Getting Connected with Firefox and Chrome - Calling the MySQLi API, continued

(Page 3 of 4 )

Within the JavaScript code, first we need to make certain we are responding to the correct command, so we add a global variable at the top of the source file to hold the last command issued:

  var K_XUL_NAMESPACE = "http://www.mozilla.org/keymaster/
      gatekeeper/there.is.only.xul";

  var USER_LOGGED_IN = 0;

  var lastCommand = ""; 

and modify the doLogin function to save the last command sent:

  function doLogin(event) {

  try { // try
  var theArgs = new Array;
  theArgs[0] = new commandArg("un",document.getElementById("userName").value);
  theArgs[1] = new commandArg("pd",document.getElementById("password").value);
  lastCommand = "login";
  doServerRequest("login",theArgs);
   } // try
   catch (e) { //
    alert("doLogin exception: " + e);
   }//
  }

When processing the server response, we use the JavaScriptsplit()function to break our comma-delimited responses into an array of name-value pairs. We then compare the value of the first entry to"true"before extracting the second returned value and setting the status text:

  function retrieveServerResponse() {
   if (theServerRequest.readyState == 4) { // all done
    // Check return code
     if (theServerRequest.status == 200) { // request terminated OK
      dump("Received from server: " + theServerRequest.responseText + "\n");

      //
      var theResults = theServerRequest.responseText.split(",");
      //

      var rCode = (theResults[0].substring((theResults[0].indexOf("=")+1),
                                theResults[0].length)).toLowerCase();

      if (lastCommand == "login") { // process login command

      if (rCode == "true") { // everything OK, we know next parameter is
                             // session info
       var lastSession = "Last login was ";
       lastSession += (theResults[1].substring((theResults[1].indexOf("=")+1),
                               theResults[1].length)).toLowerCase();
       loginOK();
       setStatusText(lastSession);

      } // everthing OK
      else { // user NG
       loginFail();
       setStatusText("No user logged in");
      } // user NG

     } // process login command

    } // request terminated OK
    else { // something is wrong
     alert("Response failed.");
    } // something is wrong
   } // all done
  }

This version of the program will now log into the database, and if the username and password match (and the account is active), the welcome screen will include a status line along the bottom of the display reporting the last date and time of the user’s login:

  Last login was 0000-00-00 00:00:00

All zeros appear because our initial script to create the database tables did not set an initial date in the database. Once we log in under a valid account name, the next login will yield a more welcoming message. 

Next: Troubleshooting >>
 

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