Extra Path functionality

• alias remove for unlink on Path
• add copy() and rmtree() from shutil to Path
• add hash() to path return the hashlib.new() value on the file content (defaults to 'sha224', other algorithms can be given as parameter: print(p.hash('md5').hexdigest()))

when you have blake3 installed and do import ruamel.std.pathlib.blake3, you can also use that method on Path instances.

Transition helper

If you are starting to use the standard pathlib library, it is cumbersome to change everything at once, and also to change all the arguments to calls to os.path.join, os.rename, os.path.dirname to be made encapsulated in str()

By making an instance of PathLibConversionHelper named pl you can change os.path.join() to pl.path.join(), etc., and then start passing in Path instances instead of strings.

PathLibConversionHelper currently supports the following replacements for os,

os.path, shutil and built-in functions:

.chdir()             replaces: os.chdir()
.copy()              replaces: shutil.copy()
.glob()              replaces: glob.glob()
.listdir()           replaces: os.listdir()
.makedirs()          replaces: os.makedirs()
.mkstemp()           replaces: tempfile.mkstemp()
.open()              replaces: built-in open()
.path.basename()     replaces: os.path.basename()
.path.dirname()      replaces: os.path.dirname()
.path.exists()       replaces: os.path.exists()
.path.expanduser()   replaces: os.path.expanduser()
.path.getmtime()     replaces: os.path.getmtime()
.path.isdir()        replaces: os.path.isdir()
.path.join()         replaces: os.path.join()
.path.splitext()     replaces: os.path.splitext()
.remove()            replaces: os.remove()
.rename()            replaces: os.rename()
.rmdir()             replaces: os.rmdir()
.rmtree()            replaces: shutil.rmtree()
.walk()              replaces: os.walk()

You can provide a check level when you create the PathLibConversionHelper() instance.

• If check is non-zero, all calls are being logged and the invocations can be dumped e.g. at the end of the program with pl.dump(stream, show_all=False) This will include the number of invocations not using Path (and using Path uniquely as well if show_all=True)
• If check is greater than 1, first usage is dumped immediately.

If you start with the following code:

# coding: utf-8

import os
import glob
import tempfile
import shutil
import random


class TempDir(object):
    """self removing (unless keep=True) temporary directory"""
    def __init__(self, keep=False, basedir=None, prefix=None):
        self._keep = keep
        # mkdtemp creates with permissions rwx------
        kw = dict(dir=basedir)
        if prefix is not None:
            kw['prefix'] = prefix
        # mkdtemp doesn't do the right thing if None is passed in
        # as it has prefix=template in definition
        self._tmpdir = tempfile.mkdtemp(**kw)

    def remove(self):
        shutil.rmtree(self._tmpdir)

    def chdir(self):
        os.chdir(self._tmpdir)

    def tempfilename(self, extension=''):
        fd, name = tempfile.mkstemp(suffix=extension, dir=self._tmpdir)
        os.close(fd)
        return name

    def tempfilename2(self, extension=''):
        while True:
            name = os.path.join(
                self._tmpdir,
                '%08d' % random.randint(0, 100000) + extension
            )
            if not os.path.exists(name):
                break
        return name

    @property
    def directory(self):
        return self._tmpdir

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        if not self._keep:
            self.remove()


def main():
    """contrived example using TempDir"""
    org_dir = os.getcwd()
    with TempDir() as td:
        for n in range(3):
            t1 = td.tempfilename(extension='.sample')
            with open(t1, 'w') as fp:
                fp.write('content\n')
        t2 = td.tempfilename2(extension='.sample2')
        with open(t2, 'w') as fp:
            fp.write('content\n')
        os.chdir(td.directory)
        count = 0
        for file_name in glob.glob('*.samp*'):
            full_name = os.path.join(os.getcwd(), file_name)  # noqa
            # print(full_name)
            count += 1
        os.chdir('/tmp')  # not using Path
        os.chdir(org_dir)
    print('{} files found in temporary directory'.format(count))

main()

you get:

4 files found in temporary directory

When you start to change TempDir() to store the actual directory as a Path, things start to break immediately:

