Go Live v7 - nodeGame/nodegame GitHub Wiki

• status: complete
• version: 7.x
• follows from: Logging

Before you run your experiment (online or in the lab) you need to make sure that the environment is properly configured for "production" (that is when the application is accessed by real users). Production settings differ from "development" settings, and below a checklist is provided.

Have you already inserted an inform consent page in your experiment? If not, you can use one of the default templates.

In file channel/channel.settings.js:

• Hide the game name. If the address bar of the browser is visible (as it is usually the case), the name of the game will be readable there. It might be that the name is already indicative of the research question at stake. For example, if the name of the game contains the word "sharing," this might prime participants towards more cooperative behavior. To avoid this, you can setup a neutral alias, such as "game" or "experiment" that will be displayed instead of the actual game name. Alternatively, you can set the channel of the game as the "default" channel, and in such a case no name will appear at all (beware: when you specify a default channel, other games might no longer be reachable). Notice that the name of the pages and treatments are never displayed in the address bar, so you don't have to worry about those. To add one or more aliases, edit the file and type the name of the aliases inside the alias field. Alternatively you can run your game as default (see below).

• Enable reconnection. When reconnection is on, clients that disconnect and then reconnect are put back into their old game room (instead of the waiting room). To enable reconnection set enableReconnections equal to true. Depending on the design of your game, you might have to write a custom reconnection handler. Reconnection also requires authorization to be enabled and properly configured (see below).

• Disable Channel Query Parameters. Channel query parameters (also called socket-io query parameters) are passed as extra parameters along the url of the nodeGame server. They instruct a nodeGame channel to setup the incoming connection in a given way, for example defining the client type and connecting room. Channel query parameters should be disabled when running experiments online (remember you can still add computer-controlled players from the monitor interface), while they might be kept on in the lab as long the browser runs in kiosk mode (see point 3. of this list). To disable channel query parameters set sioQuery = false.

• Change the default admin endpoint. If you are running an online game, you should change the administrative endpoint from /admin to something else; to do so set adminServer = '/myendpoint'. See the Game Advanced page for details.

In file game/game.setup.js:

• Disable debug mode. When debug mode is enabled runtime errors will cause the server to stop immediately. This is useful when developing and debugging the application, but undesirable in production mode. To disable debug mode set setup.debug = false (assuming that the name of your returning variable is setup).

• Set the verbosity level of the clients. Clients log a lot of information while running a game. It is usually a good idea to hide away this information from end-users for two reasons: to prevent malicious usage of such information, and also because excessive console printing can lower the game performance in older browser. To log errors and warnings set: setup.verbosity = 0 (assuming that the name of the returning variable is setup).

• Setup the User Interface (UI) of the browser. Depending on if you are running the game in the lab or online the recommended settings differ. Generally, it is not recommended to restrict the browser's features for online games. In the lab, ideally you should try to run the browser in kiosk mode. Kiosk mode is independent of nodeGame, and must be configured separately. If kiosk mode is not available in your university lab, you can restrict some of the UI functionlities by editing _game/game.setup.js_:

  // Assuming `setup` is the name of the returning variable.
  setup.window = {
      // Block right-clicking.
      disableRightClick: true,
      // Display a message if a user tries to close the browser.
      promptOnleave: true,
      // Disable the back button.    
      disableBackButton: true
  };

  Furthermore, is a good idea to know if a player is switching between tabs. In the init function of your game you can add something like:

  // This is called when a new tab is open (but not on a new window).
  W.onFocusOut(function() {
      // For example, if this is a lab experimenter:
      alert("Go back to the experiment's tab. " +
            "If unsure how to do it contact the experimenter.");
      // Or just log it (logic must listen to the message).
      node.say('tabswitch');
      // Or count them and log them at the end.
      node.game.tabswitches++; // (must be initialized before)
  });
  
  // This is called when the focus returns on the experiment's tab.
  W.onFocusIn(function() {
      // Log it, or do nothing.
  });

  Alternatively, if you are running a lab experiment on the Chrome browser, you can make use of the Kiosk extension. Notice that this extension only simulates a real kiosk mode (e.g. alt+Tab will let the user switch between applications, etc.).

