PHP syntax for Mongo $set order statement - php

Question

I am attempting to update multiple array elements using a PHP version of the query described in how to update sequence number in mongodb safely
Which describes the query:
db.so.update(
{ _id: new ObjectId("4f55e7ba362e2f2a734c92f8")},
{ $set : { 'subs.1.order' : 3, 'subs.2.order' : 2 } }
);
I'm building a query to add an 'order' field to my document
{
"_id": {
"$oid": "5209acfd0de2316335000001"
},
"bookListId": "116ad5af-7cc6-4652-9bb3-aea852e584e8",
"favoriteBook": [
{
"title": "One Favorite Book",
},
{
"title": "Another Favorite Book",
},
{
"title": "A Third Favorite Book",
}
]
}
..and am doing it in PHP with
$criteria = array('bookListId' => $bookListId);
$favoriteBookOrder = array();
for($i=0;$i<sizeof($order);$i++) {
$key = 'favoriteBook.'.($i+1).'.order';
$val = $order[$i];
$favoriteBookOrder[] = array($key=>intval($val));
}
$setFavoriteBookOrder = array('$set' => $favoriteBookOrder);
$collection->update($criteria, $setFavoriteBookOrder);
but this doesn't produce any result because the query doesn't have the correct organization of arrays..
error_log(json_encode($setupdated));
outputs
{"$set":[{"favoriteBook.1.order":2},{"favoriteBook.2.order":1},{"favoriteBook.3.order":3}]}
which if you notice has too many quotes, brackets around the entire array, and curly braces around each item. I believe this is what is causing the error:
"Invalid modifier specified: $set"
What is the correct syntax for building the array in PHP? Thanks!
EDIT
this is the fix
$favoriteBookOrder[] = array($key=>intval($val));
should be
$favoriteBookOrder[$key] = intval($val);
also i removed the +1 from $i because Mongo indexes are 0 based
correct query now
{"$set":{"favoriteBook.0.order":1,"favoriteBook.1.order":2,"favoriteBook.2.order":3}}

Answer 1

To make you query work right you have to change one line:
$favoriteBookOrder[] = array($key=>intval($val));
to
$favoriteBookOrder[$key] = intval($val);
But I think you wont be happy with result, because it will something like this:
"favoriteBook" : {
"0" : { "order" : NumberLong(123) },
"1" : { "order" : NumberLong(321) },
"2" : { "order" : NumberLong(456) }
}
I suggest you rewrite code in this way:
for($i=0;$i<sizeof($order);$i++)
$favoriteBookOrder[$i]['order'] = $order[$i];
$setupdated = array('$set' => ['favoriteBookOrder' => $favoriteBookOrder]);
and you'll get:
"favoriteBookOrder" : [
{ "order" : NumberLong(123) },
{ "order" : NumberLong(321) },
{ "order" : NumberLong(456) }
]
P.S. you can play with $pushAll modificator instead of $set, it could be more suitable for you.