PHP Cookbook

18.3. Opening a Remote File

Problem

You want to open a file that’s accessible to you via HTTP or FTP.

Solution

Pass the file’s URL to fopen( ) :

$fh = fopen('http://www.example.com/robots.txt','r') or die($php_errormsg);

Discussion

When fopen( ) is passed a filename that begins with http://, it retrieves the given page with an HTTP/1.0 GET request (although a Host: header is also passed along to deal with virtual hosts). Only the body of the reply can be accessed using the file handle, not the headers. Files can be read, not written, via HTTP.

When fopen( ) is passed a filename that begins with ftp://, it returns a pointer to the specified file, obtained via passive mode FTP. You can open files via FTP for either reading or writing, but not both.

To open URLs that require a username and a password with fopen( ), embed the authentication information in the URL like this:

$fh = fopen('ftp://username:[e-mail]/pub/Index','r');
$fh = fopen('http://username:[e-mail]/robots.txt','r');

Opening remote files with fopen( ) is implemented via a PHP feature called the URL fopen wrapper . It’s enabled by default but is disabled by setting allow_url_fopen to off in your php.ini or web server configuration file. If you can’t open remote files with fopen( ), check your server configuration.

See Also

Section 11.2 through Section 11.6, which discuss retrieving URLs; documentation on fopen( ) at http://www.php.net/fopen and on the URL fopen wrapper feature at http://www.php.net/features.remote-files ...