Skip to content

Documented that headers must fit in buffer #220

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
timmc wants to merge 1 commit into from
Closed

Documented that headers must fit in buffer #220

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 3 additions & 1 deletion xml/en/docs/http/ngx_http_proxy_module.xml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -158,7 +158,9 @@ This directive is available as part of our
<para>
Sets the <value>size</value> of the buffer used for reading the first part
of the response received from the proxied server.
This part usually contains a small response header.
This part usually contains a small response header;
the HTTP response headers must fit entirely within this buffer
Copy link
Copy Markdown
Collaborator

@pluknet pluknet Feb 16, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

"the HTTP response headers" can be shortened to "it" without loss of meaning.
"must" is probably not the correct term: backends aren't formally obliged to this limit; the better term I think is "should" here

or an error response will be returned.
Copy link
Copy Markdown
Collaborator

@pluknet pluknet Feb 16, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Not really, the error can be handled by passing the request to the next server or by the error_page directive.

We can write based on code that such response is treated as invalid (NGX_HTTP_UPSTREAM_FT_INVALID_HEADER) with an appropriate link to explain how to handle this.

To sum up, below is my version:

This part usually contains a small response header,
which should fit entirely within this buffer,
otherwise the response will be considered
<link id="invalid_header">invalid</link>.

By default, the buffer size is equal to one memory page.
This is either 4K or 8K, depending on a platform.
It can be made smaller, however.
Expand Down