Use custom JSON encoder for Flask

2 files changed, 14 insertions, 0 deletions

diff --git a/api/main.py b/api/main.py
index 7544333a..46782638 100755
--- a/api/main.py
+++ b/api/main.py
@@ -15,6 +15,7 @@ from oauth2client import client, crypt
 from opendc.models.user import User
 from opendc.util import rest, path_parser, database
 from opendc.util.exceptions import AuthorizationTokenError, RequestInitializationError
+from opendc.util.json import JSONEncoder
 
 load_dotenv()
 
@@ -31,6 +32,7 @@ if not TEST_MODE:
 # Set up the core app
 FLASK_CORE_APP = Flask(__name__)
 FLASK_CORE_APP.config['SECRET_KEY'] = os.environ['OPENDC_FLASK_SECRET']
+FLASK_CORE_APP.json_encoder = JSONEncoder
 
 # Set up CORS support for local setups
 if 'localhost' in os.environ['OPENDC_SERVER_BASE_URL']:
diff --git a/api/opendc/util/json.py b/api/opendc/util/json.py
new file mode 100644
index 00000000..2ef4f965
--- /dev/null
+++ b/api/opendc/util/json.py
@@ -0,0 +1,12 @@
+import flask
+from bson.objectid import ObjectId
+
+
+class JSONEncoder(flask.json.JSONEncoder):
+    """
+    A customized JSON encoder to handle unsupported types.
+    """
+    def default(self, o):
+        if isinstance(o, ObjectId):
+            return str(o)
+        return flask.json.JSONEncoder.default(self, o)