readfile
(PHP 4, PHP 5, PHP 7, PHP 8)
readfile — ファイルを出力する
説明
ファイルを読んで標準出力に書き出します。
パラメータ
filename-
読み込もうとするファイルの名前。
use_include_path-
オプションの2番目の引数を使用して、これに
trueを設定することにより、 include_path のファイルの検索も行うことができます。 context-
ストリームコンテキストリソース
戻り値
ファイルから読み込んだバイト数を返します。
失敗した場合に false を返します
エラー / 例外
失敗したときは E_WARNING が発生します。
例
例1 readfile() によるダウンロードの強制
<?php
$file = 'monkey.gif';
if (file_exists($file)) {
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="'.basename($file).'"');
header('Expires: 0');
header('Cache-Control: must-revalidate');
header('Pragma: public');
header('Content-Length: ' . filesize($file));
readfile($file);
exit;
}
?>上の例の出力は、 たとえば以下のようになります。
注意
注意:
readfile() 自体にはメモリに関する問題はなく、 巨大なファイルを送ってもかまいません。out of memoryエラーが出る場合は、 ob_get_level() で出力バッファリングを無効にしてください。
ヒント
fopen wrappers が有効の場合、この関数のファイル名として URL を使用することができます。ファイル名の指定方法に関する詳細は fopen() を参照ください。 サポートするプロトコル/ラッパー には、さまざまなラッパーの機能やその使用法、 提供される定義済み変数などの情報がまとめられています。
参考
- fpassthru() - ファイルポインタ上に残っているすべてのデータを出力する
- file() - ファイル全体を読み込んで配列に格納する
- fopen() - ファイルまたは URL をオープンする
- include - include
- require - require
- virtual() - Apache サブリクエストを実行する
- file_get_contents() - ファイルの内容を全て文字列に読み込む
- サポートするプロトコル/ラッパー
＋add a note
User Contributed Notes 24 notes
riksoft at gmail dot com ¶
10 years ago
Just a note for those who face problems on names containing spaces (e.g. "test test.pdf").
In the examples (99% of the time) you can find
header('Content-Disposition: attachment; filename='.basename($file));
but the correct way to set the filename is quoting it (double quote):
header('Content-Disposition: attachment; filename="'.basename($file).'"' );
Some browsers may work without quotation, but for sure not Firefox and as Mozilla explains, the quotation of the filename in the content-disposition is according to the RFC
http://kb.mozillazine.org/Filenames_with_spaces_are_truncated_upon_download
yura_imbp at mail dot ru ¶
16 years ago
if you need to limit download rate, use this code
<?php
$local_file = 'file.zip';
$download_file = 'name.zip';
// set the download rate limit (=> 20,5 kb/s)
$download_rate = 20.5;
if(file_exists($local_file) && is_file($local_file))
{
header('Cache-control: private');
header('Content-Type: application/octet-stream');
header('Content-Length: '.filesize($local_file));
header('Content-Disposition: filename='.$download_file);
flush();
$file = fopen($local_file, "r");
while(!feof($file))
{
// send the current file part to the browser
print fread($file, round($download_rate * 1024));
// flush the content to the browser
flush();
// sleep one second
sleep(1);
}
fclose($file);}
else {
die('Error: The file '.$local_file.' does not exist!');
}
?>
marro at email dot cz ¶
16 years ago
My script working correctly on IE6 and Firefox 2 with any typ e of files (I hope :))
function DownloadFile($file) { // $file = include path
if(file_exists($file)) {
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.basename($file));
header('Content-Transfer-Encoding: binary');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header('Content-Length: ' . filesize($file));
ob_clean();
flush();
readfile($file);
exit;
}
}
Run on Apache 2 (WIN32) PHP5
levhita at gmail dot com ¶
16 years ago
A note on the smartReadFile function from gaosipov:
Change the indexes on the preg_match matches to:
$begin = intval($matches[1]);
if( !empty($matches[2]) ) {
$end = intval($matches[2]);
}
Otherwise the $begin would be set to the entire section matched and the $end to what should be the begin.
See preg_match for more details on this.
