In the previous two articles we discussed how to read and build an RSS document with PHP. In this article we will create an application that uses the concepts discussed in the other two articles. So letís go straight to the coding.
The layout of the application is going to be very simple: A navigation bar on the left and a display area in the center. The display area is were we are going to display all the output of the code. I've not used any CSS in this application. I've instead opted to use HTML formatting to keep things simple.
As for the actual functioning of the application, we are going to use only one page to execute all the code. This is because it reduces the amount of processing power required to run the application. As a result, it makes program execution faster and reduces coding time.
We are also going to create a few functions that will help us to run the script. The functions are stored in a script called "functions.php" and need to be included in the page. In addition to the functions page, we will also need to include the xmlparser.php page, as this will help fulfill one of the core aims of the application.
When a user clicks on a link, that link will send an action variable to the page. The action variable will then be caught by the switch statement, which will in turn process it and compare its value against the conditions set within the case statements of the switch structure. This comparison, if matched, will activate the appropriate function which will use the display area to output the result. The aim of the application is to:
Read an RSS document
Create an RSS document
The second link called "Create an RSS link" is more complicated to implement than the Read RSS document link. This is because there are two different versions of an RSS document and the application has to decide which path to take based on the selection that the user made. Various functions will display various forms to take input and will create an RSS document based on the input. All new RSS documents that are created by this application will be stored in the same directory where the application resides. With a little bit of code you can change the location in which the file should be stored. In the code section we will explore what each and every function does.
When the "Read an RSS document" link is clicked the application simply calls the functions in the xmlparser.php page and then parses the RSS document. The xml parser was created in the first tutorial of the series. Please refer to it if you need to know how it works.