├── .gitignore ├── renovate.json ├── .npmignore ├── classes-preview.jpg ├── src ├── index.js ├── util.js ├── redis.js ├── update.js ├── subscribers_store.js ├── subscriber.js ├── history.js ├── authorization.js ├── server.js ├── publisher.js └── hub.js ├── .github └── main.workflow ├── .editorconfig ├── package.json ├── test ├── client.js └── server.js ├── README.md ├── docs └── API.md └── LICENSE /.gitignore: -------------------------------------------------------------------------------- 1 | node_modules 2 | -------------------------------------------------------------------------------- /renovate.json: -------------------------------------------------------------------------------- 1 | { 2 | "extends": [ 3 | "config:base" 4 | ] 5 | } 6 | -------------------------------------------------------------------------------- /.npmignore: -------------------------------------------------------------------------------- 1 | .editorconfig 2 | classes-preview.jpg 3 | renovate.json 4 | docs/ 5 | test/ 6 | -------------------------------------------------------------------------------- /classes-preview.jpg: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/Ilshidur/node-mercure/HEAD/classes-preview.jpg -------------------------------------------------------------------------------- /src/index.js: -------------------------------------------------------------------------------- 1 | const Hub = require('./hub'); 2 | const Server = require('./server'); 3 | const Publisher = require('./publisher'); 4 | 5 | module.exports = { Hub, Server, Publisher }; 6 | -------------------------------------------------------------------------------- /src/util.js: -------------------------------------------------------------------------------- 1 | // From : https://github.com/chriso/validator.js/blob/master/src/lib/isJWT.js 2 | const isJwt = jwt => jwt && /^([A-Za-z0-9\-_~+\/]+[=]{0,2})\.([A-Za-z0-9\-_~+\/]+[=]{0,2})(?:\.([A-Za-z0-9\-_~+\/]+[=]{0,2}))?$/.test(jwt); 3 | 4 | module.exports = { isJwt }; 5 | -------------------------------------------------------------------------------- /src/redis.js: -------------------------------------------------------------------------------- 1 | const bluebird = require('bluebird'); 2 | const redis = require('redis'); 3 | 4 | bluebird.promisifyAll(redis.RedisClient.prototype); 5 | bluebird.promisifyAll(redis.Multi.prototype); 6 | 7 | function createRedisClient(config) { 8 | return redis.createClient(config); 9 | } 10 | 11 | module.exports = { createRedisClient }; 12 | -------------------------------------------------------------------------------- /.github/main.workflow: -------------------------------------------------------------------------------- 1 | workflow "Build, Test, and Publish" { 2 | on = "push" 3 | resolves = ["Publish"] 4 | } 5 | 6 | action "Filter on tags" { 7 | uses = "actions/bin/filter@master" 8 | args = "tag" 9 | } 10 | 11 | action "Publish" { 12 | uses = "actions/npm@59b64a598378f31e49cb76f27d6f3312b582f680" 13 | args = "publish --access public" 14 | secrets = ["NPM_AUTH_TOKEN"] 15 | needs = ["Filter on tags"] 16 | } 17 | -------------------------------------------------------------------------------- /.editorconfig: -------------------------------------------------------------------------------- 1 | # EditorConfig helps developers define and maintain consistent 2 | # coding styles between different editors and IDEs 3 | # editorconfig.org 4 | 5 | root = true 6 | 7 | 8 | [*] 9 | 10 | # Change these settings to your own preference 11 | indent_style = space 12 | indent_size = 2 13 | 14 | # We recommend you to keep these unchanged 15 | end_of_line = lf 16 | charset = utf-8 17 | trim_trailing_whitespace = true 18 | insert_final_newline = true 19 | 20 | [*.md] 21 | trim_trailing_whitespace = false 22 | -------------------------------------------------------------------------------- /src/update.js: -------------------------------------------------------------------------------- 1 | class Update { 2 | constructor(targets, topics, event) { 3 | this.targets = targets; 4 | this.topics = topics; 5 | this.event = event; 6 | } 7 | 8 | serialize() { 9 | return JSON.stringify({ 10 | targets: this.targets, 11 | topics: this.topics, 12 | event: this.event, 13 | }); 14 | } 15 | 16 | static unserialize(str) { 17 | const data = JSON.parse(str); 18 | return new Update(data.targets, data.topics, data.event); 19 | } 20 | } 21 | 22 | module.exports = Update; 23 | -------------------------------------------------------------------------------- /package.json: -------------------------------------------------------------------------------- 1 | { 2 | "name": "mercure", 3 | "version": "0.1.0", 4 | "description": "Mercure Hub implementation in Node.js.", 5 | "main": "src/index.js", 6 | "scripts": { 7 | "test": "npm test" 8 | }, 9 | "repository": { 10 | "type": "git", 11 | "url": "https://github.com/Ilshidur/node-mercure.git" 12 | }, 13 | "author": "Ilshidur", 14 | "license": "GPL-3.0", 15 | "bugs": { 16 | "url": "https://github.com/Ilshidur/node-mercure/issues" 17 | }, 18 | "homepage": "https://github.com/Ilshidur/node-mercure#readme", 19 | "dependencies": { 20 | "axios": "^0.21.0", 21 | "bluebird": "^3.5.3", 22 | "cookie": "0.4.0", 23 | "express": "4.17.1", 24 | "jsonwebtoken": "8.5.1", 25 | "node-jose": "^2.0.0", 26 | "redis": "^2.8.0", 27 | "sse": "0.0.8", 28 | "uri-templates": "0.2.0", 29 | "uuid": "3.4.0" 30 | }, 31 | "devDependencies": { 32 | "eventsource": "1.0.7" 33 | } 34 | } 35 | -------------------------------------------------------------------------------- /test/client.js: -------------------------------------------------------------------------------- 1 | const EventSource = require('eventsource'); 2 | 3 | // The subscriber subscribes to updates for the https://example.com/foo topic 4 | // and to any topic matching https://example.com/books/{name} 5 | const url = new URL('http://localhost:3000/.well-known/mercure'); 6 | url.searchParams.append('topic', 'http://localhost:3000/books/{id}'); 7 | url.searchParams.append('topic', 'http://localhost:3000/users/dunglas'); 8 | 9 | const eventSource = new EventSource(url.toString(), { 10 | headers: { 11 | Cookie: 'mercureAuthorization=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJtZXJjdXJlIjp7InB1Ymxpc2giOlsiaHR0cDovL2xvY2FsaG9zdDozMDAwL2Jvb2tzL3tpZH0iXSwic3Vic2NyaWJlIjpbImh0dHA6Ly9sb2NhbGhvc3Q6MzAwMC9ib29rcy97aWR9Il19fQ.uTSaEacmjvpfb3qCzRnv5lWkVLVMLpskt54UgDwoauA', 12 | 'Last-Event-ID': 'bbb458bb-814a-4d25-9dc7-6c8369593584', 13 | } 14 | }); 15 | console.log(`Connected to ${eventSource.url}`); 16 | 17 | eventSource.onmessage = (data) => console.log(data); 18 | eventSource.onerror = (err) => console.error(err); 19 | 20 | console.log('Waiting ..'); 21 | -------------------------------------------------------------------------------- /src/subscribers_store.js: -------------------------------------------------------------------------------- 1 | /** 2 | * In-memory store with option to sync with a Redis instance (acts as service discovery). 3 | */ 4 | class SubscribersStore { 5 | constructor(id, redisClient) { 6 | this.id = id; 7 | this.redisClient = redisClient; 8 | this.list = new Set(); 9 | } 10 | 11 | getRedisKey() { 12 | return 'mercure-subscribers'; 13 | } 14 | 15 | async syncRedis() { 16 | await this.redisClient.HMSETAsync(this.getRedisKey(), { 17 | [`process-${this.id}`]: JSON.stringify(this.getList().map(s => s.toValue())) 18 | }); 19 | } 20 | 21 | getCount() { 22 | return this.list.size; 23 | } 24 | 25 | async getTotalCount() { 26 | if (!this.redisClient) { 27 | throw new Error(`Can't determine total subscribers count without Redis set up.`); 28 | } 29 | return (await this.getFullList()).length; 30 | } 31 | 32 | getList() { 33 | return Array.from(this.list); 34 | } 35 | 36 | async getFullList() { 37 | if (!this.redisClient) { 38 | throw new Error(`Can't get full subscribers list without Redis set up.`); 39 | } 40 | const list = await this.redisClient.HVALSAsync(this.getRedisKey()); 41 | return list 42 | .map(subscribers => subscribers && JSON.parse(subscribers)) 43 | .reduce((result, subscribers) => [ ...result, ...