RESTClient: implement AuthConfigBase.__bool__ + update docs (#1398)

* Fix AuthConfigBase so its instances always evaluate to True in bool context; change docs to suggest direct inheritance from AuthBase

* Add tests

dlt/sources/helpers/rest_client/auth.py

@@ -38,7 +38,11 @@ class AuthConfigBase(AuthBase, CredentialsConfiguration):
     configurable via env variables or toml files
     """
 
-    pass
+    def __bool__(self) -> bool:
+        # This is needed to avoid AuthConfigBase-derived classes
+        # which do not implement CredentialsConfiguration interface
+        # to be evaluated as False in requests.sessions.Session.prepare_request()
+        return True
 
 
 @configspec

docs/website/docs/general-usage/http/rest-client.md

@@ -407,7 +407,7 @@ The available authentication methods are defined in the `dlt.sources.helpers.res
 - [APIKeyAuth](#api-key-authentication)
 - [HttpBasicAuth](#http-basic-authentication)
 
-For specific use cases, you can [implement custom authentication](#implementing-custom-authentication) by subclassing the `AuthConfigBase` class.
+For specific use cases, you can [implement custom authentication](#implementing-custom-authentication) by subclassing the `AuthBase` class from the Requests library.
 
 ### Bearer token authentication
 
@@ -479,12 +479,12 @@ response = client.get("/protected/resource")
 
 ### Implementing custom authentication
 
-You can implement custom authentication by subclassing the `AuthConfigBase` class and implementing the `__call__` method:
+You can implement custom authentication by subclassing the `AuthBase` class and implementing the `__call__` method:
 
 ```py
-from dlt.sources.helpers.rest_client.auth import AuthConfigBase
+from requests.auth import AuthBase
 
-class CustomAuth(AuthConfigBase):
+class CustomAuth(AuthBase):
     def __init__(self, token):
         self.token = token
 

tests/sources/helpers/rest_client/test_client.py

@@ -1,6 +1,7 @@
 import os
 import pytest
 from typing import Any, cast
+from requests.auth import AuthBase
 from dlt.common.typing import TSecretStrValue
 from dlt.sources.helpers.requests import Response, Request
 from dlt.sources.helpers.rest_client import RESTClient
@@ -57,7 +58,6 @@ def test_page_context(self, rest_client: RESTClient) -> None:
         for page in rest_client.paginate(
             "/posts",
             paginator=JSONResponsePaginator(next_url_path="next_page"),
-            auth=AuthConfigBase(),
         ):
             # response that produced data
             assert isinstance(page.response, Response)
@@ -183,3 +183,44 @@ def test_oauth_jwt_auth_success(self, rest_client: RESTClient):
         )
 
         assert_pagination(list(pages_iter))
+
+    def test_custom_auth_success(self, rest_client: RESTClient):
+        class CustomAuthConfigBase(AuthConfigBase):
+            def __init__(self, token: str):
+                self.token = token
+
+            def __call__(self, request: Request) -> Request:
+                request.headers["Authorization"] = f"Bearer {self.token}"
+                return request
+
+        class CustomAuthAuthBase(AuthBase):
+            def __init__(self, token: str):
+                self.token = token
+
+            def __call__(self, request: Request) -> Request:
+                request.headers["Authorization"] = f"Bearer {self.token}"
+                return request
+
+        auth_list = [
+            CustomAuthConfigBase("test-token"),
+            CustomAuthAuthBase("test-token"),
+        ]
+
+        for auth in auth_list:
+            response = rest_client.get(
+                "/protected/posts/bearer-token",
+                auth=auth,
+            )
+
+            assert response.status_code == 200
+            assert response.json()["data"][0] == {"id": 0, "title": "Post 0"}
+
+            pages_iter = rest_client.paginate(
+                "/protected/posts/bearer-token",
+                auth=auth,
+            )
+
+            pages_list = list(pages_iter)
+            assert_pagination(pages_list)
+
+            assert pages_list[0].response.request.headers["Authorization"] == "Bearer test-token"