CODEWITHSUNDEEP
phpmongodbaggregation-frameworkphp-mongodb
ugotchi
ugotchi

Reputation: 1013

$limit in mongodb aggregation as an optional parameter?

I have an api with one optional parameter called limit, which takes an integer and limits the number of documents returned from the api in a get request.

Implementing this limit is fine in my PHP application when it is a required parameter, but when its not specified as part of my get request, what is the best way to handle it?

is there for example, a way to define $limit and set it to all documents? (in pseudo code, $limit = none)

$list = $collection->aggregate( array( array('$match' => array( ... )),
  '$project' => array ( ... )), '$limit' => intval($this->limit) ));

$this->limit //this is the optional input parameter

As you can see above, when the limit parameter is required it functions as required. Now when its ommitted, how can I keep the above code but specify no limit?

Upvotes: 4

Views: 1674

Answers (2)

Chin Leung
Chin Leung

Reputation: 14941

You could manually generate your where clause.

// Declare a where clause with your fixed conditions
$whereClause = array(array('$match' => array(...)), array('$project' => array(...)));

// Check if there's a limit
if($this->limit != 0)
    array_push($whereClause, array('$limit' => $this->limit));

// Finally, call with the where clause we've generated above
$list = $collection->aggregate($whereClause);

Upvotes: 2

Sede
Sede

Reputation: 61243

Short answer No!

But, you can use an if/else condition like this:

<?php

if(intval($this->limit) != 0 ) {
    $list = $collection->aggregate( array( 
        array('$match' => array( ... )),
        array('$project' => array ( ... ))
        array('$limit' => intval($this->limit)) 
    );

    ));
} else {
    $list = $collection->aggregate( array( 
        array('$match' => array( ... )),
        array('$project' => array ( ... )), 
    );
}
?>

Upvotes: 1

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