From 1f18784f7a47e7f6ba2d9f84e6fc2e45ff4d2fba Mon Sep 17 00:00:00 2001
From: Petras <petras@onecodex.com>
Date: Thu, 24 Nov 2022 16:14:14 +0200
Subject: [PATCH 1/8] Supporting multiple APIs in one App

---
 flask_smorest/__init__.py      | 10 +++--
 flask_smorest/blueprint.py     |  2 +-
 flask_smorest/etag.py          | 19 +++++-----
 flask_smorest/spec/__init__.py | 67 +++++++++++++++++++++-------------
 flask_smorest/utils.py         | 10 +++++
 tests/test_api.py              | 45 +++++++++++++++++++++--
 tests/test_etag.py             |  4 ++
 7 files changed, 113 insertions(+), 44 deletions(-)

diff --git a/flask_smorest/__init__.py b/flask_smorest/__init__.py
index 317592e4..59528cd3 100644
--- a/flask_smorest/__init__.py
+++ b/flask_smorest/__init__.py
@@ -39,9 +39,12 @@ class Api(APISpecMixin, ErrorHandlerMixin):
     parameter `API_SPEC_OPTIONS`.
     """
 
-    def __init__(self, app=None, *, spec_kwargs=None):
+    def __init__(self, app=None, *, config_prefix=None, spec_kwargs=None):
         self._app = app
         self._spec_kwargs = spec_kwargs or {}
+        self.config_prefix = config_prefix or ""
+        if self.config_prefix and not self.config_prefix.endswith("_"):
+            self.config_prefix += "_"
         self.spec = None
         # Use lists to enforce order
         self._fields = []
@@ -59,8 +62,8 @@ def init_app(self, app, *, spec_kwargs=None):
 
         # Register flask-smorest in app extensions
         app.extensions = getattr(app, "extensions", {})
-        ext = app.extensions.setdefault("flask-smorest", {})
-        ext["ext_obj"] = self
+        ext = app.extensions.setdefault("flask-smorest", {"apis": {}})
+        ext["apis"][self.config_prefix] = self
 
         # Initialize spec
         self._init_spec(**{**self._spec_kwargs, **(spec_kwargs or {})})
@@ -86,6 +89,7 @@ def register_blueprint(self, blp, *, parameters=None, **options):
         """
         blp_name = options.get("name", blp.name)
 
+        blp.config_prefix = self.config_prefix  # TODO: seems a little bit dirty
         self._app.register_blueprint(blp, **options)
 
         # Register views in API documentation for this resource
diff --git a/flask_smorest/blueprint.py b/flask_smorest/blueprint.py
index c8c001aa..107ac5e6 100644
--- a/flask_smorest/blueprint.py
+++ b/flask_smorest/blueprint.py
@@ -69,8 +69,8 @@ class Blueprint(
     DOCSTRING_INFO_DELIMITER = "---"
 
     def __init__(self, *args, **kwargs):
-
         self.description = kwargs.pop("description", "")
+        self.config_prefix = ""
 
         super().__init__(*args, **kwargs)
 
diff --git a/flask_smorest/etag.py b/flask_smorest/etag.py
index 84ffe037..ac1b6c70 100644
--- a/flask_smorest/etag.py
+++ b/flask_smorest/etag.py
@@ -11,7 +11,7 @@
 from flask import request, current_app
 
 from .exceptions import PreconditionRequired, PreconditionFailed, NotModified
-from .utils import deepupdate, resolve_schema_instance, get_appcontext
+from .utils import deepupdate, resolve_schema_instance, get_appcontext, get_config_value
 
 
 IF_NONE_MATCH_HEADER = {
@@ -35,11 +35,6 @@
 }
 
 
-def _is_etag_enabled():
-    """Return True if ETag feature enabled application-wise"""
-    return not current_app.config.get("ETAG_DISABLED", False)
-
-
 def _get_etag_ctx():
     """Get ETag section of AppContext"""
     return get_appcontext().setdefault("etag", {})
@@ -73,7 +68,7 @@ def decorator(func):
             @wraps(func)
             def wrapper(*args, **kwargs):
 
-                etag_enabled = _is_etag_enabled()
+                etag_enabled = self._is_etag_enabled()
 
                 if etag_enabled:
                     # Check etag precondition
@@ -142,7 +137,7 @@ def check_etag(self, etag_data, etag_schema=None):
         """
         if request.method not in self.METHODS_NEEDING_CHECK_ETAG:
             warnings.warn(f"ETag cannot be checked on {request.method} request.")
-        if _is_etag_enabled():
+        if self._is_etag_enabled():
             if etag_schema is not None:
                 etag_data = resolve_schema_instance(etag_schema).dump(etag_data)
             new_etag = self._generate_etag(etag_data)
@@ -150,6 +145,10 @@ def check_etag(self, etag_data, etag_schema=None):
             if new_etag not in request.if_match:
                 raise PreconditionFailed
 
+    def _is_etag_enabled(self, app=None):
+        """Return True if ETag feature enabled api-wise"""
+        return not get_config_value(app or current_app, self, "ETAG_DISABLED", False)
+
     def _verify_check_etag(self):
         """Verify check_etag was called in resource code
 
@@ -192,7 +191,7 @@ def set_etag(self, etag_data, etag_schema=None):
         """
         if request.method not in self.METHODS_ALLOWING_SET_ETAG:
             warnings.warn(f"ETag cannot be set on {request.method} request.")
-        if _is_etag_enabled():
+        if self._is_etag_enabled():
             if etag_schema is not None:
                 etag_data = resolve_schema_instance(etag_schema).dump(etag_data)
             new_etag = self._generate_etag(etag_data)
@@ -223,7 +222,7 @@ def _set_etag_in_response(self, response):
             response.set_etag(new_etag)
 
     def _prepare_etag_doc(self, doc, doc_info, *, app, spec, method, **kwargs):
-        if doc_info.get("etag", False) and not app.config.get("ETAG_DISABLED", False):
+        if doc_info.get("etag", False) and self._is_etag_enabled(app):
             responses = {}
             method_u = method.upper()
             if method_u in self.METHODS_CHECKING_NOT_MODIFIED:
diff --git a/flask_smorest/spec/__init__.py b/flask_smorest/spec/__init__.py
index 76e8351f..0f59a552 100644
--- a/flask_smorest/spec/__init__.py
+++ b/flask_smorest/spec/__init__.py
@@ -1,14 +1,16 @@
 """API specification using OpenAPI"""
-import json
 import http
+import json
 
-import flask
-from flask import current_app
-import click
 import apispec
+import click
+import flask
 from apispec.ext.marshmallow import MarshmallowPlugin
+from flask import current_app
 from webargs.fields import DelimitedList
 
+from ..utils import get_config_value, get_config_key
+
 try:  # pragma: no cover
     import yaml
 
@@ -16,12 +18,13 @@
 except ImportError:  # pragma: no cover
     HAS_PYYAML = False
 
-from flask_smorest.exceptions import MissingAPIParameterError
-from flask_smorest.utils import prepare_response
 from flask_smorest import etag as fs_etag
 from flask_smorest import pagination as fs_pagination
-from .plugins import FlaskPlugin
+from flask_smorest.exceptions import MissingAPIParameterError
+from flask_smorest.utils import prepare_response
+
 from .field_converters import uploadfield2properties
+from .plugins import FlaskPlugin
 
 
 def _add_leading_slash(string):
@@ -51,7 +54,7 @@ def _register_doc_blueprint(self):
         - json spec file
         - spec UI (ReDoc, Swagger UI).
         """
-        api_url = self._app.config.get("OPENAPI_URL_PREFIX", None)
+        api_url = get_config_value(self._app, self, "OPENAPI_URL_PREFIX", None)
         if api_url is not None:
             blueprint = flask.Blueprint(
                 "api-docs",
@@ -60,7 +63,9 @@ def _register_doc_blueprint(self):
                 template_folder="./templates",
             )
             # Serve json spec at 'url_prefix/openapi.json' by default
-            json_path = self._app.config.get("OPENAPI_JSON_PATH", "openapi.json")
+            json_path = get_config_value(
+                self._app, self, "OPENAPI_JSON_PATH", "openapi.json"
+            )
             blueprint.add_url_rule(
                 _add_leading_slash(json_path),
                 endpoint="openapi_json",
@@ -76,9 +81,9 @@ def _register_redoc_rule(self, blueprint):
 
