pystache 0.6.5

Mustache for Python

Pystache

This updated fork of Pystache is currently tested on Python 3.8+ and in Conda, on Linux, Macos, and Windows (Python 2.7 is no longer supported).

Pystache is a Python implementation of Mustache. Mustache is a framework-agnostic, logic-free templating system inspired by ctemplate and et. Like ctemplate, Mustache “emphasizes separating logic from presentation: it is impossible to embed application logic in this template language.”

The mustache(5) 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.

Pystache is semantically versioned and older versions can still be found on PyPI. This version of Pystache now passes all tests in version 1.1.3 of the spec.

Requirements

Pystache is tested with:

• Python 3.8

• Python 3.9

• Python 3.10

• Python 3.11

• Conda (py38 and py310)

JSON support is needed only for the command-line interface and to run the spec tests; PyYAML can still be used (see the Develop section).

Official support for Python 2 has ended with Pystache version 0.6.0.

Note

This project uses setuptools_scm to generate and maintain the version file, which only gets included in the sdist/wheel packages. In a fresh clone, running any of the tox commands should generate the current version file.

Quick Start

Be sure to get the latest release from either Pypi or Github.

Install It

From Pypi:

$ pip install pystache

Or Github:

$ pip install -U pystache -f https://github.com/PennyDreadfulMTG/pystache/releases/

And test it:

$ pystache-test

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

Use It

Open a python console:

>>> 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 ../pystache/tests/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 class and TemplateSpec class for more information.

You can also pre-parse a template:

>>> parsed = pystache.parse(u"Hey {{#who}}{{.}}!{{/who}}")
>>> print(parsed)
['Hey ', _SectionNode(key='who', index_begin=12, index_end=18, parsed=[_EscapeNode(key='.'), '!'])]

And then:

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

Unicode

This section describes how Pystache handles unicode, strings, and encodings.

Internally, Pystache uses only unicode strings (str in Python 3). For input, Pystache accepts byte strings (bytes in Python 3). 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). 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!) and different platforms, you can use [tox](https://pypi.python.org/pypi/tox):

$ pip install tox
$ tox -e py

To run tests on multiple versions with coverage, run:

$ tox -e py38-linux,py39-linux  # for example

(substitute your platform above, eg, macos or windows)

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 update --init

The test harness parses the spec’s (more human-readable) yaml files if PyYAML is present. Otherwise, it parses the json files. To install PyYAML:

$ pip install pyyaml  # note this is installed automatically by tox

Once the submodule is available, you can run the full test set with:

$ tox -e setup -- ext/spec/specs

Making Changes & Contributing

We use the gitchangelog action to generate our github Release page, as well as the gitchangelog message format to help it categorize/filter commits for a tidier release page. Please use the appropriate ACTION modifiers in any Pull Requests.

This repo is also pre-commit enabled for various linting and format checks. The checks run automatically on commit and will fail the commit (if not clean) with some checks performing simple file corrections.

If other checks fail on commit, the failure display should explain the error types and line numbers. Note you must fix any fatal errors for the commit to succeed; some errors should be fixed automatically (use git status and git diff to review any changes).

Note pylint is the primary check that requires your own input, as well as a decision as to the appropriate fix action. You must fix any pylint warnings (relative to the baseline config score) for the commit to succeed.

See the following pages for more information on gitchangelog and pre-commit.

• generate-changelog

• pre-commit-config

• pre-commit-usage

You will need to install pre-commit before contributing any changes; installing it using your system’s package manager is recommended, otherwise install with pip into your usual virtual environment using something like:

$ sudo emerge pre-commit  --or--
$ pip install pre-commit

then install it into the repo you just cloned:

$ git clone https://github.com/PennyDreadfulMTG/pystache
$ cd pystache/
$ pre-commit install

It’s usually a good idea to update the hooks to the latest version:

pre-commit autoupdate

Mailing List (old)

There is(was) a mailing list. Note that there is a bit of a delay between posting a message and seeing it appear in the mailing list archive.

Credits

>>> import pystache
>>> context = { 'author': 'Chris Wanstrath', 'maintainer': 'Chris Jerdonek','refurbisher': 'Steve Arnold', 'new_maintainer': 'Thomas David Baker' }
>>> print(pystache.render("Author: {{author}}\nMaintainer: {{maintainer}}\nRefurbisher: {{refurbisher}}\nNew maintainer: {{new_maintainer}}", context))
Author: Chris Wanstrath
Maintainer: Chris Jerdonek
Refurbisher: Steve Arnold
New maintainer: Thomas David Baker

Pystache logo by David Phillips is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.