如何使用 PHP 强制下载文件
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How to force file download with PHP
提问by john
I want to require a file to be downloaded upon the user visiting a web page with PHP. I think it has something to do with file_get_contents, but am not sure how to execute it.
我想要求在用户使用 PHP 访问网页时下载一个文件。我认为它与file_get_contents，但不知道如何执行它。
$url = "http://example.com/go.exe";
After downloading a file with header(location)it is not redirecting to another page. It just stops.
用header(location)它下载文件后不会重定向到另一个页面。它只是停止。
回答by Pit Digger
Read the docs about built-in PHP function readfile
阅读有关内置 PHP 函数readfile的文档
$file_url = 'http://www.myremoteserver.com/file.exe';
header('Content-Type: application/octet-stream');
header("Content-Transfer-Encoding: Binary");
header("Content-disposition: attachment; filename=\"" . basename($file_url) . "\"");
readfile($file_url);
Also make sure to add proper content type based on your file application/zip, application/pdf etc. - but only if you do not want to trigger the save-as dialog.
还要确保根据您的文件应用程序/zip、应用程序/pdf 等添加正确的内容类型 - 但前提是您不想触发另存为对话框。
回答by Marek Sebera
<?php
$file = "http://example.com/go.exe";
header("Content-Description: File Transfer");
header("Content-Type: application/octet-stream");
header("Content-Disposition: attachment; filename=\"". basename($file) ."\"");
readfile ($file);
exit();
?>
Or, when the file is not openable with the browser, you can just use the Locationheader:
或者，当文件无法用浏览器打开时，您可以只使用Location标题：
<?php header("Location: http://example.com/go.exe"); ?>
回答by genesis
header("Content-Type: application/octet-stream");
header("Content-Transfer-Encoding: Binary");
header("Content-disposition: attachment; filename=\"file.exe\"");
echo readfile($url);
is correct
是正确的
or better one for exetype of files
或更好的exe类型文件
header("Location: $url");
回答by jundell agbo
Display your file first and set its value into url.
首先显示您的文件并将其值设置为 url。
index.php
索引.php
<a href="download.php?download='.$row['file'].'" title="Download File">
download.php
下载.php
<?php
/*db connectors*/
include('dbconfig.php');
/*function to set your files*/
function output_file($file, $name, $mime_type='')
{
if(!is_readable($file)) die('File not found or inaccessible!');
$size = filesize($file);
$name = rawurldecode($name);
$known_mime_types=array(
"htm" => "text/html",
"exe" => "application/octet-stream",
"zip" => "application/zip",
"doc" => "application/msword",
"jpg" => "image/jpg",
"php" => "text/plain",
"xls" => "application/vnd.ms-excel",
"ppt" => "application/vnd.ms-powerpoint",
"gif" => "image/gif",
"pdf" => "application/pdf",
"txt" => "text/plain",
"html"=> "text/html",
"png" => "image/png",
"jpeg"=> "image/jpg"
);
if($mime_type==''){
$file_extension = strtolower(substr(strrchr($file,"."),1));
if(array_key_exists($file_extension, $known_mime_types)){
$mime_type=$known_mime_types[$file_extension];
} else {
$mime_type="application/force-download";
};
};
@ob_end_clean();
if(ini_get('zlib.output_compression'))
ini_set('zlib.output_compression', 'Off');
header('Content-Type: ' . $mime_type);
header('Content-Disposition: attachment; filename="'.$name.'"');
header("Content-Transfer-Encoding: binary");
header('Accept-Ranges: bytes');
if(isset($_SERVER['HTTP_RANGE']))
{
list($a, $range) = explode("=",$_SERVER['HTTP_RANGE'],2);
list($range) = explode(",",$range,2);
list($range, $range_end) = explode("-", $range);
$range=intval($range);
if(!$range_end) {
$range_end=$size-1;
} else {
$range_end=intval($range_end);
}
$new_length = $range_end-$range+1;
header("HTTP/1.1 206 Partial Content");
header("Content-Length: $new_length");
header("Content-Range: bytes $range-$range_end/$size");
} else {
$new_length=$size;
header("Content-Length: ".$size);
}
$chunksize = 1*(1024*1024);
$bytes_send = 0;
if ($file = fopen($file, 'r'))
{
if(isset($_SERVER['HTTP_RANGE']))
fseek($file, $range);
while(!feof($file) &&
(!connection_aborted()) &&
($bytes_send<$new_length)
)
{
$buffer = fread($file, $chunksize);
echo($buffer);
flush();
$bytes_send += strlen($buffer);
}
fclose($file);
} else
die('Error - can not open file.');
die();
}
set_time_limit(0);
/*set your folder*/
$file_path='uploads/'."your file";
/*output must be folder/yourfile*/
output_file($file_path, ''."your file".'', $row['type']);
/*back to index.php while downloading*/
header('Location:index.php');
?>
回答by Parziphal
In case you have to download a file with a size larger than the allowed memory limit (memory_limitini setting), which would cause the PHP Fatal error: Allowed memory size of 5242880 bytes exhaustederror, you can do this:
如果您必须下载大小大于允许的内存限制（memory_limitini 设置）的文件，这会导致PHP Fatal error: Allowed memory size of 5242880 bytes exhausted错误，您可以执行以下操作：
// File to download.
