fix(rtdb): Support parsing non-US RTDB instance URLs (#517)

* fix(rtdb): Support parsing non-US RTDB instance URLs

* fix: Deferred credential loading until emulator URL is determined

Author: hiranya911

firebase_admin/db.py

@@ -768,10 +768,10 @@ def __init__(self, app):
         self._credential = app.credential
         db_url = app.options.get('databaseURL')
         if db_url:
-            _DatabaseService._parse_db_url(db_url)  # Just for validation.
             self._db_url = db_url
         else:
             self._db_url = None
+
         auth_override = _DatabaseService._get_auth_override(app)
         if auth_override not in (self._DEFAULT_AUTH_OVERRIDE, {}):
             self._auth_override = json.dumps(auth_override, separators=(',', ':'))
@@ -795,15 +795,29 @@ def get_client(self, db_url=None):
         if db_url is None:
             db_url = self._db_url
 
-        base_url, namespace = _DatabaseService._parse_db_url(db_url, self._emulator_host)
-        if base_url == 'https://{0}.firebaseio.com'.format(namespace):
-            # Production base_url. No need to specify namespace in query params.
-            params = {}
-            credential = self._credential.get_credential()
-        else:
-            # Emulator base_url. Use fake credentials and specify ?ns=foo in query params.
+        if not db_url or not isinstance(db_url, str):
+            raise ValueError(
+                'Invalid database URL: "{0}". Database URL must be a non-empty '
+                'URL string.'.format(db_url))
+
+        parsed_url = parse.urlparse(db_url)
+        if not parsed_url.netloc:
+            raise ValueError(
+                'Invalid database URL: "{0}". Database URL must be a wellformed '
+                'URL string.'.format(db_url))
+
+        emulator_config = self._get_emulator_config(parsed_url)
+        if emulator_config:
             credential = _EmulatorAdminCredentials()
-            params = {'ns': namespace}
+            base_url = emulator_config.base_url
+            params = {'ns': emulator_config.namespace}
+        else:
+            # Defer credential lookup until we are certain it's going to be prod connection.
+            credential = self._credential.get_credential()
+            base_url = 'https://{0}'.format(parsed_url.netloc)
+            params = {}
+
+
         if self._auth_override:
             params['auth_variable_override'] = self._auth_override
 
@@ -813,47 +827,20 @@ def get_client(self, db_url=None):
             self._clients[client_cache_key] = client
         return self._clients[client_cache_key]
 
-    @classmethod
-    def _parse_db_url(cls, url, emulator_host=None):
-        """Parses (base_url, namespace) from a database URL.
-
-        The input can be either a production URL (https://foo-bar.firebaseio.com/)
-        or an Emulator URL (http://localhost:8080/?ns=foo-bar). In case of Emulator
-        URL, the namespace is extracted from the query param ns. The resulting
-        base_url never includes query params.
-
-        If url is a production URL and emulator_host is specified, the result
-        base URL will use emulator_host instead. emulator_host is ignored
-        if url is already an emulator URL.
-        """
-        if not url or not isinstance(url, str):
-            raise ValueError(
-                'Invalid database URL: "{0}". Database URL must be a non-empty '
-                'URL string.'.format(url))
-        parsed_url = parse.urlparse(url)
-        if parsed_url.netloc.endswith('.firebaseio.com'):
-            return cls._parse_production_url(parsed_url, emulator_host)
-
-        return cls._parse_emulator_url(parsed_url)
-
-    @classmethod
-    def _parse_production_url(cls, parsed_url, emulator_host):
-        """Parses production URL like https://foo-bar.firebaseio.com/"""
+    def _get_emulator_config(self, parsed_url):
+        """Checks whether the SDK should connect to the RTDB emulator."""
+        EmulatorConfig = collections.namedtuple('EmulatorConfig', ['base_url', 'namespace'])
         if parsed_url.scheme != 'https':
-            raise ValueError(
-                'Invalid database URL scheme: "{0}". Database URL must be an HTTPS URL.'.format(
-                    parsed_url.scheme))
-        namespace = parsed_url.netloc.split('.')[0]
-        if not namespace:
-            raise ValueError(
-                'Invalid database URL: "{0}". Database URL must be a valid URL to a '
-                'Firebase Realtime Database instance.'.format(parsed_url.geturl()))
+            # Emulator mode enabled by passing http URL via AppOptions
+            base_url, namespace = _DatabaseService._parse_emulator_url(parsed_url)
+            return EmulatorConfig(base_url, namespace)
+        if self._emulator_host:
+            # Emulator mode enabled via environment variable
+            base_url = 'http://{0}'.format(self._emulator_host)
+            namespace = parsed_url.netloc.split('.')[0]
+            return EmulatorConfig(base_url, namespace)
 
-        if emulator_host:
-            base_url = 'http://{0}'.format(emulator_host)
-        else:
-            base_url = 'https://{0}'.format(parsed_url.netloc)
-        return base_url, namespace
+        return None
 
     @classmethod
     def _parse_emulator_url(cls, parsed_url):

tests/test_db.py

@@ -15,6 +15,7 @@
 """Tests for firebase_admin.db."""
 import collections
 import json
+import os
 import sys
 import time
 
@@ -28,6 +29,9 @@
 from tests import testutils
 
 
+_EMULATOR_HOST_ENV_VAR = 'FIREBASE_DATABASE_EMULATOR_HOST'
+
+
 class MockAdapter(testutils.MockAdapter):
     """A mock HTTP adapter that mimics RTDB server behavior."""
 
