# \[ANN\] unicorn 5.0.1 - Rack HTTP server for fast clients and \*nix

**URL:** https://rubytalk.org/t/ann-unicorn-5-0-1-rack-http-server-for-fast-clients-and-nix/73316
**Category:** ruby-talk
**Created:** [17 November 2015 22:48 UTC](https://rubytalk.org/t/ann-unicorn-5-0-1-rack-http-server-for-fast-clients-and-nix/73316 "2015-11-17T22:48:17Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![Eric\_Wong2](https://avatars.discourse-cdn.com/v4/letter/e/b9e5f3/32.png) [@Eric\_Wong2](https://rubytalk.org/u/Eric_Wong2)
#### Post date: [17 November 2015 22:48 UTC](https://rubytalk.org/t/ann-unicorn-5-0-1-rack-http-server-for-fast-clients-and-nix/73316/1 "2015-11-17T22:48:17Z")

</div>

Unicorn is an HTTP server for Rack applications designed to only serve  
fast clients on low-latency, high-bandwidth connections and take  
advantage of features in Unix/Unix-like kernels. Slow clients should  
only be served by placing a reverse proxy capable of fully buffering  
both the the request and response in between unicorn and slow clients.

\* [http://unicorn.bogomips.org/](http://unicorn.bogomips.org/)  
\* public list: [unicorn-public@bogomips.org](mailto:unicorn-public@bogomips.org)  
\* mail archives: [http://bogomips.org/unicorn-public/](http://bogomips.org/unicorn-public/)  
\* git clone git://bogomips.org/unicorn.git  
\* [http://unicorn.bogomips.org/NEWS.atom.xml](http://unicorn.bogomips.org/NEWS.atom.xml)  
\* nntp://news.public-inbox.org/inbox.comp.lang.ruby.unicorn

Changes since 5.0.0:

unicorn 5.0.1 - continuing to violate Rack SPEC

Once again, we allow nil values in response headers. We've had  
this bug since March 2009, and thus cannot expect existing  
applications and middlewares running unicorn to fix this.

Unfortunately, supporting this bug contributes to application  
server lock-in, but at least we'll document it as such.

Thanks to Owen Ou \<[o@heroku.com](mailto:o@heroku.com)\> for reporting this regression:

&nbsp;&nbsp;[http://bogomips.org/unicorn-public/CAO47=rJa=zRcLn\_Xm4v2cHPr6c0UswaFC\_omYFEH+baSxHOWKQ@mail.gmail.com/](http://bogomips.org/unicorn-public/CAO47=rJa=zRcLn_Xm4v2cHPr6c0UswaFC_omYFEH+baSxHOWKQ@mail.gmail.com/)

Additionally, systemd examples are now in the examples/ directory  
based on a post by Christos Trochalakis \<[yatiohi@ideopolis.gr](mailto:yatiohi@ideopolis.gr)\>:

&nbsp;&nbsp;[http://bogomips.org/unicorn-public/20150708130821.GA1361@luke.ws.skroutz.gr/](http://bogomips.org/unicorn-public/20150708130821.GA1361@luke.ws.skroutz.gr/)

> **···**
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> --  
> EW