Reactive API extensions for Feathers
feathers-reactive adds a watch() method to services. The returned object implements all service methods as RxJS observables that automatically update on real-time events.
If you're upgrading from 0.4 and below this is going to totally break your setup. Sorry for that! Let's get you back on track:
0.4:
const reactive = require('feathers-reactive');
const Rx = require('rxjs');
// ...
app.configure(reactive(Rx, { ...options }));0.5:
const reactive = require('feathers-reactive');
const Rx = require('rxjs');
// ...
app.configure(reactive({ idField: 'id' /* depends on your DB */ , ...options }));No need to import the entire RxJS bundle and pass it to feathers-reactive any longer. However, idField has become a mandatory option. Check the Options section below.
This is where 0.5's .watch() method comes into play. Depending on your configuration, with 0.4 and lower your service calls could return either an Observable or a Promise. As of 0.5 the plain service call remains a Promise at all times:
0.4:
app.service('myService').get(someId);0.5:
app.service('myService').get(someId); // This always returns a Promise
app.service('myService').watch().get(someId); // This always returns an ObservableYou can pass service call level options into the .watch() function now. This isn't breaking though, as using options.rx is equivalent.
0.4:
app.service('myService').get(someId, {rx: { strategy: 'always' }});0.5:
app.service('myService').watch({ strategy: 'always' }).get(someId); // 0.5 syntax
app.service('myService').watch().get(someId, {rx: { strategy: 'always' }}); // still functional 0.4 syntax.Unless you configured lazy: true in 0.4's options, 0.4's Observables would be always hot, i.e. show Promise-like behavior. This is no longer the case! Observables returned by .watch().<method>() are always cold! Example:
// this service call will not be executed!
app.service('myService').watch().create(someObject);
// unless you subscribe:
app.service('myService').watch().create(someObject).subscribe(result => console.log(result));If you just want to fire-and-forget (i.e., you don't care about the result) use the non-observable service call.
The following options are supported:
idField(mandatory): The id property field of your services. Depends on your service/database. Usually 'id' (SQL, Rethinkdb, …) or '_id' (MongoDB, NeDB, … ).dataField(default:data): The data property field in paginated responseslistStrategy(default:smart): The strategy to use for streaming the data. Can besmart,alwaysorneversorter(function(query, options) {}): A function that returns a sorting function for the given query and option including pagination and limiting. Does not need to be customized unless there is a sorting mechanism other than Feathers standard in place.matcher(function(query)): A function that returns a function which returns whether an item matches the original query or not.let(function(observable) => observable) A function that lets you modify everyObservablecreated by reactive service calls. Must return anObservable. Example:let: observable => observable.do(console.log)'injects' a.dointo the observable chain.
const feathers = require('feathers');
const reactive = require('feathers-reactive');
const app = feathers().configure(reactive(options));With feathers-reactive configured on the application individual options can be set at the service level with service.rx:
// Set a different id field and always re-fetch data
app.service('todos').rx({
idField: '_id'
});Each method call can also pass its own options via params.rx:
// Always fetch fresh data for this method call
app.service('todos').watch({ listStrategy: 'always' }).find();List strategies are used to determine how a data stream behaves. Currently there are three strategies:
never- Returns a stream from the service promise that only emits the method call data and never updates after thatsmart(default) - Returns a stream that smartly emits updated list data based on the services real-time events. It does not re-query any new data (but does not cover some cases in which thealwaysstrategy can be used).always- Re-runs the original query to always get fresh data from the server on any matching real-time event.
const feathers = require('feathers');
const memory = require('feathers-memory');
const rx = require('feathers-reactive');
const app = feathers()
.configure(rx({idField: "id"}))
.use('/messages', memory());
const messages = app.service('messages');
messages.create({
text: 'A test message'
}).then(() => {
// Get and watch a specific message with id 0. Emit the message data once it resolves
// and every time it changes e.g. through an updated or patched event
messages.watch().get(0).subscribe(message => console.log('My message', message));
// Find and watch all messages and emit a new list every time anything changes
messages.watch().find().subscribe(messages => console.log('Message list', messages));
setTimeout(() => {
messages.create({ text: 'Another message' }).then(() =>
setTimeout(() => messages.patch(0, { text: 'Updated message' }), 1000)
);
}, 1000);
});Will output:
My message { text: 'A test message', id: 0 }
Message list [ { text: 'A test message', id: 0 } ]
Message list [ { text: 'A test message', id: 0 },
{ text: 'Another message', id: 1 } ]
My message { text: 'Updated message', id: 0 }
Message list [ { text: 'Updated message', id: 0 },
{ text: 'Another message', id: 1 } ]
Let's assume a simple server in app.js like this:
npm install feathers feathers-socketio feathers-memory feathers-errors/handler
const feathers = require('feathers');
const socketio = require('feathers-socketio');
const memory = require('feathers-memory');
const handler = require('feathers-errors/handler');
const app = feathers()
.configure(socketio())
.use('/todos', memory())
.use('/', feathers.static(__dirname))
.use(handler());
app.listen(3030);A real-time ReactJS Todo application (with Bootstrap styles) can look like this (see the examples/react-todos folder for a working example);
npm install react react-dom rxjs
import React from 'react';
import ReactDOM from 'react-dom';
import feathers from 'feathers/client';
import socketio from 'feathers-socketio/client';
import rx from 'feathers-reactive';
import io from 'socket.io-client';
const socket = io();
const app = feathers()
.configure(socketio(socket))
.configure(rx());
const todos = app.service('todos');
const TodoApp = React.createClass({
getInitialState() {
return {
todos: [],
text: ''
};
},
componentDidMount() {
this.todos = todos.watch().find().subscribe(todos => this.setState({ todos }));
},
componentWillUnmount() {
this.todos.unsubscribe();
},
updateText(ev) {
this.setState({ text: ev.target.value });
},
createTodo(ev) {
todos.create({
text: this.state.text,
complete: false
});
this.setState({ text: '' });
ev.preventDefault();
},
updateTodo(todo, ev) {
todo.complete = ev.target.checked;
todos.patch(todo.id, todo);
},
deleteTodo(todo) {
todos.remove(todo.id);
},
render() {
const renderTodo = todo =>
<li className={`page-header checkbox ${todo.complete ? 'done' : ''}`}>
<label>
<input type="checkbox" onChange={this.updateTodo.bind(this, todo)}
checked={todo.complete} />
{todo.text}
</label>
<a href="javascript://" className="pull-right delete"
onClick={this.deleteTodo.bind(this, todo)}>
<span className="glyphicon glyphicon-remove"></span>
</a>
</li>;
return <div className="container" id="todos">
<h1>Feathers real-time Todos</h1>
<ul className="todos list-unstyled">{this.state.todos.map(renderTodo)}</ul>
<form role="form" className="create-todo" onSubmit={this.createTodo}>
<div className="form-group">
<input type="text" className="form-control" name="description"
placeholder="Add a new Todo" onChange={this.updateText}
value={this.state.text} />
</div>
<button type="submit" className="btn btn-info col-md-12">
Add Todo
</button>
</form>
</div>;
}
});
ReactDOM.render(<TodoApp />, document.getElementById('app'));Copyright (c) 2016
Licensed under the MIT license.