@@ -702,52 +706,70 @@ def test_no_db_url(self):
         'url,emulator_host,expected_base_url,expected_namespace',
         [
             # Production URLs with no override:
-            ('https://test.firebaseio.com', None, 'https://test.firebaseio.com', 'test'),
-            ('https://test.firebaseio.com/', None, 'https://test.firebaseio.com', 'test'),
+            ('https://test.firebaseio.com', None, 'https://test.firebaseio.com', None),
+            ('https://test.firebaseio.com/', None, 'https://test.firebaseio.com', None),
 
             # Production URLs with emulator_host override:
             ('https://test.firebaseio.com', 'localhost:9000', 'http://localhost:9000', 'test'),
             ('https://test.firebaseio.com/', 'localhost:9000', 'http://localhost:9000', 'test'),
 
-            # Emulator URLs with no override.
+            # Emulator URL with no override.
             ('http://localhost:8000/?ns=test', None, 'http://localhost:8000', 'test'),
+
             # emulator_host is ignored when the original URL is already emulator.
             ('http://localhost:8000/?ns=test', 'localhost:9999', 'http://localhost:8000', 'test'),
         ]
     )
     def test_parse_db_url(self, url, emulator_host, expected_base_url, expected_namespace):
-        base_url, namespace = db._DatabaseService._parse_db_url(url, emulator_host)
-        assert base_url == expected_base_url
-        assert namespace == expected_namespace
-
-    @pytest.mark.parametrize('url,emulator_host', [
-        ('', None),
-        (None, None),
-        (42, None),
-        ('test.firebaseio.com', None),  # Not a URL.
-        ('http://test.firebaseio.com', None),  # Use of non-HTTPs in production URLs.
-        ('ftp://test.firebaseio.com', None),  # Use of non-HTTPs in production URLs.
-        ('https://example.com', None),  # Invalid RTDB URL.
-        ('http://localhost:9000/', None),  # No ns specified.
-        ('http://localhost:9000/?ns=', None),  # No ns specified.
-        ('http://localhost:9000/?ns=test1&ns=test2', None),  # Two ns parameters specified.
-        ('ftp://localhost:9000/?ns=test', None),  # Neither HTTP or HTTPS.
+        if emulator_host:
+            os.environ[_EMULATOR_HOST_ENV_VAR] = emulator_host
+
+        try:
+            firebase_admin.initialize_app(testutils.MockCredential(), {'databaseURL' : url})
+            ref = db.reference()
+            assert ref._client._base_url == expected_base_url
+            assert ref._client.params.get('ns') == expected_namespace
+            if expected_base_url.startswith('http://localhost'):
+                assert isinstance(ref._client.credential, db._EmulatorAdminCredentials)
+            else:
+                assert isinstance(ref._client.credential, testutils.MockGoogleCredential)
+        finally:
+            if _EMULATOR_HOST_ENV_VAR in os.environ:
+                del os.environ[_EMULATOR_HOST_ENV_VAR]
+
+    @pytest.mark.parametrize('url', [
+        '',
+        None,
+        42,
+        'test.firebaseio.com',  # Not a URL.
+        'http://test.firebaseio.com',  # Use of non-HTTPs in production URLs.
+        'ftp://test.firebaseio.com',  # Use of non-HTTPs in production URLs.
+        'http://localhost:9000/',  # No ns specified.
+        'http://localhost:9000/?ns=',  # No ns specified.
+        'http://localhost:9000/?ns=test1&ns=test2',  # Two ns parameters specified.
+        'ftp://localhost:9000/?ns=test',  # Neither HTTP or HTTPS.
     ])
-    def test_parse_db_url_errors(self, url, emulator_host):
+    def test_parse_db_url_errors(self, url):
+        firebase_admin.initialize_app(testutils.MockCredential(), {'databaseURL' : url})
         with pytest.raises(ValueError):
-            db._DatabaseService._parse_db_url(url, emulator_host)
+            db.reference()
 
     @pytest.mark.parametrize('url', [
-        'https://test.firebaseio.com', 'https://test.firebaseio.com/'
+        'https://test.firebaseio.com', 'https://test.firebaseio.com/',
+        'https://test.eu-west1.firebasdatabase.app', 'https://test.eu-west1.firebasdatabase.app/'
     ])
     def test_valid_db_url(self, url):
         firebase_admin.initialize_app(testutils.MockCredential(), {'databaseURL' : url})
         ref = db.reference()
-        assert ref._client.base_url == 'https://test.firebaseio.com'
+        expected_url = url
+        if url.endswith('/'):
+            expected_url = url[:-1]
+        assert ref._client.base_url == expected_url
         assert 'auth_variable_override' not in ref._client.params
+        assert 'ns' not in ref._client.params
 
     @pytest.mark.parametrize('url', [
-        None, '', 'foo', 'http://test.firebaseio.com', 'https://google.com',
+        None, '', 'foo', 'http://test.firebaseio.com', 'http://test.firebasedatabase.app',
         True, False, 1, 0, dict(), list(), tuple(), _Object()
     ])
     def test_invalid_db_url(self, url):