(subscribers || []) ], []); 44 | } 45 | 46 | async add(subscriber) { 47 | this.list.add(subscriber); 48 | 49 | if (this.redisClient) { 50 | await this.syncRedis(); 51 | } 52 | } 53 | 54 | async delete(subscriber) { 55 | this.list.delete(subscriber); 56 | 57 | if (this.redisClient) { 58 | await this.syncRedis(); 59 | } 60 | } 61 | 62 | async clear(all = false) { 63 | this.clearSync(all); 64 | 65 | if (this.redisClient) { 66 | await this.syncRedis(); 67 | } 68 | } 69 | 70 | clearSync(all) { 71 | for (const subscriber of this.getList()) { 72 | if (all || !subscriber.allTargetsAuthorized) { 73 | subscriber.closeConnection(); 74 | this.list.delete(subscriber); 75 | } 76 | } 77 | } 78 | } 79 | 80 | module.exports = SubscribersStore; 81 | -------------------------------------------------------------------------------- /src/subscriber.js: -------------------------------------------------------------------------------- 1 | class Subscriber { 2 | constructor(sseClient, allTargetsAuthorized, authorizedTargets, topics, lastEventId) { 3 | this.sseClient = sseClient; 4 | this.allTargetsAuthorized = allTargetsAuthorized; 5 | this.authorizedTargets = authorizedTargets; 6 | this.topics = topics; // URI templates (RFC 6570) 7 | this.lastEventId = lastEventId; 8 | } 9 | 10 | toValue() { 11 | return { 12 | topics: this.topics.map(t => t.toString()), 13 | ip: this.sseClient.req.socket.localAddress, 14 | all: this.allTargetsAuthorized, 15 | last: this.lastEventId, 16 | authorized: this.authorizedTargets 17 | } 18 | } 19 | 20 | send(update) { 21 | this.sseClient.send(update.event); 22 | } 23 | 24 | async sendAsync(update) { 25 | this.sseClient.send(update.event); 26 | } 27 | 28 | closeConnection() { 29 | // Ends the response. 30 | this.sseClient.close(); 31 | // Manually closes the connection. 32 | this.sseClient.res.emit('close'); 33 | } 34 | 35 | canReceive(update) { 36 | return this.isAuthorized(update) && this.isSubscribed(update); 37 | } 38 | 39 | isAuthorized(update) { 40 | // Check if the subscriber's JWT claims a target '*' and/or wants public updates. 41 | if (this.allTargetsAuthorized || this.authorizedTargets.length === 0) { 42 | // Either : 43 | // - the subscriber is authorized to receive updates destined for all targets 44 | // - the subscriber is authorized to receive public updates 45 | // => Allow all updates. 46 | return true; 47 | } 48 | 49 | if (update.targets === null) { 50 | // The update can be sent to all subscribers. 51 | return true; 52 | } 53 | 54 | return this.authorizedTargets.some(target => update.targets.includes(target)); 55 | } 56 | 57 | isSubscribed(update) { 58 | for (const subscriberTopic of this.topics) { 59 | for (const updateTopic of update.topics) { 60 | if (subscriberTopic.test(updateTopic)) { 61 | return true; 62 | } 63 | } 64 | } 65 | 66 | return false; 67 | } 68 | } 69 | 70 | module.exports = Subscriber; 71 | -------------------------------------------------------------------------------- /src/history.js: -------------------------------------------------------------------------------- 1 | const EventEmitter = require('events'); 2 | 3 | const Update = require('./update'); 4 | 5 | class History extends EventEmitter { 6 | constructor(redisClient) { 7 | super(); 8 | 9 | if (redisClient) { 10 | this.redisClient = redisClient; 11 | this.sub = redisClient.duplicate(); 12 | this.pub = redisClient.duplicate(); 13 | } 14 | 15 | if (!this.hasRedis) { 16 | this.updates = []; 17 | } 18 | } 19 | 20 | get hasRedis() { 21 | return !!this.pub && !!this.sub; 22 | } 23 | 24 | async push(update) { 25 | if (!this.running) { 26 | return; 27 | } 28 | 29 | if (this.hasRedis) { 30 | const serializedUpdate = update.serialize(); 31 | await this.pub.publishAsync('mercure', serializedUpdate); 32 | this.redisClient.rpushAsync('mercure-events', serializedUpdate); 33 | } else { 34 | this.updates.push(update); 35 | this.emit('update', update); 36 | } 37 | } 38 | 39 | async getUpdates() { 40 | if (this.hasRedis) { 41 | const entries = await this.redisClient.lrangeAsync('mercure-events', 0, -1); 42 | return entries.map(entry => JSON.parse(entry)); 43 | } 44 | return this.updates; 45 | } 46 | 47 | async findFor(subscriber) { 48 | const updates = await this.getUpdates(); 49 | 50 | let afterLastEventId = false; 51 | 52 | return updates.filter((update) => { 53 | if (!afterLastEventId) { 54 | if (update.event.id === subscriber.lastEventId) { 55 | afterLastEventId = true; 56 | } 57 | return false; 58 | } 59 | 60 | return subscriber.canReceive(update); 61 | }); 62 | } 63 | 64 | async start() { 65 | if (this.hasRedis) { 66 | this.sub.on('message', (_, message) => { 67 | this.emit('update', Update.unserialize(message)); 68 | }); 69 | 70 | await this.sub.subscribeAsync('mercure'); 71 | } 72 | 73 | this.running = true; 74 | } 75 | 76 | async end({ force = false } = {}) { 77 | if (this.hasRedis) { 78 | if (force) { 79 | this.pub.end(false); 80 | this.sub.end(false); 81 | } else { 82 | await this.pub.quitAsync(); 83 | await this.sub.quitAsync(); 84 | } 85 | } 86 | this.running = false; 87 | } 88 | 89 | endSync() { 90 | if (this.hasRedis) { 91 | this.pub.end(false); 92 | this.sub.end(false); 93 | } 94 | this.running = false; 95 | } 96 | } 97 | 98 | module.exports = History; 99 | -------------------------------------------------------------------------------- /src/authorization.js: -------------------------------------------------------------------------------- 1 | const Cookie = require('cookie'); 2 | const jwt = require('jsonwebtoken'); 3 | const url = require('url'); 4 | 5 | jwt.verifyAsync = (token, jwtKey) => new Promise((resolve, reject) => { 6 | jwt.verify(token, jwtKey, { complete: true }, (err, decoded) => { 7 | if (err) { 8 | return reject(err); 9 | } 10 | return resolve(decoded); 11 | }); 12 | }); 13 | 14 | async function authorize(req, jwtKey, publishAllowedOrigins = []) { 15 | const authHeader = req.headers['authorization']; 16 | 17 | let token; 18 | 19 | if (authHeader) { 20 | const match = /^Bearer (.*)/.exec(authHeader); 21 | if (!match || !(token = match[1])) { 22 | throw new Error('Invalid "Authorization" header.'); 23 | } 24 | 25 | return await jwt.verifyAsync(token, jwtKey); 26 | } 27 | 28 | const cookie = Cookie.parse(req.headers.cookie || ''); 29 | if (!cookie || !(token = cookie.mercureAuthorization)) { 30 | // Anonymous. 31 | return false; 32 | } 33 | 34 | // CSRF attacks cannot occur when using safe methods. 35 | if (req.method !== 'POST') { 36 | return await jwt.verifyAsync(token, jwtKey); 37 | } 38 | 39 | // Check 'Origin' & 'Referer' against publishAllowedOrigins 40 | let origin = req.headers['origin']; 41 | if (!origin) { 42 | const referer = req.headers['referer']; 43 | if (!referer) { 44 | throw new Error('An "Origin" or a "Referer" HTTP header must be present to use the cookie-based authorization mechanism'); 45 | } 46 | 47 | const parsedReferer = url.parse(referer); 48 | origin = `${parsedReferer.protocol}\/\/${parsedReferer.host}`; 49 | } 50 | 51 | const allowedOrigin = publishAllowedOrigins.find(allowedOrigin => allowedOrigin === origin); 52 | if (allowedOrigin) { 53 | return await jwt.verifyAsync(token, jwtKey); 54 | } 55 | 56 | throw new Error(`The origin "${origin}" is not allowed to post updates`); 57 | } 58 | 59 | function getAuthorizedTargets(claims, isPublisher) { 60 | if (!claims) { 61 | // If not authenticated, then only allow public updates (no targets). 62 | return { 63 | allTargetsAuthorized: false, 64 | authorizedTargets: [], 65 | }; 66 | } 67 | 68 | if (!claims.mercure) { 69 | // Only allow public updates. 70 | return { 71 | allTargetsAuthorized: false, 72 | authorizedTargets: [], 73 | }; 74 | } 75 | 76 | const providedTargets = isPublisher ? claims.mercure.publish : claims.mercure.subscribe; 77 | 78 | if (providedTargets.some(target => target === '*')) { 79 | return { 80 | allTargetsAuthorized: true, 81 | authorizedTargets: null, 82 | }; 83 | } 84 | 85 | return { 86 | allTargetsAuthorized: false, 87 | authorizedTargets: providedTargets, 88 | }; 89 | } 90 | 91 | module.exports = { authorize, getAuthorizedTargets }; 92 | -------------------------------------------------------------------------------- /test/server.js: -------------------------------------------------------------------------------- 1 | const { Server, Publisher } = require('../src'); 2 | 3 | const server = new Server({ 4 | jwtKey: '!UnsecureChangeMe!', 5 | path: '/.well-known/mercure', 6 | // Additional check for POST request made in a browser : 7 | publishAllowedOrigins: ['http://localhost:3000'], 8 | allowAnonymous: true, // Don't force subscriber authorization. 9 | maxTopics: 0, // Not limits 10 | ignorePublisherId: true, 11 | publishAllowedOrigins: null, 12 | redis: { 13 | host: 'localhost', 14 | port: 6379, 15 | }, 16 | }); 17 | 18 | process.on('SIGTERM', () => { 19 | console.log('Ending server ...'); 20 | server.endSync(); 21 | }); 22 | process.on('SIGINT', () => { 23 | console.log('Ending server ...'); 24 | server.endSync(); 25 | }); 26 | 27 | (async () => { 28 | await server.listen(3000); 29 | 30 | // === TEST === 31 | 32 | const crypto = require('crypto'); 33 | const util = require('util'); 34 | 35 | // const publisher = new Publisher(server.hub); 36 | 37 | const jwt = await server.hub.generatePublishJwt(['http://localhost:3000/books/{id}']); 38 | const publisher = new Publisher({ 39 | protocol: 'http', // or 'https' 40 | host: 'localhost', 41 | port: 3000, 42 | path: '/.well-known/mercure', 43 | jwt, 44 | }); 45 | 46 | console.log('Using encryption ...'); 47 | // await publisher.useEncryption({ 48 | // rsaPrivateKey: (await util.promisify(crypto.generateKeyPair)('rsa', { 49 | // modulusLength: 4096, 50 | // privateKeyEncoding: { 51 | // type: 'pkcs8', 52 | // format: 'pem', 53 | // }, 54 | // })).privateKey, 55 | // }); 56 | console.log('Generated keys !'); 57 | 58 | server.hub.on('subscribe', (subscriber) => { 59 | console.log('New subscriber'); 60 | }); 61 | 62 | server.hub.on('unsubscribe', (subscriber) => { 63 | console.log('Subscriber left'); 64 | }); 65 | 66 | server.hub.on('publish', (update, id) => { 67 | // console.log('Published', update); 68 | }); 69 | 70 | setInterval(async () => { 71 | if (await server.hub.subscribers.getTotalCount() === 0) { 72 | return; 73 | } 74 | if (process.env.pm_id && process.env.pm_id !