Add redirect_uri argument to InteractiveBrowserCredential

sdk/identity/azure-identity/CHANGELOG.md

@@ -13,6 +13,9 @@
   (`azure.identity.aio.CertificateCredential`) will support this in a
   future version.
   ([#10816](https://github.com/Azure/azure-sdk-for-python/issues/10816))
+- `InteractiveBrowserCredential` keyword argument `redirect_uri` enables
+  authentication with a user-specified application having a custom redirect URI
+  ([#13344](https://github.com/Azure/azure-sdk-for-python/issues/13344))  
 
 ## 1.4.0 (2020-08-10)
 ### Added

sdk/identity/azure-identity/azure/identity/_credentials/browser.py

@@ -36,6 +36,10 @@ class InteractiveBrowserCredential(InteractiveCredential):
           authenticate work or school accounts.
     :keyword str client_id: Client ID of the Azure Active Directory application users will sign in to. If
           unspecified, the Azure CLI's ID will be used.
+    :keyword str redirect_uri: a redirect URI for the application identified by `client_id` as configured in Azure
+          Active Directory, for example "http://localhost:8400". This is only required when passing a value for
+          `client_id`, and must match a redirect URI in the application's registration. The credential must be able to
+          bind a socket to this URI.
     :keyword AuthenticationRecord authentication_record: :class:`AuthenticationRecord` returned by :func:`authenticate`
     :keyword bool disable_automatic_authentication: if True, :func:`get_token` will raise
           :class:`AuthenticationRequiredError` when user interaction is required to acquire a token. Defaults to False.
@@ -48,26 +52,34 @@ class InteractiveBrowserCredential(InteractiveCredential):
 
     def __init__(self, **kwargs):
         # type: (**Any) -> None
+        self._redirect_uri = kwargs.pop("redirect_uri", None)
         self._timeout = kwargs.pop("timeout", 300)
-        self._server_class = kwargs.pop("server_class", AuthCodeRedirectServer)  # facilitate mocking
+        self._server_class = kwargs.pop("_server_class", AuthCodeRedirectServer)
         client_id = kwargs.pop("client_id", AZURE_CLI_CLIENT_ID)
         super(InteractiveBrowserCredential, self).__init__(client_id=client_id, **kwargs)
 
     @wrap_exceptions
     def _request_token(self, *scopes, **kwargs):
         # type: (*str, **Any) -> dict
 
-        # start an HTTP server on localhost to receive the redirect
-        redirect_uri = None
-        for port in range(8400, 9000):
+        # start an HTTP server to receive the redirect
+        server = None
+        redirect_uri = self._redirect_uri
+        if redirect_uri:
             try:
-                server = self._server_class(port, timeout=self._timeout)
-                redirect_uri = "http://localhost:{}".format(port)
-                break
+                server = self._server_class(redirect_uri, timeout=self._timeout)
             except socket.error:
-                continue  # keep looking for an open port
-
-        if not redirect_uri:
+                raise CredentialUnavailableError(message="Couldn't start an HTTP server on " + redirect_uri)
+        else:
+            for port in range(8400, 9000):
+                try:
+                    redirect_uri = "http://localhost:{}".format(port)
+                    server = self._server_class(redirect_uri, timeout=self._timeout)
+                    break
+                except socket.error:
+                    continue  # keep looking for an open port
+
+        if not server:
             raise CredentialUnavailableError(message="Couldn't start an HTTP server on localhost")
 
         # get the url the user must visit to authenticate
@@ -93,7 +105,6 @@ def _request_token(self, *scopes, **kwargs):
         code = self._parse_response(request_state, response)
         return app.acquire_token_by_authorization_code(code, scopes=scopes, redirect_uri=redirect_uri, **kwargs)
 
-
     @staticmethod
     def _parse_response(request_state, response):
         # type: (str, Mapping[str, Any]) -> List[str]

sdk/identity/azure-identity/azure/identity/_internal/auth_code_redirect_handler.py

@@ -2,23 +2,18 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT License.
 # ------------------------------------
-try:
-    from typing import TYPE_CHECKING
-except ImportError:
-    TYPE_CHECKING = False
+from typing import TYPE_CHECKING
 
-if TYPE_CHECKING:
-    from typing import Any, Mapping, Optional
+from six.moves.urllib_parse import parse_qs, urlparse
 
 try:
     from http.server import HTTPServer, BaseHTTPRequestHandler
 except ImportError:
     from BaseHTTPServer import HTTPServer, BaseHTTPRequestHandler  # type: ignore
 
