awesome-cheatsheets/backend/feathers.js

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/* *******************************************************************************************
* FEATHERS.JS CHEATSHEET
* https://docs.feathersjs.com/api/readme.html
*
* 1. CORE: Feathers core functionality.
* 2. TRANSPORT: Expose a Feathers application as an API server.
* 3. CLIENT: More details on how to use Feathers on the client.
* 4. AUTHENTICATION: Feathers authentication mechanism.
* 5. DATABASE: Feathers common database adapter API and querying mechanism.
* ******************************************************************************************* */
/* *******************************************************************************************
* 1. CORE: Feathers core functionality.
* ******************************************************************************************* */
```bash
# Provides the ability to initialize new application instances
npm install @feathersjs/feathers --save
# Provides a set of standard error classes used by all other Feathers modules
npm install @feathersjs/errors --save
```
const feathers = require('@feathersjs/feathers');
const app = feathers(); // application initialization
app.mixins // contains a list of service mixins
app.use(path, service) // allows registering a service object on a given path
app.service(path) // returns the wrapped service object for the given path
app.hooks(hooks) // allows registration of application-level hooks
app.publish([event,], publisher) // registers a global event publisher
app.configure(callback) // runs a callback function that gets passed the application object
app.listen(port) // starts the application on the given port
app.setup([server]) // used to initialize all services by calling each services .setup(app, path) method (if available)
app.set(name, value) // assigns setting name to value
app.get(name) // retrieves the setting name
app.on(eventname, listener) // registers a listener method for the given eventname
app.emit(eventname, data) // emits the event eventname to all event listeners
app.removeListener(eventname, [ listener ]) // removes all or the given listener for eventname
// "Services" are the heart of every Feathers application.
// Services are JavaScript objects (or instances of ES6 classes) that implement certain methods.
// Feathers itself will also add some additional methods and functionality to its services.
class MyService {
// Retrieves a list of all resources from the service.
// Provider parameters will be passed as params.query.
async find(params) {
return [];
}
// Retrieves a single resource with the given id from the service.
async get(id, params) {}
// Creates a new resource with data.
// The method should return the newly created data. data may also be an array.
async create(data, params) {}
// Replaces the resource identified by id with data.
// The method should return the complete, updated resource data.
// id can also be null when updating multiple records, with params.query containing the query criteria.
async update(id, data, params) {}
// Merges the existing data of the resource identified by id with the new data.
// id can also be null indicating that multiple resources should be patched with params.query containing the query criteria.
async patch(id, data, params) {}
// Removes the resource with id.
// The method should return the removed resource.
// id can also be null, which indicates the deletion of multiple resources, with params.query containing the query criteria.
async remove(id, params) {}
// A special method that initializes the service, passing an instance of the Feathers application
// and the path it has been registered on.
// For services registered before app.listen is invoked, the setup function of each registered service
// is called on invoking app.listen. For services registered after app.listen is invoked, setup is
// called automatically by Feathers when a service is registered.
setup(app, path) {}
}
params.query // contains the URL query parameters sent from the client
params.provider // for any service method call made through REST params.provider will be set to rest
app.use('/my-service', new MyService());
// Important: Always use the service returned by app.service(path)
const myService = app.service('my-service');
myService.hooks(hooks) // register hooks for this service
myService.publish([event,], publisher) // register an event publishing callback
myService.mixin(mixin) // extends the functionality of a service
myService.on(eventname, listener) // registers a listener method for the given eventname
myService.once(eventname, listener) // registers a listener method for the given eventname that will be triggered only one time
myService.emit(eventname, data) // emits the event eventname to all event listeners
myService.removeListener(eventname, [ listener ]) // removes all listeners (or the given listener) for eventname
// Hooks are pluggable middleware functions that can be registered
// before, after or on errors of a service method. You can register a
// single hook function or create a chain of them to create complex work-flows.
