fix Range header handling for static files (#1402)

This commit fixes the issue in the `Range` header handling that was done
while serving the file contents.

As per the HTTP response standards, a status code of 206 will be used in
case if the Range is returning a partial value and default of 200 in
other cases.

Signed-off-by: Harsha Narayana <harsha2k4@gmail.com>

sanic/handlers.py

@@ -167,17 +167,17 @@ class ContentRangeHandler:
                 )
             else:
                 # this case represents `Content-Range: bytes 5-`
-                self.end = self.total
+                self.end = self.total - 1
         else:
             if self.start is None:
                 # this case represents `Content-Range: bytes -5`
                 self.start = self.total - self.end
-                self.end = self.total
+                self.end = self.total - 1
         if self.start >= self.end:
             raise ContentRangeError(
                 "Invalid for Content Range parameters", self
             )
-        self.size = self.end - self.start
+        self.size = self.end - self.start + 1
         self.headers = {
             "Content-Range": "bytes %s-%s/%s"
             % (self.start, self.end, self.total)

sanic/response.py

@@ -302,6 +302,7 @@ async def file(
                 _range.end,
                 _range.total,
             )
+            status = 206
         else:
             out_stream = await _file.read()
 
@@ -371,6 +372,7 @@ async def file_stream(
             _range.end,
             _range.total,
         )
+        status = 206
     return StreamingHTTPResponse(
         streaming_fn=_streaming_fn,
         status=status,