Add hangout URL invalidation if no one joins

After setting a new Hangout URL in a session, start a timer (currently
20 seconds).  If no one has joined yet when the timer has finished,
invalidate the hangout URL so a new one will be created.

This addresses issue #242.

lib/server-models.js

@@ -4,6 +4,13 @@ var client_models = require('../public/js/models.js'),
     sanitize = require('validator').sanitize,
 	crypto = require('crypto');
 
+// How long do we wait for the first participant to join before we consider the
+// hangout URL to be a failure?
+var HANGOUT_CONNECTION_TIMEOUT = 20000;
+// If a participant is creating a non-farmed hangout URL, how long do we give
+// them before assuming they've skipped out?
+var HANGOUT_CREATION_TIMEOUT = 20000;
+
 // This file contains extensions to the core models defined in 
 // public/js/models.js.
 // 
@@ -299,7 +306,7 @@ exports.ServerSession = client_models.Session.extend({
 			// obj has (optionally) "userId" and definitely has "time"
 			var obj = this.get("hangout-pending");
 
-			if((new Date().getTime() - obj.time) > 15000) {
+			if((new Date().getTime() - obj.time) > HANGOUT_CREATION_TIMEOUT) {
 				logger.debug("Hangout pending was too old, returning false and resetting hangout-pending to null.");
 				this.set("hangout-pending", null);
 				return false;
@@ -323,6 +330,16 @@ exports.ServerSession = client_models.Session.extend({
 			// let anyone who was waiting for a hangout url from this session know
 			// that we have a valid one now.
 			this.trigger("hangout-url", url);
+
+            // If no one is in this hangout, set a timeout to invalidate our
+            // hangout URL if no one joins.
+            if (this.getNumConnectedParticipants() == 0) {
+                this._hangoutConnectionTimeout = setTimeout(_.bind(function() {
+                    if (this.getNumConnectedParticipants() == 0) {
+                        this.set("hangout-url", null);
+                    }
+                }, this), HANGOUT_CONNECTION_TIMEOUT);
+            }
 		} else {
             // If someone tries to overwrite an active hangout URL with a
             // different one, return false, so we can warn them what the
@@ -347,6 +364,11 @@ exports.ServerSession = client_models.Session.extend({
                 id: this.id, participants: this.get("connectedParticipants")
             });
 		}
+        // Clear the timeout that would invalidate our hangout URL if no one
+        // joined.
+        if (this._hangoutConnectionTimeout) {
+            clearTimeout(this._hangoutConnectionTimeout);
+        }
 
 		logger.debug("setting connected participants to: " + _.pluck(participants, "id"));
 	},

test/test.hangout-redirects.js

@@ -81,7 +81,8 @@ describe("HANGOUT REDIRECTS", function() {
 
             var url = "http://example.com/farmed" + suffix;
             checkRedirect(url, "regular1", function() {
-                farming.getNextHangoutUrl(function(url) {
+                farming.getNextHangoutUrl(function(err, url) {
+                    expect(err).to.be(null);
                     expect(url).to.be(null);
                     done();
                 });
@@ -90,7 +91,8 @@ describe("HANGOUT REDIRECTS", function() {
     });
     it("Uses button URL when farmed hangout links are unavailable", function(done) {
         // Ensure we have nothing farmed...
-        farming.getNextHangoutUrl(function(url) {
+        farming.getNextHangoutUrl(function(err, url) {
+            expect(err).to.be(null);
             expect(url).to.be(null);
             var url = "https://plus.google.com/hangouts/_?gid=fun&gd=sessionId:" + session.id;
             checkRedirect(url, "regular1", function() {
@@ -100,7 +102,7 @@ describe("HANGOUT REDIRECTS", function() {
         });
     });
     it("Lets a 2nd user be the pending creator if the 1st times out", function(done) {
-        this.timeout(20000); // We're testing long timeouts. :(
+        this.timeout(30000); // We're testing long timeouts. :(
         var u1 = common.server.db.users.findWhere({"sock-key": "regular1"});
         var u2 = common.server.db.users.findWhere({"sock-key": "regular2"});
         var url = "https://plus.google.com/hangouts/_?gid=fun&gd=sessionId:" + session.id;
@@ -113,6 +115,42 @@ describe("HANGOUT REDIRECTS", function() {
                 expect(session.get("hangout-pending").userId).to.be(u2.id);
                 done();
             });
-        }, 15000);
+        }, 20000);
+    });
+    it("Retains a farmed url after adding it to a session if someone joins", function(done) {
+        this.timeout(30000); // We're testing long timeouts. :(
+        var user = common.server.db.users.findWhere({"sock-key": "regular1"});
+        var url = "http://example.com/good-url";
+        farming.reuseUrl(url, function(err) {
+            expect(err).to.be(null);
+            checkRedirect(url + suffix, "regular1", function() {
+                session.setConnectedParticipants([{id: user.id}]);
+                setTimeout(function() {
+                    expect(session.getHangoutUrl()).to.be(url);
+                    done();
+                }, 25000);
+            });
+        });
+    });
+    it("Times-out a farmed url (without re-using it) after adding it to a session if no one joins", function(done) {
+        this.timeout(30000); // We're testing long timeouts. :(
+        var url = "http://example.com/poison-url";
+        expect(farming.getNumHangoutsAvailable()).to.be(0);
+        farming.reuseUrl(url, function(err) {
+            expect(err).to.be(null);
+            // We should get the farmed (poison) url...
+            checkRedirect(url + suffix, "regular1", function() {
+                // ... but we don't enter the session, and never start it.
+                setTimeout(function() {
+                    expect(session.getHangoutUrl()).to.be(null);
+                    // Ensure the URL wasn't reused..
+                    farming.getNextHangoutUrl(function(err, url) {
+                        expect(err).to.be(null);
+                        expect(url).to.be(null);
+                        done();
+                    });
+                }, 20000);
+            });
+        });
     });
 });