app.service('my-service').hooks({
before: {
all: [
// Use normal functions
function(context) { console.log('before all hook ran'); }
],
find: [
// Use ES6 arrow functions
context => console.log('before find hook 1 ran'),
context => console.log('before find hook 2 ran')
],
async create (context) {
return context
},
},
after: {
all: [],
find: [],
get: [],
create: [],
update: [],
patch: [],
remove: []
},
// Here is an example for a very useful application hook that logs every service method error
// with the service and method name as well as the error stack
error(context) {
console.error(`Error in ${context.path} calling ${context.method} method`, context.error);
}
});
context.app // [read only] contains the Feathers application object
context.service // [read only] contains the service this hook currently runs on
context.path // [read only] contains the service name (or path) without leading or trailing slashes
context.method // [read only] contains the name of the service method (find, get, create, update...)
context.type // [read only] contains the hook type (one of before, after or error)
context.params // [writable] contains the service method parameters (including params.query)
context.id // [writable] contains the id for a get, remove, update and patch service method call
context.data // [writable] contains the data of a create, update and patch service method call
context.error // [writable] contains the error object that was thrown in a failed method call (only available in error hooks)
context.result // [writable] contains the result of the successful service method call (only available in after hooks)
context.dispatch // [writable and optional] contains a "safe" version of the data that should be sent to any client
// A channel is an object that contains a number of connections.
// It can be created via app.channel and allows a connection to join or leave it.
app.channel(name) // when given a single name, returns an existing or new named channel
app.channel(name1, name2, ... nameN) // when given multiples names, will return a combined channel.
app.channels // returns a list of all existing channel names
channel.join(connection) // adds a connection to this channel
channel.leave(connection|fn) // removes a connection from this channel
channel.filter(fn) // returns a new channel filtered by a given function which gets passed the connection
channel.send(data) // returns a copy of this channel with customized data that should be sent for this event
channel.connections // contains a list of all connections in this channel
channel.length // returns the total number of connections in this channel
service.publish([event,] fn) // registers a publishing function for a specific service for a specific event or all events if no event name was given
app.publish([event,] fn) // registers an event publishing callback
app.on('connection', connection => {}) // fired every time a new real-time connection is established
app.on('login', (payload, info) => {}) // sent by the authentication module and also contains the connection in the info object that is passed as the second parameter
/* *******************************************************************************************
* 2. TRANSPORT: Expose a Feathers application as an API server.
* ******************************************************************************************* */
```bash
# Contains Express framework integrations
npm install @feathersjs/express --save
# Allows to call service methods and receive real-time events
npm install @feathersjs/socketio --save
# Allows to call service methods and receive real-time events via Primus
npm install @feathersjs/primus --save
```
// --> EXPRESS <--
const feathers = require('@feathersjs/feathers');
const express = require('@feathersjs/express');
// Create an app that is a Feathers AND Express application
const app = express(feathers());
// If no Feathers application is passed, express() returns a plain Express application
// just like a normal call to Express would
const app = express();
app.use(path, service|mw) // registers either a service object or an Express middleware on the given path
app.listen(port) // will first call Express app.listen and then internally also call the Feathers app.setup(server)
app.setup(server) // usually called internally by app.listen but in the cases described below needs to be called explicitly
express.rest() // registers a Feathers transport mechanism that allows you to expose and consume services through a RESTful API.
app.configure(express.rest()) // configures the transport provider with a standard formatter sending JSON response via res.json
express.notFound() // returns middleware that returns a NotFound (404) Feathers error
express.errorHandler() // middleware that formats any error response to a REST call as JSON and sets the appropriate error code
app.use(express.errorHandler()) // set up the error handler with the default configuration
// --> SOCKET.IO <--
const feathers = require('@feathersjs/feathers');
const socketio = require('@feathersjs/socketio');
const app = feathers();
app.configure(socketio()); // sets up the Socket.io transport with the default configuration using either the server provided by app.listen or passed in app.setup(server)
app.configure(socketio(callback)) // sets up the Socket.io transport with the default configuration and call callback with the Socket.io server object
app.configure(socketio(options [, callback])) // sets up the Socket.io transport with the given Socket.io options object and optionally calls the callback
app.configure(socketio(port, [options], [callback])) // creates a new Socket.io server on a separate port. Options and a callback are optional
// The options can also be used to initialize uWebSocket which is a WebSocket server
// implementation that provides better performace and reduced latency.
