Does Python Requests POST need numerical data to be a string rather than a float?

Question

Here is a small quote from this answer:

import requests
import json

data = {"data" : "24.3"}
data_json = json.dumps(data)
headers = {'Content-type': 'application/json'}

response = requests.post(url, data=data_json, headers=headers)

Does anyone know for sure whether it matters whether you have

data = {"data" : "24.3"}

or

data = {"data" : 24.3} ?

Yes, both seem to work, am guessing it does not matter, but I do not have access to the other end where the post request is posting, so can't really see if it is processing it right, so thought I'd ask. — cardamom, Nov 24 '17 at 18:39
You are converting your data to a string *already*, by using `json.dumps()`. — Martijn Pieters, Nov 24 '17 at 18:39
Oh.. thanks. Yes noticed that `json.dumps()` puts small quotes around it. — cardamom, Nov 24 '17 at 18:40
@ElisByberi `json.dumps({"data" : "24.3"})` gives `'{"data": "24.3"}'` — cardamom, Nov 26 '17 at 16:33
@cardamom `print(json.dumps({"data" : "24.3"}))` does print `{"data": "24.3"}`. `'{"data": "24.3"}'` is not valid JSON string either. That is why I did ask you about these single quotes (they are called single quotes). — Elis Byberi, Nov 26 '17 at 19:38

score 5 · Accepted Answer · answered Nov 24 '17 at 18:41

You are already giving a string to requests.post(), because you convert your dictionary to a JSON document with json.dumps(). It doesn't matter to requests what this string contains.

It only matters to whatever server you are sending this data; it is that server that will decode the JSON document and use your number or string.

Note that requests can do the JSON conversion for you. There is no need to use json.dumps() here, just pass your dictionary to the json keyword argumnet:

import requests

data = {"data" : "24.3"}

response = requests.post(url, json=data)

This also takes care of setting the Content-Type header to application/json.

Elis Byberi · Answer 2 · 2017-11-25T17:48:46.530

There are two unrelated questions in your post.

The first is:

Does anyone know for sure whether it matters whether you have

data = {"data" : "24.3"}

or

data = {"data" : 24.3} ?

Yes, it does matter!
They are completely different things.
Treating them the same would make JSON format usage obsolete.

If server expects key "data" to be JSON data type number and you send it as a JSON data type string instead, a HTTP status code 400 should be responded.

If server does not report any error it means that this particular key is not being used in server and/or it is not being validated in server.

If server does treat them the same it is idiotic rather than redundant. That is why JSON format is being used in the first place.

The second is:

Does Python Requests POST need numerical data to be a string rather than a float?

This question title is explained in Martijn Pieters's answer.

Does Python Requests POST need numerical data to be a string rather than a float?

2 Answers2