         The ReDoc script URL should be specified as OPENAPI_REDOC_URL.
         """
-        redoc_path = self._app.config.get("OPENAPI_REDOC_PATH")
+        redoc_path = get_config_value(self._app, self, "OPENAPI_REDOC_PATH")
         if redoc_path is not None:
-            redoc_url = self._app.config.get("OPENAPI_REDOC_URL")
+            redoc_url = get_config_value(self._app, self, "OPENAPI_REDOC_URL")
             if redoc_url is not None:
                 self._redoc_url = redoc_url
                 blueprint.add_url_rule(
@@ -93,9 +98,9 @@ def _register_swagger_ui_rule(self, blueprint):
         The Swagger UI scripts base URL should be specified as
         OPENAPI_SWAGGER_UI_URL.
         """
-        swagger_ui_path = self._app.config.get("OPENAPI_SWAGGER_UI_PATH")
+        swagger_ui_path = get_config_value(self._app, self, "OPENAPI_SWAGGER_UI_PATH")
         if swagger_ui_path is not None:
-            swagger_ui_url = self._app.config.get("OPENAPI_SWAGGER_UI_URL")
+            swagger_ui_url = get_config_value(self._app, self, "OPENAPI_SWAGGER_UI_URL")
             if swagger_ui_url is not None:
                 self._swagger_ui_url = swagger_ui_url
                 blueprint.add_url_rule(
@@ -109,9 +114,9 @@ def _register_rapidoc_rule(self, blueprint):
 
         The RapiDoc script URL should be specified as OPENAPI_RAPIDOC_URL.
         """
-        rapidoc_path = self._app.config.get("OPENAPI_RAPIDOC_PATH")
+        rapidoc_path = get_config_value(self._app, self, "OPENAPI_RAPIDOC_PATH")
         if rapidoc_path is not None:
-            rapidoc_url = self._app.config.get("OPENAPI_RAPIDOC_URL")
+            rapidoc_url = get_config_value(self._app, self, "OPENAPI_RAPIDOC_URL")
             if rapidoc_url is not None:
                 self._rapidoc_url = rapidoc_url
                 blueprint.add_url_rule(
@@ -140,7 +145,9 @@ def _openapi_swagger_ui(self):
             "swagger_ui.html",
             title=self.spec.title,
             swagger_ui_url=self._swagger_ui_url,
-            swagger_ui_config=self._app.config.get("OPENAPI_SWAGGER_UI_CONFIG", {}),
+            swagger_ui_config=get_config_value(
+                self._app, self, "OPENAPI_SWAGGER_UI_CONFIG", {}
+            ),
         )
 
     def _openapi_rapidoc(self):
@@ -149,7 +156,9 @@ def _openapi_rapidoc(self):
             "rapidoc.html",
             title=self.spec.title,
             rapidoc_url=self._rapidoc_url,
-            rapidoc_config=self._app.config.get("OPENAPI_RAPIDOC_CONFIG", {}),
+            rapidoc_config=get_config_value(
+                self._app, self, "OPENAPI_RAPIDOC_CONFIG", {}
+            ),
         )
 
 
@@ -170,7 +179,7 @@ def _init_spec(
         title=None,
         version=None,
         openapi_version=None,
-        **options
+        **options,
     ):
         # Plugins
         self.flask_plugin = flask_plugin or FlaskPlugin()
@@ -179,22 +188,27 @@ def _init_spec(
         plugins.extend(extra_plugins or ())
 
         # APISpec options
-        title = self._app.config.get("API_TITLE", title)
+        title = get_config_value(self._app, self, "API_TITLE", title)
         if title is None:
+            key = get_config_key(self, "API_TITLE")
             raise MissingAPIParameterError(
-                'API title must be specified either as "API_TITLE" '
+                f'API title must be specified either as "{key}" '
                 'app parameter or as "title" spec kwarg.'
             )
-        version = self._app.config.get("API_VERSION", version)
+        version = get_config_value(self._app, self, "API_VERSION", version)
         if version is None:
+            key = get_config_key(self, "API_VERSION")
             raise MissingAPIParameterError(
-                'API version must be specified either as "API_VERSION" '
+                f'API version must be specified either as "{key}" '
                 'app parameter or as "version" spec kwarg.'
             )
-        openapi_version = self._app.config.get("OPENAPI_VERSION", openapi_version)
+        openapi_version = get_config_value(
+            self._app, self, "OPENAPI_VERSION", openapi_version
+        )
         if openapi_version is None:
+            key = get_config_key(self, "OPENAPI_VERSION")
             raise MissingAPIParameterError(
-                'OpenAPI version must be specified either as "OPENAPI_VERSION '
+                f'OpenAPI version must be specified either as "{key}" '
                 'app parameter or as "openapi_version" spec kwarg.'
             )
         openapi_major_version = int(openapi_version.split(".")[0])
@@ -211,7 +225,7 @@ def _init_spec(
                     self.DEFAULT_REQUEST_BODY_CONTENT_TYPE,
                 ],
             )
-        options.update(self._app.config.get("API_SPEC_OPTIONS", {}))
+        options.update(get_config_value(self._app, self, "API_SPEC_OPTIONS", {}))
 
         # Instantiate spec
         self.spec = apispec.APISpec(
@@ -363,7 +377,8 @@ def _register_pagination_header(self):
 
 
 def _get_spec_dict():
-    return current_app.extensions["flask-smorest"]["ext_obj"].spec.to_dict()
+    # TODO: multiple apis
+    return current_app.extensions["flask-smorest"]["apis"][""].spec.to_dict()
 
 
 @openapi_cli.command("print")
diff --git a/flask_smorest/utils.py b/flask_smorest/utils.py
index e17eac65..ab8d4efe 100644
--- a/flask_smorest/utils.py
+++ b/flask_smorest/utils.py
@@ -137,3 +137,13 @@ def prepare_response(response, spec, content_type):
                         field
                     ]
                 ) = response.pop(field)
+
+
+def get_config_key(ctx, key):
+    """TODO: docstring"""
+    return getattr(ctx, "config_prefix", "") + key
+
+
+def get_config_value(app, ctx, key, default=None):
+    """TODO: docstring"""
+    return app.config.get(get_config_key(ctx, key), default)
diff --git a/tests/test_api.py b/tests/test_api.py
index 964651c1..271b6b14 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -1,15 +1,16 @@
 """Test Api class"""
-import pytest
+from types import SimpleNamespace
 
+import apispec
+import marshmallow as ma
+import pytest
 from flask.views import MethodView
 from werkzeug.routing import BaseConverter
-import marshmallow as ma
-import apispec
 
 from flask_smorest import Api, Blueprint
 from flask_smorest.exceptions import MissingAPIParameterError
 
-from .utils import get_schemas, get_responses
+from .utils import get_responses, get_schemas
 
 
 class TestApi:
@@ -412,3 +413,39 @@ def test(val):
 
         # Default error is now registered
         assert "DEFAULT_ERROR" in get_responses(api.spec)
+
+
+class TestWithMultipleApiPerApp:
+    @pytest.mark.parametrize(
+        "app",
+        [
+            SimpleNamespace(
+                API_TITLE="Ignore this title",
+                API_V1_API_TITLE="V1 Title",
+                API_V1_API_VERSION="1",
+                API_V1_OPENAPI_VERSION="2.0",
+                API_V2_API_TITLE="V2 Title",
+                API_V2_API_VERSION="2",
+                API_V2_OPENAPI_VERSION="3.0.2",
+            )
+        ],
+        indirect=True,
+    )
+    def test_config_prefix_attribute(self, app):
+        api1 = Api(app, config_prefix="API_V1_")
+        api2 = Api(app, config_prefix="API_V2")
+
+        assert api1.spec.title == "V1 Title"
+        assert api2.spec.title == "V2 Title"
+
+    @pytest.mark.parametrize(
+        "app",
+        [SimpleNamespace(API_TITLE="Ignore this title")],
+        indirect=True,
+    )
+    def test_raises_error(self, app):
+        with pytest.raises(
+            MissingAPIParameterError,
+            match='API title must be specified either as "API_V1_API_TITLE"',
+        ):
+            Api(app, config_prefix="API_V1_")
diff --git a/tests/test_etag.py b/tests/test_etag.py
index 8c907fda..95a5482b 100644
--- a/tests/test_etag.py
+++ b/tests/test_etag.py
@@ -540,3 +540,7 @@ def test_etag_operations_etag_disabled(self, app_with_etag):
             f"/test/{item_2_id}", headers={"If-Match": "dummy_etag"}
         )
         assert response.status_code == 204
+
+    def test_multiple_api_per_app(self):
+        # TODO:
+        pass

