Chapter 3 Templates

Templates

Django Templating Language
Jinja

##Expressing a Template from django import template
t = template.Template('{{a}}, {{b}} ,3 ,4')
c = template.Context({'a':1,'b':2})
result = t.render(c)
print(result)
1,2,3,4

##Ref methods of object
NOTE: you can only call methods that do not take an arg from django import template
t = template.Template('{{ a.isupper }}')
c = template.Context({'a': 'TEST'})
print(t.render(c))
TRUE

##Ref attribute of object

class Person(object):
def init(self,sex,name):
self.sex = sex
self.name = name

bob = Person('male','Jason')
t = template.Template('{{human.name}} is a {{human.sex}}')
c = template.Context({'human': bob})
print(t.render(c))
"Jason is a male"

##Index of a list

t = template.Template('Item number 2 is {{items.1}}')
c = template.Context({'items':['grapes','hamburger','cheese']})
print(t.render(c))
Item number 2 is hamburger

For complex data structures you can use . notation. With this you can access

1. dict keys
2. atrributes
3. methods
4. indices of object
5. object attributes

Control Structures

IF

if tags accept and,or,and not however they do not accept parenthesis to order priority
'{% if expression }% {%elif expression%} {%else%}

{%endif%}'

FOR

{%for item in item_list%}

{%empty%} what to do if item_list is empty {%endfor%}

forloop.counter = variable ref the current num of loops. one-indexed forloop.revcounter = ref the remaining # of loops till end. last loop=1 forloop.first and forloop.last = Bool for first or last loop

##Filters

filters are functions. they are applied to a variable with the | command. if there are args they come after a :

lower = convert str to lower case
addslashes = adds a backslash before any backslash,single quote, or double quote. useful for escaping date = formats a date or datetime object length = length of object

##Template Loading

in the Settings.py there are some control variables for templates:

Backend = which template language to use DIRS = list of directories where the engine should look for templates APP_DIRS = should engine look for templates inside installed apps

get_template() is a providing function that can be used to load a template by name. it locates the templates first based on App template folders then by any entries in the DIR.

to use get_template(): from django.template.loaders import get_template

render() is a django shortcut to do all these in one line from django.shortcuts import render render(http request,template name,Dict)

##The include tag## allows an import of a template into this template