fastapi form data with pydantic model

Question

I am trying to submit data from html forms and on the validate it with pydantic model.
Using this code

from fastapi import FastAPI, Form
from pydantic im         


        

Answer 1

I found a solution which can help us to use FastAPI forms as pydantic as well :)
My code:

class AnyForm(BaseModel):
    any_param: str
    any_other_param: int = 1

    @classmethod
    def as_form(
        cls,
        any_param: str = Form(...),
        any_other_param: int = Form(1)
    ) -> AnyForm:
        return cls(any_param=any_param, any_other_param=any_other_param)

@router.post('')
async def any_view(form_data: AnyForm = Depends(AnyForm.as_form)):
        ...

It's showed in the swagger as usual form
I think, it can be written more generic, maybe I will return and edit the answer.

[UPDATED]

I've written it more generic as a decorator

import inspect
from typing import Type

from fastapi import Form
from pydantic import BaseModel
from pydantic.fields import ModelField

def as_form(cls: Type[BaseModel]):
    new_parameters = []

    for field_name, model_field in cls.__fields__.items():
        model_field: ModelField  # type: ignore

        if not model_field.required:
            new_parameters.append(
                inspect.Parameter(
                    model_field.alias,
                    inspect.Parameter.POSITIONAL_ONLY,
                    default=Form(model_field.default),
                    annotation=model_field.outer_type_,
                )
            )
        else:
            new_parameters.append(
                inspect.Parameter(
                    model_field.alias,
                    inspect.Parameter.POSITIONAL_ONLY,
                    default=Form(...),
                    annotation=model_field.outer_type_,
                )
            )

    async def as_form_func(**data):
        return cls(**data)

    sig = inspect.signature(as_form_func)
    sig = sig.replace(parameters=new_parameters)
    as_form_func.__signature__ = sig  # type: ignore
    setattr(cls, 'as_form', as_form_func)
    return cls

And usage looks like

class Test1(BaseModel):
    a: str
    b: int


@as_form
class Test(BaseModel):
    param: str
    test: List[Test1]
    test1: Test1
    b: int = 1
    a: str = '2342'


@router.post('/me', response_model=Test)
async def me(request: Request, form: Test = Depends(Test.as_form)):
    return form

Answer 2

you can use data-form like below:

@app.post("/form", response_model=SimpleModel)
def form_post(no: int = Form(...),nm: str = Form(...)):
    return SimpleModel(no=no,nm=nm)

Answer 3

If you're only looking at abstracting the form data into a class you can do it with a plain class

from fastapi import Form, Depends

class AnyForm:
    def __init__(self, any_param: str = Form(...), any_other_param: int = Form(1)):
        self.any_param = any_param
        self.any_other_param = any_other_param

    def __str__(self):
        return "AnyForm " + str(self.__dict__)

@app.post('/me')
async def me(form: AnyForm = Depends()):
    print(form)
    return form

And it can also be turned into a Pydantic Model

from uuid import UUID, uuid4
from fastapi import Form, Depends
from pydantic import BaseModel

class AnyForm(BaseModel):
    id: UUID
    any_param: str
    any_other_param: int

    def __init__(self, any_param: str = Form(...), any_other_param: int = Form(1)):
        id = uuid4()
        super().__init__(id, any_param, any_other_param)

@app.post('/me')
async def me(form: AnyForm = Depends()):
    print(form)
    return form