Mongoose: MongoDB object
modelling for Node.js

Speaker: Yuriy Bogomolov
Solution Engineer at Sitecore Ukraine
@YuriyBogom...
Agenda
1. Short intro: what is Node.js.
2. Main inconveniences of using the native MongoDB driver for Node.js.
3. Mongoose...
1. Intro to Node.js
• Node.js is a server-side JavaScript execution
environment.
• Uses asynchronous event-driven model.
•...
2. Main inconveniences of native MongoDB driver
• No data validation
• No casting during inserts
• No encapsulation
• No r...
3. What is Mongoose
• Object Data Modelling (ODM) for Node.js
• Officially supported by 10gen, Inc.
• Features:
•
•
•
•
•
...
3. Mongoose setup
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost:27017/mycollection');
var Sche...
3. Mongoose features: validation
Simplest validation example: presence
var UserSchema = new Schema({ name: { type: String,...
3. Mongoose features: casting
• Each property is cast to its
mapped SchemaType in the
document, obtained by the query.
• V...
3. Mongoose features: encapsulation
Models can have static methods and instance methods:
PostSchema.statics = {
dropAllPos...
3. Mongoose features: lifecycle management
Models have .pre() and .post() middlewares, which can hook custom
functions to ...
3. Mongoose features: population
Population is the process of automatically replacing the specified paths
in the document ...
3. Mongoose features: query building
Different methods could be stacked one upon the other, but the query
itself will be g...
4. Schema-Driven Design for your applications
• Schemas should match data-access patterns of your
application.
• You shoul...
Useful links
• Node.js GitHub repo: https://github.com/joyent/node
• Mongoose GitHub repo: https://github.com/learnboost/m...
Any questions?

03.03.2014

MongoDB Meetup Dnipropetrovsk

15 /16
MongoDB Meetup Dnipropetrovsk
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Mongoose: MongoDB object modelling for Node.js

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My presentation on first MongoDB User Group in Dnepropetrovsk.

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Mongoose: MongoDB object modelling for Node.js

