mongo $where returning everything

Question

I am trying to find the documents in the database between specifit date ranges.

 var event = {
            to : 1393454361,
            from : 1393354361
};

I have event.from and event.to as unix time integers and am using this to try and only return events, that are between the two date ranges:

db.events.find({
  "event": "test",
  "message.tableid": 123,
  $where: function () { 
    return ( 
      (event.from - this._id.getTimestamp()) > (event.from - event.to) 
    )  
  }
}).sort(
  { "message.time": -1 }
).forEach(function(error, x) {
  if (error || !x) {
    console.log("error getting items");
    console.log("Current HPH in this range:");
    console.log(hph);
  } else {
    console.log(
      "Calc: ", 
      (event.from - x._id.getTimestamp() > (event.from - event.to))
    );
    if (event.from - x._id.getTimestamp() > (event.from - event.to)) {
      hph = hph + 1;
    }
  }
})

For some reason, if I use an if to check whether the date is between the ranges, it works.
But when I move my statement to the $where-clause, all documents get returned.

I just a bunch of documents in the collection that look like so:

{
"_id" : ObjectId("530cd8d610d28ebc27951eb8"),
"event" : "test",
"message" : {
    "tableid" : 123
}
}

{
"_id" : ObjectId("530cd8d610d28ebc27952fb8"),
"event" : "test",
"message" : {
    "tableid" : 123
}
}

Any ideas>?

If I try and use this as the $where to check for the last 24 hours it works fine:

 $where: function () {
     return Date.now() - this._id.getTimestamp() < (1 * 60 * 60 * 1000)  
 }

Answer 1

You are not providing valid JSON. The mongo shell is very forgiving, other things are not.

 db.events.find({ 
     "$where": 
         "function () {
             return Date.now() - this._id.getTimestamp() < (1 * 60 * 60 * 1000) 
         }" 
  }, function(err, result) {

    // test err and process result

  });

Since it's not valid, the condition means nothing. Equivalent to {} in the .find().

Also, Try and re-factor to not use $where. You just threw away your index usage and forced a full table scan.

And as mentioned in comments, your long routing logic that can be simplified.

Answer 2

Instead of using an if statement or a where clause try using the $gte and $lt operators in the query. Read this article: http://cookbook.mongodb.org/patterns/date_range/