How to send integer in POST to Tornado's AsyncHTTPTestCase.fetch()?

Question

I'm using python's Tornado framework to test my HTTP POST endpoint. To do this, I'm using the fetch method.

    data = urllib.urlencode({
        'integer_arg': 1,
        'string_arg': 'hello'
    })

    resp = AsyncHTTPTestCase.fetch('/endpoint', 
                                   method='POST',
                                   headers={'h1': 'H1', 
                                            'h2': 'H2',
                                            'Content-Type': 'application/json'}, 
                                   body=data)

When I do this, the endpoint receives integer_arg as the string "1" even though I want it to receive it as an integer. This is understandable because urllib.urlencode converts it to a string. So how can I ensure it receives an integer? Just eliminating the call to urllib.urlencode doesn't work.

By the way, when I hit the same endpoint with a naked curl call as shown below, the endpoint properly receives integer_arg as the integer 1.

curl \
--request POST \
--header "h1: H1" \
--header "h2: H2" \
--header "Content-Type: application/json" \
--data '{
    "integer_arg": 1, 
    "string_arg": "hello"
}' \
"http://localhost:8000/endpoint"

Answer 1

The body in curl is significantly different than that in AsyncHTTPClient.fetch. With python you urlencode the data in curl there is just json. So simply change urlencode with json.dumps:

import json
from tornado.ioloop import IOLoop
from tornado.httpclient import AsyncHTTPClient
from tornado.gen import coroutine

@coroutine
def main():
    client = AsyncHTTPClient()
    body = json.dumps({
        'integer_arg': 1,
        'string_arg': 'hello'
    })
    yield client.fetch(
        '/endpoint', method='POST', body=body,
         headers={'h1': 'H1',  'h2': 'H2', 'Content-Type': 'application/json'}
    )

ioloop = IOLoop.instance()
ioloop.run_sync(main)