How to download a file using php? -

i want download file server using php. searched google , found stackoverflow answer here. answer shows have write these codes purpose.

$file_url = 'http://www.myremoteserver.com/file.exe'; header('content-type: application/octet-stream'); header("content-transfer-encoding: binary");  header("content-disposition: attachment; filename=\"" . basename($file_url) .     "\"");  readfile($file_url);  

but able merely these 2 lines:

header("content-disposition:attachment; filename=uploads1/efl1.5_setup.exe"); readfile("uploads1/efl1.5_setup.exe"); 

so why should write few more lines codes above?

header('content-type: application/octet-stream'); 

the content-type should whatever known be, if know it. application/octet-stream defined "arbitrary binary data" in rfc 2046, , there's definite overlap here of being appropriate entities sole intended purpose saved disk, , point on outside of "webby". or @ direction; thing 1 can safely application/octet-stream save file , hope else knows it's for.

header("content-transfer-encoding: binary");  

content-transfer-encoding specifies encoding used transfer data within http protocol, raw binary or base64. (binary more compact base64. base64 having 33% overhead).

reference:

do need content-type: application/octet-stream file download?