From fdcba79f45f5b953459787c44321bc82dd9c9344 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=2E=20K=C3=A4rkk=C3=A4inen?=
 <tronic@users.noreply.github.com>
Date: Mon, 29 Jul 2019 18:20:03 +0300
Subject: [PATCH] PEP 594 has cgi module scheduled for deprecation in Python
 3.8. Reimplement cgi.parse_header in Sanic. The new implementation is much
 faster than either cgi.parse_header or equivalent
 werkzeug.parse_options_header, and unlike the two, handles also quoted values
 with semicolons or \" in them.

---
 sanic/headers.py | 18 ++++++++++++++++++
 sanic/request.py |  7 +++----
 2 files changed, 21 insertions(+), 4 deletions(-)
 create mode 100644 sanic/headers.py

diff --git a/sanic/headers.py b/sanic/headers.py
new file mode 100644
index 00000000..fccef120
--- /dev/null
+++ b/sanic/headers.py
@@ -0,0 +1,18 @@
+import re
+
+token, quoted = r"([\w!#$%&'*+\-.^_`|~]+)", r'"((?:[^"]|\\")*)"'
+parameter = re.compile(f';\s*{token}=(?:{token}|{quoted})', re.ASCII)
+
+
+def parse_options_header(value: str):
+    """Parse HTTP header values of Content-Type format."""
+    pos = value.find(';')
+    if pos == -1:
+        options = {}
+    else:
+        options = {
+            m.group(1).lower(): m.group(2) or m.group(3).replace(r'\"', '"')
+            for m in parameter.finditer(value[pos:])
+        }
+        value = value[:pos]
+    return value.strip().lower(), options
diff --git a/sanic/request.py b/sanic/request.py
index 285333c7..9191f8fa 100644
--- a/sanic/request.py
+++ b/sanic/request.py
@@ -4,7 +4,6 @@ import json
 import sys
 import warnings
 
-from cgi import parse_header
 from collections import defaultdict, namedtuple
 from http.cookies import SimpleCookie
 from urllib.parse import parse_qs, parse_qsl, unquote, urlunparse
@@ -13,7 +12,7 @@ from httptools import parse_url
 
 from sanic.exceptions import InvalidUsage
 from sanic.log import error_logger, logger
-
+from sanic.headers import parse_options_header
 
 try:
     from ujson import loads as json_loads
@@ -177,7 +176,7 @@ class Request(dict):
             content_type = self.headers.get(
                 "Content-Type", DEFAULT_HTTP_CONTENT_TYPE
             )
-            content_type, parameters = parse_header(content_type)
+            content_type, parameters = parse_options_header(content_type)
             try:
                 if content_type == "application/x-www-form-urlencoded":
                     self.parsed_form = RequestParameters(
@@ -551,7 +550,7 @@ def parse_multipart_form(body, boundary):
 
             colon_index = form_line.index(":")
             form_header_field = form_line[0:colon_index].lower()
-            form_header_value, form_parameters = parse_header(
+            form_header_value, form_parameters = parse_options_header(
                 form_line[colon_index + 2 :]
             )