Easily render CSVs within any flask application
Flask-CSV is packaged and you can use pip to install it:
pip install flask_csv
Flask-CSV has a simple hepler method named send_csv which allows you to send csv files in flask endpoints. It takes an iterable of dict, a filename and a list of fields. The keys of all dict in the iterable must correspond to given fields.
It will return a Response object with filename set and body containing the CSV data.
You will better understand with a short example.
Hitting this endpoint will return:
id,foo
42,bar
91,baz
The remaining arguments of send_csv will be passed to send_file. For example, to disable caching, do the following:
You can also pass additionnal parameters to the CSV writer like this:
In this example, the "bar" key will not raise a ValueError since the writer will be given the parameter extrasaction with the value "ignore".
You can also change the delimiter with the delimiter option.
Will result in:
id;foo
42;bar
91;baz
You can also specify the encoding used to send the file, with the encoding option (utf-8 by default).
You can use Schema from marshmallow by passing it as schema to send_csv. If you want to keep only ids and ensure they are integers, you could do:
And that would result in this:
id
42
91
When using uwsgi for your flask app, it might raise this kind of error on the send_file method. If that were the case, adding the following option to your uwsgi conf should solve it :
wsgi-disable-file-wrapper = true