In this chapter we will teach you how to create and write to a file on the server.
PHP Create File - fopen()
The fopen() function is also used to create a file. Maybe a little confusing, but in PHP, a file is created using the same function used to open files.
If you use fopen() on a file that does not exist, it will create it, given that the file is opened for writing (w) or appending (a).
The example below creates a new file called "testfile.txt". The file will be created in the same directory where the PHP code resides:
Example
$myfile = fopen("testfile.txt", "w")
PHP File Permissions
If you are having errors when trying to get this code to run, check that you have granted your PHP file access to write information to the hard drive.
PHP Write to File - fwrite()
The fwrite() function is used to write to a file.
The first parameter of fwrite() contains the name of the file to write to and the second parameter is the string to be written.
The example below writes a couple of names into a new file called "newfile.txt":
Example
<?php
$myfile = fopen("newfile.txt", "w") or
die("Unable to
open file!");
$txt = "John Doe\n";
fwrite($myfile, $txt);
$txt
= "Jane Doe\n";
fwrite($myfile, $txt);
fclose($myfile);
?>
Notice that we wrote to the file "newfile.txt" twice. Each time we wrote to the file we sent the string $txt that first contained "John Doe" and second contained "Jane Doe". After we finished writing, we closed the file using the fclose() function.
If we open the "newfile.txt" file it would look like this:
John Doe
Jane Doe
PHP Overwriting
Now that "newfile.txt" contains some data we can show what happens when we open an existing file for writing. All the existing data will be ERASED and we start with an empty file.
In the example below we open our existing file "newfile.txt", and write some new data into it:
Example
<?php
$myfile = fopen("newfile.txt", "w") or
die("Unable to
open file!");
$txt = "Mickey Mouse\n";
fwrite($myfile, $txt);
$txt
= "Minnie Mouse\n";
fwrite($myfile, $txt);
fclose($myfile);
?>
If we now open the "newfile.txt" file, both John and Jane have vanished, and only the data we just wrote is present:
Mickey Mouse
Minnie Mouse
Complete PHP Filesystem Reference
For a complete reference of filesystem functions, go to our complete PHP Filesystem Reference.