Python requests.post() returns None

Question

I know that this issue was discussed earlier but I am unable to find a working solution that fits my use case.

We have an internal server (sorry, no external address available) that returns data. Invoking a POST Method on the Endpoint returns a JSON. I tried the post with the Postman tool to check a valid response is received. When using a Postman I receive the response as expected. An authentication is not necessary.

However, Python Client fails to return data and an empty response is received.

code snippet :

import json
import requests

URL_PATH = "https://our.internal.server.rest.address"
HEADERS = {
    'Content-Type': 'application/json'
}

DATA = '''{
    "method"  : "object.read",
    "params"  : "",
    "id"      : 142
}'''

S = requests.session()
R = S.post(URL_PATH, headers=HEADERS, json=DATA)

if R.ok:
    print("Type: ", R.headers["Content-Type"])
    print("Text: ", str(R.text))
    print("JSON: ", R.json())
    print("Content", R.content)
else:
    R.raise_for_status()

S.close()

The output is:

Type: application/json
Text: null
JSON: None
Content b'null'

Any idea what I'm doing wrong with my Python code and why there is no data returned, but is when using a separate tool?

I also tried to use data= in the post():

S.post(URL_PATH, headers=HEADERS, data=json.dumps(DATA))

or skip the Session() by directly using requests.post().

Answer 1

1) Trying out the same code with different endpoint works.

This means that the exact parameters sent in the Postman are not added in the client.

Try using a Apache tcpmon https://ws.apache.org/tcpmon/ to snoop the request from post man and the python client.

This will help you identify the missing parameters.

Answer 2

我相信你的DATA变量应该是一个字典而不是一个字符串？

Answer 3

Thank your all for your quick support. This is the final version that works well!

import json
import requests

URL_PATH = "https://our.internal.server.rest.address"
HEADERS = {
    'Content-Type': 'application/json'
}

DATA = {
    "method"  : "object.read",
    "params"  : "",
    "id"      : 142
}

# R = requests.request("POST", URL_PATH, data=payload, headers=HEADERS)  # suggested by Postman
R = requests.post(URL_PATH, json=DATA, headers=HEADERS)

if R.ok:
    print("JSON: ", R.json())
else:
    R.raise_for_status()

Answer 4

I had the same problem getting the response and I tried a whole bunch of things. By it turned out to be the problem with the data format. The response was null (with status code 200) when I send the dictionary directly. When I send a json string as data, I am getting the response as expected.

import json

DATA = {
    "method"  : "object.read",
    "params"  : "",
    "id"      : 142
}

# R = requests.request("POST", URL_PATH, data=payload, headers=HEADERS)  # suggested by Postman
R = requests.post(URL_PATH, json=json.dumps(DATA), headers=HEADERS)