1 files changed, 141 insertions, 0 deletions
diff --git a/api/opendc/util/rest.py b/api/opendc/util/rest.py
new file mode 100644
index 00000000..abd2f3de
--- /dev/null
+++ b/api/opendc/util/rest.py
@@ -0,0 +1,141 @@
+import importlib
+import json
+import os
+
+from oauth2client import client, crypt
+
+from opendc.util import exceptions, parameter_checker
+from opendc.util.exceptions import ClientError
+
+
+class Request:
+    """WebSocket message to REST request mapping."""
+    def __init__(self, message=None):
+        """"Initialize a Request from a socket message."""
+
+        # Get the Request parameters from the message
+
+        if message is None:
+            return
+
+        try:
+            self.message = message
+
+            self.id = message['id']
+
+            self.path = message['path']
+            self.method = message['method']
+
+            self.params_body = message['parameters']['body']
+            self.params_path = message['parameters']['path']
+            self.params_query = message['parameters']['query']
+
+            self.token = message['token']
+
+        except KeyError as exception:
+            raise exceptions.MissingRequestParameterError(exception)
+
+        # Parse the path and import the appropriate module
+
+        try:
+            self.path = message['path'].strip('/')
+
+            module_base = 'opendc.api.{}.endpoint'
+            module_path = self.path.replace('{', '').replace('}', '').replace('/', '.')
+
+            self.module = importlib.import_module(module_base.format(module_path))
+        except ImportError as e:
+            print(e)
+            raise exceptions.UnimplementedEndpointError('Unimplemented endpoint: {}.'.format(self.path))
+
+        # Check the method
+
+        if self.method not in ['POST', 'GET', 'PUT', 'PATCH', 'DELETE']:
+            raise exceptions.UnsupportedMethodError('Non-rest method: {}'.format(self.method))
+
+        if not hasattr(self.module, self.method):
+            raise exceptions.UnsupportedMethodError('Unimplemented method at endpoint {}: {}'.format(
+                self.path, self.method))
+
+        # Verify the user
+
+        if "OPENDC_FLASK_TESTING" in os.environ:
+            self.google_id = 'test'
+            return
+
+        try:
+            self.google_id = self._verify_token(self.token)
+        except crypt.AppIdentityError as e:
+            raise exceptions.AuthorizationTokenError(e)
+
+    def check_required_parameters(self, **kwargs):
+        """Raise an error if a parameter is missing or of the wrong type."""
+
+        try:
+            parameter_checker.check(self, **kwargs)
+        except exceptions.ParameterError as e:
+            raise ClientError(Response(400, str(e)))
+
+    def process(self):
+        """Process the Request and return a Response."""
+
+        method = getattr(self.module, self.method)
+
+        try:
+            response = method(self)
+        except ClientError as e:
+            e.response.id = self.id
+            return e.response
+
+        response.id = self.id
+
+        return response
+
+    def to_JSON(self):
+        """Return a JSON representation of this Request"""
+
+        self.message['id'] = 0
+        self.message['token'] = None
+
+        return json.dumps(self.message)
+
+    @staticmethod
+    def _verify_token(token):
+        """Return the ID of the signed-in user.
+
+        Or throw an Exception if the token is invalid.
+        """
+
+        try:
+            id_info = client.verify_id_token(token, os.environ['OPENDC_OAUTH_CLIENT_ID'])
+        except Exception as e:
+            print(e)
+            raise crypt.AppIdentityError('Exception caught trying to verify ID token: {}'.format(e))
+
+        if id_info['aud'] != os.environ['OPENDC_OAUTH_CLIENT_ID']:
+            raise crypt.AppIdentityError('Unrecognized client.')
+
+        if id_info['iss'] not in ['accounts.google.com', 'https://accounts.google.com']:
+            raise crypt.AppIdentityError('Wrong issuer.')
+
+        return id_info['sub']
+
+
+class Response:
+    """Response to websocket mapping"""
+    def __init__(self, status_code, status_description, content=None):
+        """Initialize a new Response."""
+
+        self.id = 0
+        self.status = {'code': status_code, 'description': status_description}
+        self.content = content
+
+    def to_JSON(self):
+        """"Return a JSON representation of this Response"""
+
+        data = {'id': self.id, 'status': self.status}
+
+        if self.content is not None:
+            data['content'] = self.content
+
+        return json.dumps(data)