Flask-Pbj provides support for Google Protocol Buffers and json formatted request and response data. The api decorator serializes and deserializes json or protobuf formatted messages to and from a python dictionary.
Flask Peanut Butter and Jelly to simplifies the creation of REST APIs for C++ clients. Flask-pbj decorated app.routes accept and return protobuf messages or JSON. The JSON is useful for debugging and public API's while Google Protobuf is a well-documented compact and efficient format, particularly useful for C++/Python communication.
example_messages.proto
message Person {
required int32 id = 1;
required string name = 2;
optional string email = 3;
}
message Team {
required int32 id = 1;
required string name = 2;
required Person leader = 3
repeated Person members = 4;
}
app.py
# The route function can access the added request.data_dict data member for
# input and return a dictionary for output. The client's accept and
# content-type headers determine the format of the messages.
# Similar to flask, routes can avoid pbjs response serialization by directly
# returning a flask.Response object.
@app.route('/teams', methods=['POST'])
@api(json, protobuf(receives=Person, sends=Team, errors=Error))
def create_team():
leader = request.data_dict
if len(leader['name']) < 3:
# Optionally, return a tuple of the form dict, status_code, headers
# A 4xx HTTP error will use the 'errors' protobuf message type
return {"errorMessage": "Name too short"}, 400
# For a 200 response, just return a dict
return {
'id': get_url(2),
'name': "{0}'s Team".format(leader['name']),
'leader': get_url(person[id]),
'members': [],
}Create a team with JSON:
curl -X POST -H "Accept: application/json" \
-H "Content-type: application/json" \
http://127.0.0.1:5000/teams --data {'id': 1, 'name': 'Red Leader'}
{
"id": 2,
"name": "Red Leader's Team",
"leader": "/people/1"
"members": []
}
Create a new team with google protobuf:
# Create and save a Person structure in python
from example_messages_pb2 import Person
leader = Person()
leader.id = 1
leader.name = 'Red Leader'
with open('person.pb', 'wb') as f:
f.write(leader.SerializeToString())curl -X POST -H "Accept: application/x-protobuf" \
-H "Content-type: application/x-protobuf" \
http://127.0.0.1:5000/teams --data-binary @person.pb > team.pb
Codecs are classes see JsonCodec and ProtobufCodec for examples