Issue #8: Check if value is single value

httoop/header/auth.py

@@ -6,6 +6,7 @@
 
 class Authorization(AuthRequestElement):
 	is_request_header = True
+	is_single_value_header = True
 
 
 class ProxyAuthenticate(_ListElement, _HopByHopElement, AuthResponseElement):
@@ -16,6 +17,7 @@ class ProxyAuthenticate(_ListElement, _HopByHopElement, AuthResponseElement):
 class ProxyAuthorization(_HopByHopElement, AuthRequestElement):
 	__name__ = 'Proxy-Authorization'
 	is_request_header = True
+	is_single_value_header = True
 
 
 class WWWAuthenticate(_ListElement, AuthResponseElement):

httoop/header/cache.py

@@ -6,6 +6,7 @@
 class Age(HeaderElement):
 
 	is_response_header = True
+	is_single_value_header = True
 
 
 class CacheControl(HeaderElement):
@@ -18,6 +19,7 @@ class CacheControl(HeaderElement):
 class Expires(HeaderElement):
 
 	is_response_header = True
+	is_single_value_header = True
 
 
 class Pragma(HeaderElement):

httoop/header/conditional.py

@@ -26,6 +26,7 @@ def __eq__(self, other):
 class ETag(HeaderElement):
 
 	is_response_header = True
+	is_single_value_header = True
 
 	def __eq__(self, other):
 		if not isinstance(other, ETag):
@@ -36,23 +37,28 @@ def __eq__(self, other):
 class LastModified(_DateComparable, HeaderElement):
 	__name__ = 'Last-Modified'
 	is_response_header = True
+	is_single_value_header = True
 
 
 class IfMatch(HeaderElement):
 	__name__ = 'If-Match'
 	is_request_header = True
+	is_single_value_header = True
 
 
 class IfModifiedSince(_DateComparable, HeaderElement):
 	__name__ = 'If-Modified-Since'
 	is_request_header = True
+	is_single_value_header = True
 
 
 class IfNoneMatch(HeaderElement):
 	__name__ = 'If-None-Match'
 	is_request_header = True
+	is_single_value_header = True
 
 
 class IfUnmodifiedSince(_DateComparable, HeaderElement):
 	__name__ = 'If-Unmodified-Since'
 	is_request_header = True
+	is_single_value_header = True

httoop/header/element.py

@@ -38,6 +38,8 @@ class HeaderElement(with_metaclass(HeaderType)):
 	hop_by_hop = False
 	list_element = False
 	encode_latin1_quoted_printable = False
+	is_single_value_header = False
+	ignore_single_value_error = False
 
 	# Regular expression that matches `special' characters in parameters, the
 	# existance of which force quoting of the parameter value.
@@ -376,4 +378,5 @@ class _HopByHopElement(object):
 
 
 class _ListElement(object):
-	list_element = True
+	list_element = True  # TODO: rename list_element into something like allow_comma_separation = False, allow_split_foobar
+	is_single_value_header = False

httoop/header/headers.py

@@ -130,8 +130,13 @@ def parse(self, data):
 			value = b''.join(value).rstrip()
 			Element = HEADER.get(name, HeaderElement)
 			value = Element.decode(value)
+			name = name.decode('ascii', 'ignore')
 
-			self.append(name.decode('ascii', 'ignore'), value)
+			if name in self and Element.is_single_value_header and not Element.ignore_single_value_error:
+				# TODO: this is only for non-splitted values
+				raise InvalidHeader(_(u"Single header value given more than once: %r") % (name,))
+
+			self.append(name, value)
 
 	def compose(self):
 		return b'%s\r\n' % b''.join(b'%s: %s\r\n' % (k, v) for k, v in self.__items())
@@ -145,7 +150,7 @@ def __encoded_items(self):
 			if Element is not HeaderElement:
 				key = Element.__name__
 			key = key.encode('ascii', 'ignore')
-			if Element.list_element:
+			if Element.list_element:  # TODO: and not Element.is_single_value_header?
 				for value in Element.split(values):
 					yield key, Element.encode(value)
 			else:

httoop/header/messaging.py

@@ -95,6 +95,7 @@ class ContentDisposition(HeaderElement):
 
 	__name__ = 'Content-Disposition'
 	is_response_header = True
+	is_single_value_header = True
 
 	from httoop.date import Date
 
@@ -143,6 +144,7 @@ class ContentEncoding(CodecElement, HeaderElement):
 	__name__ = 'Content-Encoding'
 	is_request_header = True
 	is_response_header = True
+	#is_single_value_header = True
 
