feat: add handler decorator logic

src/prozorro_sale/cors/__init__.py

@@ -15,6 +15,7 @@
 """CORS support for aiohttp.
 """
 
+import functools
 from typing import Mapping, Union, Any
 
 from aiohttp import web
@@ -65,3 +66,39 @@ def setup(app: web.Application, *,
     cors = CorsConfig(app, defaults=defaults)
     app[APP_CONFIG_KEY] = cors
     return cors
+
+
+def get_base_config() -> dict:
+    """
+    returns base CORS config
+    {
+        "*": ResourceOptions(
+                allow_credentials=True,
+                expose_headers="*",
+                allow_headers="*",
+                allow_methods="*",
+            )
+    }
+    """
+    return {
+        "*": ResourceOptions(
+                allow_credentials=True,
+                expose_headers="*",
+                allow_headers="*",
+                allow_methods="*",
+            )
+        }
+
+
+def custom_handler(config=None, defaults=False):
+    if not config and defaults is True:
+        config = get_base_config()
+
+    def wrapper(func):
+        @functools.wraps(func)
+        def handler(*args, **kwargs):
+            return func(*args, **kwargs)
+        handler.apply_cors = True
+        handler.cors_config = config
+        return handler
+    return wrapper

src/prozorro_sale/cors/cors_config.py

@@ -261,3 +261,12 @@ class CorsConfig:
                           stacklevel=2)
 
         return self._cors_impl.add(routing_entity, config)
+
+    def apply(self, app: web.Application):
+        for route in list(app.router.routes()):
+            if hasattr(route.handler, "apply_cors"):
+                if hasattr(route.handler, "cors_config"):
+                    config = route.handler.cors_config
+                else:
+                    config = None
+                self.add(route, config)