A framework to keep you Ember.js apps in sync.
npm install epfEmber.js Persistence Foundation (epf) is a robust and stable framework for syncing client state with a persistent backend such as a REST API or socket connection. Defining characteristic of epf include:
* Correctness is paramount. All other features, including performance, are important, but secondary.
* Built around synchronization. Models are never locked and framework semantics assume updates are always coming in from a backend.
* Full support for relationships. Related models can be saved concurrently and the framework will automatically order requests around foreign key dependencies.
* Robust handling of conflicts and errors.
* Forking models is first-class within the framework.
* All operations are structured around javascript promises.
Epf is a functional alternative to ember-data and is used in production at GroupTalent with dozens of inter-related models.
For now, as epf is in development, follow the development instructions to use epf. The build-browser command will create browser-compatible distributables in the dist folder. Include epf.js in the page after ember.js.
By default, epf assumes that the backend is a REST api.
All models within epf are subclasses of Ep.Model. For example:
``
App.Post = Ep.Model.extend({
title: Ep.attr('string'),
body: Ep.attr('string'),
comments: Ep.hasMany(App.Comment),
user: Ep.belongsTo(App.User)
});
`
The primary means of interacting with epf is through a session. Epf automatically injects a primary session into all routes and controllers. To load data, you can use the load method on the session:
`
App.PostRoute = Ember.Route.extend({
model: function(params) {
return this.session.load('post', params.post_id);
}
});
`
For compatibility with the behavior of the Ember.js router, a find method is also placed on models. The above code is equivalent to:
`
App.PostRoute = Ember.Route.extend({
model: function(params) {
return App.Post.find(params.post_id);
}
});
`
The find method is the only method that is available on the models themselves and it is recommended to go through the session directly.
By default, Ember.js will automatically call the find method, so the above route can actually be simplified to:
`
App.PostRoute = Ember.Route.extend({
// no model method required, Ember.js will automatically call on App.Post
});
The session object also has other methods for finding data such as query.
To mutate models, simply modify their properties:
`
post.title = 'updated title';
To persist changes to the backend, simply call the flush method on the session object.
`
post.title = 'updated title';
session.flush();
In epf, most things are promises. In the above example you could listen for when the flush has completed using the promise API:
`
post.title = 'updated title';
session.flush().then(function(models) {
// this will be reached if the flush is successful
}, function(models) {
// this will be reached only if there are errors
});
Sessions can be flushed at any point (even if other flushes are pending) and re-trying errors is as simple as performing another flush:
`
post.title = 'updated title';
session.flush().then(null, function() {
// the reject promise callback will be invoked on error
});
// do something here that should correct the error (e.g. fix validations)
session.flush(); // flush again
`
Models also have an errors property which will be populated when the backend returns errors.
Changes can be isolated easily using child sessions:
`
var post = session.load(App.Post, 1);
var childSession = session.newSession(); // this creates a "child" session
var childPost = childSession.load(App.Post, 1); // this record instance is separate from its corresponding instance in the parent session
post === childPost; // returns false, they are separate instances
post.isEqual(childPost); // this will return true
childPost.title = 'something'; // this will not affect post
childSession.flush(); // this will flush changes both to the backend and the parent session, at this point post will have its title updated to reflect childPost
To build epf, follow the instructions below:
* Install node.
* git clone https://github.com/GroupTalent/epf
*
*
* Tests are run via
* To build a browser distributable, run the