Recognizes non-ASCII filenames in RFC 2231, and suport filename lengt…

…h is zero for multipart/form-data. (#1497)

* suport filename length is 0

* 1. suport filename length is zero for multipart/form-data.
2. Now recognizes non-ASCII filenames in RFC 2231, "filename*" format
3. Add some test cases in tests/test_requests.py::test_request_multipart_files.

* reformat sanic/request.py

sanic/request.py

@@ -1,11 +1,12 @@
 import asyncio
+import email.utils
 import json
 import sys
 
 from cgi import parse_header
 from collections import namedtuple
 from http.cookies import SimpleCookie
-from urllib.parse import parse_qs, urlunparse
+from urllib.parse import parse_qs, unquote, urlunparse
 
 from httptools import parse_url
 
@@ -356,28 +357,35 @@ def parse_multipart_form(body, boundary):
             )
 
             if form_header_field == "content-disposition":
-                file_name = form_parameters.get("filename")
                 field_name = form_parameters.get("name")
+                file_name = form_parameters.get("filename")
+
+                # non-ASCII filenames in RFC2231, "filename*" format
+                if file_name is None and form_parameters.get("filename*"):
+                    encoding, _, value = email.utils.decode_rfc2231(
+                        form_parameters["filename*"]
+                    )
+                    file_name = unquote(value, encoding=encoding)
             elif form_header_field == "content-type":
                 content_type = form_header_value
                 content_charset = form_parameters.get("charset", "utf-8")
 
         if field_name:
             post_data = form_part[line_index:-4]
-            if file_name:
+            if file_name is None:
+                value = post_data.decode(content_charset)
+                if field_name in fields:
+                    fields[field_name].append(value)
+                else:
+                    fields[field_name] = [value]
+            else:
                 form_file = File(
                     type=content_type, name=file_name, body=post_data
                 )
                 if field_name in files:
                     files[field_name].append(form_file)
                 else:
                     files[field_name] = [form_file]
-            else:
-                value = post_data.decode(content_charset)
-                if field_name in fields:
-                    fields[field_name].append(value)
-                else:
-                    fields[field_name] = [value]
         else:
             logger.debug(
                 "Form-data field does not have a 'name' parameter "

tests/test_requests.py

@@ -432,29 +432,49 @@ async def get(request):
 
 
 @pytest.mark.parametrize(
-    "payload",
+    "payload,filename",
     [
-        "------sanic\r\n"
-        'Content-Disposition: form-data; filename="filename"; name="test"\r\n'
-        "\r\n"
-        "OK\r\n"
-        "------sanic--\r\n",
-        "------sanic\r\n"
-        'content-disposition: form-data; filename="filename"; name="test"\r\n'
-        "\r\n"
-        'content-type: application/json; {"field": "value"}\r\n'
-        "------sanic--\r\n",
+        ("------sanic\r\n"
+         'Content-Disposition: form-data; filename="filename"; name="test"\r\n'
+         "\r\n"
+         "OK\r\n"
+         "------sanic--\r\n", "filename"),
+        ("------sanic\r\n"
+         'content-disposition: form-data; filename="filename"; name="test"\r\n'
+         "\r\n"
+         'content-type: application/json; {"field": "value"}\r\n'
+         "------sanic--\r\n", "filename"),
+        ("------sanic\r\n"
+         'Content-Disposition: form-data; filename=""; name="test"\r\n'
+         "\r\n"
+         "OK\r\n"
+         "------sanic--\r\n", ""),
+        ("------sanic\r\n"
+         'content-disposition: form-data; filename=""; name="test"\r\n'
+         "\r\n"
+         'content-type: application/json; {"field": "value"}\r\n'
+         "------sanic--\r\n", ""),
+        ("------sanic\r\n"
+         'Content-Disposition: form-data; filename*="utf-8\'\'filename_%C2%A0_test"; name="test"\r\n'
+         "\r\n"
+         "OK\r\n"
+         "------sanic--\r\n", "filename_\u00A0_test"),
+        ("------sanic\r\n"
+         'content-disposition: form-data; filename*="utf-8\'\'filename_%C2%A0_test"; name="test"\r\n'
+         "\r\n"
+         'content-type: application/json; {"field": "value"}\r\n'
+         "------sanic--\r\n", "filename_\u00A0_test"),
     ],
 )
-def test_request_multipart_files(app, payload):
+def test_request_multipart_files(app, payload, filename):
     @app.route("/", methods=["POST"])
     async def post(request):
         return text("OK")
 
     headers = {"content-type": "multipart/form-data; boundary=----sanic"}
 
     request, _ = app.test_client.post(data=payload, headers=headers)
-    assert request.files.get("test").name == "filename"
+    assert request.files.get("test").name == filename
 
 
 def test_request_multipart_file_with_json_content_type(app):