CODEWITHSUNDEEP
pythonflaskpython-requests
ilikecats
ilikecats

Reputation: 319

How to send and receive data from flask?

I am trying to send a python dictionary created from client.py to my webservice, have the webservice do something to the data, and return a boolean to client.py. This is the code I have so far for the server and client:

Server side (inside webservice.py):

from flask import Flask
from flask import request
import json

app = Flask(__name__) 

@app.route('/determine_escalation',methods = ['POST'])
def determine_escalation():
    jsondata = request.form['jsondata']
    data = json.loads(jsondata)

    #stuff happens here that involves data to obtain a result

    result = {'escalate':'True'}
    return json.dumps(result)


if __name__ == '__main__':
    app.run(debug=True)

Client side (inside client.py):

import sys
import json
import requests

conv = [{'input': 'hi', 'topic': 'Greeting'}]
s = json.dumps(conv) 
res = requests.post("http://127.0.0.1:5000/determine_escalation",data=s)
print res.text

But when I print out res.text, I get this:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<title>400 Bad Request</title>
<h1>Bad Request</h1>
<p>The browser (or proxy) sent a request that this server could not understand.</p>

What am I doing wrong, and how can I fix this? New to Flask and JSON stuff so any help is appreciated.

Upvotes: 11

Views: 16832

Answers (1)

Neil P
Neil P

Reputation: 401

OK - a few issues here:

First, you can use requests.get_json() to retrieve your JSON data at the server end:

from flask import Flask
from flask import request
import json

app = Flask(__name__) 

@app.route('/determine_escalation/', methods = ['POST'])
def determine_escalation():
    jsondata = request.get_json()
    data = json.loads(jsondata)

    #stuff happens here that involves data to obtain a result

    result = {'escalate': True}
    return json.dumps(result)


if __name__ == '__main__':
    app.run(debug=True)

Also, when you are putting your data together, rather than using "data=s" to send the request, use "json=s":

import sys
import json
import requests

conv = [{'input': 'hi', 'topic': 'Greeting'}]
s = json.dumps(conv)
res = requests.post("http://127.0.0.1:5000/determine_escalation/", json=s).json()
print(res['escalate'])

Please note that I have added trailing slashes at the end of the URL - this is just good practice :-)

I've also incorporated MarcelK's suggested changes - removing the quotes from the boolean 'True' (server side) and using .json() to parse the response on the client side - both of these are great suggestions.

I've tested this revised version (and re-revised version) and it works fine.

Upvotes: 17

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