Add streaming API in Node.js

streaming/index.js

@@ -0,0 +1,97 @@
+import dotenv from 'dotenv'
+import express from 'express'
+import redis from 'redis'
+import pg from 'pg'
+
+dotenv.config()
+
+const pgConfigs = {
+  development: {
+    database: 'mastodon_development',
+    host:     '/var/run/postgresql',
+    max:      10
+  },
+
+  production: {
+    user:     process.env.DB_USER || 'mastodon',
+    password: process.env.DB_PASS || '',
+    database: process.env.DB_NAME || 'mastodon_production',
+    host:     process.env.DB_HOST || 'localhost',
+    port:     process.env.DB_PORT || 5432,
+    max:      10
+  }
+}
+
+const app = express()
+const env = process.env.NODE_ENV || 'development'
+const pgPool = new pg.Pool(pgConfigs[env])
+
+const authenticationMiddleware = (req, res, next) => {
+  const authorization = req.get('Authorization')
+
+  if (!authorization) {
+    err = new Error('Missing access token')
+    err.statusCode = 401
+
+    return next(err)
+  }
+
+  const token = authorization.replace(/^Bearer /, '')
+
+  pgPool.connect((err, client, done) => {
+    if (err) {
+      return next(err)
+    }
+
+    client.query('SELECT oauth_access_tokens.resource_owner_id, users.account_id FROM oauth_access_tokens INNER JOIN users ON oauth_access_tokens.resource_owner_id = users.id WHERE token = $1 LIMIT 1', [token], (err, result) => {
+      done()
+
+      if (err) {
+        return next(err)
+      }
+
+      if (result.rows.length === 0) {
+        err = new Error('Invalid access token')
+        err.statusCode = 401
+
+        return next(err)
+      }
+
+      req.accountId = result.rows[0].account_id
+
+      next()
+    })
+  })
+}
+
+const errorMiddleware = (err, req, res, next) => {
+  res.writeHead(err.statusCode || 500, { 'Content-Type': 'application/json' })
+  res.end(JSON.stringify({ error: `${err}` }))
+}
+
+const streamFrom = (id, res) => {
+  res.setHeader('Content-Type', 'text/event-stream')
+  res.setHeader('Transfer-Encoding', 'chunked')
+
+  const redisClient = redis.createClient()
+
+  redisClient.on('message', (channel, message) => {
+    const { event, payload } = JSON.parse(message)
+
+    res.write(`event: ${event}\n`)
+    res.write(`data: ${payload}\n\n`)
+  })
+
+  setInterval(() => res.write('\n'), 15000)
+
+  redisClient.subscribe(id)
+}
+
+app.use(authenticationMiddleware)
+app.use(errorMiddleware)
+
+app.get('/api/v1/streaming/user',    (req, res) => streamFrom(`timeline:${req.accountId}`, res))
+app.get('/api/v1/streaming/public',  (_, res)   => streamFrom('timeline:public', res))
+app.get('/api/v1/streaming/hashtag', (req, res) => streamFrom(`timeline:hashtag:${req.params.tag}`, res))
+
+app.listen(4000)