From 2f66f21226b3780190ec2e6732fea37f212e8f6b Mon Sep 17 00:00:00 2001
From: Petras <petras@onecodex.com>
Date: Thu, 24 Nov 2022 18:16:14 +0200
Subject: [PATCH 2/8] Spec tests

---
 flask_smorest/__init__.py      | 10 +++++++---
 flask_smorest/spec/__init__.py | 20 +++++++++-----------
 tests/test_api.py              |  6 ++----
 tests/test_spec.py             | 33 +++++++++++++++++++++++++++++++++
 4 files changed, 51 insertions(+), 18 deletions(-)

diff --git a/flask_smorest/__init__.py b/flask_smorest/__init__.py
index 59528cd3..5ea71f0c 100644
--- a/flask_smorest/__init__.py
+++ b/flask_smorest/__init__.py
@@ -17,6 +17,7 @@ class Api(APISpecMixin, ErrorHandlerMixin):
 
     :param Flask app: Flask application
     :param spec_kwargs: kwargs to pass to internal APISpec instance
+    :param config_prefix: TODO
 
     The ``spec_kwargs`` dictionary is passed as kwargs to the internal APISpec
     instance. **flask-smorest** adds a few parameters to the original
@@ -39,10 +40,10 @@ class Api(APISpecMixin, ErrorHandlerMixin):
     parameter `API_SPEC_OPTIONS`.
     """
 
-    def __init__(self, app=None, *, config_prefix=None, spec_kwargs=None):
+    def __init__(self, app=None, *, spec_kwargs=None, config_prefix=""):
         self._app = app
         self._spec_kwargs = spec_kwargs or {}
-        self.config_prefix = config_prefix or ""
+        self.config_prefix = config_prefix
         if self.config_prefix and not self.config_prefix.endswith("_"):
             self.config_prefix += "_"
         self.spec = None
@@ -62,6 +63,7 @@ def init_app(self, app, *, spec_kwargs=None):
 
         # Register flask-smorest in app extensions
         app.extensions = getattr(app, "extensions", {})
+        # TODO: backwards compatibility?
         ext = app.extensions.setdefault("flask-smorest", {"apis": {}})
         ext["apis"][self.config_prefix] = self
 
@@ -89,7 +91,9 @@ def register_blueprint(self, blp, *, parameters=None, **options):
         """
         blp_name = options.get("name", blp.name)
 
-        blp.config_prefix = self.config_prefix  # TODO: seems a little bit dirty
+        # TODO: seems a little bit dirty
+        if hasattr(blp, "config_prefix"):
+            blp.config_prefix = self.config_prefix
         self._app.register_blueprint(blp, **options)
 
         # Register views in API documentation for this resource
diff --git a/flask_smorest/spec/__init__.py b/flask_smorest/spec/__init__.py
index 0f59a552..fb6aeb5c 100644
--- a/flask_smorest/spec/__init__.py
+++ b/flask_smorest/spec/__init__.py
@@ -1,16 +1,14 @@
 """API specification using OpenAPI"""
-import http
 import json
+import http
 
-import apispec
-import click
 import flask
-from apispec.ext.marshmallow import MarshmallowPlugin
 from flask import current_app
+import click
+import apispec
+from apispec.ext.marshmallow import MarshmallowPlugin
 from webargs.fields import DelimitedList
 
-from ..utils import get_config_value, get_config_key
-
 try:  # pragma: no cover
     import yaml
 
@@ -18,13 +16,12 @@
 except ImportError:  # pragma: no cover
     HAS_PYYAML = False
 
+from flask_smorest.exceptions import MissingAPIParameterError
+from flask_smorest.utils import prepare_response, get_config_key, get_config_value
 from flask_smorest import etag as fs_etag
 from flask_smorest import pagination as fs_pagination
-from flask_smorest.exceptions import MissingAPIParameterError
-from flask_smorest.utils import prepare_response
-
-from .field_converters import uploadfield2properties
 from .plugins import FlaskPlugin
+from .field_converters import uploadfield2properties
 
 
 def _add_leading_slash(string):
@@ -55,9 +52,10 @@ def _register_doc_blueprint(self):
         - spec UI (ReDoc, Swagger UI).
         """
         api_url = get_config_value(self._app, self, "OPENAPI_URL_PREFIX", None)
+        bp_name = get_config_key(self, "api-docs").replace("_", "-").lower()
         if api_url is not None:
             blueprint = flask.Blueprint(
-                "api-docs",
+                bp_name,
                 __name__,
                 url_prefix=_add_leading_slash(api_url),
                 template_folder="./templates",
diff --git a/tests/test_api.py b/tests/test_api.py
index 271b6b14..24cc193f 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -414,8 +414,6 @@ def test(val):
         # Default error is now registered
         assert "DEFAULT_ERROR" in get_responses(api.spec)
 
-
-class TestWithMultipleApiPerApp:
     @pytest.mark.parametrize(
         "app",
         [
@@ -431,7 +429,7 @@ class TestWithMultipleApiPerApp:
         ],
         indirect=True,
     )
-    def test_config_prefix_attribute(self, app):
+    def test_multiple_apis_using_config_prefix_attribute(self, app):
         api1 = Api(app, config_prefix="API_V1_")
         api2 = Api(app, config_prefix="API_V2")
 
@@ -443,7 +441,7 @@ def test_config_prefix_attribute(self, app):
         [SimpleNamespace(API_TITLE="Ignore this title")],
         indirect=True,
     )
-    def test_raises_error(self, app):
+    def test_prefixed_api_to_raise_correctly_formatted_error(self, app):
         with pytest.raises(
             MissingAPIParameterError,
             match='API title must be specified either as "API_V1_API_TITLE"',
diff --git a/tests/test_spec.py b/tests/test_spec.py
index 03ea05c0..dc91caf4 100644
--- a/tests/test_spec.py
+++ b/tests/test_spec.py
@@ -431,6 +431,39 @@ def test_apispec_serve_spec_preserve_order(self, app):
         assert response_json_docs.status_code == 200
         assert response_json_docs.json["paths"] == paths
 
+    def test_multiple_apis_serve_separate_specs(self, app):
+        client = app.test_client()
+
+        app.config["V1_OPENAPI_URL_PREFIX"] = "/v1-docs"
+        app.config["V2_OPENAPI_URL_PREFIX"] = "/v2-docs/"
+
+        for i in range(1, 3):
+            api = Api(
+                app,
+                config_prefix=f"V{i}_",
+                spec_kwargs={
+                    "title": f"V{i}",
+                    "version": f"{i}",
+                    "openapi_version": "3.0.2",
+                },
+            )
+            blp = Blueprint(f"test{i}", f"test{i}", url_prefix=f"/test-{i}")
+            blp.route("/")(lambda: None)
+            api.register_blueprint(blp)
+
+        json1 = client.get("/v1-docs/openapi.json").json
+        json2 = client.get("/v2-docs/openapi.json").json
+
+        # Should have a different info
+        assert json1["info"]["title"] == "V1"
+        assert json2["info"]["title"] == "V2"
+
+        # One api's routes should not leak into other's spec.
+        assert "/test-1/" in json1["paths"]
+        assert "/test-2/" not in json1["paths"]
+        assert "/test-1/" not in json2["paths"]
+        assert "/test-2/" in json2["paths"]
+
 
 class TestAPISpecCLICommands:
     """Test OpenAPI CLI commands"""

