README.md

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JDER FastAPI

A response builder for FastAPI.

Installation

Install this package as a dependency in the project:

This package requires fastapi to be installed.

# pip
pip install jder-fastapi

# uv
uv add jder-fastapi

# Pixi
pixi add --pypi jder-fastapi

Create a Success JSON Response

To create a JSON response without data, just use createJsonResponse function:

from fastapi import FastAPI
from fastapi.responses import Response
from jder_fastapi.responses.json import createJsonResponse

app: FastAPI = FastAPI()


@app.get("/")
async def route() -> Response:
    return createJsonResponse()

And the response will be shown as below:

{
    "success": true,
    "data": null,
    "errors": []
}

Create a Success JSON Response with Data

The createJsonResponse function can also be used to insert data to the response:

from fastapi import FastAPI
from fastapi.responses import Response
from jder_fastapi.responses.json import (
    createJsonResponse,
    createJsonSuccessResponseOptions,
)

app: FastAPI = FastAPI()


@app.get("/")
async def route() -> Response:
    return createJsonResponse(
        options=createJsonSuccessResponseOptions(
            data="Hello, World!",
        ),
    )

And the response will be shown as below:

{
    "success": true,
    "data": "Hello, World!",
    "errors": []
}

Create a Failure JSON response

To create a failure JSON response, add error field to the options:

from fastapi import FastAPI
from fastapi.responses import Response
from jder_fastapi.responses.json import (
    createJsonResponse,
    createJsonFailureResponseOptions,
    JsonResponseError,
)

app: FastAPI = FastAPI()


@app.get("/")
async def route() -> Response:
    return createJsonResponse(
        options=createJsonFailureResponseOptions(
            status=500,
            errors=[
                JsonResponseError(
                    code="server",
                ),
            ],
        ),
    )

And the response will be shown as below:

{
    "success": false,
    "data": null,
    "errors": [
        {
            "code": "server",
            "path": [],
            "message": null
        }
    ]
}

Combine additional headers from the response

To combine additional headers from the response, add response to the function:

from fastapi import FastAPI
from fastapi.responses import Response
from jder_fastapi.responses.json import (
    createJsonResponse,
    createJsonSuccessResponseOptions,
)

app: FastAPI = FastAPI()


@app.get("/")
async def route(res: Response) -> Response:
    
    res.headers["X-Test"] = "Hello, World!"

    return createJsonResponse(
        res,
        createJsonSuccessResponseOptions(
            data="Hello, World!",
        ),
    )

Create a Non-JSON response

To create a non-JSON response, use createResponse function:

from fastapi import FastAPI
from fastapi.responses import Response
from jder_fastapi.responses import (
    createResponse,
    createResponseOptions,
)

app: FastAPI = FastAPI()


@app.get("/")
async def route() -> Response:
    return createResponse(
        options=createResponseOptions(
            status=404,
            headers={
                "Content-Type": "text/plain",
            },
            body="Not Found",
        ),
    )

Request Validation Exception Handler

Enforce a validation exception handler to return a JSON response:

from fastapi import FastAPI
from fastapi.requests import Request
from fastapi.responses import Response
from fastapi.exceptions import RequestValidationError
from jder_fastapi.handlers import request_validation_exception_handler

app: FastAPI = FastAPI()


@app.exception_handler(RequestValidationError)
async def validation_exception_handler(
    req: Request,
    exc: RequestValidationError
) -> Response:
    return request_validation_exception_handler(req, exc)