Mako Filter in Chameleon?

Question

Is there any possibility to use template filters in Chameleon as I'm used to in Mako? In Mako one could do something like

${s | filter}

where filter is a function mapping strings to strings and Mako applied filter to s and outputs it (after escaping HTML entities). So one could easily do things like

${s | nl2br}

I'm aware that the Chameleon way of doing it is Line Breaking in Chameleon. But I have more applications for this filters so I'm wondering if something similar is supported in Chameleon.

score 1 · Accepted Answer · answered Feb 24 '13 at 11:49

1

No, there isn't. Do the processing in your view instead, or use python code in your TALES expressions.

answered Feb 24 '13 at 11:49

Martijn Pieters

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score 1 · Answer 2 · answered Mar 04 '13 at 12:10

In Chameleon, the pipe operator (" | ") operator means try-except, instead of "apply filter".

But since the expression language is simply Python, it shouldn't be necessary with such syntactic sugar.

Also, Chameleon has an import: expression type that can help you import helper functions:

<div tal:define="h import: helpers">
  ...
  ${structure: h.nl2br(s)}

Note that if nl2br returned an object that implemented an __html__() method, Chameleon would call this method to produce the output, and you wouldn't need structure: to avoid the HTML-escape.

That said, it's true that Mako's filter operator sometimes makes for more readable template code.

bismigalis · Answer 3 · 2013-02-24T18:27:09.950

0

The Chameleon way is

${nl2br(s)}

I'm doing it like this

views.py

form helpers import nl2br
def my_view(request):
    return {
        'nl2br':nl2br,
    }

template.pt

${structure: nl2br(s)}

edited Feb 24 '13 at 18:27

answered Feb 24 '13 at 15:44

bismigalis

171
1
8

I'm not too sure but, this only works if I disable the encoding of htmlentities of Chameleon, right? This is not a good idea - at least in my situation :-/ – born Feb 24 '13 at 16:43
add structure: if output is to be interpreted as html – bismigalis Feb 24 '13 at 18:29
just as a warning to later readers: adding structure to the output can imply a major security bug. – born Feb 24 '13 at 18:30

Mako Filter in Chameleon?

3 Answers3