fix: correct blueprint name for nested blueprints

Fixes issue python-restx#517.

doc/scaling.rst

@@ -152,8 +152,7 @@ Use With Blueprints
 -------------------
 
 See :doc:`flask:blueprints` in the Flask documentation for what blueprints are and why you should use them.
-Here's an example of how to link an :class:`Api` up to a :class:`~flask.Blueprint`. Nested Blueprints are
-not supported. 
+Here's an example of how to link an :class:`Api` up to a :class:`~flask.Blueprint`.
 
 .. code-block:: python
 

flask_restx/api.py

@@ -183,6 +183,7 @@ def __init__(
         self.resources = []
         self.app = None
         self.blueprint = None
+        self._blueprint_name = None
         # must come after self.app initialisation to prevent __getattr__ recursion
         # in self._configure_namespace_logger
         self.default_namespace = self.namespace(
@@ -525,10 +526,29 @@ def namespace(self, *args, **kwargs):
 
     def endpoint(self, name):
         if self.blueprint:
-            return "{0}.{1}".format(self.blueprint.name, name)
+            if self._blueprint_name is None:
+                self._blueprint_name = self._get_blueprint_name()
+            return "{0}.{1}".format(self._blueprint_name, name)
         else:
             return name
 
+    def _get_blueprint_name(self):
+        """
+        Get full blueprint name from the current_app.blueprints dict,
+        which contains full names for nested blueprints.
+
+        :rtype: str
+        """
+        return next(
+            (
+                name
+                for name, bp in current_app.blueprints.items()
+                if bp == self.blueprint
+            ),
+            # Fallback option when blueprint is not yet registered to the app.
+            self.blueprint.name,
+        )
+
     @property
     def specs_url(self):
         """

tests/test_api.py

@@ -43,6 +43,30 @@ def test_root_endpoint_with_blueprint_with_subdomain(self, app):
             assert url == "http://api.localhost/api/"
             assert api.base_url == "http://api.localhost/api/"
 
+    def test_root_endpoint_with_nested_blueprint(self, app):
+        blueprint = Blueprint("api", __name__, url_prefix="/api")
+        blueprint2 = Blueprint("v1", __name__, url_prefix="/v1")
+        blueprint.register_blueprint(blueprint2)
+        api = restx.Api(blueprint2, version="1.0")
+        app.register_blueprint(blueprint)
+
+        with app.test_request_context():
+            url = url_for("api.v1.root")
+            assert url == "/api/v1/"
+            assert api.base_url == "http://localhost/api/v1/"
+
+    def test_root_endpoint_with_nested_blueprint_with_subdomain(self, app):
+        blueprint = Blueprint("api", __name__, subdomain="api", url_prefix="/api")
+        blueprint2 = Blueprint("v1", __name__, url_prefix="/v1")
+        blueprint.register_blueprint(blueprint2)
+        api = restx.Api(blueprint2, version="1.0")
+        app.register_blueprint(blueprint)
+
+        with app.test_request_context():
+            url = url_for("api.v1.root")
+            assert url == "http://api.localhost/api/v1/"
+            assert api.base_url == "http://api.localhost/api/v1/"
+
     def test_parser(self):
         api = restx.Api()
         assert isinstance(api.parser(), restx.reqparse.RequestParser)