Complex Aggregation Pipelines with Vanilla PHP and MongoDB

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<?php
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require_once __DIR__ . '/vendor/autoload.php';
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use MongoDB\Client;
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use MongoDB\Driver\ServerApi;
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// Replace the placeholder with your Atlas connection string
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$uri = "<your connection string>";
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// Specify Stable API version 1
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$apiVersion = new ServerApi(ServerApi::V1);
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// Create a new client and connect to the server
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$client = new MongoDB\Client($uri, [], ['serverApi' => $apiVersion]);
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try {
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    // Send a ping to confirm a successful connection
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    $client->selectDatabase('admin')->command(['ping' => 1]);
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    echo "Pinged your deployment. You successfully connected to MongoDB!\n";
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} catch (Exception $e) {
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    printf($e->getMessage());
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}
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// We will write all the aggregation examples code from here.

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$> php aggregation.php
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$> Pinged your deployment. You successfully connected to MongoDB!

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<?php
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$commentsCollection = $client->sample_mflix->comments;
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$pipeline = [
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    [
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        '$group' => [
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            '_id' => '$email', // Group by user email
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            'totalComments' => ['$sum' => 1] // Sum the total comments of each user
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        ]
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    ],
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    [
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        '$sort' => ['totalComments' => -1] // Sort by total comments in descending order
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    ],
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    [
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        '$limit' => 5 // Limit the results to the top 5 users
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    ]
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];
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$result = $commentsCollection->aggregate($pipeline);
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$resultArray = $result->toArray();
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echo "<pre>" . print_r($resultArray, true) . "</pre>";

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Pinged your deployment. You successfully connected to MongoDB!
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[
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    {
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        "_id": "roger_ashton-griffiths@gameofthron.es",
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        "totalComments": 277
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    },
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    {
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        "_id": "ron_donachie@gameofthron.es",
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        "totalComments": 260
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    },
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    {
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        "_id": "jonathan_pryce@gameofthron.es",
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        "totalComments": 260
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    },
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    {
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        "_id": "nathalie_emmanuel@gameofthron.es",
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        "totalComments": 258
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    },
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    {
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        "_id": "robert_jordan@fakegmail.com",
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        "totalComments": 257
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    }
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]

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<?php
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$moviesCollection = $client->sample_mflix->movies;
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$pipeline = [
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    [
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        '$match' => [
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            'imdb.rating' => ['$exists' => true] // Ensure that the movie has an IMDb rating
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        ]
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    ],
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    [
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        '$addFields' => [
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            'month' => ['$month' => '$released'], // Extract month from released date
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            'year' => ['$year' => '$released'], // Extract year from released date
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        ]
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    ],
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    [
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        '$group' => [
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            '_id' => [
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                'year' => '$year',
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                'month' => '$month'
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            ],
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            'averageRating' => ['$avg' => '$imdb.rating'] // Calculate the average rating
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        ]
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    ],
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    [
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        '$sort' => [
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            '_id.year' => 1,
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            '_id.month' => 1
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        ]
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    ],
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];
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$result = $moviesCollection->aggregate($pipeline);
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// Convert the result to an array and pretty print
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$resultArray = $result->toArray();
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echo "<pre>" . print_r($resultArray, true) . "</pre>";

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Pinged your deployment. You successfully connected to MongoDB!
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[
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    {
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        "_id": {
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            "year": 1914,
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            "month": 3
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        },
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        "averageRating": 7.6
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    },
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    {
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        "_id": {
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            "year": 1914,
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            "month": 9
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        },
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        "averageRating": 7.3
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    },
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    {
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        "_id": {
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            "year": 1914,
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            "month": 12
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        },
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        "averageRating": 5.8
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    },
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    {
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        "_id": {
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            "year": 1915,
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            "month": 1
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        },
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        "averageRating": 6.4
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    },
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    {
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        "_id": {
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            "year": 1915,
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            "month": 9
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        },
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        "averageRating": 6.8
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    }
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    ...
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]

