How do I return HTTP error code without default template in Tornado?

Question

I am currently using the following to raise a HTTP bad request:

raise tornado.web.HTTPError(400)

which returns a html output:

&         


        

Answer 1

For json error response i use follow template:

Request handler:

import json
from tornado.web import RequestHandler
from src.lib.errors import HTTPBadRequest


class JsonHandler(RequestHandler):

    def prepare(self):
        content_type = ''
        if "Content-Type" in self.request.headers:
            content_type = self.request.headers['Content-Type']

        if content_type == 'application/json':
            try:
                self.request.body = json.loads(self.request.body.decode('utf-8'))
            except ValueError:
                raise HTTPBadRequest

    def write_error(self, *args, **kwargs):
        err_cls, err, traceback = kwargs['exc_info']
        self.set_status(err.status_code)
        if err.description:
            self.write_json(err.description)
        self.finish()

    def set_default_headers(self):
        self.set_header('Content-Type', 'application/json')

    def write_json(self, response):
        self.write(json.dumps(response))

Errors handler:

from typing import Any
from tornado import httputil


class BaseHTTPError(Exception):
    def __init__(
        self, status_code: int = 500, description=None, *args: Any, **kwargs: Any
    ) -> None:
        if description is None:
            description = {}
        self.status_code = status_code
        self.description = description
        self.args = args
        self.kwargs = kwargs

    def __str__(self) -> str:
        message = "HTTP %d: %s" % (
            self.status_code,
            httputil.responses.get(self.status_code, "Unknown"),
        )
        return message


class HTTPBadRequest(BaseHTTPError):
    def __init__(self, *args, **kwargs):
        super().__init__(status_code=400, description={"error": "Bad Request"}, *args, **kwargs)