Validate emails against GOV.UK Notify's validation algorithm

README.md

GOV.UK Notify email validator

This is a script that takes a CSV file containing email addresses from a dirty data source, and splits it into two CSVs, one containing valid email addresses, and the other invalid.

How to use

First, clone the alphagov/notifications-utils repository. Add this script to the root, and make it executable:

chmod +x validate-emails.py

Set up a virtual environment and install dependencies:

python3 -mvenv env
source env/bin/activate
pip install -r requirements.txt

Then run on your csv:

./validate-emails.py ./path/to/your.csv

By default, it checks a column named Email. If your email column has a different name, specify it like this:

./validate-emails.py ./path/to/your.csv --column="email-address"

If the input file is called foo.csv, valid records will be output into foo_clean.csv, and invalid records will go into foo_rejected.csv.

validate-emails.py

#!/usr/bin/env python

import argparse
import csv
from notifications_utils.recipients import validate_email_address, InvalidEmailError

def validate_emails():
    parser = argparse.ArgumentParser(description='Process some integers.')
    parser.add_argument('filename', type=str,
                        help='filename of the csv file to parse')
    parser.add_argument('--column', default='Email',
                        help='CSV column heading of the email address column')
    args = parser.parse_args()

    outfilename = args.filename.replace('.csv','_clean.csv')
    rejectfilename = args.filename.replace('.csv','_rejected.csv')

    with open(args.filename) as csvfile:
        with open(outfilename, 'w') as outfile:
            with open(rejectfilename, 'w') as rejectfile:
                csvreader = csv.DictReader(csvfile)
                csvwriter = csv.DictWriter(outfile, csvreader.fieldnames)
                rejectwriter = csv.DictWriter(rejectfile, csvreader.fieldnames)
                csvwriter.writeheader()
                rejectwriter.writeheader()
                for row in csvreader:
                    email = row[args.column]
                    try:
                        validate_email_address(email)
                        csvwriter.writerow(row)
                    except InvalidEmailError:
                        rejectwriter.writerow(row)

if __name__ == "__main__":
    validate_emails()