Add handling for cases where start is greater than end in a Range and change function name

Author: lyc8503

Lib/http/server.py

@@ -700,7 +700,7 @@ def send_head(self):
         """
         path = self.translate_path(self.path)
         f = None
-        self.range = self.get_range()
+        self.range = self.parse_range()
         if os.path.isdir(path):
             parts = urllib.parse.urlsplit(self.path)
             if not parts.path.endswith('/'):
@@ -937,7 +937,7 @@ def guess_type(self, path):
             return guess
         return 'application/octet-stream'
 
-    def get_range(self):
+    def parse_range(self):
         """Return a tuple of (start, end) representing the range header in
         the HTTP request. If the range header is missing or not resolvable,
         None is returned. This only supports single part ranges.
@@ -949,11 +949,13 @@ def get_range(self):
         m = re.match(r'bytes=(\d+)-(\d*)$', range_header)
         if not m:
             return None
-        start = m.group(1)
+        start = int(m.group(1))
         if not m.group(2):
-            return int(start), None
-        end = m.group(2)
-        return int(start), int(end)
+            return start, None
+        end = int(m.group(2))
+        if start > end:
+            return None
+        return start, end
 
 
 # Utilities for CGIHTTPRequestHandler

Lib/test/test_httpservers.py

@@ -557,6 +557,9 @@ def test_range_get(self):
         response = self.request(self.base_url + '/test', headers={'Range': 'bytes=100-200'})
         self.check_status_and_reason(response, HTTPStatus.REQUESTED_RANGE_NOT_SATISFIABLE)
 
+        response = self.request(self.base_url + '/test', headers={'Range': 'bytes=4-3'})
+        self.check_status_and_reason(response, HTTPStatus.OK, data=self.data)
+
         response = self.request(self.base_url + '/test', headers={'Range': 'bytes=wrong format'})
         self.check_status_and_reason(response, HTTPStatus.OK, data=self.data)