== '0') { 75 | return; 76 | } 77 | 78 | const data = { 79 | '@id': 'http://localhost:3000/books/666.jsonld', 80 | }; 81 | 82 | try { 83 | const updateId = await publisher.publish( 84 | ['http://localhost:3000/books/666'], 85 | JSON.stringify(data), 86 | { 87 | // allTargets: true // Only available on same instance publishers, ignored otherwise. 88 | // Not public, so sending with specific targets : 89 | targets: ['http://localhost:3000/books/{id}'], 90 | id: 'wesh', 91 | type: 'message', 92 | retry: 1000, 93 | }, 94 | ); 95 | 96 | console.log('Published', updateId); 97 | } catch (err) { 98 | console.error('[Publisher]', err); 99 | } 100 | }, 5000); 101 | 102 | })() 103 | .catch(console.error.bind(console)); 104 | -------------------------------------------------------------------------------- /src/server.js: -------------------------------------------------------------------------------- 1 | const express = require('express'); 2 | const http = require('http'); 3 | 4 | const Hub = require('./hub'); 5 | const Publisher = require('./publisher'); 6 | const { getAuthorizedTargets } = require('./authorization'); 7 | 8 | function publishEndpointHandler() { 9 | return async (req, res, next) => { 10 | const hub = req.app.get('hub'); 11 | 12 | // Authorize publisher 13 | let claims; 14 | try { 15 | claims = await hub.authorizePublish(req); 16 | } catch (err) { 17 | return res.status(401).send('Unauthorized'); 18 | } 19 | if (!claims) { 20 | return res.status(403).send('Forbidden'); 21 | } 22 | 23 | const { topic, data, target: targets, id, type } = req.body; 24 | let { retry } = req.body; 25 | 26 | if (!topic || topic === '') { 27 | return res.status(400).send('Missing "topic" parameter in body'); 28 | } 29 | if (!data || data === '') { 30 | return res.status(400).send('Missing "data" parameter in body'); 31 | } 32 | 33 | if (hub.config.maxTopics > 0 && topics.length > hub.config.maxTopics) { 34 | return res.status(400).send(`Exceeded limit of ${hub.config.maxTopics} topics`); 35 | } 36 | 37 | if (retry) { 38 | retry = parseInt(retry, 10) || 0; 39 | 40 | if (!Number.isInteger(retry)) { 41 | return res.status(400).send('Invalid "retry" parameter'); 42 | } 43 | } 44 | 45 | const { allTargetsAuthorized, authorizedTargets } = getAuthorizedTargets(claims, true); 46 | 47 | const targetsArray = Array.isArray(targets) ? targets : [targets]; 48 | 49 | // Checking if all targets are authorized. 50 | for (const target of targetsArray) { 51 | if (!allTargetsAuthorized) { 52 | if (!authorizedTargets.includes(target)) { 53 | return res.status(401).send('Unauthorized'); 54 | } 55 | } 56 | } 57 | 58 | const publisher = new Publisher(hub); 59 | 60 | try { 61 | const updateId = await publisher.publish(topic, data, { 62 | allTargets: allTargetsAuthorized, 63 | targets, 64 | ...id ? { id } : {}, 65 | ...type ? { type } : {}, 66 | ...retry ? { retry } : {}, 67 | }); 68 | 69 | return res.status(200).send(updateId); 70 | } catch (err) { 71 | return next(err); 72 | } 73 | }; 74 | } 75 | 76 | /** 77 | * Mercure server built on Express. 78 | */ 79 | class Server { 80 | constructor(config = {}) { 81 | this.config = { 82 | path: '/.well-known/mercure', 83 | ...config 84 | }; 85 | this.app = express(); 86 | 87 | if (typeof this.configure === 'function') { 88 | this.configure.call(this); 89 | } 90 | 91 | this.app.use(express.urlencoded({ extended: true })); 92 | 93 | const { server, hub } = Server.createFromExpressApp(this.app, this.config); 94 | this.server = server; 95 | this.hub = hub; 96 | } 97 | 98 | static createFromExpressApp(app, config) { 99 | app.post('/.well-known/mercure', publishEndpointHandler()); 100 | 101 | const server = http.Server(app); 102 | 103 | const hub = new Hub(server, config); 104 | app.set('hub', hub); 105 | 106 | return { server, hub }; 107 | } 108 | 109 | async listen(port, addr = null) { 110 | await this.hub.listen(port, addr); 111 | } 112 | 113 | async end({ force = false } = {}) { 114 | await this.hub.end({ force }); 115 | } 116 | 117 | endSync() { 118 | return this.hub.endSync(); 119 | } 120 | } 121 | 122 | module.exports = Server; 123 | -------------------------------------------------------------------------------- /src/publisher.js: -------------------------------------------------------------------------------- 1 | const axios = require('axios'); 2 | const crypto = require('crypto'); 3 | const jwt = require('jsonwebtoken'); 4 | const jose = require('node-jose'); 5 | const util = require('util'); 6 | const querystring = require('querystring'); 7 | 8 | const { isJwt } = require('./util'); 9 | 10 | function validateConfig(config) { 11 | const validatedConfig = config; 12 | 13 | // Required configurations 14 | if (!validatedConfig.host) { 15 | throw new Error('Missing host'); 16 | } 17 | if (!validatedConfig.jwt) { 18 | throw new Error('Missing jwt'); 19 | } 20 | 21 | // Defaults 22 | if (!validatedConfig.protocol) { 23 | validatedConfig.protocol = 'https'; 24 | } 25 | if (!validatedConfig.port) { 26 | validatedConfig.port = 80; 27 | } 28 | if (!validatedConfig.path) { 29 | validatedConfig.path = '/.well-known/mercure'; 30 | } 31 | 32 | // Validations 33 | if (!['http', 'https'].includes(validatedConfig.protocol)) { 34 | throw new Error('Invalid protocol', validatedConfig.protocol); 35 | } 36 | if (!Number.isInteger(validatedConfig.port)) { 37 | throw new Error('Invalid port', validatedConfig.port); 38 | } 39 | if (!validatedConfig.path.startsWith('/')) { 40 | throw new Error('Path must start with "/"'); 41 | } 42 | if (!isJwt(validatedConfig.jwt)) { 43 | throw new Error('Invalid jwt', validatedConfig.jwt); 44 | } 45 | 46 | return validatedConfig 47 | } 48 | 49 | class Publisher { 50 | constructor(config = {}) { 51 | if (config.isMercureHub) { 52 | this.hub = config; 53 | } else { 54 | this.config = validateConfig(config) 55 | } 56 | } 57 | 58 | // Will encrypt each POST message between the publisher and the Mercure server. 59 | async useEncryption({ 60 | rsaPrivateKey = null, 61 | // TODO: Support jwks 62 | passphrase = null 63 | // TODO: Support RSA key passphrase 64 | } = {}) { 65 | if (this.hub) { 66 | // If the Hub is in the same code base as the publisher, no need to encrypt. 67 | // This assumes that the Hub is handled by the developer, so it shall be trusted. 68 | return null; 69 | } 70 | 71 | let rsaPublicKey; 72 | if (this.config && this.config.rsaPrivateKey) { 73 | rsaPrivateKey = this.config.rsaPrivateKey 74 | } 75 | if (!rsaPrivateKey) { 76 | // If no RSA public key is provided, generate a new one. 77 | const { publicKey, privateKey } = await util.promisify(crypto.generateKeyPair)('rsa', { 78 | modulusLength: 4096, 79 | publicKeyEncoding: { 80 | type: 'pkcs1', 81 | format: 'pem' 82 | }, 83 | privateKeyEncoding: { 84 | type: 'pkcs8', 85 | format: 'pem', 86 | // TODO: USE CYPHER 87 | // cipher: 'aes-256-cbc', 88 | // passphrase: 'top secret' 89 | }, 90 | }); 91 | rsaPrivateKey = privateKey; 92 | rsaPublicKey = publicKey; 93 | } 94 | 95 | if (!rsaPublicKey) { 96 | const key = crypto.createPublicKey(rsaPrivateKey); 97 | rsaPublicKey = key.export({ type: 'pkcs1', format: 'pem' }); 98 | } 99 | 100 | // Creating private JSON Web Key. 101 | const privateJwk = await jose.JWK.asKey(rsaPrivateKey, 'pem'); 102 | // Store the JWK in a keystore in order to publish encrypted messages later. 103 | this.keystore = await jose.JWK.asKeyStore({ 104 | keys: [privateJwk], 105 | }); 106 | this.kid = privateJwk.kid; 107 | 108 | return { 109 | rsaPrivateKey, 110 | rsaPublicKey, 111 | }; 112 | } 113 | 114 | async publish(topics, message, options = {}) { 115 | if (this.hub) { 116 | return await this.hub.dispatchUpdate(topics, message, options) 117 | } 118 | 119 | if (this.keystore) { 120 | // Message can be encrypted. 