authentication and json encoding moved to separate files

czervenka · Feb 17, 2020 · 19b5091 · 19b5091
1 parent 36816dc
commit 19b5091
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Showing 6 changed files with 133 additions and 53 deletions.
diff --git a/client/index.js b/client/index.js
@@ -2,7 +2,9 @@
 //-- vim: ft=javascript tabstop=2 softtabstop=2 expandtab shiftwidth=2
 const http = require('http');
 const WebSocket = require('ws');
-const ws = new WebSocket(`ws://localhost:8080/ws/pill/${process.argv[2]}`);
+const ws_ = new WebSocket(`ws://localhost:8080/ws/pill/${process.argv[2]}`);
+const WsJsonProtocol = require('../lib/ws-json');
+const ws = new WsJsonProtocol(ws_);
 const forward_host = process.argv[3];
 const forward_port = process.argv[4];
 
@@ -55,7 +57,6 @@ class RequestForwarder extends Object {
   }
 
   _send(data) {
-    let message = JSON.stringify(data, undefined, 3);
     console.log(`Sending ${message}`)
     this._ws.send(message);
   }
@@ -71,16 +72,9 @@ ws.on('open', function open() {
   const request_forwarder = new RequestForwarder(ws, forward_host, forward_port);
   console.log("Client connection openned.");
 
-  ws.send(JSON.stringify({data:"Hallo."}));
+  ws.send({data:"Hallo."});
   ws.on("message", function (message) {
     console.log(`Got message\n------\n${message}\n------\n\n`);
-    let data;
-    try {
-      data = JSON.parse(message);
-    } catch(err) {
-      console.error(err);
-      return;
-    }
-    request_forwarder.on_message(data);
+    request_forwarder.on_message(message);
   });
 });
diff --git a/lib/index.js b/lib/index.js
diff --git a/lib/ws-json.js b/lib/ws-json.js
@@ -0,0 +1,55 @@
+'use strict';
+//-- vim: ft=javascript tabstop=2 softtabstop=2 expandtab shiftwidth=2
+
+class DecodeError extends Error {}
+
+class WsJsonProtocol extends Object {
+
+    constructor(ws) {
+        super();
+        this._ws = ws;
+    }
+
+    _encode(messageObject) {
+        return JSON.stringify(messageObject, undefined, 3);
+    }
+
+    _decode(rawMessage) {
+        try {
+            return JSON.parse(rawMessage);
+        } catch(err) {
+            throw DecodeError(`Could not decode message ... ${err.toString()}`);
+        }
+    }
+
+    send(messageObject) {
+        if (! messageObject instanceof Object) {
+            throw new Error(`Type error, expected Object but got ${typeof messageObject}.`);
+        }
+        this._ws.send(this._encode(messageObject));
+    }
+
+    on(eventName, callback) {
+        let decode_ = this._decode.bind(this);
+        let decoderCallback = function (message) {
+            let decodedMessage;
+            try {
+                let decodedMessage = decode_(message);
+            } catch(err) {
+                console.error(err);
+            }
+            if (decodedMessage !== undefined) {
+                callback(decodedMessage);
+            }
+        }
+        if (eventName == "message") {
+            return this._ws.on(eventName, decoderCallback);
+        } else {
+            return this._ws.on(eventName, callback);
+        }
+
+    }
+}
+
+
+module.exports = WsJsonProtocol;
diff --git a/server/api.js b/server/api.js
@@ -1,4 +1,5 @@
 'use strict';
+//-- vim: ft=javascript tabstop=2 softtabstop=2 expandtab shiftwidth=2
 const REQ_SIZE_LIMIT = 1024*1024;
 const uuid = require('uuid');
 const { HttpError, BadGateway } = require('./HttpError');

