Multiple arguments in Django template filters

Author: nme · Tuesday, 5 July, 2011 · ·

 

By default, it is not currently possible to pass multiple arguments to Django template filter — states: "Custom filters are just Python functions that take one or two arguments".

Here I describe solution that allows passing more arguments.

Lets say we have key and current query_string in our template context. We loop in paginator and alter query_string current key value with page. The key is to group arguments in an array. We use following custom filter:

@register.filterdef keys (first,second):    if isinstance(first,list):        return first+[second]    else:        return [first,second]

following filter allows us to:

{
    {
     "1"|keys:"2"|keys:"3" }}

which will return in our template:

[u'1', u'2', u'3']

Returning to described query_string altering problem — we use alter_query filter:

@register.filterdef alter_query (keys, query_string):    from django.http import QueryDict    query_dict = QueryDict(query_string, mutable=True)    query_dict[keys[0]] = keys[1]    return query_dict.urlencode()

inside pagination template, we use following code:

{
    { page }}

Doesn't look pretty, but works perfectly.