121 | 122 | // Currently only supports 1 key-value pair. 123 | const publicJwk = this.keystore.get(this.kid, { kty: 'RSA' }); 124 | message = await jose.JWE.createEncrypt({ format: 'compact' }, publicJwk).update(message).final(); 125 | } 126 | 127 | const url = `${this.config.protocol}://${this.config.host}:${this.config.port}${this.config.path}`; 128 | const data = { 129 | data: message, 130 | topic: topics, 131 | ...options.targets ? { target: options.targets }: {}, 132 | ...options.id ? { id: options.id }: {}, 133 | ...options.type ? { type: options.type }: {}, 134 | ...options.retry ? { retry: options.retry }: {}, 135 | }; 136 | 137 | try { 138 | const response = await axios.post(url, querystring.stringify(data), { 139 | headers: { 140 | 'Authorization': `Bearer ${this.config.jwt}`, 141 | 'Content-Type': 'application/x-www-form-urlencoded', 142 | }, 143 | }); 144 | 145 | return response.data; 146 | } catch (err) { 147 | if (err.response) { 148 | throw new Error(`${err.response.status} ${err.response.statusText} : ${err.response.data}`); 149 | } 150 | throw err; 151 | } 152 | } 153 | 154 | getClaims() { 155 | if (this.hub) { 156 | return null 157 | } 158 | 159 | return jwt.decode(this.config.jwt); 160 | } 161 | } 162 | 163 | module.exports = Publisher; 164 | -------------------------------------------------------------------------------- /src/hub.js: -------------------------------------------------------------------------------- 1 | const crypto = require('crypto'); 2 | const EventEmitter = require('events'); 3 | const http = require('http'); 4 | const jwt = require('jsonwebtoken'); 5 | const SSE = require('sse'); 6 | const uriTemplates = require('uri-templates'); 7 | const util = require('util'); 8 | const uuidv4 = require('uuid/v4'); 9 | 10 | const { authorize, getAuthorizedTargets } = require('./authorization'); 11 | const Subscriber = require('./subscriber'); 12 | const Update = require('./update'); 13 | const History = require('./history'); 14 | const { createRedisClient } = require('./redis'); 15 | const SubscribersStore = require('./subscribers_store'); 16 | 17 | const defaultOptions = { 18 | id: uuidv4(), 19 | path: '/.well-known/mercure', 20 | allowAnonymous: false, // Don't force subscriber authorization. 21 | maxTopics: 0, 22 | ignorePublisherId: true, 23 | publishAllowedOrigins: null, 24 | }; 25 | 26 | const initializeClient = SSE.Client.prototype.initialize; 27 | SSE.Client.prototype.initialize = () => {}; // Noop this in order to defer the client initialization. 28 | 29 | // TODO: Handle CORS 30 | 31 | // One Hub per server, thus one per publisher. 32 | class Hub extends EventEmitter { 33 | constructor(server, config) { 34 | super(); 35 | 36 | this.config = { 37 | ...defaultOptions, 38 | ...config || (typeof server.listen !== 'function' ? server : {}) 39 | }; 40 | 41 | if (!this.config.jwtKey && (!this.config.pubJwtKey || !this.config.subJwtKey)) { 42 | throw new Error('Missing "jwtKey" or "pubJwtKey"/"subJwtKey" option.'); 43 | } 44 | if (this.config.jwtKey && (this.config.pubJwtKey || this.config.subJwtKey)) { 45 | throw new Error('"jwtKey" and "pubJwtKey"/"subJwtKey" cannot be passed in the same time.'); 46 | } 47 | 48 | this.server = typeof server.listen === 'function' ? server : http.createServer(); 49 | 50 | this.redis = null; 51 | if (this.config.redis) { 52 | this.redis = createRedisClient(this.config.redis); 53 | } 54 | 55 | this.subscribers = new SubscribersStore(this.config.id, this.redis); 56 | this.history = new History(this.redis); 57 | } 58 | 59 | get isMercureHub() { 60 | return true; 61 | } 62 | 63 | hasRedis() { 64 | return !!this.redis; 65 | } 66 | 67 | authorizePublish(req) { 68 | return authorize(req, this.config.pubJwtKey || this.config.jwtKey, this.config.publishAllowedOrigins); 69 | } 70 | authorizeSubscribe(req) { 71 | return authorize(req, this.config.subJwtKey || this.config.jwtKey, this.config.publishAllowedOrigins); 72 | } 73 | 74 | async onSseConnection(client, { topic: topics, 'Last-Event-ID': queryLastEventId }) { 75 | // Check the allowed topics in the subscriber's JWT. 76 | let claims; 77 | try { 78 | claims = await this.authorizeSubscribe(client.req); 79 | } catch (err) { 80 | client.res.writeHead(401); 81 | client.res.write('Unauthorized'); 82 | client.res.end(); 83 | return; 84 | } 85 | 86 | if (!claims && !this.config.allowAnonymous) { 87 | client.res.writeHead(403); 88 | client.res.write('Forbidden'); 89 | client.res.end(); 90 | return; 91 | } 92 | 93 | if (!topics) { 94 | client.res.writeHead(400); 95 | client.res.write('Missing "topic" parameter'); 96 | client.res.end(); 97 | return; 98 | } 99 | 100 | const topicsArray = Array.isArray(topics) ? topics : [topics]; 101 | if (this.config.maxTopics > 0 && topicsArray.length > this.config.maxTopics) { 102 | client.res.writeHead(400); 103 | client.res.write(`Exceeded limit of ${this.config.maxTopics} topics`); 104 | client.res.end(); 105 | return; 106 | } 107 | 108 | // Set the HTTP headers to make it a persistent connection. 109 | initializeClient.call(client); 110 | 111 | const templates = []; 112 | if (topicsArray.length > 0) { 113 | for (const topic of topicsArray) { 114 | try { 115 | templates.push(uriTemplates(topic)); 116 | } catch (err) { 117 | console.error(err); 118 | client.res.writeHead(400); 119 | client.res.write(`${topic} is not a valid URI template (RFC6570)`); 120 | client.res.end(); 121 | return; 122 | } 123 | } 124 | } 125 | 126 | const { allTargetsAuthorized, authorizedTargets } = getAuthorizedTargets(claims, false); 127 | 128 | const lastEventId = client.req.headers['last-event-id'] || queryLastEventId; 129 | const subscriber = new Subscriber(client, allTargetsAuthorized, authorizedTargets, templates, lastEventId); 130 | 131 | await this.subscribers.add(subscriber); 132 | client.on('close', async () => { 133 | await this.subscribers.delete(subscriber); 134 | this.emit('unsubscribe', subscriber); 135 | }); 136 | 137 | this.emit('subscribe', subscriber); 138 | 139 | if (subscriber.lastEventId) { 140 | const updates = await this.history.findFor(subscriber); 141 | for (const update of updates) { 142 | subscriber.send(update); 143 | } 144 | } 145 | } 146 | 147 | async listen(port, addr = '0.0.0.0') { 148 | if (!port || !Number.isInteger(port)) { 149 | throw new Error('Invalid port', port); 150 | } 151 | 152 | await new Promise((resolve, reject) => { 153 | try { 154 | this.server.listen(port, addr, resolve); 155 | } catch (err) { 156 | reject(err); 157 | } 158 | }); 159 | 160 | const sse = new SSE(this.server, { 161 | path: this.config.path, 162 | verifyRequest: (req) => req.url.startsWith('/.well-known/mercure') && (req.method === 'GET' || req.method === 'HEAD' || req.method === 'OPTIONS') 163 | }); 164 | 165 | this.history.on('update', async (update) => { 166 | const subscribers = this.subscribers.getList().filter(subscriber => subscriber.canReceive(update)) 167 | 168 | for (const subscriber of subscribers) { 169 | subscriber.sendAsync(update); 170 | } 171 | 172 | this.emit('publish', update, update.event.id); 173 | }); 174 | 175 | await this.history.start(); 176 | 177 | sse.on('connection', this.onSseConnection); 178 | } 179 | 180 | async dispatchUpdate(topics, data, opts = {}) { 181 | let updateId = opts.id; 182 | if (!updateId || this.config.ignorePublisherId) { 183 | updateId = uuidv4(); 184 | } 185 | 186 | let targets = opts.targets || [] 187 | if (opts.allTargets) { 188 | targets = null 189 | } 190 | 191 | // Handle when topics is a string 192 | const topicsArray = Array.isArray(topics) ? topics : [topics]; 193 | 194 | const update = new Update(targets, topicsArray, { 195 | data, 196 | id: updateId, 197 | type: opts.type || 'message', 198 | retry: Number(opts.retry) || 0, 199 | }); 200 | 201 | await this.history.push(update); 202 | 203 | return updateId; 204 | } 205 | 206 | generateJwt(claims = {}, key = null) { 207 | return util.promisify(jwt.sign)({ 208 | mercure: claims, 209 | }, key || this.config.jwtKey); 210 | } 211 | 212 | generatePublishJwt(targets = []) { 213 | return this.generateJwt({ 214 | publish: targets, 215 | }, this.config.pubJwtKey); 216 | } 217 | 218 | generateSubscribeJwt(targets = []) { 219 | return this.generateJwt({ 220 | subscribe: targets, 221 | }, this.config.subJwtKey); 222 | } 223 | 224 | // In case of compromission of the JWT key(s). 225 | async changeJwtKey(jwtKey) { 226 | this.config.jwtKey = jwtKey; 227 | this.config.pubJwtKey = null; 228 | this.config.subJwtKey = null; 229 | 230 | // Force re-authentication on subscribers that can only 231 | // subscribe to certain topics. 232 | await this.subscribers.clear(false); 233 | } 234 | 235 | // Generates random 256 bytes JWT and outputs it in the console. 236 | async killSwitch() { 237 | const buffer = crypto.randomBytes(256); // Using sync function on purpose. 238 | const jwtKey = buffer.toString('hex'); 239 | console.log(`====================================\n\n\tNEW JWT KEY :\n\n${jwtKey}\n\n====================================`); 240 | await this.changeJwtKey(jwtKey); 241 | } 242 | 243 | async end({ force = false } = {}) { 244 | if (!force) { 245 | await this.subscribers.clear(true); 246 | } 247 | 248 | if (this.redis) { 249 | if (force) { 250 | this.redis.end(false); 251 | } else { 252 | await this.redis.quitAsync(); 253 | } 254 | } 255 | 256 | await this.history.end({ force }); 257 | await this.server.close(); 258 | } 259 | 260 | endSync() { 261 | this.subscribers.clearSync(); 262 | this.history.endSync(); 263 | if (this.redis) { 264 | this.redis.end(false); 265 | } 266 | // Server connections will be interrupted. 