Mongoose is a MongoDB object modeling tool designed to work in an asychronous environment.
Defining a model is as easy as:
var Comments = new Schema({
title : String
, body : String
, date : Date
});
var BlogPost = new Schema({
author : ObjectId
, title : String
, body : String
, date : Date
, comments : [Comments]
, meta : {
votes : Number
, favs : Number
}
});
mongoose.model('BlogPost', BlogPost);
The recommended way is through the excellent NPM:
$ npm install mongoose
Otherwise, you can check it in your repository and then expose it:
$ git clone [email protected]:LearnBoost/mongoose.git support/mongoose/
// in your code
require.paths.unshift('support/mongoose/lib')
Then you can require it:
require('mongoose')
First, we need to define a connection. If your app uses only one database, you
should use mongose.connect
. If you need to create additional connections, use
mongoose.createConnection
.
Both connect
and createConnection
take a mongodb://
URI, or the parameters
host, database, port
.
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/my_database');
Once connected, the open
event is fired on the Connection
instance. If
you're using mongoose.connect
, the Connection
is mongoose.connection
.
Otherwise, mongoose.createConnection
return value is a Connection
.
Important! Mongoose buffers all the commands until it's connected to the database. This means that you don't have to wait until it connects to MongoDB in order to define models, run queries, etc.
Models are defined through the Schema
interface.
var Schema = mongoose.Schema
, ObjectId = Schema.ObjectId;
var BlogPost = new Schema({
author : ObjectId
, title : String
, body : String
, date : Date
});
Aside from defining the structure of your documents and the types of data you're storing, a Schema handles the definition of:
- Validators (async and sync)
- Defaults
- Getters
- Setters
- Indexes
- Middleware
- Methods definition
- Statics definition
- Plugins
The following example shows some of these features:
var Comment = new Schema({
name : { type: String, default: 'hahaha' }
, age : { type: Number, min: 18, index: true }
, bio : { type: String, match: /[a-z]/ }
, date : { type: Date, default: Date.now }
});
// a setter
Comment.path('name').set(function (v) {
return v.capitalize();
});
// middleware
Comment.pre('save', function (next) {
notify(this.get('email'));
next();
});
Take a look at the example in examples/schema.js
for an end-to-end example of
(almost) all the functionality available.
Once we define a model through mongoose.model('ModelName', mySchema)
, we can
access it through the same function
var myModel = mongoose.model('ModelName');
We can then instantiate it, and save it:
var instance = new myModel();
myModel.my.key = 'hello';
myModel.save(function (err) {
//
});
Or we can find documents from the same collection
myModel.find({}, function (err, docs) {
// docs.forEach
});
You can also findOne
, findById
, update
, etc. For more details check out
the API docs.
In the first example snippet, we defined a key in the Schema that looks like:
comments: [Comments]
Where Comments
is a Schema
we created. This means that creating embedded
documents is as simple as:
// retrieve my model
var BlogPost = mongoose.model('BlogPost');
// create a blog post
var post = new BlogPost();
// create a comment
post.comments.push({ title: 'My comment' });
post.save(function (err) {
if (!err) console.log('Success!');
});
The same goes for removing them:
BlogPost.findById(myId, function (err, post) {
if (!err) {
post.comments[0].remove();
post.save(function (err) {
// do something
});
}
});
Embedded documents enjoy all the same features as your models. Defaults,
validators, middleware. Whenever an error occurs, it's bubbled to the save()
error callback, so error handling is a snap!
Mongoose interacts with your embedded documents in arrays atomically, out of the box.
Middleware is one of the most exciting features about Mongoose 1.0. Middleware takes away all the pain of nested callbacks.
Middleware are defined at the Schema level and are applied when the methods
init
(when a document is initialized with data from MongoDB), save
(when
a document or embedded document is saved).
There's two types of middleware, determined by the signature of the function you define (ie: the parameters your function accepts):
-
Serial Serial middleware are defined like:
.pre(method, function (next) { // ... })
They're executed one after the other, when each middleware calls
next
. -
Parallel Parallel middleware offer more fine-grained flow control, and are defined like
.pre(method, function (next, done) { // ... })
Parallel middleware can
next()
immediately, but the final argument will be called when all the parallel middleware have calleddone()
.
If any middleware calls next
or done
with an Error
instance, the flow is
interrupted, and the error is passed to the function passed as an argument.
For example:
schema.pre('save', function (next) {
// something goes wrong
next(new Error('something went wrong'));
});
// later...
myModel.save(function (err) {
// err can come from a middleware
});
You can find the Dox generated API docs at http://mongoosejs.com.
Please subscribe to the Google Groups mailing list.
Make a fork of mongoose
, then clone it in your computer. The master
branch
contains the current stable release, and the develop
branch the next upcoming
major release.
If master
is at 1.0
, develop
will contain the upcoming 1.1
(or 2.0
if
the 1
branch is nearing its completion).
- Please write inline documentation for new methods or class members.
- Please write tests and make sure your tests pass.
- Before starting to write code, look for existing tickets or create one for your specifc issue (unless you're addressing something that's clearly broken). That way you avoid working on something that might not be of interest or that has been addressed already in a different branch.
- Guillermo Rauch - [email protected] - Guille
- Nathan White - nw
- Brian Noguchi - bnoguchi
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