API changes, add documentation

NEWS.md

@@ -1,25 +1,12 @@
-2015-10-19
+2015-10-25
 ==========
 
 In order to support future clustering support, the legacy `/sioconfig`
 endpoint is being deprecated.  Instead, you should make a request to
-`/socketconfig/<channel name>.json`.  The response will look similar to
+`/socketconfig/<channel name>.json`.  See [the
+documentation](docs/socketconfig.md) for more information.
 these:
 
-```json
-{"url":"https://some-website.com:8443","secure":true}
-{"error":"Channel \"!@#$\" does not exist."}
-```
-
-The `url` key specifies the socket.io URL to connect to, and the `secure`
-key indicates whether the connection is secured with TLS.  If an `error` key
-is present, something went wrong and the value will contain an error
-message.
-
-For now, only one URL is returned, however in the future this may be
-extended by adding an `alt` key specifying an array of acceptable URLs to
-connect to.
-
 2015-10-04
 ==========
 

docs/socketconfig.md

@@ -0,0 +1,57 @@
+Socket.IO Client Configuration
+==============================
+
+As of 2015-10-25, the legacy `/sioconfig` JavaScript for retrieving connection
+information is being deprecated in favor of a new API.  The purpose of this
+change is to allow partitioning channels across multiple servers in order to
+bettle handle increasing traffic.
+
+To get the socket.io configuration for the server hosting a particular channel,
+make a `GET` request to `/socketconfig/<channel name>.json`.  The response will
+be a JSON object containing a list of acceptable servers to connect to, or an
+error message.
+
+Examples:
+
+```
+GET /socketconfig/test.json
+200 OK
+
+{
+    "servers": [
+        {
+            "url": "https://localhost:8443",
+            "secure": true
+        },
+        {
+            "url": "http://localhost:1337",
+            "secure": false
+        },
+        {
+            "url": "https://local6:8443",
+            "secure": true,
+            "ipv6": true
+        },
+        {
+            "url": "http://local6:1337",
+            "secure": false,
+            "ipv6": true
+        }
+    ]
+}
+
+GET /socketconfig/$invalid$.json
+404 Not Found
+
+{
+    "error": "Channel \"$invalid$\" does not exist."
+}
+```
+
+Each entry in the `servers` array has `"secure":true` if the connection is
+secured with TLS, otherwise it it is false.  An entry with `"ipv6":true`
+indicates that the server is listening on the IPv6 protocol.
+
+You can pick any URL to connect socket.io to in order to join the specified
+channel.  I recommend picking one with `"secure":true`, only choosing an
+insecure connection if implementing a TLS connection is infeasible.

src/configuration/ioconfig.js

@@ -3,21 +3,45 @@ export default class IOConfiguration {
         this.config = config;
     }
 
-    getSocketURL() {
-        return this.config.urls[0];
+    getSocketEndpoints() {
+        return this.config.endpoints.slice();
     }
 }
 
 IOConfiguration.fromOldConfig = function (oldConfig) {
     const config = {
-        urls: []
+        endpoints: []
     };
 
-    ['ipv4-ssl', 'ipv4-nossl', 'ipv6-ssl', 'ipv6-nossl'].forEach(key => {
-        if (oldConfig.get('io.' + key)) {
-            config.urls.push(oldConfig.get('io.' + key));
-        }
+    if (oldConfig.get('io.ipv4-ssl')) {
+        config.endpoints.push({
+            url: oldConfig.get('io.ipv4-ssl'),
+            secure: true
         });
+    }
+
+    if (oldConfig.get('io.ipv4-nossl')) {
+        config.endpoints.push({
+            url: oldConfig.get('io.ipv4-nossl'),
+            secure: false
+        });
+    }
+
+    if (oldConfig.get('io.ipv6-ssl')) {
+        config.endpoints.push({
+            url: oldConfig.get('io.ipv4-ssl'),
+            secure: true,
+            ipv6: true
+        });
+    }
+
+    if (oldConfig.get('io.ipv6-nossl')) {
+        config.endpoints.push({
+            url: oldConfig.get('io.ipv4-nossl'),
+            secure: false,
+            ipv6: true
+        });
+    }
 
     return new IOConfiguration(config);
 };

src/io/cluster/nullclusterclient.js

@@ -6,10 +6,9 @@ export default class NullClusterClient {
     }
 
     getSocketConfig(channel) {
-        const url = this.ioConfig.getSocketURL();
+        const servers = this.ioConfig.getSocketEndpoints();
         return Promise.resolve({
-            url: url,
-            secure: /^(https|wss)/.test(url)
+            servers: servers
         });
     }
 }

src/web/routes/socketconfig.js

@@ -2,6 +2,7 @@ import IOConfiguration from '../../configuration/ioconfig';
 import NullClusterClient from '../../io/cluster/nullclusterclient';
 import Config from '../../config';
 import CyTubeUtil from '../../utilities';
+import Logger from '../../logger';
 
 export default function initialize(app) {
     const ioConfig = IOConfiguration.fromOldConfig(Config);
@@ -9,13 +10,18 @@ export default function initialize(app) {
 
     app.get('/socketconfig/:channel.json', (req, res) => {
         if (!req.params.channel || !CyTubeUtil.isValidChannelName(req.params.channel)) {
-            return res.status(400).json({
+            return res.status(404).json({
                 error: `Channel "${req.params.channel}" does not exist.`
             });
         }
 
         clusterClient.getSocketConfig(req.params.channel).then(config => {
             res.json(config);
+        }).catch(err => {
+            Logger.errlog.log(err.stack);
+            return res.status(500).json({
+                error: err.message
+            });
         });
     });
 }

www/js/callbacks.js

@@ -1112,21 +1112,40 @@ setupCallbacks = function() {
     $.getJSON("/socketconfig/" + CHANNEL.name + ".json")
         .done(function (socketConfig) {
             if (socketConfig.error) {
-                makeAlert("Socket.io configuration returned error: " +
+                makeAlert("Error", "Socket.io configuration returned error: " +
                         socketConfig.error, "alert-danger")
                     .appendTo($("#announcements"));
                 return;
             }
 
+            var chosenServer = null;
+            socketConfig.servers.forEach(function (server) {
+                if (chosenServer === null) {
+                    chosenServer = server;
+                } else if (server.secure && !chosenServer.secure) {
+                    chosenServer = server;
+                } else if (!server.ipv6Only && chosenServer.ipv6Only) {
+                    chosenServer = server;
+                }
+            });
+
+            if (chosenServer === null) {
+                makeAlert("Error",
+                        "Socket.io configuration was unable to find a suitable server",
+                        "alert-danger")
+                    .appendTo($("#announcements"));
+            }
+
             var opts = {
                 transports: ["websocket", "polling"],
-                secure: socketConfig.secure
+                secure: chosenServer.secure
             };
 
-            socket = io(socketConfig.url, opts);
+            socket = io(chosenServer.url, opts);
             setupCallbacks();
         }).fail(function () {
-            makeAlert("Failed to retrieve socket.io configuration", "alert-danger")
+            makeAlert("Error", "Failed to retrieve socket.io configuration",
+                    "alert-danger")
                 .appendTo($("#announcements"));
             Callbacks.disconnect();
         });