How do I `jsonify` a list in Flask? [duplicate]

Currently Flask would raise an error when jsonifying a list.

I know there could be security reasons https://github.com/mitsuhiko/flask/issues/170, but I still would like to have a way to return a JSON list like the following:

[
    {'a': 1, 'b': 2},
    {'a': 5, 'b': 10}
]

instead of

{ 'results': [
    {'a': 1, 'b': 2},
    {'a': 5, 'b': 10}
]}

on responding to a application/json request. How can I return a JSON list in Flask using Jsonify?

You can't but you can do it anyway like this. I needed this for jQuery-File-Upload

import json
# get this object
from flask import Response

#example data:

    js = [ { "name" : filename, "size" : st.st_size , 
        "url" : url_for('show', filename=filename)} ]
#then do this
    return Response(json.dumps(js),  mimetype='application/json')

jsonify prevents you from doing this in Flask 0.10 and lower for security reasons.

To do it anyway, just use json.dumps in the Python standard library.

http://docs.python.org/library/json.html#json.dumps

This is working for me. Which version of Flask are you using?

from flask import jsonify

...

@app.route('/test/json')
def test_json():
    list = [
            {'a': 1, 'b': 2},
            {'a': 5, 'b': 10}
           ]
    return jsonify(results = list)