PHP: readfile - Manual (original) (raw)

(PHP 4, PHP 5, PHP 7, PHP 8)

readfile — Outputs a file

Description

Parameters

filename

The filename being read.

use_include_path

You can use the optional second parameter and set it to [true](reserved.constants.php#constant.true), if you want to search for the file in the include_path, too.

context

A context stream resource.

Return Values

Returns the number of bytes read from the file on success, or [false](reserved.constants.php#constant.false) on failure

Errors/Exceptions

Upon failure, an [E_WARNING](errorfunc.constants.php#constant.e-warning) is emitted.

Examples

Example #1 Forcing a download using readfile()

<?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;
}
?>

The above example will output something similar to:

Notes

Note:

readfile() will not present any memory issues, even when sending large files, on its own. If you encounter an out of memory error ensure that output buffering is off with ob_get_level().

Tip

A URL can be used as a filename with this function if the fopen wrappers have been enabled. See fopen() for more details on how to specify the filename. See the Supported Protocols and Wrappers for links to information about what abilities the various wrappers have, notes on their usage, and information on any predefined variables they may provide.

See Also

• fpassthru() - Output all remaining data on a file pointer
• file() - Reads entire file into an array
• fopen() - Opens file or URL
• include - include
• require - require
• virtual() - Perform an Apache sub-request
• file_get_contents() - Reads entire file into a string
• Supported Protocols and Wrappers

Found A Problem?

riksoft at gmail dot com ¶

12 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 ¶

18 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();
    <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>f</mi><mi>i</mi><mi>l</mi><mi>e</mi><mo>=</mo><mi>f</mi><mi>o</mi><mi>p</mi><mi>e</mi><mi>n</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">file = fopen(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">i</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">o</span><span class="mord mathnormal">p</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mopen">(</span></span></span></span>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!');
}

?>

Paulinator ¶

8 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).'"');

Hayley Watson ¶

18 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.

TimB ¶

18 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().

levhita at gmail dot com ¶

17 years ago

A note on the smartReadFile function from gaosipov:

Change the indexes on the preg_match matches to:
      
      <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>b</mi><mi>e</mi><mi>g</mi><mi>i</mi><mi>n</mi><mo>=</mo><mi>i</mi><mi>n</mi><mi>t</mi><mi>v</mi><mi>a</mi><mi>l</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">begin = intval(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">b</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">in</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">in</span><span class="mord mathnormal">t</span><span class="mord mathnormal" style="margin-right:0.03588em;">v</span><span class="mord mathnormal">a</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mopen">(</span></span></span></span>matches[1]);
      if( !empty($matches[2]) ) {
        <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>e</mi><mi>n</mi><mi>d</mi><mo>=</mo><mi>i</mi><mi>n</mi><mi>t</mi><mi>v</mi><mi>a</mi><mi>l</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">end = intval(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mord mathnormal">d</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">in</span><span class="mord mathnormal">t</span><span class="mord mathnormal" style="margin-right:0.03588em;">v</span><span class="mord mathnormal">a</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mopen">(</span></span></span></span>matches[2]);
      }

