How to POST JSON data with Python Requests?

I need to POST a JSON from a client to a server. I’m using Python 2.7.1 and simplejson. The client is using Requests. The server is CherryPy. I can GET a hard-coded JSON from the server (code not shown), but when I try to POST a JSON to the server, I get “400 Bad Request”.

Here is my client code:

data = {'sender':   'Alice',
    'receiver': 'Bob',
    'message':  'We did it!'}
data_json = simplejson.dumps(data)
payload = {'json_payload': data_json}
r = requests.post("http://localhost:8080", data=payload)

Here is the server code.

class Root(object):

    def __init__(self, content):
        self.content = content
        print self.content  # this works

    exposed = True

    def GET(self):
        cherrypy.response.headers['Content-Type'] = 'application/json'
        return simplejson.dumps(self.content)

    def POST(self):
        self.content = simplejson.loads(cherrypy.request.body.read())

Any ideas?

Starting with Requests version 2.4.2, you can use the json= parameter (which takes a dictionary) instead of data= (which takes a string) in the call:

>>> import requests
>>> r = requests.post('http://httpbin.org/post', json={"key": "value"})
>>> r.status_code
200
>>> r.json()
{'args': {},
 'data': '{"key": "value"}',
 'files': {},
 'form': {},
 'headers': {'Accept': '*/*',
             'Accept-Encoding': 'gzip, deflate',
             'Connection': 'close',
             'Content-Length': '16',
             'Content-Type': 'application/json',
             'Host': 'httpbin.org',
             'User-Agent': 'python-requests/2.4.3 CPython/3.4.0',
             'X-Request-Id': 'xx-xx-xx'},
 'json': {'key': 'value'},
 'origin': 'x.x.x.x',
 'url': 'http://httpbin.org/post'}

It turns out I was missing the header information. The following works:

import requests

url = "http://localhost:8080"
data = {'sender': 'Alice', 'receiver': 'Bob', 'message': 'We did it!'}
headers = {'Content-type': 'application/json', 'Accept': 'text/plain'}
r = requests.post(url, data=json.dumps(data), headers=headers)

From requests 2.4.2 (https://pypi.python.org/pypi/requests), the “json” parameter is supported. No need to specify “Content-Type”. So the shorter version:

requests.post('http://httpbin.org/post', json={'test': 'cheers'})

Which parameter between data / json / files you need to use depends on a request header named Content-Type (you can check this through the developer tools of your browser).

When the Content-Type is application/x-www-form-urlencoded, use data=:

requests.post(url, data=json_obj)

When the Content-Type is application/json, you can either just use json= or use data= and set the Content-Type yourself:

requests.post(url, json=json_obj)

requests.post(url, data=jsonstr, headers={"Content-Type":"application/json"})

When the Content-Type is multipart/form-data, it’s used to upload files, so use files=:

requests.post(url, files=xxxx)

The better way is：

url = "http://xxx.xxxx.xx"
data = {
    "cardno": "6248889874650987",
    "systemIdentify": "s08",
    "sourceChannel": 12
}
resp = requests.post(url, json=data)

headers = {"charset": "utf-8", "Content-Type": "application/json"}
url = 'http://localhost:PORT_NUM/FILE.php'

r = requests.post(url, json=YOUR_JSON_DATA, headers=headers)
print(r.text)

Works perfectly with python 3.5+

client:

import requests
data = {'sender':   'Alice',
    'receiver': 'Bob',
    'message':  'We did it!'}
r = requests.post("http://localhost:8080", json={'json_payload': data})

server:

class Root(object):

    def __init__(self, content):
        self.content = content
        print self.content  # this works

    exposed = True

    def GET(self):
        cherrypy.response.headers['Content-Type'] = 'application/json'
        return simplejson.dumps(self.content)

    @cherrypy.tools.json_in()
    @cherrypy.tools.json_out()
    def POST(self):
        self.content = cherrypy.request.json
        return {'status': 'success', 'message': 'updated'}

I solved it this way:

from flask import Flask, request
from flask_restful import Resource, Api


req = request.json
if not req :
    req = request.form
req['value']

With current requests you can pass in any data structure that dumps to valid JSON , with the json parameter, not just dictionaries (as falsely claimed by the answer by Zeyang Lin).

import requests
r = requests.post('http://httpbin.org/post', json=[1, 2, {"a": 3}])

this is particularly useful if you need to order elements in the response.

It always recommended that we need to have the ability to read the JSON file and parse an object as a request body. We are not going to parse the raw data in the request so the following method will help you to resolve it.

def POST_request():
    with open("FILE PATH", "r") as data:
        JSON_Body = data.read()
    response = requests.post(url="URL", data=JSON_Body)
    assert response.status_code == 200