From e916ff7647c6bd8a5dc9b511b9aa890788d26771 Mon Sep 17 00:00:00 2001
From: Petras <petras@onecodex.com>
Date: Thu, 24 Nov 2022 18:43:07 +0200
Subject: [PATCH 3/8] Tests for Etag

---
 tests/test_api.py  | 33 ++++++++++--------------------
 tests/test_etag.py | 50 +++++++++++++++++++++++++++++++++++++++++++---
 tests/test_spec.py |  2 +-
 3 files changed, 59 insertions(+), 26 deletions(-)

diff --git a/tests/test_api.py b/tests/test_api.py
index 24cc193f..7ddb3d5f 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -1,6 +1,4 @@
 """Test Api class"""
-from types import SimpleNamespace
-
 import apispec
 import marshmallow as ma
 import pytest
@@ -414,33 +412,24 @@ def test(val):
         # Default error is now registered
         assert "DEFAULT_ERROR" in get_responses(api.spec)
 
-    @pytest.mark.parametrize(
-        "app",
-        [
-            SimpleNamespace(
-                API_TITLE="Ignore this title",
-                API_V1_API_TITLE="V1 Title",
-                API_V1_API_VERSION="1",
-                API_V1_OPENAPI_VERSION="2.0",
-                API_V2_API_TITLE="V2 Title",
-                API_V2_API_VERSION="2",
-                API_V2_OPENAPI_VERSION="3.0.2",
-            )
-        ],
-        indirect=True,
-    )
     def test_multiple_apis_using_config_prefix_attribute(self, app):
+        app.config.update(
+            {
+                "API_TITLE": "Ignore this title",
+                "API_V1_API_TITLE": "V1 Title",
+                "API_V1_API_VERSION": "1",
+                "API_V1_OPENAPI_VERSION": "2.0",
+                "API_V2_API_TITLE": "V2 Title",
+                "API_V2_API_VERSION": "2",
+                "API_V2_OPENAPI_VERSION": "3.0.2",
+            }
+        )
         api1 = Api(app, config_prefix="API_V1_")
         api2 = Api(app, config_prefix="API_V2")
 
         assert api1.spec.title == "V1 Title"
         assert api2.spec.title == "V2 Title"
 
-    @pytest.mark.parametrize(
-        "app",
-        [SimpleNamespace(API_TITLE="Ignore this title")],
-        indirect=True,
-    )
     def test_prefixed_api_to_raise_correctly_formatted_error(self, app):
         with pytest.raises(
             MissingAPIParameterError,
diff --git a/tests/test_etag.py b/tests/test_etag.py
index 95a5482b..75978372 100644
--- a/tests/test_etag.py
+++ b/tests/test_etag.py
@@ -16,6 +16,7 @@
     PreconditionFailed,
 )
 from flask_smorest.utils import get_appcontext
+import marshmallow as ma
 
 from .mocks import ItemNotFound
 
@@ -541,6 +542,49 @@ def test_etag_operations_etag_disabled(self, app_with_etag):
         )
         assert response.status_code == 204
 
-    def test_multiple_api_per_app(self):
-        # TODO:
-        pass
+    @pytest.mark.parametrize("etag_disabled_for_v1", [False, True])
+    @pytest.mark.parametrize("etag_disabled_for_v2", [False, True])
+    def test_multiple_apis_per_app(
+        self, app, etag_disabled_for_v1, etag_disabled_for_v2
+    ):
+        # All created APIs are using prefix. So default ETAG_DISABLED should be ignored
+        app.config["ETAG_DISABLED"] = True
+        app.config["V1_ETAG_DISABLED"] = etag_disabled_for_v1
+        app.config["V2_ETAG_DISABLED"] = etag_disabled_for_v2
+
+        for i in [1, 2]:
+            api = Api(
+                app,
+                config_prefix=f"V{i}_",
+                spec_kwargs={
+                    "title": f"V{i}",
+                    "version": f"{i}",
+                    "openapi_version": "3.0.2",
+                },
+            )
+            blp = Blueprint(f"test{i}", f"test{i}", url_prefix=f"/test-{i}")
+
+            class HomeSchema(ma.Schema):
+                field = ma.fields.String()
+
+            @blp.route("/")
+            @blp.etag
+            @blp.response(200, HomeSchema)
+            def home():
+                return {"field": "value"}
+
+            api.register_blueprint(blp)
+
+        client = app.test_client()
+        headers1 = client.get("/test-1/").headers
+        headers2 = client.get("/test-2/").headers
+
+        if etag_disabled_for_v1:
+            assert "ETag" not in headers1
+        else:
+            assert "ETag" in headers1
+
+        if etag_disabled_for_v2:
+            assert "ETag" not in headers2
+        else:
+            assert "ETag" in headers2
diff --git a/tests/test_spec.py b/tests/test_spec.py
index dc91caf4..b1c5549c 100644
--- a/tests/test_spec.py
+++ b/tests/test_spec.py
@@ -437,7 +437,7 @@ def test_multiple_apis_serve_separate_specs(self, app):
         app.config["V1_OPENAPI_URL_PREFIX"] = "/v1-docs"
         app.config["V2_OPENAPI_URL_PREFIX"] = "/v2-docs/"
 
-        for i in range(1, 3):
+        for i in [1, 2]:
             api = Api(
                 app,
                 config_prefix=f"V{i}_",

From ba212e3c50b84340d9db4b47b86e275e751245ed Mon Sep 17 00:00:00 2001
From: Petras <petras@onecodex.com>
Date: Fri, 25 Nov 2022 14:43:35 +0200
Subject: [PATCH 4/8] Fixing all auto-doc rules

---
 flask_smorest/spec/__init__.py               | 13 +++++++--
 flask_smorest/spec/templates/rapidoc.html    |  2 +-
 flask_smorest/spec/templates/redoc.html      |  2 +-
 flask_smorest/spec/templates/swagger_ui.html |  2 +-
 tests/test_spec.py                           | 30 +++++++++++++++++---
 5 files changed, 39 insertions(+), 10 deletions(-)

diff --git a/flask_smorest/spec/__init__.py b/flask_smorest/spec/__init__.py
index fb6aeb5c..96e040a0 100644
--- a/flask_smorest/spec/__init__.py
+++ b/flask_smorest/spec/__init__.py
@@ -44,6 +44,9 @@ def delimited_list2param(self, field, **kwargs):
 class DocBlueprintMixin:
     """Extend Api to serve the spec in a dedicated blueprint."""
 
+    def _get_doc_blueprint_name(self):
+        return get_config_key(self, "api-docs").replace("_", "-").lower()
+
     def _register_doc_blueprint(self):
         """Register a blueprint in the application to expose the spec
 
@@ -52,10 +55,9 @@ def _register_doc_blueprint(self):
         - spec UI (ReDoc, Swagger UI).
         """
         api_url = get_config_value(self._app, self, "OPENAPI_URL_PREFIX", None)
-        bp_name = get_config_key(self, "api-docs").replace("_", "-").lower()
         if api_url is not None:
             blueprint = flask.Blueprint(
-                bp_name,
+                self._get_doc_blueprint_name(),
                 __name__,
                 url_prefix=_add_leading_slash(api_url),
                 template_folder="./templates",
@@ -134,7 +136,10 @@ def _openapi_json(self):
     def _openapi_redoc(self):
         """Expose OpenAPI spec with ReDoc"""
         return flask.render_template(
-            "redoc.html", title=self.spec.title, redoc_url=self._redoc_url
+            "redoc.html",
+            spec_url=flask.url_for(f"{self._get_doc_blueprint_name()}.openapi_json"),
+            title=self.spec.title,
+            redoc_url=self._redoc_url,
         )
 
