Large_client_header_buffers directive is accepted in server, but ignored

[Brane_FSGraSSSSnar]

Hello there!

We noticed quite lots of “414 Request URI to large” messages in nginx
error
logs for one of configured virtualhosts and decided to bump
large_client_headers_buffers directive in server (virtualhost) context.

According to wiki documentation at
http://wiki.nginx.org/NginxHttpCoreModule#large_client_header_buffers,
directive should be accepted and evaluated in http AND server context.

Directive is accepted, but completely ignored and 414 issue remains.
However,
problem is fixed if i move large_client_headers_buffers directive
outside
server context to http context.

We’re using nginx 0.8.37. Considering changelog issue should be also
present
in 0.8.49, becouse there are only two mentions of
large_client_headers_buffers
directive.

Where is bug: in implementation or documentation? Either way, it should
be
fixed

Best regards, Brane

[Brane_FSGraSSSSnar]

Hello!

On Wed, Aug 18, 2010 at 12:18:49PM +0200, Brane F. Gračnar wrote:

Directive is accepted, but completely ignored and 414 issue remains. However,
problem is fixed if i move large_client_headers_buffers directive outside
server context to http context.

We’re using nginx 0.8.37. Considering changelog issue should be also present
in 0.8.49, becouse there are only two mentions of large_client_headers_buffers
directive.

Where is bug: in implementation or documentation? Either way, it should be
fixed

It is only possible to use large_client_header_buffers from server
block which is default on a listen socket in question. The reason
is obvious: there are no information about name-based virtual
hosts before we were able to parse headers.

E.g. this will work as expected, with one 4k buffer in server1 on
port 8081 and 4 buffers in server2 on port 8082:

http {
server {
listen 8081;
server_name server1;
large_client_header_buffers 1 4k;
}
server {
listen 8081;
server_name server2;
large_client_header_buffers 4 4k;
}
}

but this won’t (for both servers one 4k buffer will be used):

http {
server {
listen 8080;
server_name server1;
large_client_header_buffers 1 4k;
}
server {
listen 8080;
server_name server2;
large_client_header_buffers 4 4k;
}
}

as one can’t distingush server1 and server2 without parsing
headers.

So wiki is basically correct (as well as docs), and code works as
intended, but there are some nuances…

Maxim D.