Handling a nested array in Flask request

Question

I built a webserver in Flask and I'm passing in the request using jsonp. One of the things I pass in is an nested array and when I retrieve the data in Flask, the array is completely messed up. Here's my code

index.html

var array = [[2,1],[2,2],[2,3]]
function getNext() {
    var data = {
        'M': 5,
        'N': 5,
        'array' : array
    };
    $.ajax({
        url: '/getNewGeneration',
        jsonp: 'callback',
        dataType: 'jsonp',
        data: data,
        success: function(response) {
            ...
        }
    });
}

server.py

@app.route('/getNewGeneration')
def getNext():
    M = request.args.get('M')
    N = request.args.get('N')
    liveCells = request.args.get('liveCells')
    ...

When I print out request.args I get ImmutableMultiDict([('callback', u'jQuery17101683842277548142_1412736365518'), ('array[2][]', u'2'), ('array[2][]', u'3'), ('array[1][]', u'2'), ('array[1][]', u'2'), ('N', u'5'), ('M', u'5'), ('_', u'1412736417145'), ('array[0][]', u'2'), ('array[0][]', u'1')])

Does anyone know how to fix this?

is request.json also that messed up?

brunsgaard
– brunsgaard

2014-10-08 03:30:22 +00:00
Commented Oct 8, 2014 at 3:30 — brunsgaard
– brunsgaard, Commented Oct 8, 2014 at 3:30
request.json returned None

user1998511
– user1998511

2014-10-08 23:45:12 +00:00
Commented Oct 8, 2014 at 23:45 — user1998511
– user1998511, Commented Oct 8, 2014 at 23:45

pydsigner · Accepted Answer · 2016-06-02 04:52:10Z

3

I see two problems with your code. First, you don't pass a key named 'liveCells'. You pass one named 'array'. You need to update this either in your JavaScript or on the Flask side. Assuming you want the former, your JavaScript should look like

var array = [[2,1],[2,2],[2,3]]
function getNext() {
    var data = {
        'M': 5,
        'N': 5,
        'liveCells' : array
    };
    $.ajax({
        url: '/getNewGeneration',
        jsonp: 'callback',
        dataType: 'jsonp',
        data: data,
        success: function(response) {
            ...
        }
    });
}

Second, you can't use the get method to retrieve multivalve keys. ImmutableMultiDicts, such as request.args, provide a method called getlist that will return a list of items for the given key rather than a single value. Update your code to

liveCells = request.args.getlist('liveCells')

More information can be found in the werkzeug documentation.

edited Jun 2, 2016 at 4:52

pydsigner

2,8871 gold badge23 silver badges35 bronze badges

answered Oct 8, 2014 at 13:35

dirn

21.1k7 gold badges75 silver badges76 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Rebs Over a year ago

This is the only answer I've found on SO that mentions there is a getList function, so thank you for pointing that out.

brunsgaard · Accepted Answer · 2014-10-08 03:37:23Z

0

Do it like this and i think it will work for you.

$.ajax({
    type: 'POST',
    contentType: 'application/json',
    data: JSON.stringify(data),
    dataType: 'json',
    url: 'getNewGeneration',
    success: function (e) {
        console.log(e);
    }
});

And try to print request.json then.

answered Oct 8, 2014 at 3:37

brunsgaard

5,2382 gold badges19 silver badges15 bronze badges

Collectives™ on Stack Overflow

Handling a nested array in Flask request

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related