how can I upload a csv file and enter the data into a database, using Flask, postgres and Python?

Question

Trying to upload a csv file, open it and then iterate through the rows to insert each field in to the postgres database, I have 2 (identified so far) problems with this. I am using Flask not Django.

I get an indentation error, although I cannot for the life of me see where. RESOLVED
The heroku logs provide no other feedback so I am unsure even if the file is correctly opened and read.

The csv file is:

first_name last_name email etc. # in all 8 columns
John       Smith     [email protected]

and the python code is:

@app.route("/uploadcsv", methods=['POST'])
def uploadcsv():
csvfile = request.files['file']
with open(csvfile):
    reader = csv.DictReader(csvfile)
    for row in reader:
        firstname = row['first_name']
        query = Prospect(first_name=firstname)
        db.session.add(query)
        db.session.commit()
        return "OK"

So, there are 2 questions:

what is the indentation problem? RESOLVED
Is the code correct for uploading, opening and insertion?

Karl Barker · Accepted Answer · 2015-11-08 13:51:32Z

1

You haven't indented the for loop body:

for row in data:
    first_name = row['first_name']
    sql = Prospect(first_name=first_name) #truncated for brevity
    db.session.add(sql)
    db.session.commit()

If it's not that, then it's probably mixed tabs and spaces. Python can handle one or the other, but never both!

You're better off using the csv Python library. There's no need to try parsing csv files yourself!

answered Nov 8, 2015 at 13:51

Karl Barker

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4 Comments

user1903663 Over a year ago

thanks I should add that I did import cvs. I will check the tabs and spaces, as you suggest. And the rest? Does it look correct at least in terms of approach?

user1903663 Over a year ago

Thank you, indentation is resolved. However, the upload and insertion does not work. Heroku gives no reason why, just a 500 response. Please could you give me your view on the code which I have now amended above? Thank you!

Karl Barker Over a year ago

If you're getting a server error, check your logs for the error message.

user1903663 Over a year ago

thanks but the heroku logs say nothing just "status 500"

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