     def _openapi_swagger_ui(self):
@@ -142,6 +147,7 @@ def _openapi_swagger_ui(self):
         return flask.render_template(
             "swagger_ui.html",
             title=self.spec.title,
+            spec_url=flask.url_for(f"{self._get_doc_blueprint_name()}.openapi_json"),
             swagger_ui_url=self._swagger_ui_url,
             swagger_ui_config=get_config_value(
                 self._app, self, "OPENAPI_SWAGGER_UI_CONFIG", {}
@@ -153,6 +159,7 @@ def _openapi_rapidoc(self):
         return flask.render_template(
             "rapidoc.html",
             title=self.spec.title,
+            spec_url=flask.url_for(f"{self._get_doc_blueprint_name()}.openapi_json"),
             rapidoc_url=self._rapidoc_url,
             rapidoc_config=get_config_value(
                 self._app, self, "OPENAPI_RAPIDOC_CONFIG", {}
diff --git a/flask_smorest/spec/templates/rapidoc.html b/flask_smorest/spec/templates/rapidoc.html
index 659e1a4f..84f1779e 100644
--- a/flask_smorest/spec/templates/rapidoc.html
+++ b/flask_smorest/spec/templates/rapidoc.html
@@ -7,7 +7,7 @@
   </head>
   <body>
     <rapi-doc
-      spec-url = "{{ url_for('api-docs.openapi_json') }}"
+      spec-url = "{{ spec_url }}"
       {% for key, val in rapidoc_config.items() -%}
         {{key}} = "{{val}}"
       {% endfor -%}
diff --git a/flask_smorest/spec/templates/redoc.html b/flask_smorest/spec/templates/redoc.html
index d05d1b76..41f519e6 100644
--- a/flask_smorest/spec/templates/redoc.html
+++ b/flask_smorest/spec/templates/redoc.html
@@ -16,7 +16,7 @@
     </style>
   </head>
   <body>
-    <redoc spec-url="{{ url_for('api-docs.openapi_json') }}" lazy-rendering></redoc>
+    <redoc spec-url="{{ spec_url }}" lazy-rendering></redoc>
     <script src="{{redoc_url}}"></script>
   </body>
 </html>
diff --git a/flask_smorest/spec/templates/swagger_ui.html b/flask_smorest/spec/templates/swagger_ui.html
index bffd8ea4..bb40c109 100644
--- a/flask_smorest/spec/templates/swagger_ui.html
+++ b/flask_smorest/spec/templates/swagger_ui.html
@@ -15,7 +15,7 @@
    <script>
 
      config = {
-       url: "{{ url_for('api-docs.openapi_json') }}",
+       url: "{{ spec_url }}",
        dom_id: '#swagger-ui-container'
      }
 
diff --git a/tests/test_spec.py b/tests/test_spec.py
index b1c5549c..1ad2aee1 100644
--- a/tests/test_spec.py
+++ b/tests/test_spec.py
@@ -434,10 +434,15 @@ def test_apispec_serve_spec_preserve_order(self, app):
     def test_multiple_apis_serve_separate_specs(self, app):
         client = app.test_client()
 
-        app.config["V1_OPENAPI_URL_PREFIX"] = "/v1-docs"
-        app.config["V2_OPENAPI_URL_PREFIX"] = "/v2-docs/"
-
         for i in [1, 2]:
+            app.config[f"V{i}_OPENAPI_URL_PREFIX"] = f"/v{i}-docs"
+            app.config[f"V{i}_OPENAPI_RAPIDOC_PATH"] = "rapidoc/"
+            app.config[f"V{i}_OPENAPI_RAPIDOC_URL"] = "/statid/rapidoc.js"
+            app.config[f"V{i}_OPENAPI_REDOC_PATH"] = "/redoc/"
+            app.config[f"V{i}_OPENAPI_SWAGGER_UI_URL"] = "/static/swagger-ui/"
+            app.config[f"V{i}_OPENAPI_SWAGGER_UI_PATH"] = "/swagger/"
+            app.config[f"V{i}_OPENAPI_REDOC_URL"] = "/static/redoc.js"
+            app.config[f"V{i}_OPENAPI_REDOC_PATH"] = "/redoc/"
             api = Api(
                 app,
                 config_prefix=f"V{i}_",
@@ -451,6 +456,8 @@ def test_multiple_apis_serve_separate_specs(self, app):
             blp.route("/")(lambda: None)
             api.register_blueprint(blp)
 
+        # Checking openapi.json
+
         json1 = client.get("/v1-docs/openapi.json").json
         json2 = client.get("/v2-docs/openapi.json").json
 
@@ -458,12 +465,27 @@ def test_multiple_apis_serve_separate_specs(self, app):
         assert json1["info"]["title"] == "V1"
         assert json2["info"]["title"] == "V2"
 
-        # One api's routes should not leak into other's spec.
+        # One api's routes should not leak into other's
         assert "/test-1/" in json1["paths"]
         assert "/test-2/" not in json1["paths"]
         assert "/test-1/" not in json2["paths"]
         assert "/test-2/" in json2["paths"]
 
+        # Checking RapiDoc
+
+        assert "/v1-docs/openapi.json" in client.get("/v1-docs/rapidoc/").text
+        assert "/v2-docs/openapi.json" in client.get("/v2-docs/rapidoc/").text
+
+        # Checking Swagger
+
+        assert "/v1-docs/openapi.json" in client.get("/v1-docs/swagger/").text
+        assert "/v2-docs/openapi.json" in client.get("/v2-docs/swagger/").text
+
+        # Checking ReDoc
+
+        assert "/v1-docs/openapi.json" in client.get("/v1-docs/redoc/").text
+        assert "/v2-docs/openapi.json" in client.get("/v2-docs/redoc/").text
+
 
 class TestAPISpecCLICommands:
     """Test OpenAPI CLI commands"""

From 17f479cc420033e7ea453a963b833225adfa255b Mon Sep 17 00:00:00 2001
From: Petras <petras@onecodex.com>
Date: Fri, 25 Nov 2022 17:22:29 +0200
Subject: [PATCH 5/8] Adding multiple API support to CLI

---
 flask_smorest/__init__.py      |  5 ++-
 flask_smorest/spec/__init__.py | 52 ++++++++++++++++++++++------
 flask_smorest/utils.py         |  7 ++++
 tests/test_spec.py             | 62 ++++++++++++++++++++++++++++++++++
 4 files changed, 113 insertions(+), 13 deletions(-)

diff --git a/flask_smorest/__init__.py b/flask_smorest/__init__.py
index 5ea71f0c..f9c3f3ef 100644
--- a/flask_smorest/__init__.py
+++ b/flask_smorest/__init__.py
@@ -6,6 +6,7 @@
 from .blueprint import Blueprint  # noqa
 from .pagination import Page  # noqa
 from .error_handler import ErrorHandlerMixin
+from .utils import normalize_config_prefix
 
 __version__ = "0.40.0"
 
@@ -43,9 +44,7 @@ class Api(APISpecMixin, ErrorHandlerMixin):
     def __init__(self, app=None, *, spec_kwargs=None, config_prefix=""):
         self._app = app
         self._spec_kwargs = spec_kwargs or {}
-        self.config_prefix = config_prefix
-        if self.config_prefix and not self.config_prefix.endswith("_"):
-            self.config_prefix += "_"
+        self.config_prefix = normalize_config_prefix(config_prefix)
         self.spec = None
         # Use lists to enforce order
         self._fields = []
diff --git a/flask_smorest/spec/__init__.py b/flask_smorest/spec/__init__.py
index 96e040a0..f882486b 100644
--- a/flask_smorest/spec/__init__.py
+++ b/flask_smorest/spec/__init__.py
@@ -17,7 +17,12 @@
     HAS_PYYAML = False
 
 from flask_smorest.exceptions import MissingAPIParameterError
-from flask_smorest.utils import prepare_response, get_config_key, get_config_value
+from flask_smorest.utils import (
+    prepare_response,
+    get_config_key,
+    get_config_value,
+    normalize_config_prefix,
+)
 from flask_smorest import etag as fs_etag
 from flask_smorest import pagination as fs_pagination
 from .plugins import FlaskPlugin
@@ -381,20 +386,35 @@ def _register_pagination_header(self):
 openapi_cli = flask.cli.AppGroup("openapi", help="OpenAPI commands.")
 