# coding: utf-8

import os
import glob
import tempfile
import shutil
import random

from ruamel.std.pathlib import Path                                   # added


class TempDir(object):
    """self removing (unless keep=True) temporary directory"""
    def __init__(self, keep=False, basedir=None, prefix=None):
        self._keep = keep
        # mkdtemp creates with permissions rwx------
        kw = dict(dir=basedir)
        if prefix is not None:
            kw['prefix'] = prefix
        # mkdtemp doesn't do the right thing if None is passed in
        # as it has prefix=template in definition
        self._tmpdir = Path(tempfile.mkdtemp(**kw))                   # changed

    def remove(self):
        shutil.rmtree(self._tmpdir)

    def chdir(self):
        os.chdir(self._tmpdir)

    def tempfilename(self, extension=''):
        fd, name = tempfile.mkstemp(suffix=extension, dir=self._tmpdir)
        os.close(fd)
        return name

    def tempfilename2(self, extension=''):
        while True:
            name = os.path.join(
                self._tmpdir,
                '%08d' % random.randint(0, 100000) + extension
            )
            if not os.path.exists(name):
                break
        return name

    @property
    def directory(self):
        return self._tmpdir

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        if not self._keep:
            self.remove()


def main():
    """contrived example using TempDir"""
    org_dir = os.getcwd()
    with TempDir() as td:
        for n in range(3):
            t1 = td.tempfilename(extension='.sample')
            with open(t1, 'w') as fp:
                fp.write('content\n')
        t2 = td.tempfilename2(extension='.sample2')
        with open(t2, 'w') as fp:
            fp.write('content\n')
        os.chdir(td.directory)
        count = 0
        for file_name in glob.glob('*.samp*'):
            full_name = os.path.join(os.getcwd(), file_name)  # noqa
            # print(full_name)
            count += 1
        os.chdir('/tmp')  # not using Path
        os.chdir(org_dir)
    print('{} files found in temporary directory'.format(count))

main()

With some errors:

Traceback (most recent call last):
  File "_example/stage1.py", line 80, in <module>
    main()
  File "_example/stage1.py", line 77, in main
    os.chdir(org_dir)
  File "_example/stage1.py", line 56, in __exit__
    self.remove()
  File "_example/stage1.py", line 27, in remove
    shutil.rmtree(self._tmpdir)
  File "/opt/python/2.7.13/lib/python2.7/shutil.py", line 228, in rmtree
    if os.path.islink(path):
  File "/home/venv/dev/lib/python2.7/posixpath.py", line 135, in islink
    st = os.lstat(path)
TypeError: coercing to Unicode: need string or buffer, PosixPath found

Instead of changing every usage in your program in one go, and hope it will work again, you replace the routines from the standard module:

# coding: utf-8

import os
import glob
import tempfile
import shutil                       # noqa
import random

from ruamel.std.pathlib import Path, PathLibConversionHelper            # changed
pl = PathLibConversionHelper()                                          # added


class TempDir(object):
    """self removing (unless keep=True) temporary directory"""
    def __init__(self, keep=False, basedir=None, prefix=None):
        self._keep = keep
        # mkdtemp creates with permissions rwx------
        kw = dict(dir=basedir)
        if prefix is not None:
            kw['prefix'] = prefix
        # mkdtemp doesn't do the right thing if None is passed in
        # as it has prefix=template in definition
        self._tmpdir = Path(tempfile.mkdtemp(**kw))

    def remove(self):
        pl.rmtree(self._tmpdir)

    def chdir(self):
        os.chdir(self._tmpdir)

    def tempfilename(self, extension=''):
        fd, name = pl.mkstemp(suffix=extension, dir=self._tmpdir)     # changed
        os.close(fd)
        return name

    def tempfilename2(self, extension=''):
        while True:
            name = pl.path.join(
                self._tmpdir,
                '%08d' % random.randint(0, 100000) + extension
            )
            if not pl.path.exists(name):                              # changed
                break
        return name