267 | } 268 | } 269 | 270 | module.exports = Hub; 271 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # mercure 2 | 3 | [Mercure](https://github.com/dunglas/mercure) Hub & Publisher implemented in Node.js. 4 | 5 | ![stability-beta](https://img.shields.io/badge/stability-beta-green.svg) 6 | [![Build Status][build-badge]][build-url] 7 | 8 | [![npm version][version-badge]][version-url] 9 | [![Known Vulnerabilities][vulnerabilities-badge]][vulnerabilities-url] 10 | [![dependency status][dependency-badge]][dependency-url] 11 | [![devdependency status][devdependency-badge]][devdependency-url] 12 | [![downloads][downloads-badge]][downloads-url] 13 | [![Code Climate][maintainability-badge]][maintainability-url] 14 | 15 | [![NPM][npm-stats-badge]][npm-stats-url] 16 | 17 | *Note: this npm package has been **transfered** for a new project by the [initial owner](https://www.npmjs.com/~francois), which serves a totally different purpose. This new version is an implementation of the [Mercure protocol](https://github.com/dunglas/mercure). The previous `mercure` package had 1 release (`0.0.1`) and served as a file downloader. You can still access it: https://www.npmjs.com/package/mercure/v/0.0.1. Please make sure to **lock** this version in your `package.json` file, as the new versions will begin at `0.0.2` and will keep following the [semver versioning](https://semver.org).* 18 | 19 | ## TODOs 20 | 21 | * **CORS** 22 | * Hearthbeat mechanism (https://github.com/dunglas/mercure/pull/53) 23 | * Docker image (iso with official image) 24 | * Prometheus metrics exporter: 25 | * Subscribers count 26 | * Events count / size (in Bytes), per publisher 27 | * Publishers IPs 28 | * Instances count 29 | * `hub.on('connect')` listeners 30 | * Events database 31 | * Export authorization.js mechanism 32 | * Discovery helpers 33 | * Handle `Forwarded` and `X-Forwarded-For` headers ([related issue](https://github.com/dunglas/mercure/issues/114)) 34 | * Provide a Socket.io adapter ([see this thread](https://github.com/socketio/socket.io-adapter)) 35 | * Allow the dev to pass an URL in the `Publisher` contructor 36 | * `Publisher`: allow the user to specify a JWT key and the claims instead of a JWT 37 | * `Publisher`: getters like `get host()`, `port`, `protocol`... 38 | * Increase code quality score 39 | * JSDoc 40 | * Logging 41 | * Unit tests 42 | * Find a way to clear Redis if the process gets interrupted 43 | * Benchmarks 44 | 45 | ## State 46 | 47 | This is a **beta version**. This has not fully been tested in production yet. 48 | 49 | This implementation does not reflect the [latest specification](https://github.com/dunglas/mercure/pull/288) since they got changed. I don't recommend to use this module. 50 | 51 | ## Requirements 52 | 53 | * node.js **>= 11.7.0** 54 | * Redis (optional) 55 | 56 | ## Features 57 | 58 | * 100% implementation of the protocol 59 | * Events asymmetric encryption 60 | * Easy integration to any existing app using `http.Server` or `express` 61 | * Redis-based clustering support 62 | * Inventory of all open connections stored in Redis, per node process 63 | * Kill switch 64 | 65 | ## Future improvements 66 | 67 | * Implement as a lambda function ? 68 | 69 | ## Installation 70 | 71 | ```bash 72 | npm install mercure --save 73 | ``` 74 | 75 | ## Usage 76 | 77 | This library provides 3 components: a `Hub`, a `Server` and a `Publisher`: 78 | 79 | ![Classes preview](classes-preview.jpg "Classes preview") 80 | 81 | ### Simple hub 82 | 83 | > -> *[Documentation](docs/API.md#hub)* 84 | 85 | The `Hub` class is the core component that uses a simple `http.Server` instance. An existing instance can be provided to the `Hub`, thus the Hub will use it instead of creating a new one. 86 | 87 | **Use case:** implanting the hub on an existing `http.Server` app, without the need to handle external publishers (only the app does the publishing). 88 | 89 | It handles: 90 | 91 | * the SSE connections 92 | * the events database 93 | * the authorization mechanism 94 | * events related to the Hub activity 95 | 96 | ```javascript 97 | const http = require('http'); 98 | const { Hub } = require('mercure'); 99 | 100 | const server = http.createServer((req, res) => { 101 | res.writeHead(200, { 'Content-Type': 'text/plain' }); 102 | res.end('200'); 103 | }); 104 | 105 | const hub = new Hub(server, { 106 | jwtKey: '!UnsecureChangeMe!', 107 | path: '/.well-known/mercure', 108 | }); 109 | 110 | hub.listen(3000); 111 | ``` 112 | 113 | ### Hub server 114 | 115 | > -> *[Documentation](docs/API.md#server)* 116 | 117 | The `Server` is built upon the `Hub` component. It creates a new Express instance and allows external publishers to `POST` an event to the hub. 118 | 119 | **Use case:** implanting he hub on an new application that is meant to accept external publishers, with no other HTTP server ... or one listening on a different port. 120 | 121 | It handles **everything the `Hub` does**, plus: 122 | 123 | * a freshly created Express instance, built upon the Hub's `http.Server` (middlewares can be applied to enhance security) 124 | * external publishers (POST requests) 125 | 126 | ```javascript 127 | const { Server } = require('mercure'); 128 | 129 | const server = new Server({ 130 | jwtKey: '!UnsecureChangeMe!', 131 | path: '/.well-known/mercure', 132 | }); 133 | 134 | server.listen(3000); 135 | ``` 136 | 137 | Because the Server leverages Express, it is possible to add middlewares in front of the internal Hub middleware: 138 | 139 | ```javascript 140 | const compression = require('compression'); 141 | 142 | class SecuredHubServer extends Server { 143 | configure() { 144 | this.app.use(compression()); 145 | } 146 | } 147 | 148 | const server = new SecuredHubServer(...); 149 | ``` 150 | 151 | ### Publisher 152 | 153 | > -> *[Documentation](docs/API.md#publisher)* 154 | 155 | It can be created in different ways: 156 | 157 | * using an existing `Hub` instance (when the app is meant to be THE ONLY publisher) 158 | * using an existing `Server` instance (when the app is meant to be a publisher) 159 | * using configuration: `host`, `port`... (when the publisher and the hub are distant) 160 | 161 | It handles: 162 | 163 | * Message publication to the Hub 164 | * Message encryption *(optional)* 165 | 166 | ```javascript 167 | const { Publisher } = require('mercure'); 168 | 169 | const publisher = new Publisher({ 170 | protocol: 'https', // or 'http', but please don't. 171 | host: 'example.com', 172 | port: 3000, 173 | path: '/.well-known/mercure', 174 | jwt: 'PUBLISHER_JWT', 175 | }); 176 | 177 | // Payload to send to the subscribers. 178 | const data = { 179 | '@id': 'http://localhost:3000/books/666.jsonld', 180 | hello: 'world', 181 | }; 182 | 183 | await publisher.publish( 184 | ['https://example.com:3000/books/666.jsonld'], // Topics. 185 | JSON.stringify(data), 186 | ); 187 | ``` 188 | 189 | ## API 190 | 191 | API docs can be found [in the docs/API.md file](docs/API.md). 192 | 193 | ## Encrypting the datas 194 | 195 | In certain cases, the Mercure hub can be hosted by a third-party host. You don't really want them to "sniff" all your cleartext messages. To make the Publisher => Hub => Subscriber flow fully encrypted, it is required that the Publisher sends encrypted data. 196 | 197 | To achieve this, the `Publisher#useEncryption()` method will activate messages encryption. Thus, the Hub will not be able to access your private datas: 198 | 199 | ```javascript 200 | const crypto = require('crypto'); 201 | const util = require('util'); 202 | 203 | const publisher = new Publisher({ 204 | // ... 205 | }); 206 | 207 | const data = { message: 'TOP SECRET DATAS' }; 208 | const { privateKey } = await util.promisify(crypto.generateKeyPair)('rsa', { 209 | modulusLength: 4096, 210 | privateKeyEncoding: { 211 | type: 'pkcs8', 212 | format: 'pem', 213 | }, 214 | }); 215 | 216 | // Start encrypting the events. 217 | await publisher.useEncryption({ 218 | rsaPrivateKey: privateKey, 219 | }); 220 | 221 | // Will send encrypted datas. 222 | await publisher.publish( 223 | [...], // Topics. 224 | JSON.stringify(data), 225 | ); 226 | ``` 227 | 228 | Decrypting: 229 | 230 | ```javascript 231 | const jose = require('node-jose'); 232 | 233 | const encryptedData = 'ENCRYPTED DATA'; 234 | const decrypted = await jose.JWE.createDecrypt(publisher.keystore).decrypt(encryptedData); 235 | 236 | console.log(decrypted.plaintext.toString()); 237 | ``` 238 | 239 | ## Kill switch 240 | 241 | In case the hub must urgently close all connections (e.g.: in case of compromission of the JWT key), a kill switch is available: 242 | 243 | ```javascript 244 | await hub.killSwitch(); 245 | ``` 246 | 247 | The new JWT Key will be output to stdout. 