Chapter 10. Working with Files

The data storage destination of choice for a web application is a database. That doesn’t mean that you’re completely off the hook from dealing with regular old files, though. Plain text files are still a handy, universal way to exchange some kinds of information.

You can do some easy customization of your web site by storing HTML templates in text files. When it’s time to generate a specialized page, load the text file, substitute real data for the template elements, and print it. Example 10-1 shows you how to do this.

Files are also good for importing or exporting tabular data between your program and a spreadsheet. In your PHP programs, you can easily read and write the CSV (“comma-separated value”) files with which spreadsheet programs work.

Working with files in PHP also means working with remote web pages. A great thing about file handling in PHP is you can open a remote file on another computer as easily as you can open a file that sits on your web server. Most file-handling functions in PHP understand URLs as well as local filenames. However, for this feature to work, the allow_url_fopen configuration directive must be enabled. It is enabled by default, but if you’re having problems loading a remote file, check this setting.

Understanding File Permissions

To read or write a file with any of the functions you’ll learn about in this chapter, the PHP interpreter must have permission from the operating system to do so. Every program that runs on a computer, ...

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