Using the PHP Library for MongoDB (PHPLIB)

After the initial driver set-up, we will continue explaining how to get started with the MongoDB driver and corresponding userland library to write our first project.

Installing the PHP Library with Composer

The last thing we still need to install to get started on the application itself, is the PHP library.

The library needs to be installed with » Composer, a package manager for PHP. Instructions for installing Composer on various platforms may be found on its website.

Install the library by running:

$ composer require mongodb/mongodb

It will output something akin to:

./composer.json has been created
Loading composer repositories with package information
Updating dependencies (including require-dev)
  - Installing mongodb/mongodb (1.0.0)
    Downloading: 100%         

Writing lock file
Generating autoload files

Composer will create several files: composer.json, composer.lock, and a vendor directory that will contain the library and any other dependencies your project might require.

Using the PHP Library

In addition to managing your dependencies, Composer will also provide you with an autoloader (for those dependencies' classes). Ensure that it is included at the start of your script or in your application's bootstrap code:


<?php
// This path should point to Composer's autoloader
require 'vendor/autoload.php';

With this done, you can now use any of the functionality as described in the » library documentation.

If you have previously used the old driver (i.e. mongo extension), the library's API should look familiar. It contains a » Client class for connecting to MongoDB, and » Database class for database-level operations (e.g. commands, collection management) and a » Collection class for collection-level operations (e.g. » CRUD methods, index management). Various Collection methods have been renamed for clarity, and to be in accordance with a new language-agnostic » specification.

As an example, this is how you insert a document into the beers collection of the demo database:


<?php
require 'vendor/autoload.php'; // include Composer's autoloader

$client = new MongoDB\Client("mongodb://localhost:27017");
$collection = $client->demo->beers;

$result = $collection->insertOne( [ 'name' => 'Hinterland', 'brewery' => 'BrewDog' ] );

echo "Inserted with Object ID '{$result->getInsertedId()}'";
?>

Instead of injecting the generated _id field into the input document (as was done in the old driver), it is now made available through the result object returned by the insertOne method.

After insertion, you can of course also query the data that you have just inserted. For that, you use the find method, which returns an iterable cursor:


<?php
require 'vendor/autoload.php'; // include Composer's autoloader

$client = new MongoDB\Client("mongodb://localhost:27017");
$collection = $client->demo->beers;

$result = $collection->find( [ 'name' => 'Hinterland', 'brewery' => 'BrewDog' ] );

foreach ($result as $entry) {
    echo $entry['_id'], ': ', $entry['name'], "\n";
}
?>

While it may not be apparent in the examples, BSON documents and arrays are unserialized as type classes in the library by default. These classes ensure that values preserve their type when being serialized back into BSON, which avoids a caveat in the old driver where arrays might turn into documents, and vice versa. Additionally, the classes extend ArrayObject for enhanced usability. You can find more information on how serialization and deserialization between PHP variables and BSON is handled by the driver and library by reading the Persisting Data specification.