[Python] Add option to select/detect content-type.

modules/openapi-generator/src/main/resources/python/api.mustache

@@ -270,6 +270,9 @@ class {{classname}}(object):
             _check_return_type (bool): specifies if type checking
                 should be done one the data received from the server.
                 Default is True.
+            _content_type (str/None): force body content-type.
+                Default is None and content-type will be predicted by allowed
+                content-types and body.
             _host_index (int/None): specifies the index of the server
                 that we want to use.
                 Default is read from the configuration.
@@ -298,6 +301,8 @@ class {{classname}}(object):
         kwargs['_check_return_type'] = kwargs.get(
             '_check_return_type', True
         )
+        kwargs['_content_type'] = kwargs.get(
+            '_content_type')
         kwargs['_host_index'] = kwargs.get('_host_index')
 {{#requiredParams}}
         kwargs['{{paramName}}'] = \

modules/openapi-generator/src/main/resources/python/api_client.mustache

@@ -129,7 +129,8 @@ class ApiClient(object):
         _preload_content: bool = True,
         _request_timeout: typing.Optional[typing.Union[int, float, typing.Tuple]] = None,
         _host: typing.Optional[str] = None,
-        _check_type: typing.Optional[bool] = None
+        _check_type: typing.Optional[bool] = None,
+        _content_type: typing.Optional[str] = None
     ):
 
         config = self.configuration
@@ -584,17 +585,24 @@ class ApiClient(object):
         else:
             return ', '.join(accepts)
 
-    def select_header_content_type(self, content_types):
+    def select_header_content_type(self, content_types, method=None, body=None):
         """Returns `Content-Type` based on an array of content_types provided.
 
         :param content_types: List of content-types.
+        :param method: http method (e.g. POST, PATCH).
+        :param body: http body to send.
         :return: Content-Type (e.g. application/json).
         """
         if not content_types:
             return 'application/json'
 
         content_types = [x.lower() for x in content_types]
 
+        if (method == 'PATCH' and
+                'application/json-patch+json' in content_types and
+                isinstance(body, list)):
+            return 'application/json-patch+json'
+
         if 'application/json' in content_types or '*/*' in content_types:
             return 'application/json'
         else:
@@ -685,7 +693,8 @@ class Endpoint(object):
             '_request_timeout',
             '_return_http_data_only',
             '_check_input_type',
-            '_check_return_type'
+            '_check_return_type',
+            '_content_type'
         ])
         self.params_map['nullable'].extend(['_request_timeout'])
         self.validations = root_map['validations']
@@ -698,7 +707,8 @@ class Endpoint(object):
             '_request_timeout': (none_type, float, (float,), [float], int, (int,), [int]),
             '_return_http_data_only': (bool,),
             '_check_input_type': (bool,),
-            '_check_return_type': (bool,)
+            '_check_return_type': (bool,),
+            '_content_type': (none_type, str)
         }
         self.openapi_types.update(extra_types)
         self.attribute_map = root_map['attribute_map']
@@ -845,12 +855,16 @@ class Endpoint(object):
             params['header']['Accept'] = self.api_client.select_header_accept(
                 accept_headers_list)
 
-        content_type_headers_list = self.headers_map['content_type']
-        if content_type_headers_list:
-            if params['body'] != "":
-                header_list = self.api_client.select_header_content_type(
-                    content_type_headers_list)
-                params['header']['Content-Type'] = header_list
+        if kwargs.get('_content_type'):
+            params['header']['Content-Type'] = kwargs['_content_type']
+        else:
+            content_type_headers_list = self.headers_map['content_type']
+            if content_type_headers_list:
+                if params['body'] != "":
+                    header_list = self.api_client.select_header_content_type(
+                        content_type_headers_list, self.settings['http_method'],
+                        params['body'])
+                    params['header']['Content-Type'] = header_list
 
         return self.api_client.call_api(
             self.settings['endpoint_path'], self.settings['http_method'],

samples/client/petstore/python/petstore_api/api/another_fake_api.py

@@ -119,6 +119,9 @@ def call_123_test_special_tags(
             _check_return_type (bool): specifies if type checking
                 should be done one the data received from the server.
                 Default is True.
+            _content_type (str/None): force body content-type.
+                Default is None and content-type will be predicted by allowed
+                content-types and body.
             _host_index (int/None): specifies the index of the server
                 that we want to use.
                 Default is read from the configuration.
@@ -147,6 +150,8 @@ def call_123_test_special_tags(
         kwargs['_check_return_type'] = kwargs.get(
             '_check_return_type', True
         )
+        kwargs['_content_type'] = kwargs.get(
+            '_content_type')
         kwargs['_host_index'] = kwargs.get('_host_index')
         kwargs['body'] = \
             body