248 | 249 | ## License 250 | 251 | GNU GENERAL PUBLIC LICENSE v3. 252 | 253 | [build-badge]: https://img.shields.io/endpoint.svg?url=https%3A%2F%2Factions-badge.atrox.dev%2FIlshidur%2Fnode-mercure%2Fbadge&style=flat 254 | [build-url]: https://actions-badge.atrox.dev/Ilshidur/node-mercure/goto 255 | [version-badge]: https://img.shields.io/npm/v/mercure.svg 256 | [version-url]: https://www.npmjs.com/package/mercure 257 | [vulnerabilities-badge]: https://snyk.io/test/npm/mercure/badge.svg 258 | [vulnerabilities-url]: https://snyk.io/test/npm/mercure 259 | [dependency-badge]: https://david-dm.org/ilshidur/mercure.svg 260 | [dependency-url]: https://david-dm.org/ilshidur/mercure 261 | [devdependency-badge]: https://david-dm.org/ilshidur/mercure/dev-status.svg 262 | [devdependency-url]: https://david-dm.org/ilshidur/mercure#info=devDependencies 263 | [downloads-badge]: https://img.shields.io/npm/dt/mercure.svg 264 | [downloads-url]: https://www.npmjs.com/package/mercure 265 | [maintainability-badge]: https://api.codeclimate.com/v1/badges/92ad8661f7de98e13f0f/maintainability 266 | [maintainability-url]: https://codeclimate.com/github/Ilshidur/node-mercure/maintainability 267 | [npm-stats-badge]: https://nodei.co/npm/mercure.png?downloads=true&downloadRank=true 268 | [npm-stats-url]: https://nodei.co/npm/mercure 269 | -------------------------------------------------------------------------------- /docs/API.md: -------------------------------------------------------------------------------- 1 | # API documentation 2 | 3 | ![Classes preview](classes-preview.jpg "Classes preview") 4 | 5 | ## Table of contents 6 | 7 | - [API documentation](#api-documentation) 8 | - [Table of contents](#table-of-contents) 9 | - [Hub](#hub) 10 | - [`Hub#constructor(server, config)` -> `Hub`](#hubconstructorserver-config---hub) 11 | - [`Hub#listen(port, addr)` -> `Promise`](#hublistenport-addr---promisevoid) 12 | - [`Hub#dispatchUpdate(topics, data, opts)` -> `Promise`](#hubdispatchupdatetopics-data-opts---promisenumber) 13 | - [`Hub#generateJwt(claims)` -> `Promise`](#hubgeneratejwtclaims---promisestring) 14 | - [`Hub#generatePublishJwt(targets)` -> `Promise`](#hubgeneratepublishjwttargets---promisestring) 15 | - [`Hub#generateSubscribeJwt(targets)` -> `Promise`](#hubgeneratesubscribejwttargets---promisestring) 16 | - [`Hub#authorizePublish(req)` -> `Promise`](#hubauthorizepublishreq---promiseobject) 17 | - [`Hub#authorizeSubscribe(req)` -> `Promise`](#hubauthorizesubscribereq---promiseobject) 18 | - [`Hub#end(opts)` -> `Promise`](#hubendopts---promisevoid) 19 | - [`Hub#endSync()` -> `void`](#hubendsync---void) 20 | - [`Hub#changeJwtKey()` -> `Promise`](#hubchangejwtkey---promisevoid) 21 | - [`Hub#killSwitch()` -> `Promise`](#hubkillswitch---promisevoid) 22 | - [Server](#server) 23 | - [`Server#constructor(config)` -> `Server`](#serverconstructorconfig---server) 24 | - [static `Server#createFromExpressApp(app, config)` -> `Objet`](#static-servercreatefromexpressappapp-config---objethttpserver-hub) 25 | - [`Server#listen(port, addr)` -> `Promise`](#serverlistenport-addr---promisevoid) 26 | - [`Server#end(opts)` -> `Promise`](#serverendopts---promisevoid) 27 | - [`Server#endSync()` -> `void`](#serverendsync---void) 28 | - [Publisher](#publisher) 29 | - [`Publisher#constructor(config || hub)` -> `Publisher`](#publisherconstructorconfig--hub---publisher) 30 | - [`Publisher#publish(topics, message, options)` -> `Promise`](#publisherpublishtopics-message-options---promisestring) 31 | - [`Publisher#useEncryption(config)` -> `Promise>`](#publisheruseencryptionconfig---promiseobjectstring-string) 32 | - [`Publisher#getClaims()` => `Object`](#publishergetclaims--object) 33 | 34 | ## Hub 35 | 36 | ### `Hub#constructor(server, config)` -> `Hub` 37 | 38 | Initializes a new Hub instance. When clustering the application, it is required to connect the hub to [Redis](https://redis.io) in order to leverage its pub/sub capabilities and scale across multiple hub instances. 39 | 40 | The instance does not immediately "listen". Calling the `Hub#listen()` method is required. 41 | 42 | **Arguments :** 43 | 44 | * `server` ([`http.Server`](https://nodejs.org/api/http.html#http_class_http_server), *optional*) : a native `http.Server` instance. If not passed, the hub will create one. 45 | * `config` (`Object`, *optional*) : 46 | * `id` (`String`, *optional*) : a unique ID identifying this instance amongst a full instances cluster. 47 | * `jwtKey` (`String`, **required**) : the publisher's AND subscriber's JSON Web Token key. Throws if either `pubJwtKey` or `subJwtKey` are passed. 48 | * `pubJwtKey` (`String`, **required**) : the publisher's jwt key. Throws if `jwtKey` is also passed. 49 | * `subJwtKey` (`String`, **required**) : the subscriber's jwt key. Throws if `jwtKey` is also passed. 50 | * `path` (`String`, *defaults to `'/.well-known/mercure'`*) : the hub's route. 51 | * `allowAnonymous` (`Boolean`, *defaults to `false`*) : set to `true` to allow subscribers with no valid JWT to connect. 52 | * `maxTopics` (`Number`, *defaults to `0`*) : maximum topics count the subscribers can subscribe to. `0` means no limit. 53 | * `ignorePublisherId` (`Boolean`, *defaults to `true`*) : set to `false` to accept the event ID by the publisher instead of creating a new one. 54 | * `publishAllowedOrigins` (`Array`, *defaults to `[]`*) : a list of origins allowed to publish (only applicable when using cookie-based auth). 55 | * `redis` (`Object`, *optional*) : if defined, the Hub will connect to a Redis instance and use it to store the events and scale across multiple instances. This option is directly passed to the `redis.createInstance()` method of the [`redis`](https://www.npmjs.com/package/redis) npm module. 56 | 57 | **Returns :** a new `Hub` instance. 58 | 59 | ### `Hub#listen(port, addr)` -> `Promise` 60 | 61 | Listens to incoming subscription requests. It can be stopped with the methods `Hub#end()` or `Hub#endSync()`. 62 | 63 | **Arguments :** 64 | 65 | * `port` (`Number`, **required**) : the port which the hub will listen to. 66 | * `addr` (`String`, *defaults to `'0.0.0.0'`*) : the listening bound address. 67 | 68 | **Returns :** a `Promise` resolving when the server has started listening. 69 | 70 | ### `Hub#dispatchUpdate(topics, data, opts)` -> `Promise` 71 | 72 | Sends an update to the subscribers. Only the subscribers watching the corresponding topics will receive the update if they are allowed to. 73 | 74 | **Arguments :** 75 | 76 | * `topics` (`Array || String`, **required**) : Topic(s) of the update. 77 | * `data` (`String`, **required**) : the message to send to the subscribers. 78 | * `opts` (`Object`, *optional*) : 79 | * `id` (`String`, *optional*) : the event ID. Will be discarded if `ignorePublisherId` is set to `true` in the hub's configuration. 80 | * `targets` (`Array`, *defaults to `[]`*) : 81 | * `allTargets` (`Boolean`, *defaults to `false`*) : 82 | * `type` (`String`, *defaults to `'message'`*) : the event message type. 83 | * `retry` (`Number`, *defaults to `0`*) : the subscriber's reconnection time. 84 | 85 | **Returns :** a `Promise` resolving with the update ID when the update has been dispatched. 86 | 87 | ### `Hub#generateJwt(claims)` -> `Promise` 88 | 89 | Generates a JWT using the stored JSON Web Token key. This JWT contains the targets the subscriber is allowed to get updates about. 90 | 91 | => [Example on jwt.io](https://jwt.io/#debugger-io?token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJtZXJjdXJlIjp7InN1YnNjcmliZSI6WyJmb28iLCJiYXIiXSwicHVibGlzaCI6WyJmb28iXX19.LRLvirgONK13JgacQ_VbcjySbVhkSmHy3IznH3tA9PM) 92 | 93 | **Arguments :** 94 | 95 | * `claims` (`Object`, **required**) : 96 | * `publish`: (`Array`, *optional*) : targets that the client can publish to. 97 | * `subscribe`: (`Array`, *optional*) : targets that the client can subscribe to. 98 | 99 | **Returns :** a `Promise` resolving a `String` containing the JWT. 100 | 101 | ### `Hub#generatePublishJwt(targets)` -> `Promise` 102 | 103 | Generates a JWT using the stored JSON Web Token key. This JWT only contains permissions to **publish** on the given targets. 104 | 105 | => [Example on jwt.io](https://jwt.io/#debugger-io?token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJtZXJjdXJlIjp7InB1Ymxpc2giOlsiZm9vIl19fQ.weCGCnFpami1oNG9nflP7jb3-d1G8uSv8vd3yGjDBDU) 106 | 107 | **Arguments :** 108 | 109 | * `targets`: (`Array`, *optional*) : targets that the client can publish to. 110 | 111 | **Returns :** a `Promise` resolving a `String` containing the JWT. 112 | 113 | ### `Hub#generateSubscribeJwt(targets)` -> `Promise` 114 | 115 | Generates a JWT using the stored JSON Web Token key. This JWT only contains permissions to **subscribe** on the given targets. 