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<?php
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$moviesCollection = $client->sample_mflix->movies;
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$pipeline = [
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    [
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        '$lookup' => [
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            'from' => 'comments',
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            'localField' => '_id',
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            'foreignField' => 'movie_id',
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            'as' => 'comments'
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        ]
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    ],
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    [
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        '$facet' => [
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            'mostCommentedMovies' => [
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                [
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                    '$project' => [
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                        '_id' => 0,
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                        'title' => 1,
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                        'comment_count' => ['$size' => '$comments']
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                    ]
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                ],
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                [
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                    '$sort' => ['comment_count' => -1]
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                ],
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                [
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                    '$limit' => 5
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                ]
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            ],
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            'mostCommentedGenre' => [
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                [
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                    '$unwind' => '$genres'
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                ],
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                [
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                    '$group' => [
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                        '_id' => '$genres',
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                        'totalComments' => ['$sum' => ['$size' => '$comments']]
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                    ]
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                ],
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                [
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                    '$sort' => ['totalComments' => -1]
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                ],
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                [
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                    '$limit' => 5
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                ]
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            ],
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        ]
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    ]
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];
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$result = $moviesCollection->aggregate($pipeline);
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// Convert the result to an array and pretty print
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$resultArray = $result->toArray();
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echo "<pre>" . print_r($resultArray, true) . "</pre>";

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Pinged your deployment. You successfully connected to MongoDB!
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[{
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    "mostCommentedMovies": [
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        {
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            "title": "The Taking of Pelham 1 2 3",
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            "comment_count": 161
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        },
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        {
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            "title": "Ocean's Eleven",
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            "comment_count": 158
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        },
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        {
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            "title": "About a Boy",
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            "comment_count": 158
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        },
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        {
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            "title": "Terminator Salvation",
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            "comment_count": 158
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        },
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        {
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            "title": "50 First Dates",
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            "comment_count": 158
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        }
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    ],
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    "mostCommentedGenre": [
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        {
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            "_id": "Comedy",
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            "totalComments": 15435
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        },
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        {
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            "_id": "Adventure",
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            "totalComments": 12363
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        },
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        {
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            "_id": "Drama",
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            "totalComments": 12339
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        },
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        {
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            "_id": "Action",
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            "totalComments": 11419
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        },
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        {
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            "_id": "Fantasy",
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            "totalComments": 6955
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        }
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    ]
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}]

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<?php
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$commentsCollection = $client->sample_mflix->comments;
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$pipeline = [
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    ['$lookup' => [
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        'from' => 'movies',
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        'localField' => 'movie_id',
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        'foreignField' => '_id',
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        'as' => 'movie'
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    ]],
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    ['$unwind' => '$movie'],
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    ['$replaceRoot' => ['newRoot' => [
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        'comment_id' => '$_id',
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        'user' => '$name',
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        'movie_id' => '$movie_id',
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        'movie_title' => '$movie.title',
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        'genres' => '$movie.genres',
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        'rating' => '$movie.imdb.rating',
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        'comment' => '$text'
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    ]]],
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    ['$unwind' => '$genres'],
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    ['$group' => [
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        '_id' => [
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            'user' => '$user',
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            'genre' => '$genres'
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        ],
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        'totalComments' => ['$sum' => 1],
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        'averageRating' => ['$avg' => '$rating']
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    ]],
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    ['$group' => [
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        '_id' => '$_id.user',
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        'preferences' => [
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            '$push' => [
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                'genre' => '$_id.genre',
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                'totalComments' => '$totalComments',
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                'averageRating' => ['$round' => ['$avg' => '$averageRating', 2]]
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            ]
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        ],
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        'totalComments' => ['$sum' => '$totalComments']
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    ]],
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    ['$sort' => ['totalComments' => -1]]
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];
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$result = $commentsCollection->aggregate($pipeline);
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// Convert the result to an array and pretty print
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$resultArray = $result->toArray();
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echo "<pre>" . print_r($resultArray, true) . "</pre>";

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<?php
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$commentsCollection = $client->sample_mflix->comments;
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$liveFeedCollection = $client->sample_mflix->live_feed;
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$changeStream = $commentsCollection->watch();
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function sendNotification($comment) {
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    printf("Notification sent for new comment by %s on movie ID %s\n", $comment['name'], $comment['movie_id']);
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}
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function updateLiveFeed($comment, $liveFeedCollection) {
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    $liveFeedDocument = [
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        'user' => $comment['name'],
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        'movie_id' => $comment['movie_id'],
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        'comment' => $comment['text'],
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        'timestamp' => new MongoDB\BSON\UTCDateTime()
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    ];
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    $liveFeedCollection->insertOne($liveFeedDocument);
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    printf("Live feed updated with new comment by %s\n", $comment['name']);
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}
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for ($changeStream->rewind(); true; $changeStream->next()) {
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    if (!$changeStream->valid()) {
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        continue;
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    }
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    $event = $changeStream->current();
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    if ($event['operationType'] === 'invalidate') {
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        break;
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    }
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    if ($event['operationType'] === 'insert') {
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        $newComment = $event['fullDocument'];
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        sendNotification($newComment);
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        updateLiveFeed($newComment, $liveFeedCollection);
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    }
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}