After the initial extension set-up, we will continue explaining how to get
started with the 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 used MongoDB drivers in other languages, the library's API
should look familiar. It contains a
» Client
class for connecting to MongoDB, a
» 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).
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()}'";
?>
Since the inserted document did not contain an _id
field, the
extension will generate an MongoDB\BSON\ObjectId for
the server to use as the _id
. This value is also made available
to the caller via the result object returned by the insertOne
method.
After insertion, you can query for 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 special classes in the library by default. These classes
extend ArrayObject for usability and implement the
extension's MongoDB\BSON\Serializable and
MongoDB\BSON\Unserializable interfaces to
ensure that values preserve their type when serialized back into BSON. This
avoids a caveat in the legacy mongo
extension where arrays
might turn into documents, and vice versa. See the
Persisting Data specification for more information on
how values are converted between PHP and BSON.