本文通过实例代码给大家介绍php下载文件的函数相关知识，介绍的非常详解，具有参考借鉴价值，感兴趣的朋友一起学习吧

通过函数完成下载文件的PHP功能代码

function download($url, $filename) {

// 获得文件大小, 防止超过2G的文件, 用sprintf来读

$filesize = sprintf ( "%u", filesize ( $url ) );

if (! $filesize) {

return;

}

header ( "Content-type:application/octet-stream\n" ); //application/octet-stream

header ( "Content-type:unknown/unknown;" );

header ( "Content-disposition: attachment; filename=\"" . $filename . "\"" );

header ( 'Content-transfer-encoding: binary' );

if ($range = getenv ( 'HTTP_RANGE' )) { // 当有偏移量的时候，采用206的断点续传头

$range = explode ( '=', $range );

$range = $range [1];

header ( "HTTP/1.1 206 Partial Content" );

header ( "Date: " . gmdate ( "D, d M Y H:i:s" ) . " GMT" );

header ( "Last-Modified: " . gmdate ( "D, d M Y H:i:s", filemtime ( $url ) ) . " GMT" );

header ( "Accept-Ranges: bytes" );

header ( "Content-Length:" . ($filesize - $range) );

header ( "Content-Range: bytes " . $range . ($filesize - 1) . "/" . $filesize );

header ( "Connection: close" . "\n\n" );

else {

header ( "Content-Length:" . $filesize . "\n\n" );

$range = 0; }

loadFile ( $url );}

function loadFile($filename, $retbytes = true) {

$buffer = ''; $cnt = 0; $handle = fopen ( $filename, 'rb' );

if ($handle === false) { return false;

} while ( ! feof ( $handle ) ) {

$buffer = fread ( $handle, 1024 * 1024 );

echo $buffer;

ob_flush ();

flush ();

if ($retbytes) {

$cnt += strlen ( $buffer );

}

}

$status = fclose ( $handle );

if ($retbytes && $status) {

return $cnt; // return num. bytes delivered like readfile() does.

}

return $status;}

输入2个参数即可完成下载 download($url, $filename)

以上所述是小编给大家介绍的PHP下载文件的函数实例代码的相关知识，希望对大家有所帮助