Otherwise the <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>b</mi><mi>e</mi><mi>g</mi><mi>i</mi><mi>n</mi><mi>w</mi><mi>o</mi><mi>u</mi><mi>l</mi><mi>d</mi><mi>b</mi><mi>e</mi><mi>s</mi><mi>e</mi><mi>t</mi><mi>t</mi><mi>o</mi><mi>t</mi><mi>h</mi><mi>e</mi><mi>e</mi><mi>n</mi><mi>t</mi><mi>i</mi><mi>r</mi><mi>e</mi><mi>s</mi><mi>e</mi><mi>c</mi><mi>t</mi><mi>i</mi><mi>o</mi><mi>n</mi><mi>m</mi><mi>a</mi><mi>t</mi><mi>c</mi><mi>h</mi><mi>e</mi><mi>d</mi><mi>a</mi><mi>n</mi><mi>d</mi><mi>t</mi><mi>h</mi><mi>e</mi></mrow><annotation encoding="application/x-tex">begin would be set to the entire section matched and the </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">b</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">in</span><span class="mord mathnormal" style="margin-right:0.02691em;">w</span><span class="mord mathnormal">o</span><span class="mord mathnormal">u</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">d</span><span class="mord mathnormal">b</span><span class="mord mathnormal">ese</span><span class="mord mathnormal">tt</span><span class="mord mathnormal">o</span><span class="mord mathnormal">t</span><span class="mord mathnormal">h</span><span class="mord mathnormal">ee</span><span class="mord mathnormal">n</span><span class="mord mathnormal">t</span><span class="mord mathnormal">i</span><span class="mord mathnormal">resec</span><span class="mord mathnormal">t</span><span class="mord mathnormal">i</span><span class="mord mathnormal">o</span><span class="mord mathnormal">nma</span><span class="mord mathnormal">t</span><span class="mord mathnormal">c</span><span class="mord mathnormal">h</span><span class="mord mathnormal">e</span><span class="mord mathnormal">d</span><span class="mord mathnormal">an</span><span class="mord mathnormal">d</span><span class="mord mathnormal">t</span><span class="mord mathnormal">h</span><span class="mord mathnormal">e</span></span></span></span>end to what should be the begin.

See preg_match for more details on this.

marro at email dot cz ¶

18 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

flobee at gmail dot com ¶

21 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;
    // <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>h</mi><mi>a</mi><mi>n</mi><mi>d</mi><mi>l</mi><mi>e</mi><mo>=</mo><mi>f</mi><mi>o</mi><mi>p</mi><mi>e</mi><mi>n</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">handle = fopen(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">han</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">o</span><span class="mord mathnormal">p</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mopen">(</span></span></span></span>filename, 'rb');
    <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>h</mi><mi>a</mi><mi>n</mi><mi>d</mi><mi>l</mi><mi>e</mi><mo>=</mo><mi>f</mi><mi>o</mi><mi>p</mi><mi>e</mi><mi>n</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">handle = fopen(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">han</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">o</span><span class="mord mathnormal">p</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mopen">(</span></span></span></span>filename, 'rb');
    if ($handle === false) {
        return false;
    }
    while (!feof($handle)) {
        <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>b</mi><mi>u</mi><mi>f</mi><mi>f</mi><mi>e</mi><mi>r</mi><mo>=</mo><mi>f</mi><mi>r</mi><mi>e</mi><mi>a</mi><mi>d</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">buffer = fread(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">b</span><span class="mord mathnormal">u</span><span class="mord mathnormal" style="margin-right:0.10764em;">ff</span><span class="mord mathnormal" style="margin-right:0.02778em;">er</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">re</span><span class="mord mathnormal">a</span><span class="mord mathnormal">d</span><span class="mopen">(</span></span></span></span>handle, $chunksize);
        echo $buffer;
        if ($retbytes) {
            <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>c</mi><mi>n</mi><mi>t</mi><mo>+</mo><mo>=</mo><mi>s</mi><mi>t</mi><mi>r</mi><mi>l</mi><mi>e</mi><mi>n</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">cnt += strlen(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6984em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">c</span><span class="mord mathnormal">n</span><span class="mord mathnormal">t</span><span class="mord">+</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">s</span><span class="mord mathnormal">t</span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mopen">(</span></span></span></span>buffer);
        }
    }
        <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>s</mi><mi>t</mi><mi>a</mi><mi>t</mi><mi>u</mi><mi>s</mi><mo>=</mo><mi>f</mi><mi>c</mi><mi>l</mi><mi>o</mi><mi>s</mi><mi>e</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">status = fclose(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6151em;"></span><span class="mord mathnormal">s</span><span class="mord mathnormal">t</span><span class="mord mathnormal">a</span><span class="mord mathnormal">t</span><span class="mord mathnormal">u</span><span class="mord mathnormal">s</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">c</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">ose</span><span class="mopen">(</span></span></span></span>handle);
    if ($retbytes && $status) {
        return $cnt; // return num. bytes delivered like readfile() does.
    } 
    return $status;

