How to save data in Mongo?

[oskar-gmerek]

• FastAPI Contrib version: 0.2.7
• FastAPI version: 0.59.0
• Python version: 3.7.7
• Operating System: MacOS

Description

Hello. I was looking for tools with what will be possible to play FastAPI with MongoDB in nice, simple way, because I never before using NoSQL. I found FastAPI_Contrib, my attention takes especially two of features:

1. ModelSerializers: serialize (pydantic) incoming request, connect data with DB model and save

2. MongoDB integration: Use models as if it was Django (based on pydantic models)

I was trying all day to understand the documentation how to use FastAPI_Contrib, unfortunately documentation is so hard for entry-level users. What I want to achieve at this time is nothing more than just:

1. Create Model
2. Create Serializer
3. Send the request with data from for example Postman
4. Save that data in MongoDB

Just a first step of CRUD...

What I Did

I was trying take it in very different ways, but for this issue I will present the most simply way based on documentation...

Project Structure:
project/
- project/
-- sample/
--- __init__.py
--- serializers.py
- __init__.py
- main.py

project/main.py:

import os

from fastapi_contrib.db.utils import setup_mongodb, create_indexes
import motor.motor_asyncio
from fastapi import FastAPI
from dotenv import load_dotenv

from project.serializers import sample_router

load_dotenv(verbose=True)
DATABASE_URL =os.getenv("DB_URL")

SECRET = os.getenv("SECRET")

CONTRIB_APPS = os.getenv("CONTRIB_APPS")
CONTRIB_APPS_FOLDER_NAME = os.getenv("CONTRIB_APPS_FOLDER_NAME")

client = motor.motor_asyncio.AsyncIOMotorClient(
    DATABASE_URL, uuidRepresentation="standard"
)
db = client["sample"]

app = FastAPI()

@app.on_event("startup")
async def startup():
    setup_mongodb(db)
    await create_indexes()
    print('Is it connected to DB?')

app.include_router(sample_router)

project/sample/serializers.py

from fastapi import APIRouter
from fastapi_contrib.db.models import MongoDBModel
from fastapi_contrib.serializers import openapi
from fastapi_contrib.serializers.common import Serializer

# from yourapp.models import SomeModel

sample_router = APIRouter()


class SomeModel(MongoDBModel):
    field1: str

    class Meta:
        collection = "test"


@openapi.patch
class SomeSerializer(Serializer):
    read_only1: str = "const"
    write_only2: int
    not_visible: str = "42"

    class Meta:
        model = SomeModel
        exclude = {"not_visible"}
        write_only_fields = {"write_only2"}
        read_only_fields = {"read_only1"}


@sample_router.post("/test/", response_model=SomeSerializer.response_model)
async def root(serializer: SomeSerializer):
    model_instance = await serializer.save()
    return model_instance.dict()

When I send data as POST to /test/ from postman

{
  "write_only2": 2,
  "field1": "string"
}

or by curl

curl -X POST "http://127.0.0.1:8000/test/" -H  "accept: application/json" -H  "Content-Type: application/json" -d "{\"id\":0,\"field1\":\"string\",\"write_only2\":0}"

Then I got errors:

if I will remove:

    class Meta:
        collection = "test"

as it in an example in documentation then I got other error:

I will be grateful if someone will explain to me using simple examples how to properly combine models, serializers, and perform CRUD operations on them reflected in MongoDB.

By the way.
I think is it good idea to rewrite documentation to be more affordable to not so advenced users. And add to them a tutorial, awesome will be to see there real world examples. I think, good documentation can make this package a very popular.

Regards,
Oskar

[ilias-ant]

I also had a similar problem, resulting in AttributeError: 'NoneType' object has no attribute 'split' - it will be awesome if we can get some guidance on this.

[smeggingsmegger]

Hey all, I forked, dove-in, and figured it out. You need an ENV variable called CONTRIB_FASTAPI_APP and it needs to be whatever your fastapi main app is in dot notation as a string.

i.e. Mine is 'main.app'

os.environ['CONTRIB_FASTAPI_APP'] = 'main.app' to test.

[levchik]

Yeah guys, sorry that this is not in the docs. Hopefully I will have time soon to update descriptions on how everything works in various topics. And @smeggingsmegger thanks for the help here!