CODEWITHSUNDEEP
javascriptjquerydjangojsondjango-views
gohnjanotis
gohnjanotis

Reputation: 7575

How do I get the same format for a javascript array and django set on the backend?

I have code that, when a user is logged in, selects recipes that apply to him based on the ingredients (items) he has previously identified identified as possessions.

This code gets the id's of the items the user already has:

if request.user.is_authenticated():
    user_items = [possession.item for possession in request.user.possession_set.all()]
    user_items_ids = [item.id for item in user_items]
    uids = set(user_items_ids)

The following code, which already existed, is where I run into problems...

recipes = [(recipe, len(set([item.id for item in recipe.items.all()]) & uids), recipe.votes) for recipe in recipes]

I created another part of the site that allows people who have not yet signed up to just pick a few ingredients. I do this with some jQuery on the front end, then send the results to the backend:

var ingredient_set = [];
$('.temp_ingredient').each(function(index){
ingredient_set[index] = $(this).attr('id').substr(4);
});

$.get('/recipes/discover', { 'ingredients': ingredient_set }, 
function(){
    alert("Success");
});

The problem is when I receive them on the Django side, with this code:

uids = request.GET['ingredients']

I get the following error:

unsupported operand type(s) for &: 'set' and 'unicode'

Basically, I know they aren't in the same format, but I don't know how to get them to be compatible.

Upvotes: 0

Views: 217

Answers (1)

Reiner Gerecke
Reiner Gerecke

Reputation: 12214

You are sending a JavaScript array in the query string of your GET request. Therefore you should use request.GET.getlist. Just using request.GET[key] gives you the last value for that key.

>> request.GET['foo[]']
u'5'
>> request.GET.getlist('foo[]')
[u'1', u'2', u'4', u'5']

Note that the values are unicode, but you probably need them as integers, so be sure to convert them.

uids = request.GET.getlist('foo[]')
uids = set([int(x) for x in uids])

I'm not sure why my key is actually foo[] and not just foo, but as you get no KeyError, request.GET.getlist('ingredients') should work.

Upvotes: 1

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