Get Python Flask to return application/json using json.dumps

Question

I am using Python Flask to create a server. I want to send application/json back to the client (my customer requires this). When I use json.dumps() it is sending back text.

(Incase your wondering, if I use jsonify() instead of json.dumps(), I do get application/json, however this function seems to have problems with some data (if I dont get a solution here, I will look further into jsonify)).

server..............

import json
from flask import Flask, render_template, url_for, current_app, request, jsonify

app = Flask(__name__)

@app.route("/<arg1>")
def route1(arg1):
    dict1 = {"prop1": "p1", "prop2": "p2"}
    #return jsonify(dict1)      # this sends 'application/json'
    return json.dumps(dict1)  # this sends ' text/html; charset=utf-8'

app.run(host="0.0.0.0", port=8080, debug=True)

Test client (actual client is provided by customer) ......

import pycurl
import cStringIO

SERVER_URL = "http://192.168.47.133:8080"  

buf = cStringIO.StringIO()
c = pycurl.Curl()

c.setopt(c.URL, SERVER_URL + '/index.html?city=perth')
c.setopt(c.HTTPHEADER, ['Accept:application/json']) 
c.setopt(c.WRITEFUNCTION, buf.write)
c.setopt(c.VERBOSE, True)

c.perform()
buf1 = buf.getvalue()
buf.close()

print(buf1)

Answer 1

Change it like this:

from flask import Response

@app.route("/<arg1>")
def route1(arg1):
    dict1 = {"prop1": "p1", "prop2": "p2"}
    return Response(json.dumps(dict1), mimetype='application/json')