Managing files is an important part of any web app. For many tasks, you need to open and work on a file.
PHP Handling Files
PHP has a number of functions that can be used to create, read, upload, and edit files.
When you change files, be careful!
You have to be very careful when you change files.
If you do something wrong, you can hurt a lot of people. Common mistakes include editing the wrong file, filling up a hard drive with useless data, and accidentally deleting the contents of a file.
The PHP Function readfile()
The readfile() function takes the contents of a file and puts them in the output buffer.
Let’s say that we have a text file on the server called “webhelpers.txt” that looks like this:
AJAX = Asynchronous JavaScript and XML
CSS = Cascading Style Sheets
HTML = Hyper Text Markup Language
PHP = PHP Hypertext Preprocessor
SQL = Structured Query Language
SVG = Scalable Vector Graphics
XML = EXtensible Markup Language
Here is the PHP code to read the file and write it to the output buffer (if the readfile() function works, it will return the number of bytes read):
Example
<!DOCTYPE html>
<html>
<body><?php
echo readfile(“webhelpers.txt”);
?></body>
</html>
Output
If all you want to do is open a file and read its contents, you can use the readfile() function.
In the next chapters, you’ll learn more about how to work with files.