fix(header): ignore invalid cookies

In the spirit of Postel's law, ignore invalid cookies rather than
completely discard the entire Cookie header, which is what the current
code does, and which will lead to confusion when dealing with headers
with invalid cookies injected by proxies and intermediate apps servers.

src/header/common/cookie.rs

@@ -102,8 +102,6 @@ impl Header for Cookie {
                 let key_val = (key_val.next(), key_val.next());
                 if let (Some(key), Some(val)) = key_val {
                     vec_map.insert(key.trim().to_owned().into(), val.trim().to_owned().into());
-                } else {
-                    return Err(::Error::Header);
                 }
             }
         }
@@ -213,10 +211,20 @@ mod tests {
         cookie.append("foo", "bar");
         assert_eq!(cookie, parsed);
 
+        let parsed = Cookie::parse_header(&b"foo=bar;".to_vec().into()).unwrap();
+        assert_eq!(cookie, parsed);
+
         let parsed = Cookie::parse_header(&b"foo=bar; baz=quux".to_vec().into()).unwrap();
         cookie.append("baz", "quux");
         assert_eq!(cookie, parsed);
 
+        let parsed = Cookie::parse_header(&b"foo=bar;; baz=quux".to_vec().into()).unwrap();
+        assert_eq!(cookie, parsed);
+
+        let parsed = Cookie::parse_header(&b"foo=bar; invalid ; bad; ;; baz=quux".to_vec().into())
+            .unwrap();
+        assert_eq!(cookie, parsed);
+
         let parsed = Cookie::parse_header(&b" foo  =    bar;baz= quux  ".to_vec().into()).unwrap();
         assert_eq!(cookie, parsed);
 
@@ -241,9 +249,6 @@ mod tests {
                 .unwrap();
         cookie.append("double", "=2");
         assert_eq!(cookie, parsed);
-
-        Cookie::parse_header(&b"foo;bar=baz;quux".to_vec().into()).unwrap_err();
-
     }
 }