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https://github.com/defunkt/pystache

Mustache in Python
https://github.com/defunkt/pystache

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Mustache in Python

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README 

        
Pystache

========



![](http://defunkt.github.com/pystache/images/logo_phillips.png "mustachioed, monocled snake by David Phillips")



![](https://secure.travis-ci.org/defunkt/pystache.png "Travis CI current build status")



[Pystache](http://defunkt.github.com/pystache) is a Python

implementation of [Mustache](http://mustache.github.com/). Mustache is a

framework-agnostic, logic-free templating system inspired by

[ctemplate](http://code.google.com/p/google-ctemplate/) and

[et](http://www.ivan.fomichev.name/2008/05/erlang-template-engine-prototype.html).

Like ctemplate, Mustache "emphasizes separating logic from presentation:

it is impossible to embed application logic in this template language."



The [mustache(5)](http://mustache.github.com/mustache.5.html) man page

provides a good introduction to Mustache's syntax. For a more complete

(and more current) description of Mustache's behavior, see the official

[Mustache spec](https://github.com/mustache/spec).



Pystache is [semantically versioned](http://semver.org) and can be found

on [PyPI](http://pypi.python.org/pypi/pystache). This version of

Pystache passes all tests in [version

1.1.2](https://github.com/mustache/spec/tree/v1.1.2) of the spec.



Requirements

------------



Pystache is tested with--



-   Python 2.4 (requires simplejson [version

    2.0.9](http://pypi.python.org/pypi/simplejson/2.0.9) or earlier)

-   Python 2.5 (requires

    [simplejson](http://pypi.python.org/pypi/simplejson/))

-   Python 2.6

-   Python 2.7

-   Python 3.1

-   Python 3.2

-   Python 3.3

-   [PyPy](http://pypy.org/)



[Distribute](http://packages.python.org/distribute/) (the setuptools fork)

is recommended over [setuptools](http://pypi.python.org/pypi/setuptools),

and is required in some cases (e.g. for Python 3 support).

If you use [pip](http://www.pip-installer.org/), you probably already satisfy

this requirement.



JSON support is needed only for the command-line interface and to run

the spec tests. We require simplejson for earlier versions of Python

since Python's [json](http://docs.python.org/library/json.html) module

was added in Python 2.6.



For Python 2.4 we require an earlier version of simplejson since

simplejson stopped officially supporting Python 2.4 in simplejson

version 2.1.0. Earlier versions of simplejson can be installed manually,

as follows:



    pip install 'simplejson<2.1.0'



Official support for Python 2.4 will end with Pystache version 0.6.0.



Install It

----------



    pip install pystache



And test it--



    pystache-test



To install and test from source (e.g. from GitHub), see the Develop

section.



Use It

------



    >>> import pystache

    >>> print pystache.render('Hi {{person}}!', {'person': 'Mom'})

    Hi Mom!



You can also create dedicated view classes to hold your view logic.



Here's your view class (in .../examples/readme.py):



    class SayHello(object):

        def to(self):

            return "Pizza"



Instantiating like so:



    >>> from pystache.tests.examples.readme import SayHello

    >>> hello = SayHello()



Then your template, say\_hello.mustache (by default in the same

directory as your class definition):



    Hello, {{to}}!



Pull it together:



    >>> renderer = pystache.Renderer()

    >>> print renderer.render(hello)

    Hello, Pizza!



For greater control over rendering (e.g. to specify a custom template

directory), use the `Renderer` class like above. One can pass attributes

to the Renderer class constructor or set them on a Renderer instance. To

customize template loading on a per-view basis, subclass `TemplateSpec`.

See the docstrings of the

[Renderer](https://github.com/defunkt/pystache/blob/master/pystache/renderer.py)

class and

[TemplateSpec](https://github.com/defunkt/pystache/blob/master/pystache/template_spec.py)

class for more information.



You can also pre-parse a template:



    >>> parsed = pystache.parse(u"Hey {{#who}}{{.}}!{{/who}}")

    >>> print parsed

    [u'Hey ', _SectionNode(key=u'who', index_begin=12, index_end=18, parsed=[_EscapeNode(key=u'.'), u'!'])]



And then:



    >>> print renderer.render(parsed, {'who': 'Pops'})

    Hey Pops!

    >>> print renderer.render(parsed, {'who': 'you'})

    Hey you!



Python 3

--------



Pystache has supported Python 3 since version 0.5.1. Pystache behaves

slightly differently between Python 2 and 3, as follows:



-   In Python 2, the default html-escape function `cgi.escape()` does

    not escape single quotes.  In Python 3, the default escape function

    `html.escape()` does escape single quotes.

