Define global function using in jinja templates

原文是Call a python function from jinja2, 原文中点赞数量最高的并不是完美的答案,我采用的下面的方案。

Variables can easily be created:

def example():
    return dict(myexample='This is an example')

The above can be used in a Jinja2 template with Flask like so:

{{ myexample }}

(Which outputs This is an example)

As well as full fledged functions:

def utility_processor():
    def format_price(amount, currency=u'€'):
        return u'{0:.2f}{1}'.format(amount, currency)
    return dict(format_price=format_price)

The above when used like so:

{{ format_price(0.33) }}

(Which outputs the input price with the currency symbol)

Alternatively, you can use jinja filters, baked into Flask. E.g. using decorators:

def reverse_filter(s):
    return s[::-1]

Or, without decorators, and manually registering the function:

def reverse_filter(s):
    return s[::-1]
app.jinja_env.filters['reverse'] = reverse_filter

Filters applied with the above two methods can be used like this:

{% for x in mylist | reverse %}
{% endfor %}