[feat] Add OAuth2 support for OpenStreetMap (#877)

* [feat] Add OAuth2 support for OpenStreetMap

Fixes #758

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---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

social_core/backends/openstreetmap_oauth2.py

@@ -0,0 +1,57 @@
+"""
+OpenStreetMap OAuth 2.0 support.
+
+This adds support for OpenStreetMap OAuth service. An application must be
+registered first on OpenStreetMap and the settings
+SOCIAL_AUTH_OPENSTREETMAP_OAUTH2_KEY and SOCIAL_AUTH_OPENSTREETMAP_OAUTH2_SECRET
+must be defined with the corresponding values.
+
+More info: https://wiki.openstreetmap.org/wiki/OAuth
+"""
+
+from .oauth import BaseOAuth2PKCE
+
+
+class OpenStreetMapOAuth2(BaseOAuth2PKCE):
+    """OpenStreetMap OAuth2 authentication backend"""
+
+    name = "openstreetmap-oauth2"
+    AUTHORIZATION_URL = "https://www.openstreetmap.org/oauth2/authorize"
+    ACCESS_TOKEN_URL = "https://www.openstreetmap.org/oauth2/token"
+    ACCESS_TOKEN_METHOD = "POST"
+    SCOPE_SEPARATOR = " "
+    STATE_PARAMETER = True
+    DEFAULT_SCOPE = ["read_prefs"]
+    EXTRA_DATA = [
+        ("id", "id"),
+        ("avatar", "avatar"),
+        ("account_created", "account_created"),
+    ]
+    PKCE_DEFAULT_CODE_CHALLENGE_METHOD = "S256"
+    DEFAULT_USE_PKCE = True
+
+    def get_user_details(self, response):
+        """Return user details from OpenStreetMap account"""
+        return {
+            "username": response["username"],
+            "email": "",
+            "fullname": "",
+            "first_name": "",
+            "last_name": "",
+        }
+
+    def user_data(self, access_token, *args, **kwargs):
+        """Return user data provided"""
+
+        headers = {"Authorization": f"Bearer {access_token}"}
+        response = self.get_json(
+            url="https://api.openstreetmap.org/api/0.6/user/details.json",
+            headers=headers,
+        )
+
+        return {
+            "id": response["user"]["id"],
+            "username": response["user"]["display_name"],
+            "account_created": response["user"]["account_created"],
+            "avatar": response["user"].get("img", {}).get("href"),
+        }

social_core/tests/backends/test_openstreetmap_oauth2.py

@@ -0,0 +1,30 @@
+import json
+
+from .oauth import OAuth2Test
+
+
+class OpenStreetMapOAuth2Test(OAuth2Test):
+    backend_path = "social_core.backends.openstreetmap_oauth2.OpenStreetMapOAuth2"
+    user_data_url = "https://api.openstreetmap.org/api/0.6/user/details.json"
+    expected_username = "Steve"
+    access_token_body = json.dumps({"access_token": "foobar", "token_type": "bearer"})
+    user_data_body = json.dumps(
+        {
+            "version": "0.6",
+            "generator": "OpenStreetMap server",
+            "copyright": "OpenStreetMap and contributors",
+            "attribution": "http://www.openstreetmap.org/copyright",
+            "license": "http://opendatacommons.org/licenses/odbl/1-0/",
+            "user": {
+                "id": 1,
+                "display_name": "Steve",
+                "account_created": "2005-09-13T15:32:57Z",
+            },
+        }
+    )
+
+    def test_login(self):
+        self.do_login()
+
+    def test_partial_pipeline(self):
+        self.do_partial_pipeline()