Tornado application/json support

Question

Does Tornado support Content-Type "application/json"?

According to the call stack (assuming stream_request_body = False), the only method called to parse the request body is parse_body_arguments (httputil.py 662), which only accepts "application/x-www-form-urlencoded" and "multipart/form-data"

Answer 1

The solution is pretty trivial. You just have to json.loads() the received body and trust that it's a proper JSON-encoded dictionary (if you want, catch the exception and provide meaningful feedback). You can't expect application/json to be in the Content-Type; during a POST that'll already be application/x-www-form-urlencoded.

Here is a sample server:

import json
import tornado.httpserver
import tornado.ioloop
import tornado.web

class MyHandler(tornado.web.RequestHandler):
    def post(self):
        data = json.loads(self.request.body.decode('utf-8'))
        print('Got JSON data:', data)
        self.write({ 'got' : 'your data' })

if __name__ == '__main__':
    app = tornado.web.Application([ tornado.web.url(r'/', MyHandler) ])
    http_server = tornado.httpserver.HTTPServer(app)
    http_server.listen(8888)
    print('Starting server on port 8888')
    tornado.ioloop.IOLoop.instance().start()

You can test this using e.g. curl:

curl -H 'Content-Type: application/json' -d '{"hello": "world"}' http://localhost:8888/