Question

As a total newbie I have been trying to get the geoNear command working in my rails application and it appear to be working fine. The major annoyance for me is that it is returning an array with strings rather than keys which I can call on to pull out data.

Having dug around, I understand that MongoMapper uses Plucky to turn the the query resultant into a friendly object which can be handled easily but I haven’t been able to find out how to transform the result of my geoNear query into a plucky object.

My questions are:
(a) Is it possible to turn this into a plucky object and how do i do that?
(b) If it is not possible how can I most simply and systematically extract each record and each field?

here is the query in my controller

@mult = 3963 * (3.14159265 / 180 ) # Scale to miles on earth
@results = @db.command( {'geoNear' => "places", 'near'=> @search.coordinates , 'distanceMultiplier' => @mult, 'spherical' => true})

Here is the object i’m getting back (with document content removed for simplicity)

{"ns"=>"myapp-development.places", "near"=>"1001110101110101100100110001100010100010000010111010", "results"=>[{"dis"=>0.04356444023196527, "obj"=>{"_id"=>BSON::ObjectId('4ee6a7d210a81f05fe000001'),...}}], "stats"=>{"time"=>0, "btreelocs"=>0, "nscanned"=>1, "objectsLoaded"=>1, "avgDistance"=>0.04356444023196527, "maxDistance"=>0.0006301239824196907}, "ok"=>1.0}

Help is much appreciated!!

Answer 1

Ok so lets say you store the results into a variable called places_near:

places_near = t.command( {'geoNear' => "places", 'near'=> [50,50] , 'distanceMultiplier' => 1, 'spherical' => true})

This command returns an hash that has a key (results) which maps to a list of results for the query. The returned document looks like this:

{
    "ns": "test.places",
    "near": "1100110000001111110000001111110000001111110000001111",
    "results": [
    {
        "dis": 69.29646421910687,
        "obj": {
            "_id": ObjectId("4b8bd6b93b83c574d8760280"),
            "y": [
            1,
            1
            ],
            "category": "Coffee"
        }
    },
    {
        "dis": 69.29646421910687,
        "obj": {
            "_id": ObjectId("4b8bd6b03b83c574d876027f"),
            "y": [
            1,
            1
            ]
        }
    }
    ],
    "stats": {
        "time": 0,
        "btreelocs": 1,
        "btreelocs": 1,
        "nscanned": 2,
        "nscanned": 2,
        "objectsLoaded": 2,
        "objectsLoaded": 2,
        "avgDistance": 69.29646421910687
    },
    "ok": 1
}

To iterate over the responses just iterate as you would over any list in ruby:

places_near['results'].each do |result|
  # do stuff with result object
end