# Kcar - bytestream to Rack response converter

**URL:** <https://www.ruby-forum.com/t/kcar-bytestream-to-rack-response-converter/187768>\
**Category:** Ruby\
**Created:** [April 29, 2010, 12:42am UTC](https://www.ruby-forum.com/t/kcar-bytestream-to-rack-response-converter/187768 "2010-04-29T00:42:10Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [April 29, 2010, 12:42am UTC](https://www.ruby-forum.com/t/kcar-bytestream-to-rack-response-converter/187768/1 "2010-04-29T00:42:10Z")

</div>

kcar features an HTTP parser that will convert a bytestream into a  
3-element array suitable for use as a Rack response. It is IO interface  
agnostic, so it may be used with HTTP streams over Unix domain sockets,  
regular files, FIFOs, StringIOs as well as traditional TCP sockets.

- [kcar - bytestream to Rack response converter](http://bogomips.org/kcar/)
- removed\_email\_address@domain.invalid
- git://git.bogomips.org/kcar.git

== Features

- RFC2616-compliant Ragel+C parser adapted from Unicorn and Mongrel

- decodes chunked response bodies with an optional pass-through mode  
(to avoid rechunking with Rack::Chunked)

- handles odd things like trailers and multiline headers

- streaming interface for response bodies allows for incremental  
processing of arbitrarily large responses.

== Problems

- kcar is only lightly tested and is not yet aware of all quirks found  
in  
all real (possibly broken) web servers.

== Install

If you’re using a packaged Ruby distribution, make sure you have a C  
compiler and the matching Ruby development libraries and headers.

If you use RubyGems:

```
gem install kcar

```

Otherwise grab the latest tarball from:

[http://bogomips.org/kcar/files/](http://bogomips.org/kcar/files/)

Unpack it, and run “ruby setup.rb”

== Usage:

While you can use the Kcar::Parser directly, you’ll usually want the  
higher-level interface of Kcar::Response:

```
require 'rack' # for Rack::Utils::HeaderHash, which is optional
require 'socket' # for TCPSocket
require 'kcar'
sock = TCPSocket.new('example.com', 80)
sock.write("GET / HTTP/1.0\r\n\r\n")

# instead of a Rack::Utils::HeaderHash object below, you can also
# pass a regular Hash or Array object.
response = Kcar::Response.new(sock, Rack::Utils::HeaderHash.new)
status, headers, body = response.rack

```

You can now do further processing on the status, headers, or iterate  
through the body with body.each.

== Development

You can get the latest source via git from the following locations:

git://git.bogomips.org/kcar.git  
git://repo.or.cz/kcar.git (mirror)

You may browse the code from the web and download the latest snapshot  
tarballs here:

- [bytestream to Rack response converter](http://git.bogomips.org/cgit/kcar.git) (cgit)
- [Public Git Hosting - kcar.git/summary](http://repo.or.cz/w/kcar.git) (gitweb)

Inline patches (from “git format-patch”) to the mailing list are  
preferred because they allow code review and comments in the reply to  
the patch.

We will adhere to mostly the same conventions for patch submissions as  
git itself. See the Documentation/SubmittingPatches document  
distributed with git on on patch submission guidelines to follow. Just  
don’t email the git mailing list or maintainer with kcar patches.

== Contact

All feedback (bug reports, user/development discussion, patches, pull  
requests) go to the mailing list: [mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)

== TODO

Patches to removed\_email\_address@domain.invalid (via git format-patch + git send-email)  
for  
these would be greatly appreciated

- optional drop-in monkey patch for Net::HTTP
- optional EventMachine support
- optional Rev support