$file = '/path/to/file';
// Maximum size of chunks (in bytes).
$maxRead = 1 * 1024 * 1024; // 1MB
// Give a nice name to your download.
$fileName = 'download_file.txt';
// Open a file in read mode.
$fh = fopen($file, 'r');
// These headers will force download on browser,
// and set the custom file name for the download, respectively.
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="' . $fileName . '"');
// Run this until we have read the whole file.
// feof (eof means "end of file") returns `true` when the handler
// has reached the end of file.
while (!feof($fh)) {
// Read and output the next chunk.
echo fread($fh, $maxRead);
// Flush the output buffer to free memory.
ob_flush();
}
// Exit to make sure not to output anything else.
exit;
回答by Jure Sah
A modification of the accepted answer above, which also detects the MIME type in runtime:
上面接受的答案的修改，它也检测运行时的 MIME 类型：
$finfo = finfo_open(FILEINFO_MIME_TYPE);
header('Content-Type: '.finfo_file($finfo, $path));
$finfo = finfo_open(FILEINFO_MIME_ENCODING);
header('Content-Transfer-Encoding: '.finfo_file($finfo, $path));
header('Content-disposition: attachment; filename="'.basename($path).'"');
readfile($path); // do the double-download-dance (dirty but worky)
回答by Grigor Nazaryan
The following code is a correct way of implementing a download service in php as explained in the following tutorial
以下代码是在 php 中实现下载服务的正确方法，如以下教程中所述
header('Content-Type: application/zip');
header("Content-Disposition: attachment; filename=\"$file_name\"");
set_time_limit(0);
$file = @fopen($filePath, "rb");
while(!feof($file)) {
print(@fread($file, 1024*8));
ob_flush();
flush();
}
回答by nqobile
try this:
尝试这个：
header('Content-type: audio/mp3');
header('Content-disposition: attachment;
filename=“'.$trackname'”');
readfile('folder name /'.$trackname);
exit();
回答by Assasin
http://php.net/manual/en/function.readfile.php
http://php.net/manual/en/function.readfile.php
That's all you need. "Monkey.gif" change to your file name. If you need to download from other server, "monkey.gif" change to "http://www.exsample.com/go.exe"
这就是你所需要的。“Monkey.gif”更改为您的文件名。如果需要从其他服务器下载，将“monkey.gif”改为“ http://www.exsample.com/go.exe”
回答by Saud Qureshi
You can stream download too which will consume significantly less resource. example:
您也可以流式下载，这将消耗更少的资源。例子：
$readableStream = fopen('test.zip', 'rb');
$writableStream = fopen('php://output', 'wb');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="test.zip"');
stream_copy_to_stream($readableStream, $writableStream);
ob_flush();
flush();
In the above example, I am downloading a test.zip (which was actually the android studio zip on my local machine).
php://output is a write-only stream (generally used by echo or print).
after that, you just need to set the required headers and call stream_copy_to_stream(source, destination).
stream_copy_to_stream() method acts as a pipe which takes the input from the source stream (read stream) and pipes it to the destination stream (write stream) and it also avoid the issue of allowed memory exhaustedso you can actually download files that are bigger than your PHP memory_limit.
在上面的例子中，我正在下载一个 test.zip（它实际上是我本地机器上的 android studio zip）。php://output 是一个只写流（通常由 echo 或 print 使用）。之后，您只需要设置所需的标头并调用 stream_copy_to_stream(source, destination)。stream_copy_to_stream() 方法充当管道，从源流（读取流）获取输入并将其通过管道传输到目标流（写入流），它还避免了允许内存耗尽的问题，因此您可以实际下载更大的文件比你的 PHP memory_limit。
