本文实例为大家分享了php header函数下载文件实现代码，供大家参考，具体内容如下

http://www.php.net/manual/en/function.readfile.php

<?php /** * 下载文件 * header函数 * */ dl_file($_GET ['filename']); function dl_file($file) { $file = ".//images//" . $file; //First, see if the file exists if (! is_file ( $file )) { die ( "<b>404 File not found!</b>" ); } // Gather relevent info about file $len = filesize ( $file ); $filename = basename ( $file ); $file_extension = strtolower ( substr ( strrchr ( $filename, "." ), 1 ) ); // This will set the Content-Type to the appropriate setting for the file switch ($file_extension) { case "pdf" : $ctype = "application/pdf"; break; case "exe" : $ctype = "application/octet-stream"; break; case "zip" : $ctype = "application/zip"; break; case "doc" : $ctype = "application/msword"; break; case "xls" : $ctype = "application/vnd.ms-excel"; break; case "ppt" : $ctype = "application/vnd.ms-powerpoint"; break; case "gif" : $ctype = "image/gif"; break; case "png" : $ctype = "image/png"; break; case "jpeg" : case "jpg" : $ctype = "image/jpg"; break; case "mp3" : $ctype = "audio/mpeg"; break; case "wav" : $ctype = "audio/x-wav"; break; case "mpeg" : case "mpg" : case "mpe" : $ctype = "video/mpeg"; break; case "mov" : $ctype = "video/quicktime"; break; case "avi" : $ctype = "video/x-msvideo"; break; // The following are for extensions that shouldn't be downloaded // (sensitive stuff, like php files) case "php" : case "htm" : case "html" : case "txt" : die ( "<b>Cannot be used for " . $file_extension . " files!</b>" ); break; default : $ctype = "application/force-download"; } $file_temp = fopen ( $file, "r" ); // Begin writing headers header ( "Pragma: public" ); header ( "Expires: 0" ); header ( "Cache-Control: must-revalidate, post-check=0, pre-check=0" ); header ( "Cache-Control: public" ); header ( "Content-Description: File Transfer" ); // Use the switch-generated Content-Type header ( "Content-Type: $ctype" ); // Force the download $header = "Content-Disposition: attachment; filename=" . $filename . ";"; header ( $header ); header ( "Content-Transfer-Encoding: binary" ); header ( "Content-Length: " . $len ); //@readfile ( $file ); echo fread ( $file_temp, filesize ( $file ) ); fclose ( $file_temp ); exit (); } ?>

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持查字典教程网。