From zedshaw at zedshaw.com  Tue May  6 02:27:29 2008
From: zedshaw at zedshaw.com (Zed A. Shaw)
Date: Tue, 6 May 2008 02:27:29 -0400
Subject: [Mongrel-development] Pure Ruby HTTP parser
In-Reply-To: <3ae7f4480804240438g62ed7190if2a84ff08dd2fe34@mail.gmail.com>
References: <c7e6b2b00804231750o1c86d377i25c83d5e99f41dd1@mail.gmail.com>
	<3ae7f4480804240438g62ed7190if2a84ff08dd2fe34@mail.gmail.com>
Message-ID: <20080506022729.f0db321e.zedshaw@zedshaw.com>

On Thu, 24 Apr 2008 13:38:03 +0200
"ry dahl" <ry at tinyclouds.org> wrote:

> One could replace http11's parser with some regular expressions and
> out-of-bounds checking rather easily. I think Kirk Haines did this (?)
> and said it was rather comparable in speed to the C/Ragel state
> machine. I guess that wasn't really the point of your exercise, but
> it's worth noting, if anyone actually wants a pure ruby http parser.

Yes, fast, but not correct.  The main difference between a generated
parser based on algorithms and hand crafted regex is when the parser
blows up it says:

"Syntax error at character #34 expecting BLAH, FOO, and BAR symbols."

Regexen do this:

"Hi, oh thanks, I *love* hacks like this.  You crafted this shellcode
really well so that it looks mildly like a payload.  Super awesome I'll
just pass this vaguely HTTP string right on to our app."

:-)

-- 
Zed A. Shaw
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