Fix content type of post request messages

setup.cfg

@@ -6,6 +6,9 @@ max_line_length = 80
 ignore = E402 F401 W504 E121 E125 E241
 statistics = True
 
+[mypy]
+warn_unreachable = True
+
 [mypy-google.auth.*]
 ignore_missing_imports = True
 

setup.py

@@ -47,6 +47,7 @@
             'google-oauth>=1.0',
         ],
     },
+    python_requires='>3.5',
     install_requires=[
         'pydicom>=1.0',
         'requests>=2.18',

src/dicomweb_client/api.py

@@ -142,8 +142,6 @@ def _create_dataelement(
                 elem_value = value[0].split('\\')
             else:
                 elem_value = value
-    if value is None:
-        logger.warning('missing value for data element "{}"'.format(tag))
     try:
         return pydicom.dataelem.DataElement(tag=tag, value=elem_value, VR=vr)
     except Exception:
@@ -375,7 +373,7 @@ def __init__(
             port = match.group('port')
         except AttributeError:
             raise ValueError('Malformed URL: {}'.format(self.base_url))
-        if port is not None:
+        if port:
             self.port = int(port)
         else:
             if self.protocol == 'http':
@@ -836,7 +834,7 @@ def _assert_media_type_is_valid(self, media_type: str):
 
     def _build_range_header_field_value(
             self,
-            byte_range: Tuple[int, int]
+            byte_range: Optional[Tuple[int, int]]
         ) -> str:
         '''Builds a range header field value for HTTP GET request messages.
 
@@ -1436,7 +1434,7 @@ def _invoke_post_request(
                 data: bytes,
                 headers: Optional[Dict[str, str]] = None
             ) -> requests.models.Response:
-            return self._session.post(url, headers, data)
+            return self._session.post(url, data=data, headers=headers)
 
         if self._chunk_size is not None and len(data) > self._chunk_size:
             logger.info('store data in chunks using chunked transfer encoding')

tests/test_api.py

@@ -619,6 +619,10 @@ def test_store_instance_error_with_retries(httpserver, client, cache_dir):
     with pytest.raises(RetryError):
         client.store_instances([dataset])
     assert len(httpserver.requests) == max_attempts
+    request = httpserver.requests[0]
+    assert request.headers['Content-Type'].startswith(
+        'multipart/related; type="application/dicom"'
+    )
 
 
 def test_store_instance_error_with_no_retries(httpserver, client, cache_dir):
@@ -634,6 +638,10 @@ def test_store_instance_error_with_no_retries(httpserver, client, cache_dir):
     with pytest.raises(HTTPError):
         client.store_instances([dataset])
     assert len(httpserver.requests) == 1
+    request = httpserver.requests[0]
+    assert request.headers['Content-Type'].startswith(
+        'multipart/related; type="application/dicom"'
+    )
 
 
 def test_load_json_dataset_da(httpserver, client, cache_dir):