-try:
-    from urllib.parse import parse_qs
-except ImportError:
-    from urlparse import parse_qs  # type: ignore
+if TYPE_CHECKING:
+    # pylint:disable=ungrouped-imports
+    from typing import Any, Mapping
 
 
 class AuthCodeRedirectHandler(BaseHTTPRequestHandler):
@@ -46,13 +41,14 @@ def log_message(self, format, *args):  # pylint: disable=redefined-builtin,unuse
 
 
 class AuthCodeRedirectServer(HTTPServer):
-    """HTTP server that listens on localhost for the redirect request following an authorization code authentication"""
+    """HTTP server that listens for the redirect request following an authorization code authentication"""
 
     query_params = {}  # type: Mapping[str, Any]
 
-    def __init__(self, port, timeout):
-        # type: (int, int) -> None
-        HTTPServer.__init__(self, ("localhost", port), AuthCodeRedirectHandler)
+    def __init__(self, uri, timeout):
+        # type: (str, int) -> None
+        parsed = urlparse(uri)
+        HTTPServer.__init__(self, (parsed.hostname, parsed.port), AuthCodeRedirectHandler)
         self.timeout = timeout
 
     def wait_for_redirect(self):

sdk/identity/azure-identity/tests/test_browser_credential.py

@@ -22,14 +22,15 @@
     build_id_token,
     get_discovery_response,
     mock_response,
+    msal_validating_transport,
     Request,
     validating_transport,
 )
 
 try:
-    from unittest.mock import Mock, patch
+    from unittest.mock import ANY, Mock, patch
 except ImportError:  # python < 3.3
-    from mock import Mock, patch  # type: ignore
+    from mock import ANY, Mock, patch  # type: ignore
 
 
 WEBBROWSER_OPEN = InteractiveBrowserCredential.__module__ + ".webbrowser.open"
@@ -77,7 +78,7 @@ def test_authenticate():
                 _cache=TokenCache(),
                 authority=environment,
                 client_id=client_id,
-                server_class=server_class,
+                _server_class=server_class,
                 tenant_id=tenant_id,
                 transport=transport,
             )
@@ -126,7 +127,7 @@ def test_policies_configurable():
     server_class = Mock(return_value=Mock(wait_for_redirect=lambda: auth_code_response))
 
     credential = InteractiveBrowserCredential(
-        policies=[policy], client_id=client_id, transport=transport, server_class=server_class, _cache=TokenCache()
+        policies=[policy], client_id=client_id, transport=transport, _server_class=server_class, _cache=TokenCache()
     )
 
     with patch("azure.identity._credentials.browser.uuid.uuid4", lambda: oauth_state):
@@ -152,15 +153,16 @@ def test_user_agent():
     server_class = Mock(return_value=Mock(wait_for_redirect=lambda: auth_code_response))
 
     credential = InteractiveBrowserCredential(
-        client_id=client_id, transport=transport, server_class=server_class, _cache=TokenCache()
+        client_id=client_id, transport=transport, _server_class=server_class, _cache=TokenCache()
     )
 
     with patch("azure.identity._credentials.browser.uuid.uuid4", lambda: oauth_state):
         credential.get_token("scope")
 
 
 @patch("azure.identity._credentials.browser.webbrowser.open")
-def test_interactive_credential(mock_open):
+@pytest.mark.parametrize("redirect_url", ("https://localhost:8042", None))
+def test_interactive_credential(mock_open, redirect_url):
     mock_open.side_effect = _validate_auth_request_url
     oauth_state = "state"
     client_id = "client-id"
@@ -171,17 +173,15 @@ def test_interactive_credential(mock_open):
     tenant_id = "tenant_id"
     endpoint = "https://{}/{}".format(authority, tenant_id)
 
-    discovery_response = get_discovery_response(endpoint=endpoint)
-    transport = validating_transport(
-        requests=[Request(url_substring=endpoint)] * 3
+    transport = msal_validating_transport(
+        endpoint="https://{}/{}".format(authority, tenant_id),
+        requests=[Request(url_substring=endpoint)]
         + [
             Request(
                 authority=authority, url_substring=endpoint, required_data={"refresh_token": expected_refresh_token}
             )
         ],
         responses=[
-            discovery_response,  # instance discovery
-            discovery_response,  # tenant discovery
             mock_response(
                 json_payload=build_aad_response(
                     access_token=expected_token,
@@ -203,37 +203,38 @@ def test_interactive_credential(mock_open):
     auth_code_response = {"code": "authorization-code", "state": [oauth_state]}
     server_class = Mock(return_value=Mock(wait_for_redirect=lambda: auth_code_response))
 
