Fix notice 1013 for headers that permit both singular and plural values

CHANGELOG.rst

@@ -21,6 +21,8 @@ Added
 
 Fixed
 -----
+- Notice `1013`_ is no longer wrongly reported for some headers
+  such as ``Vary``.
 - Fixed a crash on some pathological values of ``charset`` in ``Content-Type``.
 
 .. _Forwarded: https://tools.ietf.org/html/rfc7239
@@ -29,6 +31,7 @@ Fixed
 .. _1298: http://pythonhosted.org/HTTPolice/notices.html#1298
 .. _1296: http://pythonhosted.org/HTTPolice/notices.html#1296
 .. _1297: http://pythonhosted.org/HTTPolice/notices.html#1297
+.. _1013: http://pythonhosted.org/HTTPolice/notices.html#1013
 
 
 0.5.2 - 2017-03-24

httpolice/header.py

@@ -285,12 +285,24 @@ class MultiHeaderView(HeaderView):
 
     def _parse(self):
         entries, values = self._pre_parse()
-        self._value = []
-        for sub_values in values:
-            if isinstance(sub_values, Unavailable):
-                self._value.append(sub_values)
+        # Some headers, such as ``Vary``, permit both a comma-separated list
+        # (which can be spread over multiple entries) as well as a singular
+        # value (which cannot be combined with any other).
+        singular = [v for v in values
+                    if not isinstance(v, (list, Unavailable))]
+        if singular:
+            if len(singular) == len(entries) == 1:
+                self._value = singular[0]
             else:
-                self._value.extend(sub_values)
+                self._value = [Unavailable()]
+                self.message.complain(1013, header=self, entries=entries)
+        else:
+            self._value = []
+            for v in values:
+                if isinstance(v, Unavailable):
+                    self._value.append(v)
+                else:
+                    self._value.extend(v)
         self._entries = entries
 
     def __iter__(self):

httpolice/known/header.csv

@@ -10,7 +10,7 @@ Accept-Features,,,,4229,,,,,,,,,,,,,,,
 Accept-Language,,,,7231,5.3.5,,,,rfc7231,Accept_Language,,,True,False,standard,False,True,,multi
 Accept-Patch,,,,5789,3.1,,,,rfc5789,Accept_Patch,,,False,True,,,,,multi
 Accept-Post,,,,,,,https://www.w3.org/TR/ldp/,,,,,,,,standard,,,,
-Accept-Ranges,,,,7233,2.3,,,,rfc7233,Accept_Ranges,,,False,True,standard,,,,single
+Accept-Ranges,,,,7233,2.3,,,,rfc7233,Accept_Ranges,,,False,True,standard,,,,multi
 Access-Control,,,,,,,http://www.w3.org/2006/appformats/,W3C Web Application Formats Working Group,,,,,,,deprecated,,,,
 Access-Control-Allow-Credentials,,,citation,,,,https://www.w3.org/TR/cors/#access-control-allow-credentials-response-header,W3C Cross-Origin Resource Sharing,,,,,,,,,,,
 Access-Control-Allow-Headers,,,citation,,,,https://www.w3.org/TR/cors/#access-control-allow-headers-response-header,W3C Cross-Origin Resource Sharing,,,,,,,,,,,
@@ -21,7 +21,7 @@ Access-Control-Request-Headers,,,citation,,,,https://www.w3.org/TR/cors/#access-
 Access-Control-Request-Method,,,citation,,,,https://www.w3.org/TR/cors/#access-control-request-method-request-header,W3C Cross-Origin Resource Sharing,,,,,,,,,,,
 Age,,,,7234,5.1,,,,rfc7234,Age,True,True,False,True,standard,,,,single
 Allow,,,,7231,7.4.1,,,,rfc7231,Allow,,,False,True,standard,,,,multi
-Alt-Svc,,,,7838,3,,,,rfc7838,Alt_Svc,,,False,True,standard,,,,single
+Alt-Svc,,,,7838,3,,,,rfc7838,Alt_Svc,,,False,True,standard,,,,multi
 Alt-Used,,,,7838,5,,,,rfc7838,Alt_Used,,True,True,False,standard,False,False,,single
 Alternates,,,,4229,,,,,,,,,,,,,,,
 Apply-To-Redirect-Ref,,,,4437,,,,,,,,,,,,,,,
@@ -79,9 +79,9 @@ Hobareg,,,,7486,6.1.1,,,,,,,,,,experimental,,,,
 Host,,,,7230,5.4,,,,rfc7230,Host,,True,True,False,standard,False,False,,single
 IM,,,,4229,,,,,,,,,,,,,,,
 If,,,,4918,10.4,,,,,,,True,,,standard,True,,,
-If-Match,,,,7232,3.1,,,,rfc7232,If_Match,,True,True,False,standard,True,False,,single
+If-Match,,,,7232,3.1,,,,rfc7232,If_Match,,True,True,False,standard,True,False,,multi
 If-Modified-Since,,,,7232,3.3,,,,rfc7232,If_Modified_Since,,True,True,False,standard,True,False,,single
-If-None-Match,,,,7232,3.2,,,,rfc7232,If_None_Match,,True,True,False,standard,True,False,,single
+If-None-Match,,,,7232,3.2,,,,rfc7232,If_None_Match,,True,True,False,standard,True,False,,multi
 If-Range,,,,7233,3.2,,,,rfc7233,If_Range,,True,True,False,standard,False,False,,single
 If-Schedule-Tag-Match,,,,6638,8.3,,,,,,,True,,,standard,True,,,
 If-Unmodified-Since,,,,7232,3.4,,,,rfc7232,If_Unmodified_Since,,True,True,False,standard,True,False,,single
@@ -176,7 +176,7 @@ Upgrade,,,,7230,6.7,,,,rfc7230,Upgrade,,,True,True,standard,False,False,,multi
 Urgency,,,,8030,5.3,,,,,,,,,,standard,,,,
 User-Agent,,,,7231,5.5.3,,,,rfc7231,User_Agent,,,True,False,standard,False,False,,single
 Variant-Vary,,,,4229,,,,,,,,,,,,,,,
-Vary,,,,7231,7.1.4,,,,rfc7231,Vary,True,True,False,True,standard,,,,single
+Vary,,,,7231,7.1.4,,,,rfc7231,Vary,True,True,False,True,standard,,,,multi
 Version,,,,4229,,,,,,,,,,,,,,,
 Via,,,,7230,5.7.1,,,,rfc7230,Via,True,,True,True,standard,False,False,,multi
 WWW-Authenticate,,,,7235,4.1,,,,rfc7235,WWW_Authenticate,True,,False,True,standard,,,,multi