-   In both Python 2 and 3, the string and file encodings default to

    `sys.getdefaultencoding()`. However, this function can return

    different values under Python 2 and 3, even when run from the same

    system. Check your own system for the behavior on your system, or do

    not rely on the defaults by passing in the encodings explicitly

    (e.g. to the `Renderer` class).



Unicode

-------



This section describes how Pystache handles unicode, strings, and

encodings.



Internally, Pystache uses [only unicode

strings](http://docs.python.org/howto/unicode.html#tips-for-writing-unicode-aware-programs)

(`str` in Python 3 and `unicode` in Python 2). For input, Pystache

accepts both unicode strings and byte strings (`bytes` in Python 3 and

`str` in Python 2). For output, Pystache's template rendering methods

return only unicode.



Pystache's `Renderer` class supports a number of attributes to control

how Pystache converts byte strings to unicode on input. These include

the `file_encoding`, `string_encoding`, and `decode_errors` attributes.



The `file_encoding` attribute is the encoding the renderer uses to

convert to unicode any files read from the file system. Similarly,

`string_encoding` is the encoding the renderer uses to convert any other

byte strings encountered during the rendering process into unicode (e.g.

context values that are encoded byte strings).



The `decode_errors` attribute is what the renderer passes as the

`errors` argument to Python's built-in unicode-decoding function

(`str()` in Python 3 and `unicode()` in Python 2). The valid values for

this argument are `strict`, `ignore`, and `replace`.



Each of these attributes can be set via the `Renderer` class's

constructor using a keyword argument of the same name. See the Renderer

class's docstrings for further details. In addition, the `file_encoding`

attribute can be controlled on a per-view basis by subclassing the

`TemplateSpec` class. When not specified explicitly, these attributes

default to values set in Pystache's `defaults` module.



Develop

-------



To test from a source distribution (without installing)--



    python test_pystache.py



To test Pystache with multiple versions of Python (with a single

command!), you can use [tox](http://pypi.python.org/pypi/tox):



    pip install 'virtualenv<1.8'  # Version 1.8 dropped support for Python 2.4.

    pip install 'tox<1.4'  # Version 1.4 dropped support for Python 2.4.

    tox



If you do not have all Python versions listed in `tox.ini`--



    tox -e py26,py32  # for example



The source distribution tests also include doctests and tests from the

Mustache spec. To include tests from the Mustache spec in your test

runs:



    git submodule init

    git submodule update



The test harness parses the spec's (more human-readable) yaml files if

[PyYAML](http://pypi.python.org/pypi/PyYAML) is present. Otherwise, it

parses the json files. To install PyYAML--



    pip install pyyaml



To run a subset of the tests, you can use

[nose](http://somethingaboutorange.com/mrl/projects/nose/0.11.1/testing.html):



    pip install nose

    nosetests --tests pystache/tests/test_context.py:GetValueTests.test_dictionary__key_present



### Using Python 3 with Pystache from source



Pystache is written in Python 2 and must be converted to Python 3 prior to

using it with Python 3.  The installation process (and tox) do this

automatically.



To convert the code to Python 3 manually (while using Python 3)--



    python setup.py build



This writes the converted code to a subdirectory called `build`.

By design, Python 3 builds

[cannot](https://bitbucket.org/tarek/distribute/issue/292/allow-use_2to3-with-python-2)

be created from Python 2.



To convert the code without using setup.py, you can use

[2to3](http://docs.python.org/library/2to3.html) as follows (two steps)--



    2to3 --write --nobackups --no-diffs --doctests_only pystache

    2to3 --write --nobackups --no-diffs pystache



This converts the code (and doctests) in place.



To `import pystache` from a source distribution while using Python 3, be

sure that you are importing from a directory containing a converted

version of the code (e.g. from the `build` directory after converting),

and not from the original (unconverted) source directory.  Otherwise, you will

get a syntax error.  You can help prevent this by not running the Python

IDE from the project directory when importing Pystache while using Python 3.



Mailing List

------------



There is a [mailing list](http://librelist.com/browser/pystache/). Note

that there is a bit of a delay between posting a message and seeing it

appear in the mailing list archive.



Credits

-------



    >>> context = { 'author': 'Chris Wanstrath', 'maintainer': 'Chris Jerdonek' }

    >>> print pystache.render("Author: {{author}}\nMaintainer: {{maintainer}}", context)

    Author: Chris Wanstrath

    Maintainer: Chris Jerdonek



Pystache logo by [David Phillips](http://davidphillips.us/) is licensed

under a [Creative Commons Attribution-ShareAlike 3.0 Unported

License](http://creativecommons.org/licenses/by-sa/3.0/deed.en_US).

![](http://i.creativecommons.org/l/by-sa/3.0/88x31.png "Creative

Commons Attribution-ShareAlike 3.0 Unported License")