 	# IANA assigned HTTP Content-Encoding values
 	CODECS = {
@@ -161,30 +163,35 @@ class ContentLanguage(HeaderElement):
 	__name__ = 'Content-Language'
 	is_request_header = True
 	is_response_header = True
+	is_single_value_header = True
 
 
 class ContentLength(HeaderElement):
 	__name__ = 'Content-Length'
 	is_request_header = True
 	is_response_header = True
+	is_single_value_header = True
 
 
 class ContentLocation(HeaderElement):
 	__name__ = 'Content-Location'
 	is_response_header = True
+	is_single_value_header = True
 
 
 class ContentMD5(HeaderElement):
 	__name__ = 'Content-MD5'
 	is_request_header = True
 	is_response_header = True
+	is_single_value_header = True
 
 
 class ContentType(HeaderElement, MimeType, CodecElement):
 
 	__name__ = 'Content-Type'
 	is_request_header = True
 	is_response_header = True
+	is_single_value_header = True
 
 	raise_on_missing_codec = False
 
@@ -231,11 +238,13 @@ class Date(HeaderElement):
 
 	priority = '\x01'
 	is_response_header = True
+	is_single_value_header = True
 
 
 class Expect(HeaderElement):
 
 	is_response_header = True
+	is_single_value_header = True
 
 	@property
 	def is_100_continue(self):
@@ -244,6 +253,7 @@ def is_100_continue(self):
 
 class From(HeaderElement):
 	is_request_header = True
+	is_single_value_header = True
 
 
 class Forwarded(HeaderElement):
@@ -275,6 +285,7 @@ def parse(cls, elementstr):
 class Host(HeaderElement):
 
 	is_request_header = True
+	is_single_value_header = True
 
 	priority = '\x03'
 	RE_HOSTNAME = re.compile(r'^([^\x00-\x1F\x7F()^\'"<>@,;:/\[\]={} \t\\\\"]+)$')
@@ -339,28 +350,33 @@ class XForwardedHost(Host):
 
 class Location(HeaderElement):
 	is_response_header = True
+	is_single_value_header = True
 
 
 class MaxForwards(HeaderElement):
 
 	__name__ = 'Max-Forwards'
 	is_response_header = True
+	is_single_value_header = True
 
 
 class Referer(HeaderElement):
 	is_request_header = True
+	is_single_value_header = True
 
 
 class RetryAfter(HeaderElement):
 
 	__name__ = 'Retry-After'
 	is_response_header = True
+	is_single_value_header = True
 
 
 class Server(HeaderElement):
 
 	priority = '\x02'
 	is_response_header = True
+	is_single_value_header = True
 
 
 class SetCookie(_ListElement, _CookieElement):
@@ -458,6 +474,7 @@ class UserAgent(HeaderElement):
 	__name__ = 'User-Agent'
 	is_response_header = True
 	is_request_header = True
+	is_single_value_header = True
 
 
 class Via(HeaderElement):

httoop/header/range.py

@@ -11,6 +11,7 @@ class ContentRange(HeaderElement):
 
 	__name__ = 'Content-Range'
 	is_response_header = True
+	is_single_value_header = True
 
 	def __init__(self, value, range_, length):
 		self.range = range_
@@ -56,11 +57,13 @@ def parse(cls, elementstr):
 class IfRange(HeaderElement):
 	__name__ = 'If-Range'
 	is_request_header = True
+	is_single_value_header = True
 
 
 class Range(HeaderElement):
 
 	is_request_header = True
+	is_single_value_header = True
 
 	def __init__(self, value, ranges, params=None):
 		self.ranges = ranges

httoop/header/security.py

@@ -39,6 +39,7 @@ class StrictTransportSecurity(HeaderElement):
 
 	__name__ = 'Strict-Transport-Security'
 	is_response_header = True
+	is_single_value_header = True
 
 	@property
 	def include_sub_domains(self):
@@ -53,6 +54,7 @@ class ContentTypeOptions(HeaderElement):
 
 	__name__ = 'X-Content-Type-Options'
 	is_response_header = True
+	is_single_value_header = True
 
 	@property
 	def nosniff(self):
@@ -70,6 +72,7 @@ class FrameOptions(HeaderElement):
 
 	__name__ = 'X-Frame-Options'
 	is_response_header = True
+	is_single_value_header = True
 
 	RE_PARAMS = re.compile('\\s+')
 
@@ -106,6 +109,7 @@ class XSSProtection(HeaderElement):
 
 	__name__ = 'X-XSS-Protection'
 	is_response_header = True
+	is_single_value_header = True
 
 	@property
 	def enabled(self):