PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

440 Chapter 19 Interacting with the File System and the Server
This script makes use of the opendir(), closedir(), and readdir()functions.
The function opendir() opens a directory for reading. Its use is similar to the use of
fopen() for reading from files. Instead of passing it a filename, you should pass it a directory
name:
$dir = opendir($current_dir);
The function returns a directory handle, again in much the same way as fopen() returns
a file handle.
When the directory is open, you can read a filename from it by calling
readdir($dir), as shown in the example.This function returns false when there are
no more files to be read. Note that it will also return false if it reads a file called “0”;in
order to guard against this, we explicitly test to make sure the return value is not equal
to false:
while(false !== ($file = readdir($dir)))
When you are finished reading from a directory, you call closedir($dir) to finish.This
is again similar to calling fclose() for a file.
Sample output of the directory browsing script is shown in Figure 19.3.
Figure 19.3
The directory listing shows all the files in the chosen directory.
Typically the . (the current directory) and .. (one level up) directories would also display
in the list in Figure 19.3. However, we stripped these directories out with the following
line of code:
if($file != "." && $file != "..")
If you delete this line of code, the . and .. directories will be added to the list of files that
are displayed.