Responsible Silex controllers

Micro-framework Silex is an excellent wrapper around the Symfony components. It abstracts away a lot of the complexities, so you can get right to the nitty gritty details.

$app = new Application();
$app->get('/foo', function() {
    return new Response('Bar');
});

You can also pull in TwigServiceProvider for an excellent rendering engine to craft your beautiful websites. However, what happens if what you want to show is not a website but formatted data? What if you are building an API?

API responses

I recently bumped into this problem where I first wanted to assemble the data in my controller and then have it formatted to JSON or XML, depending on what was requested.

$app->get('/foo', function(Request $request) {
    $data = assembleData();
    if (/* check if $request supports JSON */) {
        return new Response(
            json_encode('Bar'),
            200,
            ['Content-Type' => 'application/json']
        );
    } elseif (/* check if $request supports XML */) {
        return new Response(
            /* format $data in XML */,
            200,
            ['Content-Type' => 'application/xml']
        );
    }
});

It works, but copying that across every controller makes for some really shitty code. I could of course chuck it into $app['format'] and use that in my controllers but I wanted to take it one step further to free my controllers doing anything other than fetching and assembling data.

The result is ResponsibleServiceProvider!

Automatic response formatting

With ResponsibleServiceProvider all you need to do is return an array. An event listener will then pick that up, check what format has been requested and do the appropriate formatting.

$app->get('/foo', function() {
    return ['Bar'];
});

When a client requests the JSON representation of your data, it will get it.

$ curl -I -H 'Accept: application/json' http://example.com/foo
HTTP/1.1 200 OK
Date: Tue, 07 May 2013 08:30:58 GMT
Server: Apache/2.2.22 (Ubuntu)
X-Powered-By: PHP/5.4.9-4ubuntu2
Cache-Control: no-cache
Transfer-Encoding: chunked
Content-Type: application/json

["Bar"]

And the same goes for XML.

$ curl -I -H 'Accept: application/xml' http://example.com/foo
HTTP/1.1 200 OK
Date: Tue, 07 May 2013 08:30:58 GMT
Server: Apache/2.2.22 (Ubuntu)
X-Powered-By: PHP/5.4.9-4ubuntu2
Cache-Control: no-cache
Transfer-Encoding: chunked
Content-Type: application/xml

<?xml version="1.0"?>
<response><item key="0">Bar</item></response>

ResponsibleServiceProvider is released under the MIT license and all you need to start using it is to fetch the Packagist package.