JoseKilo / web-error

Web based exceptions for JSON apis.

Web Errors v0.5.4

web_error is a set of exceptions and handlers for use in web apis to support easy error management and responses

Each exception easily marshals to JSON for use in api errors. Handlers for different web frameworks are provided.

Errors

The base web_error.error.HttpException accepts a message, debug_message, code and status (default 500)

And will render a response with status as the status code:

{
    "code": "code",
    "message": "message",
    "debug_message": "debug_message",
}

Some convenience Exceptions are provided, to create custom error subclass these and define message and code attributes.

• web_error.error.ServerException provides status 500 errors
• web_error.error.BadRequestException provides status 400 errors
• web_error.error.UnauthorisedException provides status 401 errors
• web_error.error.NotFoundException provides status 404 errors

Custom Errors

Subclassing the convenience classes provide a simple way to consistently raise the same error and message.

Code is an optional attribute to provide a unique value to parse in a frontend/client instead of matching against messages.

from web_error.error import NotFoundException


class UserNotFoundError(NotFoundException):
    message = "User not found."
    code = "E001"

FastAPI

Include the exception_handler in your app.

    exception_handler = web_error.handler.fastapi.exception_handler

    return FastAPI(
        exception_handlers={
            Exception: exception_handler,
            RequestValidationError: exception_handler,
            HTTPException: exception_handler,
        },
    )

Pyramid

Include the pyramid exception handlers in your config.

def main(global_config, **config_blob):
    config = Configurator(settings=config_blob)

    ...

    config.scan("web_error.handler.pyramid")

    return config.make_wsgi_app()

This will handle all unexpected errors, and any app specific errors.

@view_config(route_name="test", renderer="json")
def test(request):
    raise UserNotFoundError("debug message")

Flask

Register the error handler with your application

app.register_error_handler(Exception, web_error.handler.flask.exception_handler)

Aiohttp

Decorate your views with the error handler.

@web_error.handler.aiohttp.view_error_handler
async def user(self):
    raise UserNotFoundError("debug message")