// npm install uws --save
app.configure(socketio({
wsEngine: 'uws'
}));
// --> PRIMUS <--
app.configure(primus(options)) // sets up the Primus transport with the given Primus options
app.configure(primus(options, callback)) // sets up the Primus transport with the given Primus options and calls the callback with the Primus server instance
/* *******************************************************************************************
* 3. CLIENT: More details on how to use Feathers on the client.
* ******************************************************************************************* */
```bash
# Bundles the separate Feathers client side modules into one providing the code as ES5 (compatible with modern browsers)
# You do not have to install or load any of the other modules listed below
npm install @feathersjs/client --save
# Allows to connect to services through REST HTTP
npm install @feathersjs/rest-client --save
# Allows to connect to services through Socket.io
npm install @feathersjs/socketio-client --save
# Allows to connect to services through Primus
npm install @feathersjs/primus-client --save
# Allows you to easily authenticate against a Feathers server
npm install @feathersjs/authentication-client --save
```
// --> REST CLIENT <--
rest([baseUrl]) // Initialize a client object with a base URL
app.configure(restClient.jquery(window.jQuery)); // connect to a service using jQuery
app.configure(restClient.request(requestClient)); // connect to a service using request
app.configure(restClient.superagent(superagent)); // connect to a service using Superagent
app.configure(restClient.axios(axios)); // connect to a service using Axion
app.configure(restClient.fetch(window.fetch)); // connect to a service using Fetch
// --> SOCKET.IO <--
socketio(socket) // initialize the Socket.io client using a given socket and the default options
socketio(socket, options) // initialize the Socket.io client using a given socket and the given options
// --> PRISMUS <--
primus(socket) // initialize the Primus client using a given socket and the default options
primus(socket, options) // initialize the Primus client using a given socket and the given options
/* *******************************************************************************************
* 4. AUTHENTICATION: Feathers authentication mechanism.
* ******************************************************************************************* */
```bash
# Assists in using JWT for authentication
npm install @feathersjs/authentication --save
# Wraps the passport-local authentication strategy (username and password)
npm install @feathersjs/authentication-local --save
# Wraps the passport-jwt authentication strategy (JSON Web Token access token)
npm install @feathersjs/authentication-jwt --save
# Allows you to use any Passport OAuth1 authentication strategy (most notably Twitter)
npm install @feathersjs/authentication-oauth1 --save
# Allows you to use any Passport OAuth2 authentication strategy (FB, Instagram, Github, Google...)
npm install @feathersjs/authentication-oauth2 --save
```
/* *******************************************************************************************
* 5. DATABASE: Feathers common database adapter API and querying mechanism.
* ******************************************************************************************* */
```bash
# [MEMORY/FILESYSTEM] In-memory database adapter
npm install feathers-memory --save
# [MEMORY/FILESYSTEM] Database adapter for NeDB an in-memory or file system based standalone database
npm install feathers-nedb --save
# [MEMORY/FILESYSTEM] Adapter for Client side Feathers that can use the browsers LocalStorage or ReactNative's AsyncStorage
npm install feathers-localstorage --save
# [SQL] Adapter for KnexJS, an SQL query builder for NodeJS supporting PostgreSQL, MySQL, SQLite and MSSQL
npm install feathers-knex --save
# [SQL] Adapter for Sequelize an ORM for NodeJS supporting PostgreSQL, MySQL, SQLite and MSSQL
npm install feathers-sequelize --save
# [NOSSQL] Database adapter for MongoDB using the official NodeJS database driver
npm install feathers-mongodb --save
# [NOSSQL] Database adapter for Mongoose an Object Modelling library for NodeJS and MongoDB
npm install feathers-mongoose --save
# [NOSSQL] Database adapter for Elasticsearch
npm install feathers-elasticsearch --save
# [NOSSQL] Database adapter for RethinkDB a real-time database.
npm install feathers-rethinkdb --save
```