} 
?>

jorensmerenjanu at gmail dot com ¶

5 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()

gaosipov at gmail dot com ¶

17 years ago

Send file with HTTPRange support (partial download):

<?php
function smartReadFile($location, <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>f</mi><mi>i</mi><mi>l</mi><mi>e</mi><mi>n</mi><mi>a</mi><mi>m</mi><mi>e</mi><mo separator="true">,</mo></mrow><annotation encoding="application/x-tex">filename, </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">i</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mord mathnormal">nam</span><span class="mord mathnormal">e</span><span class="mpunct">,</span></span></span></span>mimeType='application/octet-stream')
{ if(!file_exists($location))
  { header ("HTTP/1.0 404 Not Found");
    return;
  }
  
  <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>s</mi><mi>i</mi><mi>z</mi><mi>e</mi><mo>=</mo><mi>f</mi><mi>i</mi><mi>l</mi><mi>e</mi><mi>s</mi><mi>i</mi><mi>z</mi><mi>e</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">size=filesize(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6595em;"></span><span class="mord mathnormal">s</span><span class="mord mathnormal">i</span><span class="mord mathnormal">ze</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">i</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">es</span><span class="mord mathnormal">i</span><span class="mord mathnormal">ze</span><span class="mopen">(</span></span></span></span>location);
  <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>t</mi><mi>i</mi><mi>m</mi><mi>e</mi><mo>=</mo><mi>d</mi><mi>a</mi><mi>t</mi><mi>e</mi><msup><mo stretchy="false">(</mo><mo mathvariant="normal" lspace="0em" rspace="0em">′</mo></msup><msup><mi>r</mi><mo mathvariant="normal" lspace="0em" rspace="0em">′</mo></msup><mo separator="true">,</mo><mi>f</mi><mi>i</mi><mi>l</mi><mi>e</mi><mi>m</mi><mi>t</mi><mi>i</mi><mi>m</mi><mi>e</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">time=date(&#x27;r&#x27;,filemtime(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6595em;"></span><span class="mord mathnormal">t</span><span class="mord mathnormal">im</span><span class="mord mathnormal">e</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1.0019em;vertical-align:-0.25em;"></span><span class="mord mathnormal">d</span><span class="mord mathnormal">a</span><span class="mord mathnormal">t</span><span class="mord mathnormal">e</span><span class="mopen"><span class="mopen">(</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.7519em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">′</span></span></span></span></span></span></span></span></span><span class="mord"><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.7519em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">′</span></span></span></span></span></span></span></span></span><span class="mpunct">,</span><span class="mspace" style="margin-right:0.1667em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">i</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mord mathnormal">m</span><span class="mord mathnormal">t</span><span class="mord mathnormal">im</span><span class="mord mathnormal">e</span><span class="mopen">(</span></span></span></span>location));
  
  <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>f</mi><mi>m</mi><mo>=</mo><mi mathvariant="normal">@</mi><mi>f</mi><mi>o</mi><mi>p</mi><mi>e</mi><mi>n</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">fm=@fopen(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">m</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord">@</span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">o</span><span class="mord mathnormal">p</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mopen">(</span></span></span></span>location,'rb');
  if(!$fm)
  { header ("HTTP/1.0 505 Internal server error");
    return;
  }
  
