Fixed gzip automatic content-type assignment and added automatic compression header configuration (#251)

* Fixed gzip automatic content-type assignment and added automatic compression setting

This implements the fix for detecting the proper content-type even when the file has the ".gz" extension. It further makes sure the compression headers are set properly if a "gz." file is detected, but the compression headers weren't explicitly set by the user.

* Added a test for properly auto-determining mime types and setting content encoding header

* Modified the gzip file header assignments and following tests according to the feedback.

---------

Co-authored-by: Lukáš Kremla <lukas.kremla@bonnel.cz>

src/microdot/microdot.py

@@ -774,7 +774,10 @@ class Response:
         first.
         """
         if content_type is None:
-            ext = filename.split('.')[-1]
+            if compressed and filename.endswith('.gz'):
+                ext = filename[:-3].split('.')[-1]
+            else:
+                ext = filename.split('.')[-1]
             if ext in Response.types_map:
                 content_type = Response.types_map[ext]
             else:

tests/files/test.txt.gz

@@ -0,0 +1 @@
+foo

tests/test_response.py

@@ -280,6 +280,17 @@ class TestResponse(unittest.TestCase):
                          'application/octet-stream')
         self.assertEqual(res.headers['Content-Encoding'], 'gzip')
 
+    def test_send_file_gzip_handling(self):
+        res = Response.send_file('tests/files/test.txt.gz')
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.headers['Content-Type'],
+                         'application/octet-stream')
+
+        res = Response.send_file('tests/files/test.txt.gz', compressed=True)
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.headers['Content-Type'], 'text/plain')
+        self.assertEqual(res.headers['Content-Encoding'], 'gzip')
+
     def test_default_content_type(self):
         original_content_type = Response.default_content_type
         res = Response('foo')