In file auth/auth.settings.js:

• Specify authorization rules. When authorization is on, only one tab per browser is allowed to connect to the game. Connecting a second tab will disconnect the previous one. To enable authorization set enabled equal to true and specify an authorization mode. When authorization is enabled, all players must connect through the address http://yourserver/yourgame/auth/id/password, where id and password are as you specified in your codes list.

• Adjust number of codes. Remember to adjust the number of authorization codes to the expected size of your experiment (setting nCodes). In online experiment, you must consider also those who will start the experiment, but not finish it. As a rule-of-thumb, if you plan to collect 100 observations, you should create at least 150 codes, or even more for group-experiments.

• Lab vs Online. Notice that authorization rules are not required for lab experiments, but there some advantages in using them. In the unlikely event of a technical failure of a computer, a disconnection will be detected. If you are running your experiment without authorization there is no way to recover this participant. If authorization is on, you can open a new browser window on any other computer to the address localhost:8080/MYGAME/auth/PLAYER_ID and then the player is back where he/she left.

Inside dictory channel/:

• Monitor. Make sure you have valid channel.credentials.js and channel.secret.js files (not the sample ones). The former contains the monitor user name and password to access the monitor interface from the address: http://yourserver/yourgame/auth/id/password; the latter should contain a random string used to sign the authorization tokens.

In file requirements/requirements.settings.js:

• ES7.and other rules. If you are running an online experiment with custom features, you must check that your experiment will be fully supported. To do so, you need to specify some requirement settings or write custom rules. For instance, if you are using ES6 features , you should set the ES7.flag to true; if your experiment requires multimedia content, you could play a video file and asking for its content. See all the options here.

• Set auto-push/disconnect feature. This feature is recommended for multiplayer online games. If enabled, non-responsive clients will be pinged and asked to advance to the next step, after the step timer has expired. If still unresponsive, clients are forced to disconnect. To enable, add pushClients: true to all the steps and/or stages of the game sequence where you would like the logic to execute this feature. Read about custom pushClients settings.

• Clean up your code. Make sure to remove all debugger statements. If you made use of the Node.js debugger there is a good chance that you forgot a debugger statement. To check for forgotten debugger statements you can run the grep program in your game/ folder: grep debugger ./ -R. In Windows you must download an equivalent grep program, for example wingrep. Moreover, you should run jshint on your sources. JSHint is a tool that helps to detect errors and potential problems in your JavaScript code. No matter how good a programmer you (think) you are, you will always benefit from using jshint. Install jshint globally with the command npm install -g jshint (might need admin rights), and then run jshint inside your game/ folder: jshint --show-non-errors *.

If you are running only one game on your nodeGame server, it is a good idea to run it as default on port 80. The goal is to access the game at the address http://server.com (instead of http://server.com:8080/yourgame).

• Edit server setting. Inside the installation folder of nodeGame, find file conf/servernode.js and set servernode.homePage = false and servernode.port = 80.

• Check the player endpoint. Locate the file where you establish the connection to the nodeGame server. This is usually public/js/index.js. Find the line containing the statement node.connect and make sure that the connect parameter matches the player endpoint of your game. The player endpoint is usually equal to the name of your game, but you can change it in the channel settings. For instance, if your game name is yourgame, the connect line should be:

  node.connect('/yourgame');

• Launcher options. Launch your game with the option --default:

  node launcher.js --default yourgame

More launcher options here.

It is strongly recommended to use a process manager to run your nodeGame server. A process manager, will take care of automatically restarting your server in case of failure and will monitor the overall health of your application.

PM2 is powerful process manager with lots of features and a well-maintained documentation. If you install pm2 globally, you can simply start your server with the command:

pm2 start launcher.js

and stop it with:

pm2 stop launcher

To pass additional options, e.g., enabling https:

pm2 start launcher.js -- --ssl

Make sure you re-run your game at least once after having edited your sources with production settings...and you are good to go!

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