  1. 1. Mongoose: MongoDB object modelling for Node.js Speaker: Yuriy Bogomolov Solution Engineer at Sitecore Ukraine @YuriyBogomolov | fb.me/yuriy.bogomolov
  2. 2. Agenda 1. Short intro: what is Node.js. 2. Main inconveniences of using the native MongoDB driver for Node.js. 3. Mongoose: what is it and what are its killer features: • • • • • • Validation Casting Encapsulation Middlewares (lifecycle management) Population Query building 4. Schema-Driven Design for your applications. 5. Useful links and Q&A 03.03.2014 MongoDB Meetup Dnipropetrovsk 2 /16
  3. 3. 1. Intro to Node.js • Node.js is a server-side JavaScript execution environment. • Uses asynchronous event-driven model. • Major accent on non-blocking operations for I/O and DB access. • Based on Google’s V8 Engine. • Open-source • Has own package management system — NPM. • Fast, highly scalable, robust environment. 03.03.2014 MongoDB Meetup Dnipropetrovsk 3 /16
  4. 4. 2. Main inconveniences of native MongoDB driver • No data validation • No casting during inserts • No encapsulation • No references (joins) 03.03.2014 MongoDB Meetup Dnipropetrovsk 4 /16
  5. 5. 3. What is Mongoose • Object Data Modelling (ODM) for Node.js • Officially supported by 10gen, Inc. • Features: • • • • • Async and sync validation of models Model casting Object lifecycle management (middlewares) Pseudo-joins! Query builder npm install mongoose 03.03.2014 MongoDB Meetup Dnipropetrovsk 5 /16
  6. 6. 3. Mongoose setup var mongoose = require('mongoose'); mongoose.connect('mongodb://localhost:27017/mycollection'); var Schema = mongoose.Schema; var PostSchema = new Schema({ title: { type: String, required: true }, body: { type: String, required: true }, author: { type: ObjectId, required: true, ref: 'User' }, tags: [String], date: { type: Date, default: Date.now } }); Reference Simplified declaration Default value mongoose.model('Post', PostSchema); 03.03.2014 Validation of presence MongoDB Meetup Dnipropetrovsk 6 /16
  7. 7. 3. Mongoose features: validation Simplest validation example: presence var UserSchema = new Schema({ name: { type: String, required: true } }); var UserSchema = new Schema({ name: { type: String, required: 'Oh snap! Name is required.' } }); Passing validation function: var UserSchema = new Schema({ name: { type: String, validator: validate } }); var validate = function (value) { /*...*/ }; // synchronous validator var validateAsync = function (value, respond) { respond(false); }; // async validator Via .path() API call: UserSchema.path('email').validate(function (email, respond) { var User = mongoose.model('User'); User.find({ email: email }).exec(function (err, users) { return respond(!err && users.length === 0); }); }, 'Such email is already registered'); 03.03.2014 MongoDB Meetup Dnipropetrovsk 7 /16
  8. 8. 3. Mongoose features: casting • Each property is cast to its mapped SchemaType in the document, obtained by the query. • Valid SchemaTypes are: • • • • • • • • String Number Date Buffer Boolean Mixed ObjectId Array 03.03.2014 var PostSchema = new Schema({ _id: ObjectId, // implicitly exists title: { type: String, required: true }, body: { type: String, required: true }, author: { type: ObjectId, required: true, ref: 'User' }, tags: [String], date: { type: Date, default: Date.now }, is_featured: { type: Boolean, default: false } }); MongoDB Meetup Dnipropetrovsk 8 /16
  9. 9. 3. Mongoose features: encapsulation Models can have static methods and instance methods: PostSchema.statics = { dropAllPosts: function (areYouSure) { // drop the posts! } }; 03.03.2014 PostSchema.methods = { addComment: function (user, comment, callback) { // add comment here }, removeComment: function (user, comment, callback) { // remove comment here } }; MongoDB Meetup Dnipropetrovsk 9 /16
  10. 10. 3. Mongoose features: lifecycle management Models have .pre() and .post() middlewares, which can hook custom functions to init, save, validate and remove model methods: schema.pre('save', true, function (next, done) { // calling next kicks off the next middleware in parallel next(); doAsync(done); }); schema.post('save', function (doc) { console.log('%s has been saved', doc._id); }); 03.03.2014 MongoDB Meetup Dnipropetrovsk 10 /16
  11. 11. 3. Mongoose features: population Population is the process of automatically replacing the specified paths in the document with document(s) from other collection(s): PostSchema.statics = { load: function (permalink, callback) { this.findOne({ permalink: permalink }) .populate('author', 'username avatar_url') .populate('comments', 'author body date') .exec(callback); } }; 03.03.2014 MongoDB Meetup Dnipropetrovsk 11 /16
  12. 12. 3. Mongoose features: query building Different methods could be stacked one upon the other, but the query itself will be generated and executed only after .exec(): var options = { perPage: 10, page: 1 }; this.find(criteria) .populate('author', 'username') .sort({'date_published': -1}) .limit(options.perPage) .skip(options.perPage * options.page) .exec(callback); 03.03.2014 MongoDB Meetup Dnipropetrovsk 12 /16
  13. 13. 4. Schema-Driven Design for your applications • Schemas should match data-access patterns of your application. • You should pre-join data where it’s possible (and use Mongoose’s .populate() wisely!). • You have no constraints and transactions — keep that in mind. • Using Mongoose for designing your application’s Schemas is similar to OOP design of your code. 03.03.2014 MongoDB Meetup Dnipropetrovsk 13 /16
  14. 14. Useful links • Node.js GitHub repo: https://github.com/joyent/node • Mongoose GitHub repo: https://github.com/learnboost/mongoose • Mongoose API docs and tutorials: http://mongoosejs.com/ • MongoDB native Node.js driver docs: http://mongodb.github.io/node-mongodb-native/ 03.03.2014 MongoDB Meetup Dnipropetrovsk 14 /16
  15. 15. Any questions? 03.03.2014 MongoDB Meetup Dnipropetrovsk 15 /16
  16. 16. MongoDB Meetup Dnipropetrovsk

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