 
-def _get_spec_dict():
-    # TODO: multiple apis
-    return current_app.extensions["flask-smorest"]["apis"][""].spec.to_dict()
+def _get_spec_dict(config_prefix):
+    ext = current_app.extensions["flask-smorest"]
+    if config_prefix not in ext["apis"]:
+        if config_prefix == "":
+            click.echo(
+                "Error: Your API is using config_prefix. "
+                "Please provide a --config-prefix option.",
+                err=True,
+            )
+        else:
+            click.echo(f"Error: `{config_prefix}` not available. Use one of:", err=True)
+            for key in ext["apis"].keys():
+                click.echo(f"    {key}", err=True)
+        raise click.exceptions.Exit()
+
+    return ext["apis"][config_prefix].spec.to_dict()
 
 
 @openapi_cli.command("print")
 @click.option("-f", "--format", type=click.Choice(["json", "yaml"]), default="json")
-def print_openapi_doc(format):
+@click.option("--config-prefix", type=click.STRING, metavar="", help="TODO", default="")
+def print_openapi_doc(format, config_prefix):
     """Print OpenAPI JSON document."""
+    config_prefix = normalize_config_prefix(config_prefix)
     if format == "json":
-        click.echo(json.dumps(_get_spec_dict(), indent=2))
+        click.echo(json.dumps(_get_spec_dict(config_prefix), indent=2))
     else:  # format == "yaml"
         if HAS_PYYAML:
-            click.echo(yaml.dump(_get_spec_dict()))
+            click.echo(yaml.dump(_get_spec_dict(config_prefix)))
         else:
             click.echo(
                 "To use yaml output format, please install PyYAML module", err=True
@@ -403,15 +423,27 @@ def print_openapi_doc(format):
 
 @openapi_cli.command("write")
 @click.option("-f", "--format", type=click.Choice(["json", "yaml"]), default="json")
+@click.option("--config-prefix", type=click.STRING, metavar="", help="TODO", default="")
 @click.argument("output_file", type=click.File(mode="w"))
-def write_openapi_doc(format, output_file):
+def write_openapi_doc(format, output_file, config_prefix):
     """Write OpenAPI JSON document to a file."""
+    config_prefix = normalize_config_prefix(config_prefix)
     if format == "json":
-        click.echo(json.dumps(_get_spec_dict(), indent=2), file=output_file)
+        click.echo(
+            json.dumps(_get_spec_dict(config_prefix), indent=2),
+            file=output_file,
+        )
     else:  # format == "yaml"
         if HAS_PYYAML:
-            yaml.dump(_get_spec_dict(), output_file)
+            yaml.dump(_get_spec_dict(config_prefix), output_file)
         else:
             click.echo(
                 "To use yaml output format, please install PyYAML module", err=True
             )
+
+
+@openapi_cli.command("list-config-prefixes")
+def list_config_prefixes():
+    """List available API config prefixes."""
+    for prefix in current_app.extensions["flask-smorest"]["apis"].keys():
+        click.echo(prefix)
diff --git a/flask_smorest/utils.py b/flask_smorest/utils.py
index ab8d4efe..43f52a3e 100644
--- a/flask_smorest/utils.py
+++ b/flask_smorest/utils.py
@@ -139,6 +139,13 @@ def prepare_response(response, spec, content_type):
                 ) = response.pop(field)
 
 
+def normalize_config_prefix(config_prefix: str):
+    result = config_prefix.strip().upper()
+    if result and not result.endswith("_"):
+        result += "_"
+    return result
+
+
 def get_config_key(ctx, key):
     """TODO: docstring"""
     return getattr(ctx, "config_prefix", "") + key
diff --git a/tests/test_spec.py b/tests/test_spec.py
index 1ad2aee1..9a1ec9c6 100644
--- a/tests/test_spec.py
+++ b/tests/test_spec.py
@@ -583,3 +583,65 @@ def test_apispec_command_write_output_yaml_no_yaml_module(self, app, tmp_path):
         assert result.output.startswith(
             "To use yaml output format, please install PyYAML module"
         )
+
+    def test_apispec_command_print_with_multiple_apis(self, app):
+        spec_kwargs = {
+            "version": "1",
+            "openapi_version": "3.0.2",
+        }
+        Api(app, config_prefix="V1", spec_kwargs={**spec_kwargs, "title": "V1"})
+        Api(app, config_prefix="V2", spec_kwargs={**spec_kwargs, "title": "V2"})
+
+        result = app.test_cli_runner().invoke(args=["openapi", "print"])
+        assert "Error: " in result.output
+
+        r1 = app.test_cli_runner().invoke(
+            args=["openapi", "print", "--config-prefix=v1"]
+        )
+        assert "V1" in r1.output
+        assert "V2" not in r1.output
+        r2 = app.test_cli_runner().invoke(
+            args=["openapi", "print", "--config-prefix=v2"]
+        )
+        assert "V1" not in r2.output
+        assert "V2" in r2.output
+
+    def test_apispec_command_write_with_multiple_apis(self, app, tmp_path):
+        temp_file1 = tmp_path / "output1"
+        temp_file2 = tmp_path / "output2"
+
+        spec_kwargs = {
+            "version": "1",
+            "openapi_version": "3.0.2",
+        }
+        Api(app, config_prefix="V1", spec_kwargs={**spec_kwargs, "title": "V1"})
+        Api(app, config_prefix="V2", spec_kwargs={**spec_kwargs, "title": "V2"})
+
+        result = app.test_cli_runner().invoke(args=["openapi", "write"])
+        assert "Error: " in result.output
+
+        app.test_cli_runner().invoke(
+            args=["openapi", "write", "--config-prefix=v1", str(temp_file1)]
+        )
+        with open(temp_file1, encoding="utf-8") as spec_file1:
+            content1 = spec_file1.read()
+            assert "V1" in content1
+            assert "V2" not in content1
+
+        app.test_cli_runner().invoke(
+            args=["openapi", "write", "--config-prefix=v2", str(temp_file2)]
+        )
+        with open(temp_file2, encoding="utf-8") as spec_file2:
+            content2 = spec_file2.read()
+            assert "V1" not in content2
+            assert "V2" in content2
+
+    def test_apispec_command_list_config_prefixes(self, app):
+        spec_kwargs = {
+            "version": "1",
+            "openapi_version": "3.0.2",
+        }
+        Api(app, config_prefix="V1", spec_kwargs={**spec_kwargs, "title": "V1"})
+        Api(app, config_prefix="V2", spec_kwargs={**spec_kwargs, "title": "V2"})
+        result = app.test_cli_runner().invoke(args=["openapi", "list-config-prefixes"])
+        assert set(result.output.strip().splitlines()) == {"V1_", "V2_"}

From d4c4bdfe501797e227c3795ab3a4a90ce0e24142 Mon Sep 17 00:00:00 2001
From: Petras <petras@onecodex.com>
Date: Fri, 25 Nov 2022 23:26:30 +0200
Subject: [PATCH 6/8] Docstrings and documentation update

---
 CHANGELOG.rst                  |  5 +++++
 docs/openapi.rst               | 13 +++++++++++++
 flask_smorest/__init__.py      |  9 +++++----
 flask_smorest/spec/__init__.py |  4 ++--
 flask_smorest/utils.py         | 22 ++++++++++++++++++++--
 5 files changed, 45 insertions(+), 8 deletions(-)

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 55accdeb..338322d5 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -4,6 +4,11 @@ Changelog
 0.41.0 (unreleased)
 *******************
 
+Features:
+
+- Support multiple APIs in a single application via ``Api.__init__`` param
+  ``config_prefix``.
+
 Other changes:
 
 - Official Python 3.11 support (:pr:`416`).
diff --git a/docs/openapi.rst b/docs/openapi.rst
index df3ff962..f129810d 100644
--- a/docs/openapi.rst
+++ b/docs/openapi.rst
@@ -280,6 +280,19 @@ interactively. This feature is accessible through Flask app parameters.
 