-    credential = InteractiveBrowserCredential(
-        authority=authority,
-        tenant_id=tenant_id,
-        client_id=client_id,
-        server_class=server_class,
-        transport=transport,
-        instance_discovery=False,
-        validate_authority=False,
-        _cache=TokenCache(),
-    )
+    args = {
+        "authority": authority,
+        "tenant_id": tenant_id,
+        "client_id": client_id,
+        "transport": transport,
+        "_cache": TokenCache(),
+        "_server_class": server_class,
+    }
+    if redirect_url:  # avoid passing redirect_url=None
+        args["redirect_uri"] = redirect_url
+
+    credential = InteractiveBrowserCredential(**args)
 
     # The credential's auth code request includes a uuid which must be included in the redirect. Patching to
     # set the uuid requires less code here than a proper mock server.
     with patch("azure.identity._credentials.browser.uuid.uuid4", lambda: oauth_state):
         token = credential.get_token("scope")
     assert token.token == expected_token
     assert mock_open.call_count == 1
+    assert server_class.call_count == 1
+
+    if redirect_url:
+        server_class.assert_called_once_with(redirect_url, timeout=ANY)
 
     # token should be cached, get_token shouldn't prompt again
     token = credential.get_token("scope")
     assert token.token == expected_token
     assert mock_open.call_count == 1
-
-    # As of MSAL 1.0.0, applications build a new client every time they redeem a refresh token.
-    # Here we patch the private method they use for the sake of test coverage.
-    # TODO: this will probably break when this MSAL behavior changes
-    app = credential._get_app()
-    app._build_client = lambda *_: app.client  # pylint:disable=protected-access
-    now = time.time()
+    assert server_class.call_count == 1
 
     # expired access token -> credential should use refresh token instead of prompting again
+    now = time.time()
     with patch("time.time", lambda: now + expires_in):
         token = credential.get_token("scope")
     assert token.token == expected_token
@@ -259,7 +260,7 @@ def test_interactive_credential_timeout():
 
     credential = InteractiveBrowserCredential(
         client_id="guid",
-        server_class=server_class,
+        _server_class=server_class,
         timeout=timeout,
         transport=transport,
         instance_discovery=False,  # kwargs are passed to MSAL; this one prevents an AAD verification request
@@ -277,7 +278,8 @@ def test_redirect_server():
     for _ in range(4):
         try:
             port = random.randint(1024, 65535)
-            server = AuthCodeRedirectServer(port, timeout=10)
+            url = "http://127.0.0.1:{}".format(port)
+            server = AuthCodeRedirectServer(url, timeout=10)
             break
         except socket.error:
             continue  # keep looking for an open port
@@ -293,8 +295,7 @@ def test_redirect_server():
     thread.start()
 
     # send a request, verify the server exposes the query
-    url = "http://127.0.0.1:{}/?{}={}".format(port, expected_param, expected_value)  # nosec
-    response = urllib.request.urlopen(url)  # nosec
+    response = urllib.request.urlopen(url + "?{}={}".format(expected_param, expected_value))  # nosec
 
     assert response.code == 200
     assert server.query_params[expected_param] == [expected_value]
@@ -304,7 +305,7 @@ def test_redirect_server():
 def test_no_browser():
     transport = validating_transport(requests=[Request()] * 2, responses=[get_discovery_response()] * 2)
     credential = InteractiveBrowserCredential(
-        client_id="client-id", server_class=Mock(), transport=transport, _cache=TokenCache()
+        client_id="client-id", _server_class=Mock(), transport=transport, _cache=TokenCache()
     )
     with pytest.raises(ClientAuthenticationError, match=r".*browser.*"):
         credential.get_token("scope")
@@ -313,11 +314,25 @@ def test_no_browser():
 def test_cannot_bind_port():
     """get_token should raise CredentialUnavailableError when the redirect listener can't bind a port"""
 
-    credential = InteractiveBrowserCredential(server_class=Mock(side_effect=socket.error))
+    credential = InteractiveBrowserCredential(_server_class=Mock(side_effect=socket.error))
     with pytest.raises(CredentialUnavailableError):
         credential.get_token("scope")
 
 
+def test_cannot_bind_redirect_uri():
+    """When a user specifies a redirect URI, the credential shouldn't attempt to bind another"""
+
+    expected_uri = "http://localhost:42"
+
+    server = Mock(side_effect=socket.error)
+    credential = InteractiveBrowserCredential(redirect_uri=expected_uri, _server_class=server)
+
+    with pytest.raises(CredentialUnavailableError):
+        credential.get_token("scope")
+
+    server.assert_called_once_with(expected_uri, timeout=ANY)
+
+
 def _validate_auth_request_url(url):
     parsed_url = urllib_parse.urlparse(url)
     params = urllib_parse.parse_qs(parsed_url.query)