Hayley Watson ¶
17 years ago
To avoid the risk of choosing themselves which files to download by messing with the request and doing things like inserting "../" into the "filename", simply remember that URLs are not file paths, and there's no reason why the mapping between them has to be so literal as "download.php?file=thingy.mpg" resulting in the download of the file "thingy.mpg".
It's your script and you have full control over how it maps file requests to file names, and which requests retrieve which files.
But even then, as ever, never trust ANYTHING in the request. Basic first-day-at-school security principle, that.
flobee at gmail dot com ¶
19 years ago
regarding php5:
i found out that there is already a disscussion @php-dev about readfile() and fpassthru() where only exactly 2 MB will be delivered.
so you may use this on php5 to get lager files
<?php
function readfile_chunked($filename,$retbytes=true) {
$chunksize = 1*(1024*1024); // how many bytes per chunk
$buffer = '';
$cnt =0;
// $handle = fopen($filename, 'rb');
$handle = fopen($filename, 'rb');
if ($handle === false) {
return false;
}
while (!feof($handle)) {
$buffer = fread($handle, $chunksize);
echo $buffer;
if ($retbytes) {
$cnt += strlen($buffer);
}
}
$status = fclose($handle);
if ($retbytes && $status) {
return $cnt; // return num. bytes delivered like readfile() does.
}
return $status;
}
?>
TimB ¶
16 years ago
To anyone that's had problems with Readfile() reading large files into memory the problem is not Readfile() itself, it's because you have output buffering on. Just turn off output buffering immediately before the call to Readfile(). Use something like ob_end_flush().
Paulinator ¶
6 years ago
Always using MIME-Type 'application/octet-stream' is not optimal. Most if not all browsers will simply download files with that type.
If you use proper MIME types (and inline Content-Disposition), browsers will have better default actions for some of them. Eg. in case of images, browsers will display them, which is probably what you'd want.
To deliver the file with the proper MIME type, the easiest way is to use:
header('Content-Type: ' . mime_content_type($file));
header('Content-Disposition: inline; filename="'.basename($file).'"');
gaosipov at gmail dot com ¶
16 years ago
Send file with HTTPRange support (partial download):
<?php
function smartReadFile($location, $filename, $mimeType='application/octet-stream')
{ if(!file_exists($location))
{ header ("HTTP/1.0 404 Not Found");
return;
}
$size=filesize($location);
$time=date('r',filemtime($location));
$fm=@fopen($location,'rb');
if(!$fm)
{ header ("HTTP/1.0 505 Internal server error");
return;
}
$begin=0;
$end=$size;
if(isset($_SERVER['HTTP_RANGE']))
{ if(preg_match('/bytes=\h*(\d+)-(\d*)[\D.*]?/i', $_SERVER['HTTP_RANGE'], $matches))
{ $begin=intval($matches[0]);
if(!empty($matches[1]))
$end=intval($matches[1]);
}
}
if($begin>0||$end<$size)
header('HTTP/1.0 206 Partial Content');
else
header('HTTP/1.0 200 OK');
header("Content-Type: $mimeType");
header('Cache-Control: public, must-revalidate, max-age=0');
header('Pragma: no-cache');
header('Accept-Ranges: bytes');
header('Content-Length:'.($end-$begin));
header("Content-Range: bytes $begin-$end/$size");
header("Content-Disposition: inline; filename=$filename");
header("Content-Transfer-Encoding: binary\n");
header("Last-Modified: $time");
header('Connection: close');
$cur=$begin;
fseek($fm,$begin,0);
while(!feof($fm)&&$cur<$end&&(connection_status()==0))
{ print fread($fm,min(1024*16,$end-$cur));
$cur+=1024*16;
}
}
?>
Usage:
<?php
smartReadFile("/tmp/filename","myfile.mp3","audio/mpeg")
?>
It can be slow for big files to read by fread, but this is a single way to read file in strict bounds. You can modify this and add fpassthru instead of fread and while, but it sends all data from begin --- it would be not fruitful if request is bytes from 100 to 200 from 100mb file.
jorensmerenjanu at gmail dot com ¶
3 years ago
For anyone having the problem of your html page being outputted in the downloaded file: call the functions ob_clean() and flush() before readfile()
daren -remove-me- schwenke ¶
13 years ago
If you are lucky enough to not be on shared hosting and have apache, look at installing mod_xsendfile.
