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 StringIOimport csvfrom 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

You need to add newlines. Anyway, your method of making csvs (printing the list and removing brackets from it) is not the best way to do it. Try this instead:

csvList = '\n'.join(','.join(row) for row in csvList)

Or use the csv module:

import io, csvdest = io.StringIO()writer = csv.writer(dest)for row in csvList:    writer.writerow(row)# Now dest is a file-like object containing your csv

One alternative::

from flask import Flask, make_responseimport pyexcel as peimport StringIO # py2.7, for python3, please use import ioapp = Flask(__name__)data = [    ["REVIEW_DATE","AUTHOR","ISBN","DISCOUNTED_PRICE"],    ["1985/01/21","Douglas Adams",'0345391802',5.95],    ["1990/01/12","Douglas Hofstadter",'0465026567',9.95],    ["1998/07/15","Timothy \"The Parser\" Campbell",'0968411304',18.99],    ["1999/12/03","Richard Friedman",'0060630353',5.95],    ["2004/10/04","Randel Helms",'0879755725',4.50]]@app.route('/download')def download():    sheet = pe.Sheet(data)    io = StringIO.StringIO()    sheet.save_to_memory("csv", io)    output = make_response(io.getvalue())    output.headers["Content-Disposition"] = "attachment; filename=export.csv"    output.headers["Content-type"] = "text/csv"    return outputif __name__ == "__main__":    app.debug=True    app.run()

Another alternative is to use Flask-Excel:

from flask import Flask, make_responsefrom flask.ext import excelapp = Flask(__name__)data = [    ["REVIEW_DATE","AUTHOR","ISBN","DISCOUNTED_PRICE"],    ["1985/01/21","Douglas Adams",'0345391802',5.95],    ["1990/01/12","Douglas Hofstadter",'0465026567',9.95],    ["1998/07/15","Timothy \"The Parser\" Campbell",'0968411304',18.99],    ["1999/12/03","Richard Friedman",'0060630353',5.95],    ["2004/10/04","Randel Helms",'0879755725',4.50]]@app.route('/download')def download():    output = excel.make_response_from_array(data, 'csv')    output.headers["Content-Disposition"] = "attachment; filename=export.csv"    output.headers["Content-type"] = "text/csv"    return outputif __name__ == "__main__":    app.debug=True    app.run()