
PATCH http://example.org/item/123: Calls the PSGI application patch to update an existing resource identified by http://example.org/item/123. The application may reject updates of resources.
OPTIONS http://example.org/item/: Calls the PSGI application to return the allowed methods for the resource.

Other requests result either result in a PSGI response with error code 405 and a list of possible request types in the Accept header, or the request is passed to the underlying application in the middleware stack, if option pass_through is set.

CONFIGURATION

get

create

upsert

delete

list

patch

The options get, create, upsert, delete, list, patch can be set to PSGI applications to enable the corresponding REST request type. One can also use string aliases, including app to pass the request in the middleware stack:

    builder {
        enable 'REST',
            get          => 'app',   # pass GET requests on resource to $wrapped
            create       => $create, # pass POST to base URL to $create
            upsert       => $update; # pass PUT requests on resources to $update
            pass_through => 0;       # respond other requests with 405
        $wrapped;
    };

head

By default (head => 1) the app configured to get and/or list resources are also assumed to handle HEAD requests. Setting this configuration to 0 will disallow HEAD requests. The special value auto will rewrite HEAD requests with Plack::Middleware::Head.

COPYRIGHT AND LICENSE

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

CONTRIBUTORS

Jakob Voß and Chris Kirke