PHP Content-Length header not working
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26-12-2019 - |
Pergunta
I am trying to use this code to download a .zip file
<?php
$file = "something.zip";
$size = filesize($file);
header('Content-type: application/octet-stream');
header("Content-length: $size");
header('Content-Disposition: attachment; filename="downloaded.zip"');
readfile($file);
?>
but it does not seem to work, even when I try to set the filesize to a number like header("Content-length: 567247784");
. I only get a file that either has no size declared, or a small file size like 28 bytes.
I looked at this question, and I think I have the same problem as the poster, but his solution is "there was a server problem". I think I also have a server configuration issue, but his answer does not help me at all.
Solução
it has to do with mod_deflate getting in the way. I spent a day messing with .htaccess and trying a million different things, in the end this fixed it but I can't really explain why:
header('Content-Length: '.$filesize);
header("Content-Range: 0-".($filesize-1)."/".$filesize);
I want to add that my PHP was configured with less than 256MB of memory.
Outras dicas
Try to remove the trailing ?>
in cases like this. The newlines or whitespace after the ?>
can alter the result.
Usually, the webserver will set the Content-Length header automatically.
For debugging, you can use the very awesome http://fiddler2.com/ to inspect the headers or even compose an arbitrary request to test your assumptions. Fiddler will warn if the content body is different from the Content-Length
header.
I think the easiest and the best way is:
$head = array_change_key_case(get_headers($file, TRUE));
$filesize = $head['content-length'];
Following on from TeeraMusic great analysis https://stackoverflow.com/a/30569921/820841 which identified mod_deflate as the culprit 👍
Option 1: (Disable DEFLATE for this request)
apache_setenv('no-gzip', '1');
Proper way to stop mod_deflate for this request.
Option 2: (Disable DEFLATE for all requests of this Content-Type)
The option which controls which files are DEFLATE will most likely be in your .htaccess
or httpd.conf
:
AddOutputFilterByType DEFLATE "application/atom+xml" \
"application/javascript" \
...
- Ensure you are actually setting the correct
Content-Type
for your response and it is not just matching astext/html
. - Remove the specific
Content-Type
from this list if you do not want it to be passed through mod_deflate.
Maybe the problem in this:
header("Content-length:" . $size);
but I could be wrong
I had the same problem, and in my case it was solved when I found in some php file included one escape character before <?php
tag. Then, the returned by page is bigger than informed in $size = filesize($file);
And this cause the error.