116 | 117 | => [Example on jwt.io](https://jwt.io/#debugger-io?token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJtZXJjdXJlIjp7InN1YnNjcmliZSI6WyJmb28iLCJiYXIiXX19.DNa7vHxKE-l_NBc1a_JrfLPDjq0rG1_gAOZMBeC3xh0) 118 | 119 | **Arguments :** 120 | 121 | * `targets`: (`Array`, *optional*) : targets that the client can subscribe to. 122 | 123 | **Returns :** a `Promise` resolving a `String` containing the JWT. 124 | 125 | ### `Hub#authorizePublish(req)` -> `Promise` 126 | 127 | Extracts the claims from a request (header or cookie) addressed to the hub. This only extracts claims from a request sent by a **publisher**. 128 | 129 | **Arguments :** 130 | 131 | * `req` ([`http.ClientRequest`](https://nodejs.org/api/http.html#http_class_http_clientrequest)) : 132 | 133 | **Returns :** a `Promise` resolving the claims extracted from the request's JWT. 134 | 135 | ### `Hub#authorizeSubscribe(req)` -> `Promise` 136 | 137 | Extracts the claims from a request (header or cookie) addressed to the hub. This only extracts claims from a request sent by a **subscriber**. 138 | 139 | **Arguments :** 140 | 141 | * `req` ([`http.ClientRequest`](https://nodejs.org/api/http.html#http_class_http_clientrequest)) : 142 | 143 | **Returns :** a `Promise` resolving the claims extracted from the request's JWT. 144 | 145 | ### `Hub#end(opts)` -> `Promise` 146 | 147 | Gracefully stops the hub **asynchronously**. This will close the connections to the subscribers. 148 | 149 | **Arguments :** 150 | 151 | * `opts` (`Object`, *optional*) : 152 | * `force` (`Boolean`, *defaults to `false`*) : set to `true` to forcefully close all connections. 153 | 154 | **Returns :** a `Promise` resolving when the hub is stopped. 155 | 156 | ### `Hub#endSync()` -> `void` 157 | 158 | *Forcefully* stops the hub **synchronously**. 159 | 160 | **Arguments :** *(none)* 161 | 162 | **Returns :** *(void)* 163 | 164 | ### `Hub#changeJwtKey()` -> `Promise` 165 | 166 | Changes the JSON Web Token key. This will close all subscribers' open connections, except the ones from subscribers who have full subscription rights to the hub. 167 | 168 | **Arguments :** *(none)* 169 | 170 | **Returns :** a `Promise` resolving when the JWT has been changed. 171 | 172 | ### `Hub#killSwitch()` -> `Promise` 173 | 174 | Will : 175 | 176 | * generate a new JWT key. 177 | * close all subscribers' open connections, except the ones from subscribers who have full subscription rights to the hub. 178 | * outputs the new JWT Key to stdout. 179 | 180 | **Use case :** in case the hub must urgently close all connections (e.g.: in case of compromission of the JWT key). 181 | 182 | **Arguments :** *(none)* 183 | 184 | **Returns :** a `Promise` resolving when the JWT has been changed. 185 | 186 | ## Server 187 | 188 | ### `Server#constructor(config)` -> `Server` 189 | 190 | Initializes a new Server instance. When clustering the application, it is required to connect the server to [Redis](https://redis.io) in order to leverage its pub/sub capabilities and scale across multiple hub instances. 191 | 192 | The instance does not immediately "listen". Calling the `Server#listen()` method is required. 193 | 194 | **Arguments :** 195 | 196 | *Note :* this constructor takes the same options as `Hub#constructor()`. 197 | 198 | * `server` ([`http.Server`](https://nodejs.org/api/http.html#http_class_http_server), *optional*) : a native `http.Server` instance. If not passed, the hub will create one. 199 | * `config` (`Object`, *optional*) : 200 | * `id` (`String`, *optional*) : a unique ID identifying this instance amongst a full instances cluster. 201 | * `jwtKey` (`String`, **required**) : the publisher's AND subscriber's JSON Web Token key. Throws if either `pubJwtKey` or `subJwtKey` are passed. 202 | * `pubJwtKey` (`String`, **required**) : the publisher's jwt key. Throws if `jwtKey` is also passed. 203 | * `subJwtKey` (`String`, **required**) : the subscriber's jwt key. Throws if `jwtKey` is also passed. 204 | * `path` (`String`, *defaults to `'/.well-known/mercure'`*) : the hub's route. 205 | * `allowAnonymous` (`Boolean`, *defaults to `false`*) : set to `true` to allow subscribers with no valid JWT to connect. 206 | * `maxTopics` (`Number`, *defaults to `0`*) : maximum topics count the subscribers can subscribe to. `0` means no limit. 207 | * `ignorePublisherId` (`Boolean`, *defaults to `true`*) : set to `false` to accept the event ID by the publisher instead of creating a new one. 208 | * `publishAllowedOrigins` (`Array`, *defaults to `[]`*) : a list of origins allowed to publish (only applicable when using cookie-based auth). 209 | * `redis` (`Object`, *optional*) : if defined, the Hub will connect to a Redis instance and use it to store the events and scale across multiple instances. This option is directly passed to the `redis.createInstance()` method of the [`redis`](https://www.npmjs.com/package/redis) npm module. 210 | 211 | **Returns :** a new `Server` instance. 212 | 213 | ### static `Server#createFromExpressApp(app, config)` -> `Objet` 214 | 215 | Creates a `http.Server` instance and a Hub from an existing Express app. The created hub is bound to the http server. 216 | 217 | The `http.Server` instance does not immediately "listen". Calling the `http.Server#listen()` method is required. 218 | 219 | *Note :* the Hub requires data encoded to `x-form-urlencoded`, thus the Express app **MUST** use the [`express.urlencoded()` middleware](https://expressjs.com/en/api.html#express.urlencoded) beforehand, in order to parse the requests datas. 220 | 221 | **Arguments :** 222 | 223 | * `app` : the Express application. 224 | * `config` (`Object`) : the configuration to pass to the Hub. See `Hub#constructor()`. 225 | 226 | **Returns :** an `Object` : 227 | 228 | * `server` (`http.Server` instance) : the created http server from the Express app. 229 | * `hub` (`Hub` instance) : the Hub that will handle the SSE connections. 230 | 231 | ### `Server#listen(port, addr)` -> `Promise` 232 | 233 | Listens to incoming subscription requests. It can be stopped with the methods `Hub#end()` or `Hub#endSync()`. 234 | 235 | **Arguments :** 236 | 237 | * `port` (`Number`, **required**) : the port which the hub will listen to. 238 | * `addr` (`String`, *defaults to `'0.0.0.0'`*) : the listening bound address. 239 | 240 | **Returns :** a `Promise` resolving when the server has started listening. 241 | 242 | ### `Server#end(opts)` -> `Promise` 243 | 244 | Gracefully stops the hub **asynchronously**. This will close the connections to the subscribers. 245 | 246 | **Arguments :** 247 | 248 | * `opts` (`Object`, *optional*) : 249 | * `force` (`Boolean`, *defaults to `false`*) : set to `true` to forcefully close all connections. 250 | 251 | **Returns :** a `Promise` resolving when the hub is stopped. 252 | 253 | ### `Server#endSync()` -> `void` 254 | 255 | *Forcefully* stops the hub **synchronously**. 256 | 257 | **Arguments :** *(none)* 258 | 259 | **Returns :** *(void)* 260 | 261 | ## Publisher 262 | 263 | ### `Publisher#constructor(config || hub)` -> `Publisher` 264 | 265 | Initializes a new publisher, ready to send messages to its hub. 266 | 267 | **Arguments :** 268 | 269 | * The 1st and only argument is **required**. It is either : 270 | * a `Hub` instance (for publisher that are located in the same code base as the hub). 271 | * a configuration `Object` : (usually for remote publishers) 272 | * `protocol` (`String`, *defaults to `'https'`*) 273 | * `host` (`String`, **required**) 274 | * `port` (`Number`, *defaults to `80`*) 275 | * `path` (`String`, *defaults to `'/.well-known/mercure'`*) 276 | * `jwt` (`String`, **required**) 277 | * `rsaPrivateKey` (`String`, *optional*) : 278 | 279 | ### `Publisher#publish(topics, message, options)` -> `Promise` 280 | 281 | Sends a message to the hub. The hub will dispatch the event to the appropriate subscribers. 282 | 283 | **Arguments :** 284 | 285 | * `topics` (`Array || String`, **required**) : the topics of the publication. 286 | * `message` (`String`, **required**) : The content to send to the subscribers. 287 | * `options` (`Object`, *optional*) : 288 | * `targets` (`Array || String`, *optional*) : the targets that will receive the update. Passing nothing will publish the update to all subscribers. 289 | * `id` (`String`, *optional*) : the ID to give to the sent update. The server can discard it if it's configured to do so. 290 | * `type` (`String`, *defaults to `'message'`*) : the type of the event to send to the subscribers. 291 | * `retry` (`Number`, *optional*) : the reconnection cooldown to send to the subscribers. 292 | * `allTargets` (`Boolean`, *optional*) : set to `true` to dispatch the update to all subscribers. Only available when the publisher is directly linked to the Hub instance. 