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Pythonic parameterized cache paths.

Project description

=========
CachePath
=========


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:target: https://pypi.python.org/pypi/cachepath

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:target: https://travis-ci.org/haydenflinner/cachepath

.. image:: https://readthedocs.org/projects/cachepath/badge/?version=latest
:target: https://cachepath.readthedocs.io/en/latest/?badge=latest
:alt: Documentation Status




A small package for pythonic parameterized cache paths.


* Free software: MIT license
* Documentation: https://cachepath.readthedocs.io.


.. _getting-started:
Getting Started
-----------
**Install:**
``pip install cachepath``
**Import:**
``from cachepath import CachePath, Path``

**Why?**
1. Integrates ``pathlib`` with ``tempfile`` and ``shutil``
2. Wraps ``pathlib`` import for Py2/3 compat. (not in ``six``)

**Why? But longer:**
Just need a temp path to pass to some random tool for its logfile?
Behold, a gaping hole in ``pathlib``::

def easy_get_tempfile():
return CachePath() # Path('/tmp/213kjdsrandom')
def hard_get_tempfile():
return Path(tempfile.mkstemp()) # I forgot to call Path the first time

Now, I'm running this tool multiple times, how do I attach some info to the
filename? ::

def easy_get_tempfile(param):
return CachePath(param, suffix='.txt') # Path('/tmp/param.txt')
def hard_get_tempfile(param):
return (Path(tempfile.gettempdir())/param).with_suffix('txt')

Ew. Now, I'm running this tool *a lot*, maybe even over a tree of data that looks
like this! ::

2018-12-23
person1
person2
2018-12-24
person1
2018-12-25
person1

I want my logs to be structured the same way. How hard can it be? ::

2018-12-23/
person1_output.txt
person2_output.txt
2018-12-24/
person1_output.txt
2018-12-25/
person1_output.txt

Let's find out::

def easy_get_path(date, person):
return CachePath(date, person, suffix='_output.txt')
def hard_get_path(date, person):
personfilename = '{}_output.txt'.format(person)
returning = Path(tempfile.gettempdir())/date/personfilename
return returning

Actually, we made a mistake. These aren't equivalent. We may find out when we
pass our path to another tool that it refuses to create the ``date`` folder
if it doesn't already exist. This issue can show itself as a Permission Denied
error on Unix systems rather than the "File/Folder not found" you might think
you would get. Regardless, we figured it out, let's try again::

def hard_get_path():
personfilename = '{}_output.txt'.format(person)
returning = Path(tempfile.gettempdir())/date/personfilename
# Does this mkdir update the modified timestamp of the folders we're in?
# Might matter if we're part of a larger toolset...
returning.parent.mkdir(exist_ok=True, parents=True)
return returning

Now, how do we clear out some day's results so that we can be sure we're looking
at fresh output of the tool? ::

def easy_clear_date(date):
CachePath(date).clear() # rm -r /tmp/date/*
def hard_clear_date(date):
# We happen to know that date is a folder and not a file (at least in our
# current design), so we know we need some form of .remove rather than
# .unlink(). Unfortunately, pathlib doesn't offer one for folders with
# files still in them. If you google how to do it, you will find plenty of
# answers, one of which is a pure pathlib recursive solution! But we're lazy:
p = Path(tempfile.gettempdir(), date)
import shutil
if p.exists():
shutil.rmtree(p)
p.mkdir(exist_ok=True, parents=True)
# This still isn't exactly equivalent, because we've lost whatever
# permissions were set on the date folder, or if it were actually a symlink
# to somewhere else, that's gone now.

And all of this is ignoring the hacky imports you have to do to get ``pathlib``
in Py3 and ``pathlib2`` in Py2::

from cachepath import Path # py2/3
# or
try:
from pathlib import Path
except:
from pathlib2 import Path


Convinced yet? ``pip install cachepath`` or copy `the source`_ into your local
``utils.py`` (you know you have one.)
:ref:`API doc is here.<genned>`


Shameless Promo
----------------
Find yourself working with paths a lot in cmd-line tools? You might like
`invoke`_ and/or `magicinvoke`_!

.. [*] The source for CachePath can be downloaded from the `Github repo`_.

.. _Github repo: https://github.com/haydenflinner/cachepath
.. [*] This package was created with Cookiecutter_ and the `audreyr/cookiecutter-pypackage`_ project template.

.. _`the source`: https://github.com/haydenflinner/cachepath/blob/master/cachepath/__init__.py
.. _Cookiecutter: https://github.com/audreyr/cookiecutter
.. _`audreyr/cookiecutter-pypackage`: https://github.com/audreyr/cookiecutter-pypackage
.. _`invoke`: https://www.pyinvoke.org
.. _`magicinvoke`: https://magicinvoke.readthedocs.io/en/latest/


=======
History
=======

0.1.0 (2018-12-08)
------------------

* First release on PyPI. Adds CachePath, TempPath, Path.


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