make it possible to stream public timelines without authorization (#5977)

* make it possible to stream public timelines without authorization

* Fix

* Make eslint allow `value == null`

* Remove redundant line

* Improve style and revert .eslintrc.yml

* Fix streamWsEnd

* Show IP address instead of (anonymous user)

* Add missing semicolon

streaming/index.js

@@ -97,6 +97,8 @@ const startWorker = (workerId) => {
   };
 
   const app    = express();
+  app.set('trusted proxy', process.env.TRUSTED_PROXY_IP || 'loopback,uniquelocal');
+
   const pgPool = new pg.Pool(Object.assign(pgConfigs[env], dbUrlToConfig(process.env.DATABASE_URL)));
   const server = http.createServer(app);
   const redisNamespace = process.env.REDIS_NAMESPACE || null;
@@ -177,6 +179,12 @@ const startWorker = (workerId) => {
     next();
   };
 
+  const setRemoteAddress = (req, res, next) => {
+    req.remoteAddress = req.connection.remoteAddress;
+
+    next();
+  };
+
   const accountFromToken = (token, req, next) => {
     pgPool.connect((err, client, done) => {
       if (err) {
@@ -208,17 +216,22 @@ const startWorker = (workerId) => {
     });
   };
 
-  const accountFromRequest = (req, next) => {
+  const accountFromRequest = (req, next, required = true) => {
     const authorization = req.headers.authorization;
     const location = url.parse(req.url, true);
     const accessToken = location.query.access_token;
 
     if (!authorization && !accessToken) {
+      if (required) {
         const err = new Error('Missing access token');
         err.statusCode = 401;
 
         next(err);
         return;
+      } else {
+        next();
+        return;
+      }
     }
 
     const token = authorization ? authorization.replace(/^Bearer /, '') : accessToken;
@@ -226,7 +239,17 @@ const startWorker = (workerId) => {
     accountFromToken(token, req, next);
   };
 
+  const PUBLIC_STREAMS = [
+    'public',
+    'public:local',
+    'hashtag',
+    'hashtag:local',
+  ];
+
   const wsVerifyClient = (info, cb) => {
+    const location = url.parse(info.req.url, true);
+    const authRequired = !PUBLIC_STREAMS.some(stream => stream === location.query.stream);
+
     accountFromRequest(info.req, err => {
       if (!err) {
         cb(true, undefined, undefined);
@@ -234,16 +257,24 @@ const startWorker = (workerId) => {
         log.error(info.req.requestId, err.toString());
         cb(false, 401, 'Unauthorized');
       }
-    });
+    }, authRequired);
   };
 
+  const PUBLIC_ENDPOINTS = [
+    '/api/v1/streaming/public',
+    '/api/v1/streaming/public/local',
+    '/api/v1/streaming/hashtag',
+    '/api/v1/streaming/hashtag/local',
+  ];
+
   const authenticationMiddleware = (req, res, next) => {
     if (req.method === 'OPTIONS') {
       next();
       return;
     }
 
-    accountFromRequest(req, next);
+    const authRequired = !PUBLIC_ENDPOINTS.some(endpoint => endpoint === req.path);
+    accountFromRequest(req, next, authRequired);
   };
 
   const errorMiddleware = (err, req, res, {}) => {
@@ -275,8 +306,10 @@ const startWorker = (workerId) => {
   };
 
   const streamFrom = (id, req, output, attachCloseHandler, needsFiltering = false, notificationOnly = false) => {
+    const accountId = req.accountId || req.remoteAddress;
+
     const streamType = notificationOnly ? ' (notification)' : '';
-    log.verbose(req.requestId, `Starting stream from ${id} for ${req.accountId}${streamType}`);
+    log.verbose(req.requestId, `Starting stream from ${id} for ${accountId}${streamType}`);
 
     const listener = message => {
       const { event, payload, queued_at } = JSON.parse(message);
@@ -286,7 +319,7 @@ const startWorker = (workerId) => {
         const delta          = now - queued_at;
         const encodedPayload = typeof payload === 'object' ? JSON.stringify(payload) : payload;
 
-        log.silly(req.requestId, `Transmitting for ${req.accountId}: ${event} ${encodedPayload} Delay: ${delta}ms`);
+        log.silly(req.requestId, `Transmitting for ${accountId}: ${event} ${encodedPayload} Delay: ${delta}ms`);
         output(event, encodedPayload);
       };
 
@@ -313,6 +346,7 @@ const startWorker = (workerId) => {
             return;
           }
 
+          if (!req.accountId) {
             const queries = [
               client.query(`SELECT 1 FROM blocks WHERE (account_id = $1 AND target_account_id IN (${placeholders(targetAccountIds, 2)})) OR (account_id = $2 AND target_account_id = $1) UNION SELECT 1 FROM mutes WHERE account_id = $1 AND target_account_id IN (${placeholders(targetAccountIds, 2)})`, [req.accountId, unpackedPayload.account.id].concat(targetAccountIds)),
             ];
@@ -333,6 +367,9 @@ const startWorker = (workerId) => {
               done();
               log.error(err);
             });
+          } else {
+            transmit();
+          }
         });
       } else {
         transmit();
@@ -345,13 +382,15 @@ const startWorker = (workerId) => {
 
   // Setup stream output to HTTP
   const streamToHttp = (req, res) => {
+    const accountId = req.accountId || req.remoteAddress;
+
     res.setHeader('Content-Type', 'text/event-stream');
     res.setHeader('Transfer-Encoding', 'chunked');
 
     const heartbeat = setInterval(() => res.write(':thump\n'), 15000);
 
     req.on('close', () => {
-      log.verbose(req.requestId, `Ending stream for ${req.accountId}`);
+      log.verbose(req.requestId, `Ending stream for ${accountId}`);
       clearInterval(heartbeat);
     });
 
@@ -383,8 +422,10 @@ const startWorker = (workerId) => {
 
   // Setup stream end for WebSockets
   const streamWsEnd = (req, ws, closeHandler = false) => (id, listener) => {
+    const accountId = req.accountId || req.remoteAddress;
+
     ws.on('close', () => {
-      log.verbose(req.requestId, `Ending stream for ${req.accountId}`);
+      log.verbose(req.requestId, `Ending stream for ${accountId}`);
       unsubscribe(id, listener);
       if (closeHandler) {
         closeHandler();
@@ -392,7 +433,7 @@ const startWorker = (workerId) => {
     });
 
     ws.on('error', () => {
-      log.verbose(req.requestId, `Ending stream for ${req.accountId}`);
+      log.verbose(req.requestId, `Ending stream for ${accountId}`);
       unsubscribe(id, listener);
       if (closeHandler) {
         closeHandler();
@@ -401,6 +442,7 @@ const startWorker = (workerId) => {
   };
 
   app.use(setRequestId);
+  app.use(setRemoteAddress);
   app.use(allowCrossDomain);
   app.use(authenticationMiddleware);
   app.use(errorMiddleware);
@@ -451,6 +493,7 @@ const startWorker = (workerId) => {
     const req      = ws.upgradeReq;
     const location = url.parse(req.url, true);
     req.requestId  = uuid.v4();
+    req.remoteAddress = ws._socket.remoteAddress;
 
     ws.isAlive = true;