# Nginx module dev question **URL:** \ **Category:** NGINX\ **Created:** [March 25, 2009, 10:36am UTC](https://www.ruby-forum.com/t/nginx-module-dev-question/163832 "2009-03-25T10:36:32Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Delta\_Y](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f9ae1b/32.png) [@Delta\_Y](https://www.ruby-forum.com/u/Delta_Y)\ **Post date:** [March 25, 2009, 10:36am UTC](https://www.ruby-forum.com/t/nginx-module-dev-question/163832/1 "2009-03-25T10:36:32Z")
Hi all, I want to implement the following feature: 1. client HEAD request arrive , my module send it to an upstream. 2. the upstream return response. 3. my module check the response, if it is not the data I want, send the origin request to another upstream I know the block mode will work. I want to know if there is asynchronous mode which will fit into nginx better? BR, DeltaY ---
**Author:** ![Delta\_Y](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f9ae1b/32.png) [@Delta\_Y](https://www.ruby-forum.com/u/Delta_Y)\ **Post date:** [April 3, 2009, 1:00pm UTC](https://www.ruby-forum.com/t/nginx-module-dev-question/163832/2 "2009-04-03T13:00:40Z")
I think you can write an upstream module to resolve it. use the HEAD you get, to make a request, send the new request to the upstream you want to sent, get the response, check it, and then you can use ngx\_http\_internal\_redirect£¨£© function to redirect the origin request to another upstream you defined. just do it, good luck! 2009/3/25 Delta Y. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): ---
**Author:** ![Delta\_Y](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/f9ae1b/32.png) [@Delta\_Y](https://www.ruby-forum.com/u/Delta_Y)\ **Post date:** [April 3, 2009, 2:19pm UTC](https://www.ruby-forum.com/t/nginx-module-dev-question/163832/3 "2009-04-03T14:19:48Z")
Thanks for your suggestion. 2009/4/3 Yu.Cheung [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)