PHP复制类里面的其他价值

Question

What I am trying to accomplish, is for a file to be downloaded of one of two places. If the file doesn't exist it needs to try to download it from another location. However if the first file does exist, it needs to stop and not try to download the second file, otherwise the second file will still be downloaded as a blank file, overwriting the first one. How would I do this using something such as a else value?

<?php

$source_file = 'http://somesitehere.tld/' . $_GET["u"] . '.png'; 
$dest_file = '/enter/directory/here/' . $_GET["u"] . '.png';

copy($source_file, $dest_file);

?>

Answer 1

Have you tried using something like this, using either the file_exists, file_get_contents or fopen functions depending on your needs.

If you are using an internal file, try using file_exists():

if( file_exists( $source_file ) ) { 

copy( $source_file, $dest_file );

} else {

copy( $source_file2, $dest_file2 );

}

And if you are using an external file try this using file_get_contents():

if( file_get_contents( $source_file ) ) { 

copy( $source_file, $dest_file );

} else {

copy( $source_file2, $dest_file2 );

}

Alternatively you can try using fopen():

if( fopen( $source_file ) ) { 

copy( $source_file, $dest_file );

} else {

copy( $source_file2, $dest_file2 );

}