diff --git a/server/authenticator.js b/server/authenticator.js
@@ -0,0 +1,33 @@
+'use strict';
+//-- vim: ft=javascript tabstop=2 softtabstop=2 expandtab shiftwidth=2
+
+class KeyAuthenticator extends Object {
+    constructor(allowed_keys) {
+        super();
+        this.allowed_keys = new Set(allowed_keys);
+        this._clients_by_id = {};
+    }
+
+    authenticate(request, callback) {
+      console.log(`Authenticating request ${request} on ${request.url}.`);
+      const match = /^\/ws\/pill\/(?<client_key>.*)$/.exec(request.url);
+      if (! match) return callback(new Error("Unknown url."));
+      if (this.allowed_keys.has(match.groups.client_key)) {
+        console.log(`Key ${match.groups.client_key} accepted`);
+        callback(null, {"key": match.groups.client_key});
+      } else {
+        console.log('Invalid key');
+        callback(new Error("Invalid key."), null);
+      }
+    }
+
+    onConnected (ws, client) {
+        this._clients_by_id[client.key] = ws;
+    }
+
+    clientFromId (id) {
+        return this._clients_by_id[id];
+    }
+}
+
+module.exports = KeyAuthenticator;
diff --git a/server/index.js b/server/index.js
@@ -4,55 +4,52 @@
 const http = require('http');
 const WebSocket = require('ws');
 const Api = require('./api');
-
-let CLIENTS_BY_ID = {};
-const server = http.createServer(new Api('/api', (id)=>CLIENTS_BY_ID[id]).request_handler);
+const KeyAuthenticator = require('./authenticator');
+const authenticator = new KeyAuthenticator(['kpz-1', 'kpz-2', 'kpz-3']);
+const server = http.createServer(
+  new Api(
+    '/api',
+    authenticator.clientFromId.bind(authenticator)
+  ).request_handler
+);
 const wss = new WebSocket.Server({ noServer: true });
 
-const registered_keys = new Set(['kpz-1', 'kpz-2', 'kpz-3']);
-
-const authenticate = (request, cb) => {
-  console.log(`Authenticating request ${request} on ${request.url}.`);
-  const match = /^\/ws\/pill\/(?<client_key>.*)$/.exec(request.url);
-  if (! match) return cb(new Error("Unknown url."));
-  if (registered_keys.has(match.groups.client_key)) {
-    console.log(`Key ${match.groups.client_key} accepted`);
-    cb(null, {"name": "one", "key": match.groups.client_key});
-  } else {
-    console.log('Invalid key');
-    cb(new Error("Invalid key."), null);
-  }
-}
-
 
+/*
+ * @authenticator ... function (request, callback) which calls callback(err, client).
+ *                    `err` is empty on success and client which should be an object with `key` property.
+ */
+function createServer(authenticator) {
+  wss.on('connection', function connection(ws, request, client) {
 
-wss.on('connection', function connection(ws, request, client) {
-
-  ws.id = client.key;
-  CLIENTS_BY_ID[client.key] = ws;
-  wss.clients.forEach(function each(client) {
-        console.log('Client.ID: ' + client.id);
+    // TODO: should be run in debug mode only
+    wss.clients.forEach(function each(client) {
+          console.log('Client.ID: ' + client.id);
+      });
+    ws.on('message', function message(msg) {
+      console.log(`Received message ${msg} from client ${client.key}`);
     });
-  ws.on('message', function message(msg) {
-    console.log(`Received message ${msg} from client ${client.key}`);
   });
-});
-
-server.on('upgrade', function upgrade(request, socket, head) {
-  console.log("Upgrading protocol.");
-  authenticate(request, (err, client) => {
-    if (err || !client) {
-      console.log("Destroying connection");
-      socket.destroy();
-      return;
-    }
 
-    wss.handleUpgrade(request, socket, head, function done(ws) {
-      console.log("Emitting ws connection");
-      wss.emit('connection', ws, request, client);
+  server.on('upgrade', function upgrade(request, socket, head) {
+    console.log("Upgrading protocol.");
+    authenticator.authenticate(request, (err, client) => {
+      if (err || !client) {
+        console.log("Destroying connection");
+        socket.destroy();
+        return;
+      }
+
+      wss.handleUpgrade(request, socket, head, function done(ws) {
+        console.log("Emitting ws connection");
+        authenticator.onConnected(ws, client);
+        ws.client = client;
+        wss.emit('connection', ws, request, client);
+      });
     });
   });
-});
-
+  return server;
+}
 
-server.listen(8080);
+createServer(authenticator)
+  .listen(8080);