[PATCH 0/2] strip leading/trailing linear whitespace in headers

[PATCH 0/2] strip leading/trailing linear whitespace in headers

[Eric Wong]

Hello, I've pushed the following two changes to my git repo,
based on "master" of git://github.com/fauna/mongrel.git

  [PATCH 1/2] ragel.rake: rebuild on http11_parser_common.rl changes
  [PATCH 2/2] strip trailing and leading linear whitespace in headers

The first patch is a trivial rake dependency fix.

I could definitely use a more pairs of eyes to review my second patch
which I've included inline below.  I'm also planning this for the
unicorn and kcar projects.

RFC 2616, section 4.2:
> The field-content does not include any leading or trailing LWS:
> linear white space occurring before the first non-whitespace
> character of the field-value or after the last non-whitespace
> character of the field-value. Such leading or trailing LWS MAY be
> removed without changing the semantics of the field value. Any LWS
> that occurs between field-content MAY be replaced with a single SP
> before interpreting the field value or forwarding the message
> downstream.
---
  You can pull from my repo here:

    git pull git://bogomips.org/mongrel.git http11-lws

  If you like web browsers (I don't) you can view the changes here:

    http://bogomips.org/mongrel.git?h=http11-lws

 ext/http11/http11_parser.c         |  435 +++++++++++++++++++-----------------
 ext/http11/http11_parser_common.rl |    5 +-
 test/test_http11.rb                |   66 ++++++
 3 files changed, 304 insertions(+), 202 deletions(-)

 (removed ext/http11/http11_parser.c diff for brevity)

diff --git a/ext/http11/http11_parser_common.rl b/ext/http11/http11_parser_common.rl
index 53c805f..2ef1d31 100644
--- a/ext/http11/http11_parser_common.rl
+++ b/ext/http11/http11_parser_common.rl
@@ -18,6 +18,7 @@
   uchar = (unreserved | escape);
   pchar = (uchar | ":" | "@" | "&" | "=" | "+");
   tspecials = ("(" | ")" | "<" | ">" | "@" | "," | ";" | ":" | "\\" | "\"" | "/" | "[" | "]" | "?" | "=" | "{" | "}" | " " | "\t");
+  lws = (" " | "\t");
 
 # elements
   token = (ascii -- (CTL | tspecials));
@@ -43,9 +44,9 @@
 
   field_name = ( token -- ":" )+ >start_field $snake_upcase_field %write_field;
 
-  field_value = any* >start_value %write_value;
+  field_value = (""|(any*(any -- lws))) >start_value %write_value;
 
-  message_header = field_name ":" " "* field_value :> CRLF;
+  message_header = field_name ":" lws* field_value lws* :> CRLF;
 
   Request = Request_Line ( message_header )* ( CRLF @done );
 
diff --git a/test/test_http11.rb b/test/test_http11.rb
index da311af..2b55909 100644
--- a/test/test_http11.rb
+++ b/test/test_http11.rb
@@ -81,6 +81,72 @@ class HttpParserTest < Test::Unit::TestCase
     assert_equal 'posts-17408', req['FRAGMENT']
   end
 
+  def test_leading_tab
+    parser = HttpParser.new
+    req = {}
+    get = "GET / HTTP/1.1\r\nHost:\texample.com\r\n\r\n"
+    assert_nothing_raised do
+      parser.execute(req, get, 0)
+    end
+    assert parser.finished?
+    assert_equal 'example.com', req['HTTP_HOST']
+  end
+
+  def test_trailing_whitespace
+    parser = HttpParser.new
+    req = {}
+    get = "GET / HTTP/1.1\r\nHost: example.com \r\n\r\n"
+    assert_nothing_raised do
+      parser.execute(req, get, 0)
+    end
+    assert parser.finished?
+    assert_equal 'example.com', req['HTTP_HOST']
+  end
+
+  def test_trailing_tab
+    parser = HttpParser.new
+    req = {}
+    get = "GET / HTTP/1.1\r\nHost: example.com\t\r\n\r\n"
+    assert_nothing_raised do
+      parser.execute(req, get, 0)
+    end
+    assert parser.finished?
+    assert_equal 'example.com', req['HTTP_HOST']
+  end
+
+  def test_trailing_multiple_linear_whitespace
+    parser = HttpParser.new
+    req = {}
+    get = "GET / HTTP/1.1\r\nHost: example.com\t \t \t\r\n\r\n"
+    assert_nothing_raised do
+      parser.execute(req, get, 0)
+    end
+    assert parser.finished?
+    assert_equal 'example.com', req['HTTP_HOST']
+  end
+
+  def test_embedded_linear_whitespace_ok
+    parser = HttpParser.new
+    req = {}
+    get = "GET / HTTP/1.1\r\nX-Space: hello\t world\t \r\n\r\n"
+    assert_nothing_raised do
+      parser.execute(req, get, 0)
+    end
+    assert parser.finished?
+    assert_equal "hello\t world", req["HTTP_X_SPACE"]
+  end
+
+  def test_empty_header
+    parser = HttpParser.new
+    req = {}
+    get = "GET / HTTP/1.1\r\nHost:  \r\n\r\n"
+    assert_nothing_raised do
+      parser.execute(req, get, 0)
+    end
+    assert parser.finished?
+    assert_equal '', req['HTTP_HOST']
+  end
+
   # lame random garbage maker
   def rand_data(min, max, readable=true)
     count = min + ((rand(max)+1) *10).to_i
-- 
Eric Wong