This was the only way I found to both protect and transfer very large files with PHP (gigabytes).
It's also proved to be much faster for basically any file.
Available directives have changed since the other note on this and XSendFileAllowAbove was replaced with XSendFilePath to allow more control over access to files outside of webroot.
Download the source.
Install with: apxs -cia mod_xsendfile.c
Add the appropriate configuration directives to your .htaccess or httpd.conf files:
# Turn it on
XSendFile on
# Whitelist a target directory.
XSendFilePath /tmp/blah
Then to use it in your script:
<?php
$file = '/tmp/blah/foo.iso';
$download_name = basename($file);
if (file_exists($file)) {
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.$download_name);
header('X-Sendfile: '.$file);
exit;
}
?>
chrisputnam at gmail dot com ¶
19 years ago
In response to flowbee@gmail.com --
When using the readfile_chunked function noted here with files larger than 10MB or so I am still having memory errors. It's because the writers have left out the all important flush() after each read. So this is the proper chunked readfile (which isn't really readfile at all, and should probably be crossposted to passthru(), fopen(), and popen() just so browsers can find this information):
<?php
function readfile_chunked($filename,$retbytes=true) {
$chunksize = 1*(1024*1024); // how many bytes per chunk
$buffer = '';
$cnt =0;
// $handle = fopen($filename, 'rb');
$handle = fopen($filename, 'rb');
if ($handle === false) {
return false;
}
while (!feof($handle)) {
$buffer = fread($handle, $chunksize);
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;
}
?>
All I've added is a flush(); after the echo line. Be sure to include this!
simbiat at outlook dot com ¶
3 years ago
flobee.at.gmail.dot.com shared "readfile_chunked" function. It does work, but you may encounter memory exhaustion using "fread". Meanwhile "stream_copy_to_stream" seems to utilize the same amount of memory as "readfile". At least, when I was testing "download" function for my https://github.com/Simbiat/HTTP20 library on 1.5G file with 256M memory limitation that was the case: "fread" I got peak memory usage of ~240M, while with "stream_copy_to_stream" - ~150M.
It does not mean that you can fully escape memory exhaustion, though: if you are reading too much at a time, you can still encounter it. That is why in my library I use a helper function ("speedLimit") to calculate whether selected speed limit will fit the available memory (while allowing some headroom).
You can read comments in the code itself for more details and raise issues for the library, if you think something is incorrect there (especially since it's WIP at the moment of writing this), but so far I am able to get consistent behavior with it.
mAu ¶
18 years ago
Instead of using
<?php
header('Content-Type: application/force-download');
?>
use
<?php
header('Content-Type: application/octet-stream');
?>
Some browsers have troubles with force-download.
antispam [at] rdx page [dot] com ¶
19 years ago
Just a note: If you're using bw_mod (current version 0.6) to limit bandwidth in Apache 2, it *will not* limit bandwidth during readfile events.
Brian ¶
10 years ago
If you are looking for an algorithm that will allow you to download (force download) a big file, may this one will help you.
$filename = "file.csv";
$filepath = "/path/to/file/" . $filename;
// Close sessions to prevent user from waiting until
// download will finish (uncomment if needed)
//session_write_close();
set_time_limit(0);
ignore_user_abort(false);
ini_set('output_buffering', 0);
ini_set('zlib.output_compression', 0);
$chunk = 10 * 1024 * 1024; // bytes per chunk (10 MB)
$fh = fopen($filepath, "rb");
if ($fh === false) {
echo "Unable open file";
}
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="' . $filename . '"');
header('Expires: 0');
header('Cache-Control: must-revalidate');
header('Pragma: public');
header('Content-Length: ' . filesize($filepath));
// Repeat reading until EOF
while (!feof($fh)) {
echo fread($handle, $chunk);
ob_flush(); // flush output
flush();
}
exit;