mdounin at mdounin.ru
Mon Apr 16 10:37:45 UTC 2012
On Mon, Apr 16, 2012 at 01:53:39AM -0700, hagai avrahami wrote:
> I am appreciate any help I can get on the following issues.
> I am writing my own module.
> 1. I can see in function ngx_http_send_special_response
> that it calculates the content length of the error page even if the request signed as header only (r->header_only = 1)
> and set the content length header with value, after sending the header it does not send the body ( because r->header_only = 1)
> so the response arrive with content length different than 0 but without body
> Is it a BUG?
No. The r->header_only flag should is set when body isn't
expected per protocol (HEAD requests, 304 responses). Having
Content-Length present in such responses is ok.
> 2.In the module I am trying to redirect the request with status code 302 (NGX_HTTP_MOVED_TEMPORARILY)
> Trying to user->headers_out.location for the Alternate URL failed, I looked in the code and saw the Location must start with "/" - why?
You have to set it correctly, i.e. add to r->headers_out.headers
and link to r->headers_out.location. If it starts with "/" it
works even if set incorrectly due to adding of a server_name,
that's probably what confused you.
> In the end I add it to r->headers_out.headers
> using header = ngx_list_push(&r->headers_out.headers);
> Is it the write way to do it?
> 3. Can you explain please the different between
> a. r->headers_out.content_length_n
> b. r->headers_out.content_length
The content_length_n is a numeric length, this what you normaly
should set when generating response in nginx. The content_length
is a pointer to a headers array element, it might be present if
there is string representation of a Content-Length header
available for some reason (e.g. from a backend).
> 4. Can you explain the usage of the hash field in ngx_table_elt_t
Normally the hash field is used for fast lookups in hash
structures. In case of r->headers_out it's usually just set to 1
indicate the header is valid (or reset to 0 to indicate the
header should not be sent as it was superseeded by some other
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