    @property
    def directory(self):
        return self._tmpdir

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        if not self._keep:
            self.remove()


def main():
    """contrived example using TempDir"""
    org_dir = os.getcwd()
    with TempDir() as td:
        for n in range(3):
            t1 = td.tempfilename(extension='.sample')
            with open(t1, 'w') as fp:
                fp.write('content\n')
        t2 = td.tempfilename2(extension='.sample2')
        with pl.open(t2, 'w') as fp:
            c = 'content\n'                                           # added
            if not isinstance(fp, file):                              # added
                c = unicode(c)                                        # added
            fp.write(c)                                               # changed
        pl.chdir(td.directory)
        count = 0
        for file_name in glob.glob('*.samp*'):
            full_name = pl.path.join(os.getcwd(), file_name)  # noqa  # changed
            # print(full_name)
            count += 1
        pl.chdir('/tmp')  # not using Path
        pl.chdir(org_dir)                                             # changed
    print('{} files found in temporary directory'.format(count))

main()

giving (again):

4 files found in temporary directory

Change back just the creation of self._tempdir to the original:

self._tmpdir = tempfile.mkdtemp(**kw)

and the output stays:

4 files found in temporary directory

If you now change the creation of pl to:

pl = PathLibConversionHelper(check=2)

you get as output:

update .mkstemp to use Path.mkstemp() [_example/stage3.py:34 / Path (True,)]
update .path.join to use "/" [_example/stage3.py:42 / Path (True, False)]
update .exists to use Path.exists() [_example/stage3.py:44 / Path (True,)]
update .open to use Path.open() [_example/stage3.py:69 / Path (True,)]
update .chdir to use Path.chdir() or os.chdir(str(Path)) [_example/stage3.py:74 / Path (True,)]
update .path.join to use "/" [_example/stage3.py:77 / Path (False, False)]
update .chdir to use Path.chdir() or os.chdir(str(Path)) [_example/stage3.py:80 / Path (False,)]
update .chdir to use Path.chdir() or os.chdir(str(Path)) [_example/stage3.py:81 / Path (False,)]
update .rmtree to use Path.rmtree() or shutil.rmtree(str(Path)) [_example/stage3.py:28 / Path (True,)]
4 files found in temporary directory

If you use check=1 and at the end pl.dump(), you get:

4 files found in temporary directory
update .path.join to use "/" [_example/stage4.py:42 / 1 / Path (True, False)]
update .chdir to use Path.chdir() or os.chdir(str(Path)) [_example/stage4.py:81 / 1 / Path (False,)]
update .path.join to use "/" [_example/stage4.py:77 / 4 / Path (False, False)]
update .chdir to use Path.chdir() or os.chdir(str(Path)) [_example/stage4.py:80 / 1 / Path (False,)]

showing where you still use string based paths/filenames.

The message part file_name.py: 123 / 2 / Path (True, False) means that there were two calls on line 123 in file_name.py and that they were called with the first parameter being a Path, the second not being a Path (when replacing os.path.join() with Path's "/" concatenation operator that would be a good starting point, for other situation you might want to convert the second parameter to a Path instance as well).

Extending PathLibConversionHelper

If PathLibConversionHelper doesn't contain a particular function (yet) you can easily subclass it and add your own:

from ruamel.std.pathlib import Path, PathLibConversionHelper


class MyPLCH(PathLibConversionHelper):
    # an example, ruamel.std.pathlib already adds mkstemp
    def mkstemp(self, suffix="", prefix=None, dir=None, text=False):
        import tempfile
        # would be much better if prefix defaults to built-in value (int, None, string)
        if prefix is None:
            prefix = tempfile.template
        self.__add_usage(dir, 'update .mkstemp to use Path.mkstemp()')
        if isinstance(dir, Path):
            dir = str(dir)
        return tempfile.mkstemp(suffix, prefix, dir, text)

pl = MyPLCH(check=1)

The first parameter for self.add_usage() is used to determine if a Path is used or not. This should be a list of all relevant variables (that could be Path instances or not). If the list would only have a single element it doesn't have to be passed in as a list (as in the example). The second parameter should be a string with some help on further getting rid of the call to .mkstemp().