No-database Flash-PHP chat. Part III: Security and Usability features (continued)

In this tutorial we will implement the Logout functionality for the Flash-PHP chat application we have being working on in the two previous articles of the series: Creating Basic Chat Functionality and Security and Usability features.

Before implementing the actual Logout procedure we will quickly cover another important topic: maintaining the visible List of Users, the interface element allowing each user to see the list of all the chat participants. For this purpose we will utilise the Flash MX 2004 … List Component which will be refreshed every time someone logs-in or logs-out.

As most of functionality required for this feature is already in place (we built it in the previous article while working on the on the Log-in procedure), it would only be wise to implement it now as the feature will require only minor code modification in order to work for the Logout method.

Select the Interface layer, then simply drag and drop the List Component from Components Panel to the stage, place it where you think it makes sense, label it and resize to your liking. Name the instance Users_lst.

No-database Flash-PHP chat. Part II Security and Usability features

Objectives

In the first article of the series we have built some basic functionality for our “No-database” Flash-PHP Chat application. Once the concept has been proven, application security becomes developers’ top priority.

Although the topic is broad and complex, in this case it does not involve much coding. Meanwhile it will require a fair amount of instructions and explanations, mostly because it’s it closely related to another important element – application usability.
To make sure we cover all the aspects the iterations #2 and #3 have both been entirely dedicated to this subject.

In this article you will learn about the following:

• Server directory Security.
  We will talk about simple measures designed to prevent hackers from uploading, accessing and executing scripts on the server. You will find out how with the aid of PHP Flash can load the content of a file which is not accessible from the web.
  
  
• Application Security.
  We will start talking about user level security, things like preventing simultaneous multiple log-ins by the same users, maintaining the list of active chat users and tracking log-ins.
  
  

In the next article we will continue working on the user-level security and will concentrate on the Logout procedure:

• Tracking  log-outs as well as making sure the application is notified by the server when a user logs-out by closing the browser window. Dramatically titled section “The last wish of Flash” will describe a method allowing to notify the web server when the browser window is being closed.
  
  
• Enforcing log-out if a participant is utilizing more then one browser window for that same chat session.
  
  
• We will add the interface element which will not only display the list of chat participants but will also, if desired, allow for additional functionality such as private messaging.

Data Components - XML made easy!

Flash MX 2004 Professional comes with a set of data components that allow you to include external content in your Flash movies. You only have to write one line of code to make these components work. They are very easy to configure using the Component Inspector and you can bind them directly to UI components to create simple applications.

In this tutorial, we'll look at the XMLConnector component. It's a very easy way to connect to external XML files. If you've found using the XML Class a little tricky, then this might be a good alternative for you. The component will certainly save you from having to write long paths like myXML.firstChild.childNodes[2].firstChild.nodeValue every time you want to use a value from an XML file!

We'll use the XMLConnector to create a navigation system. The system will use a ComboBox to select and load a URL. Some people call this a jump menu. The URLs will be stored in an external XML file. That way, we can update the navigation system without having to update the Flash movie.

To create the navigation system, we'll load in the XML file , bind it to a ComboBox component and add an event handler that loads the site. And we'll do all of this in only 8 lines of ActionScript!

You'll learn how to add an XMLConnector to your movie and configure it with the Component Inspector. You'll also learn about binding the XML data to other UI components such as a ComboBox and the List component. We won't cover XML documents because that in included in the earlier tutorials.

This tutorial assumes that you have Flash MX 2004. You can't use any other version of Flash because they don't include the data components we'll need. It also assumes that you have a basic understanding of XML files.

You can download the source files for the tutorial from the blue Properties box that contains the article PDF. There's a heading titled Code Download and you can click the Details link next to it to get the zip file. The download includes the XML files you'll need as as well as the completed files.