7.6. Integration of templating engines

For those who are familiar with templating engines, Karrigell makes their integration very straightforward. Three engines are available though built-in functions, the others can be used like in normal Python scripts

7.6.1 Python string substitution

WARNING: PythonStringSubst has been superceded by KT, and will be dropped from the next release of Karrigell

This templating system uses the string substitution syntax that was introduced in Python 2.4. Template files use placeholders of the form $foo

To use it in scripts, use the built-in function PythonStringSubst(url,arg1=val1,arg2=val2...) : it will get the source string from the file at the specified url, and apply the keyword arguments to this source string

For instance, suppose the template source is 

<HTML>
<HEAD><TITLE>$title</TITLE></HEAD>
<BODY>
$contents
</BODY>
</HTML>
The result of 

print PythonStringSubst(src_url,
    title='Python String Substitution', contents='Hello World example'
    )

will be : 

<HTML>
<HEAD><TITLE>Python String Substitution</TITLE></HEAD>
<BODY>
Hello World example
</BODY>
</HTML>

7.6.2 KT - Karrigell Templates

The built-in KT function supercedes PythonStringSubst. In addition to string substitution, KT provides a mechanism for including other templates and specifying translations strings, which are passed to the Karrigell translation engine. KT is fully documented in this page

KT templates are stored in text files with .kt extension. Conversion of existing PythonStringSubst templates is easy:

  1. Change the extension of existing PythonStringSubst template files to .kt
  2. Replace "PythonStringSubst" with "KT" in Python and ks scripts.

7.6.3 Cheetah

If the Cheetah templating engine is available, you can use it the same way as above, with a built-in function Cheetah(url,arg1=val1,arg2=val2...). url is the template url, and the keyword arguments are used to produce the resulting HTML code

7.6.4 Other engines

To use another engine, you must apply its syntax in the script. Though the implementation details may vary, your code will probably look like this : 

import Template # or raise Exception
# get template source from file
templateDef = open(template_file_name).read()
# apply keywords to the template definition and print the result
print Template(templateDef,arg1=val1,arg2=val2, ...)