    Default: ``openapi.json``
 
+`Note`: To support multiple APIs in the single application a ``config_prefix``
+parameter needs to be passed to :class:`Api <Api>` constructor. In that case
+Flask app parameters need to be prefixed with a custom prefix.
+
+.. code-block:: python
+
+   api1 = Api(config_prefix="V1_")
+
+
+   class Config:
+       V1_OPENAPI_VERSION = "3.0.2"  # Instead of OPENAPI_VERSION
+       V1_OPENAPI_URL_PREFIX = "/v1/"  # Instead of OPENAPI_URL_PREFIX
+
 `ReDoc`_, `Swagger UI`_ and `RapiDoc` interfaces are available to present the
 API.
 
diff --git a/flask_smorest/__init__.py b/flask_smorest/__init__.py
index f9c3f3ef..ea5269bc 100644
--- a/flask_smorest/__init__.py
+++ b/flask_smorest/__init__.py
@@ -18,7 +18,11 @@ class Api(APISpecMixin, ErrorHandlerMixin):
 
     :param Flask app: Flask application
     :param spec_kwargs: kwargs to pass to internal APISpec instance
-    :param config_prefix: TODO
+    :param str config_prefix: Should be used if the user is planning to use
+        multiple `Api`'s in the single app. If it is not empty then
+        all application parameters will be prefixed with it. For example:
+        if ``config_prefix`` is ``V1_`` then ``V1_API_TITLE`` is going to
+        be used instead of ``API_TITLE``.
 
     The ``spec_kwargs`` dictionary is passed as kwargs to the internal APISpec
     instance. **flask-smorest** adds a few parameters to the original
@@ -62,7 +66,6 @@ def init_app(self, app, *, spec_kwargs=None):
 
         # Register flask-smorest in app extensions
         app.extensions = getattr(app, "extensions", {})
-        # TODO: backwards compatibility?
         ext = app.extensions.setdefault("flask-smorest", {"apis": {}})
         ext["apis"][self.config_prefix] = self
 
@@ -89,8 +92,6 @@ def register_blueprint(self, blp, *, parameters=None, **options):
         Must be called after app is initialized.
         """
         blp_name = options.get("name", blp.name)
-
-        # TODO: seems a little bit dirty
         if hasattr(blp, "config_prefix"):
             blp.config_prefix = self.config_prefix
         self._app.register_blueprint(blp, **options)
diff --git a/flask_smorest/spec/__init__.py b/flask_smorest/spec/__init__.py
index f882486b..7f5b3522 100644
--- a/flask_smorest/spec/__init__.py
+++ b/flask_smorest/spec/__init__.py
@@ -406,7 +406,7 @@ def _get_spec_dict(config_prefix):
 
 @openapi_cli.command("print")
 @click.option("-f", "--format", type=click.Choice(["json", "yaml"]), default="json")
-@click.option("--config-prefix", type=click.STRING, metavar="", help="TODO", default="")
+@click.option("--config-prefix", type=click.STRING, metavar="", default="")
 def print_openapi_doc(format, config_prefix):
     """Print OpenAPI JSON document."""
     config_prefix = normalize_config_prefix(config_prefix)
@@ -423,7 +423,7 @@ def print_openapi_doc(format, config_prefix):
 
 @openapi_cli.command("write")
 @click.option("-f", "--format", type=click.Choice(["json", "yaml"]), default="json")
-@click.option("--config-prefix", type=click.STRING, metavar="", help="TODO", default="")
+@click.option("--config-prefix", type=click.STRING, metavar="", default="")
 @click.argument("output_file", type=click.File(mode="w"))
 def write_openapi_doc(format, output_file, config_prefix):
     """Write OpenAPI JSON document to a file."""
diff --git a/flask_smorest/utils.py b/flask_smorest/utils.py
index 43f52a3e..794676e3 100644
--- a/flask_smorest/utils.py
+++ b/flask_smorest/utils.py
@@ -140,6 +140,11 @@ def prepare_response(response, spec, content_type):
 
 
 def normalize_config_prefix(config_prefix: str):
+    """Normalize custom API config prefix
+
+    :param str config_prefix: raw prefix
+    :return: normalized prefix. Underscore is automatically added if prefix misses one.
+    """
     result = config_prefix.strip().upper()
     if result and not result.endswith("_"):
         result += "_"
@@ -147,10 +152,23 @@ def normalize_config_prefix(config_prefix: str):
 
 
 def get_config_key(ctx, key):
-    """TODO: docstring"""
+    """Get flask config key potentially affected by config_prefix
+
+    :param flask_smorest.Blueprint|flask_smorest.Api ctx: object
+        containing ``config_prefix`` attribute.
+    :param str key: full flask config key is constructed as ``config_prefix + key``.
+    :return: full flask config key
+    """
     return getattr(ctx, "config_prefix", "") + key
 
 
 def get_config_value(app, ctx, key, default=None):
-    """TODO: docstring"""
+    """Get flask config key potentially affected by config_prefix
+
+    :param flask_smorest.Blueprint|flask_smorest.Api ctx: object
+        containing ``config_prefix`` attribute.
+    :param str key: full flask config key is constructed as ``config_prefix + key``.
+    :param default: return this value if full key is not found.
+    :return: a flask config value or ``default``.
+    """
     return app.config.get(get_config_key(ctx, key), default)

From 39427d21b183207371cef90829ce0cc17a7213fa Mon Sep 17 00:00:00 2001
From: Petras <petras@onecodex.com>
Date: Mon, 28 Nov 2022 13:29:43 +0200
Subject: [PATCH 7/8] Keyword-only args for get_config_{key,value}

---
 flask_smorest/__init__.py      |  2 +-
 flask_smorest/etag.py          |  4 ++-
 flask_smorest/spec/__init__.py | 54 ++++++++++++++++++++++------------
 flask_smorest/utils.py         |  6 ++--
 4 files changed, 43 insertions(+), 23 deletions(-)

diff --git a/flask_smorest/__init__.py b/flask_smorest/__init__.py
index ea5269bc..75c307fa 100644
--- a/flask_smorest/__init__.py
+++ b/flask_smorest/__init__.py
@@ -19,7 +19,7 @@ class Api(APISpecMixin, ErrorHandlerMixin):
     :param Flask app: Flask application
     :param spec_kwargs: kwargs to pass to internal APISpec instance
     :param str config_prefix: Should be used if the user is planning to use
-        multiple `Api`'s in the single app. If it is not empty then
+        multiple `Api`'s in a single app. If it is not empty then
         all application parameters will be prefixed with it. For example:
         if ``config_prefix`` is ``V1_`` then ``V1_API_TITLE`` is going to
         be used instead of ``API_TITLE``.
diff --git a/flask_smorest/etag.py b/flask_smorest/etag.py
index ac1b6c70..552b4eb7 100644
--- a/flask_smorest/etag.py
+++ b/flask_smorest/etag.py
@@ -147,7 +147,9 @@ def check_etag(self, etag_data, etag_schema=None):
 
     def _is_etag_enabled(self, app=None):
         """Return True if ETag feature enabled api-wise"""
-        return not get_config_value(app or current_app, self, "ETAG_DISABLED", False)
+        return not get_config_value(
+            app=app or current_app, ctx=self, key="ETAG_DISABLED", default=False
+        )
 
     def _verify_check_etag(self):
         """Verify check_etag was called in resource code
diff --git a/flask_smorest/spec/__init__.py b/flask_smorest/spec/__init__.py
index 7f5b3522..038ef717 100644
--- a/flask_smorest/spec/__init__.py
+++ b/flask_smorest/spec/__init__.py
@@ -50,7 +50,7 @@ class DocBlueprintMixin:
     """Extend Api to serve the spec in a dedicated blueprint."""
 
     def _get_doc_blueprint_name(self):
-        return get_config_key(self, "api-docs").replace("_", "-").lower()
+        return get_config_key(ctx=self, key="api-docs").replace("_", "-").lower()
 
     def _register_doc_blueprint(self):
         """Register a blueprint in the application to expose the spec
@@ -59,7 +59,7 @@ def _register_doc_blueprint(self):
         - json spec file
         - spec UI (ReDoc, Swagger UI).
         """
-        api_url = get_config_value(self._app, self, "OPENAPI_URL_PREFIX", None)
+        api_url = get_config_value(app=self._app, ctx=self, key="OPENAPI_URL_PREFIX")
         if api_url is not None:
             blueprint = flask.Blueprint(
                 self._get_doc_blueprint_name(),
@@ -69,7 +69,7 @@ def _register_doc_blueprint(self):
             )
             # Serve json spec at 'url_prefix/openapi.json' by default
             json_path = get_config_value(
-                self._app, self, "OPENAPI_JSON_PATH", "openapi.json"
+                app=self._app, ctx=self, key="OPENAPI_JSON_PATH", default="openapi.json"
             )
             blueprint.add_url_rule(
                 _add_leading_slash(json_path),
@@ -86,9 +86,11 @@ def _register_redoc_rule(self, blueprint):
 
