Writing a CSV from Flask framework [duplicate]

I did something like this recently, I found that I needed to first place the csv into a StringIO and then return the StringIO. If you want the csv to be a download, here’s what I did:

import StringIO
import csv
from flask import make_response

@app.route('/download')
def post(self):
    si = StringIO.StringIO()
    cw = csv.writer(si)
    cw.writerows(csvList)
    output = make_response(si.getvalue())
    output.headers["Content-Disposition"] = "attachment; filename=export.csv"
    output.headers["Content-type"] = "text/csv"
    return output