fix: Allow empty segment names

RFC requires the presence of a name option in the Content-Disposition header, but the value is allowed to be empty.

fixes #56

multipart.py

@@ -407,7 +407,8 @@ class MultipartSegment:
 
     #: List of headers as name/value pairs with normalized (Title-Case) names.
     headerlist: List[Tuple[str, str]]
-    #: The required 'name' option of the Content-Disposition header.
+    #: The 'name' option of the Content-Disposition header. Always a string,
+    #: but may be empty.
     name: str
     #: The optional 'filename' option of the Content-Disposition header.
     filename: Optional[str]
@@ -449,7 +450,7 @@ def __init__(self, parser: PushMultipartParser):
         self._size_limit = parser.max_segment_size
 
     def _add_headerline(self, line: bytearray):
-        assert line and not self.name
+        assert line and self.name is None
         parser = self._parser
 
         if line[0] in b" \t":  # Multi-line header value
@@ -477,15 +478,17 @@ def _add_headerline(self, line: bytearray):
         self.headerlist.append((name.title(), value))
 
     def _close_headers(self):
-        assert not self.name and not self.complete
+        assert self.name is None
 
         cdisp = self.header("Content-Disposition")
         if not cdisp:
             raise self._fail("Missing Content-Disposition segment header")
         cdisp, args = parse_options_header(cdisp)
-        if cdisp != "form-data" or "name" not in args:
-            raise self._fail("Invalid Content-Disposition segment header")
-        self.name = args.get("name")
+        if cdisp != "form-data":
+            raise self._fail("Invalid Content-Disposition segment header: Wrong type")
+        if "name" not in args and self._parser.strict:
+            raise self._fail("Invalid Content-Disposition segment header: Missing name option")
+        self.name = args.get("name", "")
         self.filename = args.get("filename")
 
         content_type = self.header("Content-Type", "application/octet-stream")
@@ -495,15 +498,15 @@ def _close_headers(self):
         self._clen = int(self.header("Content-Length", -1))
 
     def _update_size(self, bytecount: int):
-        assert self.name and not self.complete
+        assert self.name is not None and not self.complete
         self.size += bytecount
         if self._clen >= 0 and self.size > self._clen:
             raise self._fail("Segment Content-Length exceeded")
         if self.size > self._size_limit:
             raise self._fail("Maximum segment size exceeded")
 
     def _mark_complete(self):
-        assert self.name and not self.complete
+        assert self.name is not None and not self.complete
         if self._clen >= 0 and self.size != self._clen:
             raise self._fail("Segment size does not match Content-Length header")
         self.complete = True

test/test_push_parser.py

@@ -168,16 +168,30 @@ def test_header_bad_name(self):
                 b"--boundary\r\ninvalid\xc3\x28:value\r\n\r\ndata\r\n--boundary--"
             )
 
-    def test_header_bad_disposition(self):
-        with self.assertMPE("Invalid Content-Disposition segment header"):
+    def test_header_wrong_segment_subtype(self):
+        with self.assertMPE("Invalid Content-Disposition segment header: Wrong type"):
             self.parse(
                 b"--boundary\r\nContent-Disposition: mixed\r\n\r\ndata\r\n--boundary--"
             )
-        self.reset()
-        with self.assertMPE("Invalid Content-Disposition segment header"):
-            self.parse(
-                b"--boundary\r\nContent-Disposition: form-data\r\n\r\ndata\r\n--boundary--"
-            )
+
+    def test_segment_empty_name(self):
+        self.parse(b"--boundary\r\n")
+        parts = self.parse(b"Content-Disposition: form-data; name\r\n\r\n")
+        self.assertEqual(parts[0].name, "")
+        self.parse(b"\r\n--boundary\r\n")
+        parts = self.parse(b"Content-Disposition: form-data; name=\r\n\r\n")
+        self.assertEqual(parts[0].name, "")
+        self.parse(b"\r\n--boundary\r\n")
+        parts = self.parse(b'Content-Disposition: form-data; name=""\r\n\r\n')
+        self.assertEqual(parts[0].name, "")
+
+    @assertStrict("Invalid Content-Disposition segment header: Missing name option")
+    def test_segment_missing_name(self, strict):
+        self.reset(strict=strict)
+        self.parse(b"--boundary\r\n")
+        parts = self.parse(b"Content-Disposition: form-data;\r\n\r\n")
+        print(parts)
+        self.assertEqual(parts[0].name, "")
 
     def test_segment_count_limit(self):
         self.reset(max_segment_count=1)
@@ -261,3 +275,4 @@ def test_segment_handle_access(self):
         self.assertEqual(part.filename, "bar.txt")
         with self.assertRaises(KeyError):
             part["Missing"]
+