  $begin=0;
  <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>e</mi><mi>n</mi><mi>d</mi><mo>=</mo></mrow><annotation encoding="application/x-tex">end=</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mord mathnormal">d</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span></span></span></span>size;
  
  if(isset($_SERVER['HTTP_RANGE']))
  { if(preg_match('/bytes=\h*(\d+)-(\d*)[\D.*]?/i', <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msub><mrow></mrow><mi>S</mi></msub><mi>E</mi><mi>R</mi><mi>V</mi><mi>E</mi><mi>R</mi><msup><mo stretchy="false">[</mo><mo mathvariant="normal" lspace="0em" rspace="0em">′</mo></msup><mi>H</mi><mi>T</mi><mi>T</mi><msub><mi>P</mi><mi>R</mi></msub><mi>A</mi><mi>N</mi><mi>G</mi><msup><mi>E</mi><mo mathvariant="normal" lspace="0em" rspace="0em">′</mo></msup><mo stretchy="false">]</mo><mo separator="true">,</mo></mrow><annotation encoding="application/x-tex">_SERVER[&#x27;HTTP_RANGE&#x27;], </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.0019em;vertical-align:-0.25em;"></span><span class="mord"><span></span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.3283em;"><span style="top:-2.55em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight" style="margin-right:0.05764em;">S</span></span></span></span><span class="vlist-s">​</span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal" style="margin-right:0.00773em;">ER</span><span class="mord mathnormal" style="margin-right:0.22222em;">V</span><span class="mord mathnormal" style="margin-right:0.00773em;">ER</span><span class="mopen"><span class="mopen">[</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.7519em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">′</span></span></span></span></span></span></span></span></span><span class="mord mathnormal" style="margin-right:0.08125em;">H</span><span class="mord mathnormal" style="margin-right:0.13889em;">TT</span><span class="mord"><span class="mord mathnormal" style="margin-right:0.13889em;">P</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.3283em;"><span style="top:-2.55em;margin-left:-0.1389em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight" style="margin-right:0.00773em;">R</span></span></span></span><span class="vlist-s">​</span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal">A</span><span class="mord mathnormal">NG</span><span class="mord"><span class="mord mathnormal" style="margin-right:0.05764em;">E</span><span class="msupsub"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.7519em;"><span style="top:-3.063em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">′</span></span></span></span></span></span></span></span></span><span class="mclose">]</span><span class="mpunct">,</span></span></span></span>matches))
    { <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>b</mi><mi>e</mi><mi>g</mi><mi>i</mi><mi>n</mi><mo>=</mo><mi>i</mi><mi>n</mi><mi>t</mi><mi>v</mi><mi>a</mi><mi>l</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">begin=intval(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">b</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">in</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">in</span><span class="mord mathnormal">t</span><span class="mord mathnormal" style="margin-right:0.03588em;">v</span><span class="mord mathnormal">a</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mopen">(</span></span></span></span>matches[0]);
      if(!empty($matches[1]))
        <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>e</mi><mi>n</mi><mi>d</mi><mo>=</mo><mi>i</mi><mi>n</mi><mi>t</mi><mi>v</mi><mi>a</mi><mi>l</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">end=intval(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mord mathnormal">d</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">in</span><span class="mord mathnormal">t</span><span class="mord mathnormal" style="margin-right:0.03588em;">v</span><span class="mord mathnormal">a</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mopen">(</span></span></span></span>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-$begin));
  header("Content-Range: bytes <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>b</mi><mi>e</mi><mi>g</mi><mi>i</mi><mi>n</mi><mo>−</mo></mrow><annotation encoding="application/x-tex">begin-</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">b</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.03588em;">g</span><span class="mord mathnormal">in</span><span class="mord">−</span></span></span></span>end/$size");
  header("Content-Disposition: inline; filename=$filename");
  header("Content-Transfer-Encoding: binary\n");
  header("Last-Modified: $time");
  header('Connection: close');  
  
  <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>c</mi><mi>u</mi><mi>r</mi><mo>=</mo></mrow><annotation encoding="application/x-tex">cur=</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.4306em;"></span><span class="mord mathnormal">c</span><span class="mord mathnormal">u</span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span></span></span></span>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.