293 | 294 | **Returns :** a `Promise` resolving the event ID when the message has been sent to the hub. 295 | 296 | ### `Publisher#useEncryption(config)` -> `Promise>` 297 | 298 | Allows encryption of the sent update to the Hub. 299 | 300 | **Arguments :** 301 | 302 | * `config` (`Object`, *optional*) 303 | * `rsaPrivateKey` (`String`, *optional*) : the private RSA key that will be used to cypher the messages. If nothing is passed, the method will use the key passed in the class constructor. If nothing was passed, the method generates a new RSA public/private key pair. 304 | 305 | **Returns :** a `Promise` resolving an `Object` when the encryption mechanism is ready : 306 | 307 | * `rsaPrivateKey` (`String`) : the used RSA private key. 308 | * `rsaPublicKey` (`String`) : the public RSA key, calculated from the private RSA key. 309 | 310 | ### `Publisher#getClaims()` => `Object` 311 | 312 | Decodes the stored JWT used to send updates. If no JWT is used (e.g.: the Publisher is created with a `Hub` instance), returns `null`. 313 | 314 | **Arguments :** *(none)* 315 | 316 | **Returns :** an `Object` containing the decoded JWT's payload. 317 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. 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Patents. 472 | 473 | A "contributor" is a copyright holder who authorizes use under this 474 | License of the Program or a work on which the Program is based. The 475 | work thus licensed is called the contributor's "contributor version". 476 | 477 | A contributor's "essential patent claims" are all patent claims 478 | owned or controlled by the contributor, whether already acquired or 479 | hereafter acquired, that would be infringed by some manner, permitted 480 | by this License, of making, using, or selling its contributor version, 481 | but do not include claims that would be infringed only as a 482 | consequence of further modification of the contributor version. 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"Knowingly relying" means you have 508 | actual knowledge that, but for the patent license, your conveying the 509 | covered work in a country, or your recipient's use of the covered work 510 | in a country, would infringe one or more identifiable patents in that 511 | country that you have reason to believe are valid. 512 | 513 | If, pursuant to or in connection with a single transaction or 514 | arrangement, you convey, or propagate by procuring conveyance of, a 515 | covered work, and grant a patent license to some of the parties 516 | receiving the covered work authorizing them to use, propagate, modify 517 | or convey a specific copy of the covered work, then the patent license 518 | you grant is automatically extended to all recipients of the covered 519 | work and works based on it. 520 | 521 | A patent license is "discriminatory" if it does not include within 522 | the scope of its coverage, prohibits the exercise of, or is 523 | conditioned on the non-exercise of one or more of the rights that are 524 | specifically granted under this License. You may not convey a covered 525 | work if you are a party to an arrangement with a third party that is 526 | in the business of distributing software, under which you make payment 527 | to the third party based on the extent of your activity of conveying 528 | the work, and under which the third party grants, to any of the 529 | parties who would receive the covered work from you, a discriminatory 530 | patent license (a) in connection with copies of the covered work 531 | conveyed by you (or copies made from those copies), or (b) primarily 532 | for and in connection with specific products or compilations that 533 | contain the covered work, unless you entered into that arrangement, 534 | or that patent license was granted, prior to 28 March 2007. 535 | 536 | Nothing in this License shall be construed as excluding or limiting 537 | any implied license or other defenses to infringement that may 538 | otherwise be available to you under applicable patent law. 539 | 540 | 12. No Surrender of Others' Freedom. 541 | 542 | If conditions are imposed on you (whether by court order, agreement or 543 | otherwise) that contradict the conditions of this License, they do not 544 | excuse you from the conditions of this License. If you cannot convey a 545 | covered work so as to satisfy simultaneously your obligations under this 546 | License and any other pertinent obligations, then as a consequence you may 547 | not convey it at all. For example, if you agree to terms that obligate you 548 | to collect a royalty for further conveying from those to whom you convey 549 | the Program, the only way you could satisfy both those terms and this 550 | License would be to refrain entirely from conveying the Program. 551 | 552 | 13. Use with the GNU Affero General Public License. 553 | 554 | Notwithstanding any other provision of this License, you have 555 | permission to link or combine any covered work with a work licensed 556 | under version 3 of the GNU Affero General Public License into a single 557 | combined work, and to convey the resulting work. The terms of this 558 | License will continue to apply to the part which is the covered work, 559 | but the special requirements of the GNU Affero General Public License, 560 | section 13, concerning interaction through a network will apply to the 561 | combination as such. 562 | 563 | 14. Revised Versions of this License. 564 | 565 | The Free Software Foundation may publish revised and/or new versions of 566 | the GNU General Public License from time to time. Such new versions will 567 | be similar in spirit to the present version, but may differ in detail to 568 | address new problems or concerns. 569 | 570 | Each version is given a distinguishing version number. If the 571 | Program specifies that a certain numbered version of the GNU General 572 | Public License "or any later version" applies to it, you have the 573 | option of following the terms and conditions either of that numbered 574 | version or of any later version published by the Free Software 575 | Foundation. If the Program does not specify a version number of the 576 | GNU General Public License, you may choose any version ever published 577 | by the Free Software Foundation. 578 | 579 | If the Program specifies that a proxy can decide which future 580 | versions of the GNU General Public License can be used, that proxy's 581 | public statement of acceptance of a version permanently authorizes you 582 | to choose that version for the Program. 583 | 584 | Later license versions may give you additional or different 585 | permissions. However, no additional obligations are imposed on any 586 | author or copyright holder as a result of your choosing to follow a 587 | later version. 588 | 589 | 15. Disclaimer of Warranty. 590 | 591 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY 592 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT 593 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY 594 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, 595 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 596 | PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM 597 | IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF 598 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 599 | 600 | 16. Limitation of Liability. 601 | 602 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS 604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY 605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE 606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF 607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), 609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF 610 | SUCH DAMAGES. 611 | 612 | 17. Interpretation of Sections 15 and 16. 613 | 614 | If the disclaimer of warranty and limitation of liability provided 615 | above cannot be given local legal effect according to their terms, 616 | reviewing courts shall apply local law that most closely approximates 617 | an absolute waiver of all civil liability in connection with the 618 | Program, unless a warranty or assumption of liability accompanies a 619 | copy of the Program in return for a fee. 620 | 621 | END OF TERMS AND CONDITIONS 622 | 623 | How to Apply These Terms to Your New Programs 624 | 625 | If you develop a new program, and you want it to be of the greatest 626 | possible use to the public, the best way to achieve this is to make it 627 | free software which everyone can redistribute and change under these terms. 628 | 629 | To do so, attach the following notices to the program. It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | mercure 635 | Copyright (C) 2018 Nicolas Coutin 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | mercure Copyright (C) 2018 Nicolas Coutin 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . 675 | --------------------------------------------------------------------------------