         The ReDoc script URL should be specified as OPENAPI_REDOC_URL.
         """
-        redoc_path = get_config_value(self._app, self, "OPENAPI_REDOC_PATH")
+        redoc_path = get_config_value(app=self._app, ctx=self, key="OPENAPI_REDOC_PATH")
         if redoc_path is not None:
-            redoc_url = get_config_value(self._app, self, "OPENAPI_REDOC_URL")
+            redoc_url = get_config_value(
+                app=self._app, ctx=self, key="OPENAPI_REDOC_URL"
+            )
             if redoc_url is not None:
                 self._redoc_url = redoc_url
                 blueprint.add_url_rule(
@@ -103,9 +105,13 @@ def _register_swagger_ui_rule(self, blueprint):
         The Swagger UI scripts base URL should be specified as
         OPENAPI_SWAGGER_UI_URL.
         """
-        swagger_ui_path = get_config_value(self._app, self, "OPENAPI_SWAGGER_UI_PATH")
+        swagger_ui_path = get_config_value(
+            app=self._app, ctx=self, key="OPENAPI_SWAGGER_UI_PATH"
+        )
         if swagger_ui_path is not None:
-            swagger_ui_url = get_config_value(self._app, self, "OPENAPI_SWAGGER_UI_URL")
+            swagger_ui_url = get_config_value(
+                app=self._app, ctx=self, key="OPENAPI_SWAGGER_UI_URL"
+            )
             if swagger_ui_url is not None:
                 self._swagger_ui_url = swagger_ui_url
                 blueprint.add_url_rule(
@@ -119,9 +125,13 @@ def _register_rapidoc_rule(self, blueprint):
 
         The RapiDoc script URL should be specified as OPENAPI_RAPIDOC_URL.
         """
-        rapidoc_path = get_config_value(self._app, self, "OPENAPI_RAPIDOC_PATH")
+        rapidoc_path = get_config_value(
+            app=self._app, ctx=self, key="OPENAPI_RAPIDOC_PATH"
+        )
         if rapidoc_path is not None:
-            rapidoc_url = get_config_value(self._app, self, "OPENAPI_RAPIDOC_URL")
+            rapidoc_url = get_config_value(
+                app=self._app, ctx=self, key="OPENAPI_RAPIDOC_URL"
+            )
             if rapidoc_url is not None:
                 self._rapidoc_url = rapidoc_url
                 blueprint.add_url_rule(
@@ -155,7 +165,7 @@ def _openapi_swagger_ui(self):
             spec_url=flask.url_for(f"{self._get_doc_blueprint_name()}.openapi_json"),
             swagger_ui_url=self._swagger_ui_url,
             swagger_ui_config=get_config_value(
-                self._app, self, "OPENAPI_SWAGGER_UI_CONFIG", {}
+                app=self._app, ctx=self, key="OPENAPI_SWAGGER_UI_CONFIG", default={}
             ),
         )
 
@@ -167,7 +177,7 @@ def _openapi_rapidoc(self):
             spec_url=flask.url_for(f"{self._get_doc_blueprint_name()}.openapi_json"),
             rapidoc_url=self._rapidoc_url,
             rapidoc_config=get_config_value(
-                self._app, self, "OPENAPI_RAPIDOC_CONFIG", {}
+                app=self._app, ctx=self, key="OPENAPI_RAPIDOC_CONFIG", default={}
             ),
         )
 
@@ -198,25 +208,29 @@ def _init_spec(
         plugins.extend(extra_plugins or ())
 
         # APISpec options
-        title = get_config_value(self._app, self, "API_TITLE", title)
+        title = get_config_value(
+            app=self._app, ctx=self, key="API_TITLE", default=title
+        )
         if title is None:
-            key = get_config_key(self, "API_TITLE")
+            key = get_config_key(ctx=self, key="API_TITLE")
             raise MissingAPIParameterError(
                 f'API title must be specified either as "{key}" '
                 'app parameter or as "title" spec kwarg.'
             )
-        version = get_config_value(self._app, self, "API_VERSION", version)
+        version = get_config_value(
+            app=self._app, ctx=self, key="API_VERSION", default=version
+        )
         if version is None:
-            key = get_config_key(self, "API_VERSION")
+            key = get_config_key(ctx=self, key="API_VERSION")
             raise MissingAPIParameterError(
                 f'API version must be specified either as "{key}" '
                 'app parameter or as "version" spec kwarg.'
             )
         openapi_version = get_config_value(
-            self._app, self, "OPENAPI_VERSION", openapi_version
+            app=self._app, ctx=self, key="OPENAPI_VERSION", default=openapi_version
         )
         if openapi_version is None:
-            key = get_config_key(self, "OPENAPI_VERSION")
+            key = get_config_key(ctx=self, key="OPENAPI_VERSION")
             raise MissingAPIParameterError(
                 f'OpenAPI version must be specified either as "{key}" '
                 'app parameter or as "openapi_version" spec kwarg.'
@@ -235,7 +249,11 @@ def _init_spec(
                     self.DEFAULT_REQUEST_BODY_CONTENT_TYPE,
                 ],
             )
-        options.update(get_config_value(self._app, self, "API_SPEC_OPTIONS", {}))
+        options.update(
+            get_config_value(
+                app=self._app, ctx=self, key="API_SPEC_OPTIONS", default={}
+            )
+        )
 
         # Instantiate spec
         self.spec = apispec.APISpec(
diff --git a/flask_smorest/utils.py b/flask_smorest/utils.py
index 794676e3..b54f08b3 100644
--- a/flask_smorest/utils.py
+++ b/flask_smorest/utils.py
@@ -151,7 +151,7 @@ def normalize_config_prefix(config_prefix: str):
     return result
 
 
-def get_config_key(ctx, key):
+def get_config_key(*, ctx, key):
     """Get flask config key potentially affected by config_prefix
 
     :param flask_smorest.Blueprint|flask_smorest.Api ctx: object
@@ -162,7 +162,7 @@ def get_config_key(ctx, key):
     return getattr(ctx, "config_prefix", "") + key
 
 
-def get_config_value(app, ctx, key, default=None):
+def get_config_value(*, app, ctx, key, default=None):
     """Get flask config key potentially affected by config_prefix
 
     :param flask_smorest.Blueprint|flask_smorest.Api ctx: object
@@ -171,4 +171,4 @@ def get_config_value(app, ctx, key, default=None):
     :param default: return this value if full key is not found.
     :return: a flask config value or ``default``.
     """
-    return app.config.get(get_config_key(ctx, key), default)
+    return app.config.get(get_config_key(ctx=ctx, key=key), default)

From 4e7989f337a353aff01da28824089d24d4cd5837 Mon Sep 17 00:00:00 2001
From: Petras <petras@onecodex.com>
Date: Mon, 28 Nov 2022 14:25:33 +0200
Subject: [PATCH 8/8] Authors

---
 AUTHORS.rst | 1 +
 1 file changed, 1 insertion(+)

diff --git a/AUTHORS.rst b/AUTHORS.rst
index 754e6b8d..5eb59fac 100644
--- a/AUTHORS.rst
+++ b/AUTHORS.rst
@@ -25,3 +25,4 @@ Contributors (chronological)
 - Choudhury Noor `@Cnoor0171 <https://github.com/Cnoor0171>`_
 - Dmitry Erlikh `@derlikh-smart <https://github.com/derlikh-smart>`_
 - 0x78f1935 `@0x78f1935 <https://github.com/0x78f1935>`_
+- One Codex, Inc. `@onecodex <https://github.com/onecodex>`_