How can I POST a JSON to an Express server with python module "requests"?
Question:
So, I’m trying to post a JSON to a Node.JS server running Express with Python using the "requests" module. I’ve made a lot of tries, all of them failed.
Closest I got was this:
Server code:
const fs = require('fs');
const express = require('express');
const app = express();
app.use(express.static("public"));
app.use(express.json());
app.get('/', function(_, res) {
var data = fs.readFileSync("./get.json");
res.json(JSON.parse(data));
});
app.post('/', function(req, res) {
fs.writeFile('./get.json', JSON.stringify(req.body), err => {
if (err) {
res.json(JSON.parse('{"status":false,"err":"%s"}', (err)));
} else {
res.json(JSON.parse('{"status":true}'));
};
});
});
app.listen(3000, function() {
console.log(`Up and running on port 3000.`);
});
Python script:
import requests
data = {'test':'Hello World!'}
response = requests.post("XXXXX.herokuapp.com/", data=data)
It sort of works, but on a GET request, it returns a blank JSON ({}
), same when logging req.body
on the POST request. I want it to return what was sent in the POST request ({'test':'Hello World!'}
).
Answers:
Passing the data
keyword arg does not convert the data to JSON. Instead use the json
keyword arg. This will convert your dictionary to a JSON serialized string that the server can parse.
import requests
data = {'test':'Hello World!'}
response = requests.post("XXXXX.herokuapp.com/", json=data)
What’s the difference? We can see what happens by looking at the PreparedRequest
object that is created before the request is sent.
import requests
### using data param
req = requests.Request('POST', 'http://localhost:8000', data={'test': 'hello world'})
preq = req.prepare()
preq.body
# returns:
'test=hello+world'
req = requests.Request('POST', 'http://localhost:8000', json={'test': 'hello world'})
preq = req.prepare()
preq.body
# returns:
b'{"test": "hello world"}'
The first is not parsable as JSON, where the second is proper JSON.
It looks like the issue may be with how you are sending the data in the Python script. When sending data with a POST request using the "requests" module, you should use the "json" parameter instead of the "data" parameter. This will set the "Content-Type" header to "application/json" and serialize the JSON data in the request body.
Try the code below,
import requests
data = {'test': 'Hello World!'}
response = requests.post("XXXXX.herokuapp.com/", json=data)
print(response.json())
This should send the JSON data in the request body and allow the server to parse it correctly.
So, I’m trying to post a JSON to a Node.JS server running Express with Python using the "requests" module. I’ve made a lot of tries, all of them failed.
Closest I got was this:
Server code:
const fs = require('fs');
const express = require('express');
const app = express();
app.use(express.static("public"));
app.use(express.json());
app.get('/', function(_, res) {
var data = fs.readFileSync("./get.json");
res.json(JSON.parse(data));
});
app.post('/', function(req, res) {
fs.writeFile('./get.json', JSON.stringify(req.body), err => {
if (err) {
res.json(JSON.parse('{"status":false,"err":"%s"}', (err)));
} else {
res.json(JSON.parse('{"status":true}'));
};
});
});
app.listen(3000, function() {
console.log(`Up and running on port 3000.`);
});
Python script:
import requests
data = {'test':'Hello World!'}
response = requests.post("XXXXX.herokuapp.com/", data=data)
It sort of works, but on a GET request, it returns a blank JSON ({}
), same when logging req.body
on the POST request. I want it to return what was sent in the POST request ({'test':'Hello World!'}
).
Passing the data
keyword arg does not convert the data to JSON. Instead use the json
keyword arg. This will convert your dictionary to a JSON serialized string that the server can parse.
import requests
data = {'test':'Hello World!'}
response = requests.post("XXXXX.herokuapp.com/", json=data)
What’s the difference? We can see what happens by looking at the PreparedRequest
object that is created before the request is sent.
import requests
### using data param
req = requests.Request('POST', 'http://localhost:8000', data={'test': 'hello world'})
preq = req.prepare()
preq.body
# returns:
'test=hello+world'
req = requests.Request('POST', 'http://localhost:8000', json={'test': 'hello world'})
preq = req.prepare()
preq.body
# returns:
b'{"test": "hello world"}'
The first is not parsable as JSON, where the second is proper JSON.
It looks like the issue may be with how you are sending the data in the Python script. When sending data with a POST request using the "requests" module, you should use the "json" parameter instead of the "data" parameter. This will set the "Content-Type" header to "application/json" and serialize the JSON data in the request body.
Try the code below,
import requests
data = {'test': 'Hello World!'}
response = requests.post("XXXXX.herokuapp.com/", json=data)
print(response.json())
This should send the JSON data in the request body and allow the server to parse it correctly.