[WIP] Filters in Automatic Endpoints

[igorbenav]

This is a work in progress, but it will close #15. This PR adds optional filters to automatic endpoints.

• [x] Create a class to validate passed filters
• [x] Validate that filters are indeed columns of the db
• [x] Create function to dynamically add filters to endpoints
• [x] Accept filter_config in both EndpointCreator and crud_router, dynamically add filters as query parameters
• [x] Decide whether get_multi and get_paginated only are changed by filter_config
• [x] Get the type of the query parameters and pass it to FastAPI
• [x] Tests covering changes
• [x] Documentation updates

The usage idea after it is merged is something like:

Passing Filters as a Dict to crud_router

from fastapi import FastAPI
from fastcrud import crud_router, FilterConfig
from myapp.models import MyModel
from myapp.schemas import CreateMyModel, UpdateMyModel
from myapp.database import async_session

app = FastAPI()

router = crud_router(
    session=async_session,
    model=MyModel,
    create_schema=CreateMyModel,
    update_schema=UpdateMyModel,
    filter_config=FilterConfig(filters={"id": None, "name": "default"})
)
# Adds CRUD routes with filtering capabilities
app.include_router(router, prefix="/mymodel")

Explanation:

• The FilterConfig specifies that 'id' should be a query parameter with no default value and 'name' should be a query parameter with a default value of 'default'.
• When fetching multiple items, you can filter by these parameters.
• Example GET request: /mymodel/get_multi?id=1&name=example

Passing Filters as Keyword Arguments to EndpointCreator

It's also possible to use FilterConfig with keyword arguments or with EndpointCreator instead of crud_router:

from fastapi import FastAPI
from fastcrud import EndpointCreator, FilterConfig
from myapp.models import MyModel
from myapp.schemas import CreateMyModel, UpdateMyModel
from myapp.database import async_session

app = FastAPI()

# Using FilterConfig with keyword arguments
endpoint_creator_kw = EndpointCreator(
    session=async_session,
    model=MyModel,
    create_schema=CreateMyModel,
    update_schema=UpdateMyModel,
    filter_config=FilterConfig(id=None, name="default")
)
# Adds CRUD routes with filtering capabilities
endpoint_creator_kw.add_routes_to_router()
# Include the internal router into the FastAPI app
app.include_router(endpoint_creator_kw.router, prefix="/mymodel")

Of course one could also pass as keyword arguments to crud_router or as a dict to EndpointCreator.

Notes:

• for this first version, get_multi and get_paginated only are getting filters. If people request, we may rethink this
• for now, we're also accepting a dict being passed instead of a FilterConfig

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[igorbenav]

Btw @AndreGuerra123 @samuel-favarin-dbc you guys might be interested in taking a look at this

[igorbenav]

@JakNowy not for this iteration, but for the next one we should get supported_filters list somewhere easy to access outside FastCRUD so we can also use advanced filters in the automatic endpoints.

[PaleNeutron]

The filter is wonderful! But can it be applied on joined models?

For example, filter user by user.company.name == 'A' ? Or filter company by user's name, company.users.any(User.name == 'B')