Add --generator-class argument to management command

Closes #140

docs/settings.rst

@@ -43,6 +43,14 @@ The possible settings and their default values are as follows:
 Default classes
 ===============
 
+DEFAULT_GENERATOR_CLASS
+-------------------------
+
+:class:`~.generators.OpenAPISchemaGenerator` subclass that will be used by default for generating the final
+:class:`.Schema` object. Can be overriden by the ``generator_class`` argument to :func:`.get_schema_view`.
+
+**Default**: :class:`drf_yasg.generators.OpenAPISchemaGenerator`
+
 DEFAULT_AUTO_SCHEMA_CLASS
 -------------------------
 
@@ -102,7 +110,7 @@ DEFAULT_INFO
 ------------
 
 An import string to an :class:`.openapi.Info` object. This will be used when running the ``generate_swagger``
-management command, or if no ``info`` argument is passed to ``get_schema_view``.
+management command, or if no ``info`` argument is passed to :func:`.get_schema_view`.
 
 **Default**: :python:`None`
 

src/drf_yasg/app_settings.py

@@ -2,6 +2,7 @@ from django.conf import settings
 from rest_framework.settings import perform_import
 
 SWAGGER_DEFAULTS = {
+    'DEFAULT_GENERATOR_CLASS': 'drf_yasg.generators.OpenAPISchemaGenerator',
     'DEFAULT_AUTO_SCHEMA_CLASS': 'drf_yasg.inspectors.SwaggerAutoSchema',
 
     'DEFAULT_FIELD_INSPECTORS': [
@@ -68,6 +69,7 @@ REDOC_DEFAULTS = {
 }
 
 IMPORT_STRINGS = [
+    'DEFAULT_GENERATOR_CLASS',
     'DEFAULT_AUTO_SCHEMA_CLASS',
     'DEFAULT_FIELD_INSPECTORS',
     'DEFAULT_FILTER_INSPECTORS',

src/drf_yasg/management/commands/generate_swagger.py

@@ -2,6 +2,7 @@ import json
 import logging
 import os
 from collections import OrderedDict
+from importlib import import_module
 
 from django.contrib.auth.models import User
 from django.core.exceptions import ImproperlyConfigured
@@ -12,7 +13,15 @@ from rest_framework.views import APIView
 from ... import openapi
 from ...app_settings import swagger_settings
 from ...codecs import OpenAPICodecJson, OpenAPICodecYaml
-from ...generators import OpenAPISchemaGenerator
+
+
+def import_class(import_string):
+    if not import_string:
+        return None
+
+    module_path, class_name = import_string.rsplit('.', 1)
+    module = import_module(module_path)
+    return getattr(module, class_name)
 
 
 class Command(BaseCommand):
@@ -64,6 +73,11 @@ class Command(BaseCommand):
                  'OpenAPISchemaGenerator.get_schema().\n'
                  'This option implies --mock-request.'
         )
+        parser.add_argument(
+            '-g', '--generator-class', dest='generator_class_name',
+            default='',
+            help='Import string pointing to an OpenAPISchemaGenerator subclass to use for schema generation.'
+        )
 
     def write_schema(self, schema, stream, format):
         if format == 'json':
@@ -89,7 +103,8 @@ class Command(BaseCommand):
         request = APIView().initialize_request(request)
         return request
 
-    def handle(self, output_file, overwrite, format, api_url, mock, user, private, *args, **options):
+    def handle(self, output_file, overwrite, format, api_url, mock, user, private, generator_class_name,
+               *args, **kwargs):
         # disable logs of WARNING and below
         logging.disable(logging.WARNING)
 
@@ -117,7 +132,8 @@ class Command(BaseCommand):
 
         request = self.get_mock_request(api_url, format, user) if mock else None
 
-        generator = OpenAPISchemaGenerator(
+        generator_class = import_class(generator_class_name) or swagger_settings.DEFAULT_GENERATOR_CLASS
+        generator = generator_class(
             info=info,
             url=api_url
         )

src/drf_yasg/views.py

@@ -11,7 +11,6 @@ from rest_framework.settings import api_settings
 from rest_framework.views import APIView
 
 from .app_settings import swagger_settings
-from .generators import OpenAPISchemaGenerator
 from .renderers import OpenAPIRenderer, ReDocRenderer, SwaggerJSONRenderer, SwaggerUIRenderer, SwaggerYAMLRenderer
 
 SPEC_RENDERERS = (SwaggerYAMLRenderer, SwaggerJSONRenderer, OpenAPIRenderer)
@@ -46,7 +45,7 @@ def deferred_never_cache(view_func):
 
 
 def get_schema_view(info=None, url=None, patterns=None, urlconf=None, public=False, validators=None,
-                    generator_class=OpenAPISchemaGenerator,
+                    generator_class=swagger_settings.DEFAULT_GENERATOR_CLASS,
                     authentication_classes=api_settings.DEFAULT_AUTHENTICATION_CLASSES,
                     permission_classes=api_settings.DEFAULT_PERMISSION_CLASSES):
     """Create a SchemaView class with default renderers and generators.

tests/test_management.py

@@ -11,17 +11,18 @@ import pytest
 from django.contrib.auth.models import User
 from django.core.management import call_command
 
+from drf_yasg import openapi
 from drf_yasg.codecs import yaml_sane_load
+from drf_yasg.generators import OpenAPISchemaGenerator
 
 
 def call_generate_swagger(output_file='-', overwrite=False, format='', api_url='',
-                          mock=False, user='', private=False, **kwargs):
+                          mock=False, user='', private=False, generator_class_name='', **kwargs):
     out = StringIO()
     call_command(
         'generate_swagger', stdout=out,
-        output_file=output_file, overwrite=overwrite, format=format,
-        api_url=api_url, mock=mock, user=user, private=private,
-        **kwargs
+        output_file=output_file, overwrite=overwrite, format=format, api_url=api_url, mock=mock, user=user,
+        private=private, generator_class_name=generator_class_name, **kwargs
     )
     return out.getvalue()
 
@@ -46,6 +47,17 @@ def test_no_mock(db):
     assert len(output_schema['paths']) > 0
 
 
+class EmptySchemaGenerator(OpenAPISchemaGenerator):
+    def get_paths(self, endpoints, components, request, public):
+        return openapi.Paths(paths={}), ''
+
+
+def test_generator_class(db):
+    output = call_generate_swagger(generator_class_name='test_management.EmptySchemaGenerator')
+    output_schema = json.loads(output, object_pairs_hook=OrderedDict)
+    assert len(output_schema['paths']) == 0
+
+
 def silentremove(filename):
     try:
         os.remove(filename)