main.py

from dataclasses import dataclass
from typing import Annotated, ClassVar, Iterator
from annotated_types import SLOTS, BaseMetadata, GroupedMetadata
from fastapi import FastAPI
from pydantic import ConfigDict, Field
from pydantic_forms.core import FormPage, post_form
from pydantic_forms.types import State
from pydantic_forms.exception_handlers.fastapi import form_error_handler
from pydantic_forms.exceptions import FormException
from pydantic_forms.core import FormPage as PydanticFormsFormPage
from pydantic_forms.types import JSON


class FormPage(PydanticFormsFormPage):
    meta__: ClassVar[JSON] = {"hasNext": True}


class SubmitFormPage(FormPage):
    meta__: ClassVar[JSON] = {"hasNext": False}


app = FastAPI()
app.add_exception_handler(FormException, form_error_handler)  # type: ignore[arg-type]


@app.get("/")
def read_root():
    return {"Hello": "World"}

@dataclass(frozen=True, **SLOTS)
class ExtraData(GroupedMetadata):
    props: dict

    def __iter__(self) -> Iterator[BaseMetadata]:
        yield Field(json_schema_extra=self.props)

@app.post("/form")
async def form(form_data: list[dict]=[]):
    def form_generator(state: State):
        class TestForm(FormPage):
            model_config = ConfigDict(title="Form Title")

            name: Annotated[str, Field(min_length=3)]
            # input: Annotated[str, ExtraData(props={"prop1": "val", "prop2": "val"})]

        form_data_1 = yield TestForm

        class TestForm2(SubmitFormPage):
            model_config = ConfigDict(title="Form 2 Title")

            name_2: str | None = None

        form_data_2 = yield TestForm2
        return form_data_1.model_dump() | form_data_2.model_dump()

    data = post_form(form_generator, state={}, user_inputs=form_data)
    return data