Add MongoDB adapter for Zend\Cache

[alexdenvir]

Adds a MongoDB adapter for Zend\Cache, along with its own Options class.

Usage is the same as any other adapter - just throw an array of config at StorageFactory::factory() and it will handle the rest.

$config = array(
    'adapter' => array(
        'name'    => 'mongodb',
        'options' => array(
            'libOptions' => array(
                'server' => '',
                'database' => '',
                'collection' => '',
                'options' => array(),
                'driverOptions' => array(),
            ),
            'namespaceSeparator' => '',
            'resourceId' => ''
        ),
    ),
);

The libOptions for collection, server and database are required. server will most likely look something like mongodb://localhost. database and collection should be used to define the name of the MongoDB database and collection to use for the cache (Mongo will create these on first use if they do not exist).
libOptions->options is passed to Mongo|MongoClient's __construct as the options parameter - so you can set fsync, write concern, username, password etc here. libOptions->driverOptions is also passed as the third parameter - these are generally used for connection context settings or logging callbacks. See http://www.php.net/manual/en/mongoclient.construct.php for all options

Tests are included following the example of the existing adapter test cases

[Ocramius]

Is this public setter needed?

[alexdenvir]

Technically, no. This could get away with using the parents public setter instead. However this would mean the options object would not be an instance of MongoDBOptions.

I could drop the MongoDBOptions altogether, but I'm not a fan of the magic __get and __set functions. However I will go with whatever is required on this

[Ocramius]

It's fine, didn't know there was a setter in the parent class.

[moderndeveloperllc]

I would be a little leary of trying to instantiate a Mongo connection here. I'm thinking it should be injected. The SessionHandler for Mongo injects an instance and checks that it's Mongo or MongoClient. Unless I'm missing it somewhere, ZF2 can still support older Mongo extensions that do not include MongoClient.

[alexdenvir]

This is a fair point.
The first problem I can see with injecting Mongo/MongoClient in is that it would not quite work well with StorageFactory::factory without modification - but it can be done I think.

On the same trail of thought, I'm also considering adding https://github.com/mongofill/mongofill as a recommends in composer.json, as this is a pure php implementation that should supposedly work as a drop in replacement for the Mongo extension where the Mongo extension isn't/cannot be installed. If its also added as a require-dev, it allows us to test this code on Travis again (its not currently tested because it completely halts the test run under hhvm - even if hhvm isn't fully supported yet completely breaking it is not something I want to do).

So, I'll take a look at adding some kind of factory for Mongo that will provide an instance of Mongo or MongoClient depending on whats available, and update both this and the SessionHandler to use that. Sound good?

[marc-mabe]

This should be done on an own MongoDbResourceManager similar to Memcache[d]ResourceManager and RedisResourceManager

[samsonasik]

no new blank line after <?php for consistency with other files.

[marc-mabe]

Great additional feature and most of my notes should be simple do fix 👍

I'm missing changes to composer.json and the method internalGetCapabilities isn't overwritten - please contact me if you need help do define capabilities.

Also I think MongoCollection::drop() could be used to implement FlushableInterface and on creating a new colletion the key should be indexed. That do you think?

[marc-mabe]

This setter looks like not a good idea to as it modifies the internal data structure of the $resource array.
It would be better to define different setter to define each of the possible configurations:

• setCollectionName
• setDatabaseName
• setDriverOptions
• setConnectionOptions (this will be the second argument of MongoClient - It's named optins in php.net but documented as An array of options for the connection)
• setServer

[marc-mabe]

@alexdenvir Please update the resource manager and review/explain return false of simple operations. By default the storage adapter should throw exceptions in cases of an error and only return false in cases of not executed operations (like removing an not existing item)

[marc-mabe]

@alexdenvir ping - last chance to go into 2.4 I think

[Ocramius]

Should not prefix with \.

[Ocramius]

I rebased, merged and cleaned up some CS issues in the PR in d24ef90

Thanks @alexdenvir and @marc-mabe!