I'm trying to read a txt file from another site but no matter what I try I get the below error.

Code:
Warning: fopen(http://www.mysite.com/files/myfile.txt): failed to open stream: HTTP request failed! HTTP/1.1 400 Bad Request
This is the code I've tried....

PHP Code:
$handle = fopen("http://www.mysite.com/files/myfile.txt", "r");

and 

$handle = file('http://www.mysite.com/files/myfile.txt');