A node.js module for mongodb, that emulates the official mongodb API as much as possible. It wraps mongodb-native and is available through npm
npm install mongojs
mongojs is easy to use:
var mongojs = require('mongojs');
var db = mongojs(connectionString, [collections]);The connection string should follow the format desribed in the mongo connection string docs. Some examples of this could be:
// simple usage for a local db
var db = mongojs('mydb', ['mycollection']);
// the db is on a remote server (the port default to mongo)
var db = mongojs('example.com/mydb', ['mycollection']);
// we can also provide some credentials
var db = mongojs('username:[email protected]/mydb', ['mycollection']);
// connect now, and worry about collections later
var db = mongojs('mydb');
var mycollection = db.collection('mycollection');After we connected we can query or update the database just how we would using the mongo API with the exception that we use a callback
The format for callbacks is always callback(error, value) where error is null if no exception has occured.
// find everything
db.mycollection.find(function(err, docs) {
// docs is an array of all the documents in mycollection
});
// find everything, but sort by name
db.mycollection.find().sort({name:1}, function(err, docs) {
// docs is now a sorted array
});
// iterate over all whose level is greater than 90.
db.mycollection.find({level:{$gt:90}}).forEach(function(err, doc) {
if (!doc) {
// we visited all docs in the collection
return;
}
// doc is a document in the collection
});
// find all named 'mathias' and increment their level
db.mycollection.update({name:'mathias'}, {$inc:{level:1}}, {multi:true}, function() {
// the update is complete
});
// find one named 'mathias', tag him as a contributor and return the modified doc
db.mycollection.findAndModify({
query: { name: 'mathias' },
update: { $set: { tag:'maintainer' } },
new: true
}, function(err, doc) {
// doc.tag === 'maintainer'
});
// use the save function to just save a document (callback is optional for all writes)
db.mycollection.save({created:'just now'});If you provide a callback to find or any cursor config operation mongojs will call toArray for you
db.mycollection.find({}, function(err, docs) { ... });
db.mycollection.find({}).limit(2).skip(1, function(err, docs) { ... });is the same as
db.mycollection.find({}).toArray(function(err, docs) { ... });
db.mycollection.find({}).limit(2).skip(1).toArray(function(err, docs) { ... });For more detailed information about the different usages of update and quering see the mongo docs
As of 0.7.0 all cursors are a readable stream of objects.
var JSONStream = require('JSONStream');
// pipe all documents in mycollection to stdout
db.mycollection.find({}).pipe(JSONStream.stringify()).pipe(process.stdout);Notice that you should pipe the cursor through a stringifier (like JSONStream) if you want to pipe it to a serial stream like a http response.
If you are using a capped collection you can create a tailable cursor to that collection by adding tailable:true to the find options
var cursor = db.mycollection.find({}, {}, {tailable:true, timeout:false});
// since all cursors are streams we can just listen for data
cursor.on('data', function(doc) {
console.log('new document', doc);
});Note that you need to explicitly set the selection parameter in the find call.
With mongojs you can run database commands just like with the mongo shell using db.runCommand()
db.runCommand({ping:1}, function(err, result) {
if(!err && result.ok) console.log("we're up");
});or db.collection.runCommand()
db.things.runCommand('count', function(err, res) {
console.log(res);
});Mongojs can also connect to a mongo replication set by providing a connection string with multiple hosts
var db = mongojs('rs-1.com,rs-2.com,rs-3.com/mydb?slaveOk=true', ['mycollection']);For more detailed information about replica sets see the mongo replication docs