Incorrect content-length header breaks HTTP/2 with net::err_http2_protocol_error

There are assets system changes in Drupal 10. Did you have an opportunity to review the release notes?

I made this a support request so we can gather more information.

I don’t remember ever having seen it with Drupal. See also https://stackoverflow.com/questions/58215104/whats-the-neterr-http2-prot...

I have the same problem with OVH :

• PHP 8.1
• Mysql
• https
• Drupal 10.2.2 fresh install.

Here is my test url : https://drupal1022.monsitedev.com
You may see the error on Chrome on the front page
I spended hours of researches and tests in vain, so if a kind soul is willing to solve this problem, I will be forever grateful!

Same problem here, Drupal 10.2.2 on PHP 8.1.

Is any solution available?

EDIT: Looks like the content-length header on gzipped CSS and JS assets is incorrect (uncompressed size?).

Also OVH?

There is a lot of debugging advice in https://stackoverflow.com/questions/58215104/whats-the-neterr-http2-prot.... If you haven’t done those things you haven’t done everything.

It looks like Drupal sends an invalid "content-length" header for JS and CSS gzipped assets on first load.

Disabling gzip using SetEnv no-gzip 1 in my .htaccess file fixes the problem, but that's not really a solution.

@mably if you can reliably reproduce that with a set of steps that would be really helpful, as we can turn it into a test case.

Content-Length was added to fix other issues: https://www.drupal.org/node/3298551

However perhaps this is now incorrectly calculated in the case of gzipped content?

@frondeau

Wrong content-length header is mentioned a lot at https://stackoverflow.com/questions/58215104/whats-the-neterr-http2-prot.... There are many possible answers.

I've opened an MR with a potential fix - to just stop adding the content length header for BinaryFileResponse (which is what the first asset request returns). Would be great if people experiencing this issue on OVH could try it out (at least once we've had a green test run here). We should probably add some minimum test coverage to the existing content length tests to make sure files are skipped too.

Can you confirm that asset aggregates are actually getting written and this problem is only for the first request that builds them? After that they should be served as actual files and would expect it to work again.

If the server gzips the response from Drupal, it should also be responsible for updating the content length header, so this is perhaps mis-configuration on OVH's side? But also don't feel that we have a strong use case for setting the content length header for binary files and if we can save people hours/days of fruitless debugging that would be good.

The proposed fix doesn't seem to work on my side.
Looks like we never go through the related code when generating aggregated CSS and JS.
But may be I'm doing something wrong.

@frondeau you should be able to use the diff from https://git.drupalcode.org/project/drupal/-/merge_requests/6453.diff with a 10.2.x site, the affected code is identical.

@frondeau I don't understand your question. The diff, https://git.drupalcode.org/project/drupal/-/merge_requests/6453.diff, applies to the 10.2.x branch as well as to version 10.2.2.

On the second page reload: the message is displayed only on document

Can you try temporarily disabling CSS and JavaScript aggregation (admin/config/development/performance) and let us know if you still see the same error anywhere? If so, then this isn't specific to BinaryFileResponse at all and could be a much wider problem with the content length header.

This is probably due to how HTTP/2 multiplexes.

Hi,

I have exactly the same problem as you with the same configuration. Strangely, there's no problem when I'm logged in, only when I'm anonymous.

Hi i have the same problem as you on 10.2 after a migration from 9.5.. and im on OVH too
to add more information, i got the same error on some ajax update request such as custom batch step who need me manualy refresh the page to see what batch update.. and somme other custom ajax request ending the same way...

I wonder if this is the same as the issue described at https://github.com/symfony/symfony/issues/46449#issuecomment-1140985890 - which also related to Drupal and the Content-Length header on OVH hosting.

It appears that zlib.output_compression is not enabled on OVH but perhaps they are doing something else to compress content which means Content-Length is incorrect.

A non-Drupal issue where the solution is also to unset the Content-Length header on OVH: https://help.nextcloud.com/t/shared-hosting-ovh-web-nextcloud-issue-with...

Anyone affected by this can try adding this to their .htaccess:

Header always unset Content-Length

Hid the MR because that was a complete red herring.

@frondeau Drupal's .htaccess file is intended to be modifiable, we won't add OVH-specific information in there since it could get confusing for sites that don't run into this problem.

