Querying a MongoDB documents in real-time

Question

I'm building a web application that will work with Big Data. I will mine Twitter data using the Apache Storm, subsequently saving them in a MongoDB database. At same time, this data has to be fetched via Node.js in real time and be sent via socket.io to my front-end. Exist a way to querying MongoDB via Node.js in real time? Thanks.

Answer 1

I am working on a project with mongoDB, I used the mongodb npm module to query the database in real time.

First I get a list of collections which are in my database:

  //My server controller page
    var MongoClient = require('mongodb').MongoClient
    , assert = require('assert');

    exports.getCollections = function(req,res){
        mongoose.connection.db.collectionNames(function(err, names) {
            if (err){ 
               console.log(err)
            } else {
                res.status(200).send({collections: names});
            }
        });
    };

On the front end, I do an Angular ng-repeat to list my collections, then when I click on the collection name, I run the following code:

      MongoClient.connect(url, function (err, db) {
            assert.equal(null, err);
            var collection = db.collection(req.body.collName);
            collection.find({}).limit(req.body.limit).toArray(function (err, docs) {
                if (err) {
                   console.log(err)
                } else {
                    res.status(200).send({r: docs, count: docs.length});
                    db.close();
                }
            })
        });

Here is my client side angular code:

 //get the collection list upon page load
  $http.get('collections')
    .success(function(c){
         $scope.collList = c.collections;
    })
    .error(function(err){
         $scope.error = err;
     });


  //function run when collection is selected
 $scope.doFind = function(coll){            
            $scope.collViewing = coll;
            $http.post('/basicfind',{collName: coll,limit:$scope.limiter})
                .success(function(data){
                  $scope.results = data.r;
                  $scope.countOfResults = data.count;
                })
                .error(function(err){
                    $scope.error = err.message;
                });
        };

Hope that helps, let me know if you need me to share any more code