You want to extract the input parameters that were submitted as part of a form or specified at the end of a URL.
Each API provides a means of accessing the names and values of the input parameters in the execution environment of a web script.
Earlier sections of this chapter discuss how to retrieve information from MySQL and use it to generate various forms of output, such as static text, hyperlinks, or form elements. In this section, we’ll discuss the opposite problem—how to collect input from the Web. Applications for such input are many. For example, you can use the techniques shown in this section to extract the contents of a form submitted by a user. You might interpret the information as search keywords, then run a query against a product catalog and show the matching items to a customer. In this case, you use the Web to collect information from which you can determine the client’s interests. From that you construct an appropriate search query and display the results. If a form represents a survey, a mailing list sign-up sheet, or a poll, you might just store the values, using the data to create a new database record (or perhaps to update an existing record).
A script that receives input over the Web and uses it to interact with MySQL generally processes the information in a series of stages:
Extract the input from the execution environment. When a request arrives that contains input parameters, the web server places the input ...