hagai avrahami hagaizzz at
Mon Apr 16 11:29:18 UTC 2012

WOW thanks for the quick and elaborate response

So what is the right way to send response with status code 302 on GET request but
with content length 0 and no body (I want to redirect the request to other Server)



> From: Maxim Dounin <mdounin at>
>To: nginx at 
>Sent: Monday, April 16, 2012 12:37 PM
>Subject: Re: ngx_http_send_special_response
>On Mon, Apr 16, 2012 at 01:53:39AM -0700, hagai avrahami wrote:
>> Hi
>> 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 
>Maxim Dounin
>nginx mailing list
>nginx at
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