httpolice/syntax/rfc7233.py

@@ -3,7 +3,8 @@
 from httpolice.citation import RFC
 from httpolice.parse import (auto, can_complain, fill_names, literal, maybe,
                              pivot, skip, string, string1, subst)
-from httpolice.structure import ContentRange, RangeSpecifier, RangeUnit
+from httpolice.structure import (CaseInsensitive, ContentRange, RangeSpecifier,
+                                 RangeUnit)
 from httpolice.syntax.common import CHAR, DIGIT, SP, VCHAR
 from httpolice.syntax.rfc7230 import comma_list1, token__excluding
 from httpolice.syntax.rfc7231 import HTTP_date
@@ -13,9 +14,8 @@
 bytes_unit = RangeUnit << literal('bytes')                              > auto
 other_range_unit = RangeUnit << token__excluding(['bytes'])             > auto
 range_unit = bytes_unit | other_range_unit                              > pivot
-acceptable_ranges = (
-    subst([]) << literal('none') |
-    comma_list1(range_unit))                                            > pivot
+acceptable_ranges = (CaseInsensitive << literal('none') |
+                     comma_list1(range_unit))                           > pivot
 Accept_Ranges = acceptable_ranges                                       > pivot
 
 @can_complain

test/combined_data/1013_4

@@ -0,0 +1,19 @@
+1235
+
+# The presence of no. 1235 here means that we correctly recognize the multiple
+# values.
+
+======== BEGIN INBOUND STREAM ========
+GET / HTTP/1.1
+Host: example.com
+User-Agent: demo
+
+======== BEGIN OUTBOUND STREAM ========
+HTTP/1.1 200 OK
+Date: Thu, 31 Dec 2015 18:26:56 GMT
+Vary: accept-encoding
+Content-Type: text/plain
+Content-Length: 14
+Vary: host
+
+Hello world!

test/combined_data/1013_5

@@ -0,0 +1,20 @@
+1013 1013
+
+======== BEGIN INBOUND STREAM ========
+GET / HTTP/1.1
+Host: example.com
+User-Agent: demo
+If-none-match: *
+
+======== BEGIN OUTBOUND STREAM ========
+HTTP/1.1 200 OK
+Date: Thu, 31 Dec 2015 18:26:56 GMT
+Content-Type: text/plain
+Content-Length: 14
+Vary: *
+Accept-Ranges: none
+Alt-Svc: clear
+Vary: accept-encoding
+Accept-Ranges: none
+
+Hello world!

test/test_structure.py

@@ -243,3 +243,13 @@ def test_prefer():
 def test_decode_brotli():
     [exch1] = load_from_file('content_encoding_br')
     assert exch1.responses[0].decoded_body.startswith(b'Lorem ipsum dolor')
+
+
+def test_singular_vs_plural():
+    [exch] = load_from_file('1013_5')
+    assert exch.request.headers.if_none_match == u'*'
+    assert exch.responses[0].headers.alt_svc == u'clear'
+    assert all(isinstance(v, Unavailable)
+               for v in exch.responses[0].headers.accept_ranges)
+    assert all(isinstance(v, Unavailable)
+               for v in exch.responses[0].headers.vary)

test/test_syntax.py

@@ -354,8 +354,8 @@ def test_http_date():
 
 def test_acceptable_ranges():
     p = rfc7233.acceptable_ranges
-    assert parse(p, b'none') == []
-    assert parse(p, b'NONE') == []
+    assert parse(p, b'none') == u'none'
+    assert parse(p, b'NONE') == u'none'
     assert parse(p, b'none,') == [u'none']
     assert parse(p, b', ,Bytes, Pages') == [unit.bytes, u'pages']