daren -remove-me- schwenke ¶

15 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'; <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>d</mi><mi>o</mi><mi>w</mi><mi>n</mi><mi>l</mi><mi>o</mi><mi>a</mi><msub><mi>d</mi><mi>n</mi></msub><mi>a</mi><mi>m</mi><mi>e</mi><mo>=</mo><mi>b</mi><mi>a</mi><mi>s</mi><mi>e</mi><mi>n</mi><mi>a</mi><mi>m</mi><mi>e</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">download_name = basename(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8444em;vertical-align:-0.15em;"></span><span class="mord mathnormal">d</span><span class="mord mathnormal">o</span><span class="mord mathnormal" style="margin-right:0.02691em;">w</span><span class="mord mathnormal">n</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">o</span><span class="mord mathnormal">a</span><span class="mord"><span class="mord mathnormal">d</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.1514em;"><span style="top:-2.55em;margin-left:0em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight">n</span></span></span></span><span class="vlist-s">​</span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal">am</span><span class="mord mathnormal">e</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">ba</span><span class="mord mathnormal">se</span><span class="mord mathnormal">nam</span><span class="mord mathnormal">e</span><span class="mopen">(</span></span></span></span>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 ¶

20 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;
   // <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>h</mi><mi>a</mi><mi>n</mi><mi>d</mi><mi>l</mi><mi>e</mi><mo>=</mo><mi>f</mi><mi>o</mi><mi>p</mi><mi>e</mi><mi>n</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">handle = fopen(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">han</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">o</span><span class="mord mathnormal">p</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mopen">(</span></span></span></span>filename, 'rb');
   <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>h</mi><mi>a</mi><mi>n</mi><mi>d</mi><mi>l</mi><mi>e</mi><mo>=</mo><mi>f</mi><mi>o</mi><mi>p</mi><mi>e</mi><mi>n</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">handle = fopen(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">han</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">o</span><span class="mord mathnormal">p</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mopen">(</span></span></span></span>filename, 'rb');
   if ($handle === false) {
       return false;
   }
   while (!feof($handle)) {
       <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>b</mi><mi>u</mi><mi>f</mi><mi>f</mi><mi>e</mi><mi>r</mi><mo>=</mo><mi>f</mi><mi>r</mi><mi>e</mi><mi>a</mi><mi>d</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">buffer = fread(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">b</span><span class="mord mathnormal">u</span><span class="mord mathnormal" style="margin-right:0.10764em;">ff</span><span class="mord mathnormal" style="margin-right:0.02778em;">er</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">re</span><span class="mord mathnormal">a</span><span class="mord mathnormal">d</span><span class="mopen">(</span></span></span></span>handle, $chunksize);
       echo $buffer;
       ob_flush();
       flush();
       if ($retbytes) {
           <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>c</mi><mi>n</mi><mi>t</mi><mo>+</mo><mo>=</mo><mi>s</mi><mi>t</mi><mi>r</mi><mi>l</mi><mi>e</mi><mi>n</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">cnt += strlen(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6984em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">c</span><span class="mord mathnormal">n</span><span class="mord mathnormal">t</span><span class="mord">+</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">s</span><span class="mord mathnormal">t</span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mopen">(</span></span></span></span>buffer);
       }
   }
       <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>s</mi><mi>t</mi><mi>a</mi><mi>t</mi><mi>u</mi><mi>s</mi><mo>=</mo><mi>f</mi><mi>c</mi><mi>l</mi><mi>o</mi><mi>s</mi><mi>e</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">status = fclose(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6151em;"></span><span class="mord mathnormal">s</span><span class="mord mathnormal">t</span><span class="mord mathnormal">a</span><span class="mord mathnormal">t</span><span class="mord mathnormal">u</span><span class="mord mathnormal">s</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">c</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">ose</span><span class="mopen">(</span></span></span></span>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!