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CallTag - Just like include, but can pass parameters to it

Author:
limodou
Posted:
February 25, 2007
Language:
Python
Version:
Pre .96
Score:
10 (after 10 ratings)

I knew that template in myght template system can receive some parameters just like a function. And I also want to implement this function in django template. So I finish a rough one, the code is pasted here. It just like include, but in order to distinguish with "include" tag, I call it "call". So you can use it:

{% call "some.html" %}

This way just like include tag, and the advanced way:

{% call "some.html" with "a" "b"|capfirst title="title1" %}
{% call "some.html" with "c" "d" title="title2" %}

So you can see, "call" tag can do like a python function, it can receive tuple parameters and key word parameters, just like the function:

def func(*args, **kwargs):pass

How to use it

test_call.html

{% expr "limodou" as name %}
{% call "test/test_sub.html" with "a"|capfirst "b" title="title1" %}<br/>
{% call "test/test_sub.html" with "c" "d" title="title2" %}

expr is also a custom tag written by me. It'll calculate a python expression and save to result to a variable. In this case, the variable it "name".

test_sub.html

{% for i in args %}{{ i }}{% endfor %}
<h2>{{ title }}</h2>
<p>{{ name }}</p>
<h3>args</h3>
{{ args }}
<h3>kwargs</h3>
{{ kwargs }}

And you also can see, call tag will auto create args and kwargs context variables.

I hope this will be some useful. 

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from django import template
from django.template.loader import get_template
from django.conf import settings

import tokenize
import StringIO

register = template.Library()

class CallNode(template.Node):
   def __init__(self, template_name, *args, **kwargs):
       self.template_name = template_name
       self.args = args
       self.kwargs = kwargs

   def render(self, context):
       try:
           template_name = self.template_name.resolve(context)
           t = get_template(template_name)
           d = {}
           args = d['args'] = []
           kwargs = d['kwargs'] = {}
           for i in self.args:
               args.append(i.resolve(context))
           for key, value in self.kwargs.items():
               kwargs[key] = d[key] = value.resolve(context)

           context.update(d)
           result = t.render(context)
           context.pop()
           return result
       except:
           if settings.TEMPLATE_DEBUG:
              raise
           return ''

def do_call(parser, token):
   """
   Loads a template and renders it with the current context.

   Example::

       {% call "foo/some_include" %}
       {% call "foo/some_include" with arg1 arg2 ... argn %}
   """
   bits = token.contents.split()
   if 'with' in bits: #has 'with' key
       pos = bits.index('with')
       argslist = bits[pos+1:]
       bits = bits[:pos]
   else:
       argslist = []
   if len(bits) != 2:
       raise template.TemplateSyntaxError, "%r tag takes one argument: the name of the template to be included" % bits[0]
   path = parser.compile_filter(bits[1])
   if argslist:
       args = []
       kwargs = {}
       for i in argslist:
           if '=' in i:
               a, b = i.split('=', 1)
               a = a.strip()
               b = b.strip()
               buf = StringIO.StringIO(a)
               keys = list(tokenize.generate_tokens(buf.readline))
               if keys[0][0] == tokenize.NAME:
                   kwargs[a] = parser.compile_filter(b)
               else:
                   raise template.TemplateSyntaxError, "Argument syntax wrong: should be key=value"
           else:
               args.append(parser.compile_filter(i))
   return CallNode(path, *args, **kwargs)

register.tag('call', do_call)

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Comments

mat (on May 6, 2008):

very use full ;) thanks

#

doesnotvalidate (on January 23, 2009):

I had to shuffle some variable assignments around to get this to work.

Move: args = [] kwargs = {}

outside of the IF block.

#

albrun (on February 1, 2009):

Hi,

very good idea this call function. But it have a template error when i send parameters.

Exception Type: TemplateSyntaxError

Exception Value: Caught an exception while rendering: init() keywords must be strings

Do someone have a way to resolved it ??

Thanks

#

simplylizz (on October 27, 2010):

bits = token.contents.split() on line 46 doesn't works correctly if you pass string with whitespaces as argument (for example {% call "some.html" with "c" "d e" title="title 2" %}).

#

simplylizz (on October 27, 2010):

You can use instead: bits = token.split_contents()

#

leopd (on October 29, 2010):

@albrun the problem is that the keyword is a unicode string. Here's a hack to make it work. Change line 62 to:

a = a.strip().encode('utf8')

#

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