NAME
McBain::WithPSGI - Load a McBain API as a RESTful PSGI web service
SYNOPSIS
# write your API as you normally would, and create
# a simple psgi file:
#!/usr/bin/perl -w
use warnings;
use strict;
use MyAPI -withPSGI;
my $app = MyAPI->to_app;
DESCRIPTION
"McBain::WithPSGI" turns your McBain API into a RESTful PSGI web service
based on Plack, thus making "McBain" a web application framework.
The created web service will be a JSON-in JSON-out service. Requests to
your application are expected to have a "Content-Type" of
"application/json; charset=UTF-8". The JSON body of a request will be
the payload. The results of the API will be formatted into JSON as well.
Note that if an API method does not return a hash-ref, this runner
module will automatically turn it into a hash-ref to ensure that
conversion into JSON will be possible. The created hash-ref will have
one key - holding the method's name, with whatever was returned from the
method as its value. For example, if method "GET:/divide" in topic
"/math" returns an integer (say 7), then the client will get the JSON "{
"GET:/math/divide": 7 }".
SUPPORTED HTTP METHODS
This runner support all methods natively supported by McBain. That is:
"GET", "PUT", "POST", "DELETE" and "OPTIONS". To add support for "HEAD"
requests, use Plack::Middleware::Head.
The "OPTIONS" method is special. It returns a list of all HTTP methods
allowed by a specific route (in the "Allow" header). The response body
will be the same hash-ref returned by "McBain" for "OPTIONS" requests,
JSON encoded.
CAVEATS AND CONSIDERATIONS
The HTTP protocol does not allow "GET" requests to have content, so your
"GET" routes will not be able to receive parameters from a request's
JSON body as all other methods do. If your "GET" routes *must* receive
parameters (for example, you might have a route that returns a list of
objects with support for pagination), "McBain::WithPSGI" supports
parameters from the query string. They will be validated like all
parameters, and they can be used in non-"GET" requests too. Note that
they take precedence over body parameters.
The downside to this is that the parameters cannot be complex
structures, though if the query string defines a certain key several
times, its generated value will be an array reference. For example,
let's look at the following route:
get '/params_from_query' => (
params => {
some_string => { required => 1 },
some_array => { array => 1, min_length => 2 }
},
cb => sub {
my ($api, $params) = @_;
return $params;
}
);
This route isn't particularly interesting, as it simply returns the
parameters it receives. It does, however, enforce the existence of the
"some_string" parameter, and expects "some_array" to be an array
reference of at least 2 items. A request to
"/params_from_query?some_string=this_is_my_string&some_array=Hello&some_
array=World" will yield the following result:
{ "some_string": "this_is_my_string", "some_array": ["Hello", "World"] }
METHODS EXPORTED TO YOUR API
None.
METHODS REQUIRED BY MCBAIN
init( $target )
Makes the root topic of your API inherit Plack::Component, so that it
officially becomes a Plack app. This will provide your API with the
"to_app()" method.
generate_env( $psgi_env )
Receives the PSGI env hash-ref and creates McBain's standard env
hash-ref from it.
generate_res( $env, $res )
Converts the result of an API method to JSON, and returns a standard
PSGI response array-ref.
handle_exception( $err )
Formats exceptions into JSON and returns a standard PSGI array-ref.
CONFIGURATION AND ENVIRONMENT
No configuration files are required.
DEPENDENCIES
"McBain::WithPSGI" depends on the following CPAN modules:
* Carp
* JSON::MaybeXS
* Plack
INCOMPATIBILITIES WITH OTHER MODULES
None reported.
BUGS AND LIMITATIONS
Please report any bugs or feature requests to
"bug-McBain-WithPSGI@rt.cpan.org", or through the web interface at
<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=McBain-WithPSGI>.
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc McBain::WithPSGI
You can also look for information at:
* RT: CPAN's request tracker
<http://rt.cpan.org/NoAuth/Bugs.html?Dist=McBain-WithPSGI>
* AnnoCPAN: Annotated CPAN documentation
<http://annocpan.org/dist/McBain-WithPSGI>
* CPAN Ratings
<http://cpanratings.perl.org/d/McBain-WithPSGI>
* Search CPAN
<http://search.cpan.org/dist/McBain-WithPSGI/>
AUTHOR
Ido Perlmuter <ido@ido50.net>
LICENSE AND COPYRIGHT
Copyright (c) 2013-2015, Ido Perlmuter "ido@ido50.net".
This module is free software; you can redistribute it and/or modify it
under the same terms as Perl itself, either version 5.8.1 or any later
version. See perlartistic and perlgpl.
The full text of the license can be found in the LICENSE file included
with this module.
DISCLAIMER OF WARRANTY
BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH
YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
NECESSARY SERVICING, REPAIR, OR CORRECTION.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE
TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF
SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
DAMAGES.