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Flask-CSV
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Easily render CSVs within any flask application
Install
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Flask-CSV is packaged and you can use pip to install it::
pip install flask_csv
How to use ?
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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.
.. code-block:: python
@app.route("/")
def index():
return send_csv([{"id": 42, "foo": "bar"}, {"id": 91, "foo": "baz"}],
"test.csv", ["id", "foo"])
Hitting this endpoint will return::
id,foo
42,bar
91,baz
Passing additionnal parameters
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The remaining arguments of `send_csv` will be passed to `send_file`. For
example, to disable caching, do the following:
.. code-block:: python
send_csv([{"id": 42, "foo": "bar"}, {"id": 91, "foo": "baz"}],
"test.csv", ["id", "foo"], cache_timeout=0)
You can also pass additionnal parameters to the CSV writer like this:
.. code-block:: python
send_csv([{"foo": 42}, {"bar": "baz"}], "test.csv", ["foo"],
writer_kwargs={"extrasaction": "ignore"})
In this example, the "bar" key will not raise a `ValueError` since the writer
will be given the parameter `extrasaction` with the value "ignore".
Change delimiter
################
You can also change the delimiter with the `delimiter` option.
.. code-block:: python
send_csv([{"id": 42, "foo": "bar"}, {"id": 91, "foo": "baz"}],
"test.csv", ["id", "foo"], delimiter=';')
Will result in::
id;foo
42;bar
91;baz
Specifying file encoding
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You can also specify the encoding used to send the file, with the `encoding` option (`utf-8` by default).
.. code-block:: python
send_csv([{"id": 42, "foo": "bar"}, {"id": 91, "foo": "baz"}],
"test.csv", ["id", "foo"], encoding='iso-8859-1')
Use Marshmallow Schemas
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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:
.. code-block:: python
class IdSchema(Schema):
id = fields.Integer()
send_csv([{"id": 42, "foo": "bar"}, {"id": 91, "foo": "baz"}],
"test.csv", ["id", "foo"], schema=IdSchema())
And that would result in this::
id
42
91
SystemError returned a result with an error set
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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`