However we could add this information to the change record for the issue that added the content length header and/or Drupal 10.2.0 release notes as a known issue.

Hi Everyone, #35 @longwave work for me too.

#35 seems to also fix some stability problems when running locally on Docker (Drupal 10.2.3, PHP 8.3, Apache with Nginx proxy).

#35 + issue https://www.drupal.org/project/drupal/issues/3432990 works for me.

1. Set 'Header always unset Content-Length' in the .htaccess AND
2. Patch /public_html/core/lib/Drupal/Core/StackMiddleware/ContentLength.php #48:
From: $response->headers->set('Content-Length', strlen($content), TRUE);
To: $response->headers->set('Content-Length', strlen($content)+2, TRUE);

Thanks @longwave and the referrer to issues #3432990

Marcel

Thanks #35 !!

My config was :
OVH
10.1.8 ALL FINE, no problem
10.2.5 migration => HTTP/2 with net::err_http2_protocol_error + slowness

Solved by adding 'Header always unset Content-Length' in .htaccess of www

<IfModule mod_headers.c>
         Header onsuccess unset X-Content-Type-Options
         Header always set X-Content-Type-Options nosniff
Header always unset Content-Length
        RequestHeader unset Proxy
</IfModule>

This community is awesome ;)

#35 work for me too on OVH

Hi everyone!

It was an image upload issue on my side and got errors. First patched like below; the error gone, uploaded successfully.

Patch /public_html/core/lib/Drupal/Core/StackMiddleware/ContentLength.php #48:
From: $response->headers->set('Content-Length', strlen($content), TRUE);
To: $response->headers->set('Content-Length', strlen($content)+2, TRUE);

But then some http2 protocol errors appeared on XHR requests. After billion attempts, changed the patch like (switching from +2 to +1) and errors gone forever.

$response->headers->set('Content-Length', strlen($content)+1, TRUE);

Same error for me with 10.3.2.
With #35 the loading of my Js continue, but i can have some slowness for some page.
It' very visible because the first image to be loaded is a 50px of width (then the correct image is loaded ) Some page may took 1sec or more to complete load properly.

So for me, it's not really a complete solution.

All was fine on my Dev server (Nginx) but as soon i migrate to an OVH performance ... Issues on chrome.
Does anyone had the same issue on another environment ?

Edit: it seems that when the slowness occur is when ressources are loaded on after the other. Not in parallel. So if there is a lot of JS ressources, it took way longer :)

Same issue on AWS using CloudFront, Load balancer and WAF (not sure where is a problem, on D9 it was ok). Currently trying to update to 10.2.4 and got this error..

I wrote a patch for a content-length issue I encountered. I'm not sure if the issues are related but here's the other issue: https://www.drupal.org/project/drupal/issues/3494148

Hello,
Same here:
OVH performance
D 10.4.1
PHP 8.1.29
#35 solves it for me as well thanks!
However, my .htaccess is not versionned and re-created by core-composer-scaffold on every composer install... how do you suggest I apply this fix? How do you guys handle it?

@nicolas bouteille you can use this in your composer.json to patch it during scafolding :

    "extra": {
        "drupal-scaffold": {
            "file-mapping": {
                "[web-root]/sites/development.services.yml": false,
                "[web-root]/.htaccess": {
                    "prepend": "patches/drupal/3419024.txt"
                }
            },

And then you put this code in patches/drupal/3419024.txt

# Fix error on OVH due to incorrect content-length header
# https://www.drupal.org/project/drupal/issues/3419024

<IfModule mod_headers.c>
  Header always unset Content-Length
</IfModule>

thank you for the quick reply! gotta try this! there is one thing though, I installed Shield and it looked like enabling / disabling it did rewrite .htaccess thus erased my custom modifications... I have to test it more thoroughly though.

Thank you your solution works perfect! and Shield module does not actually work with .htaccess so no pb.
Still curious to understand why this is only happening with OVH though and only since pretty recently as well...

Shame on me: I faced this problem again recently and totally forgot that I had already solved it earlier! And I did not find this issue when I googled it. Or maybe it is because I did not Google it but asked ChatGPT instead ^^
Hopefully OVH support did answer me and provided me with an article with the same solution.
https://habeuk.com/fr/drupal-neterrhttp2protocolerror