Mailing List Archive: making your own DirEntry.

making your own DirEntry.

Dec 22, 2023, 4:00 AM

Post #1 of 6 (190 views)

I am writing a program that goes through file hierarchies and I am mostly
using scandir for that which produces DirEntry instances.

At times it would be usefull if I could make my own DirEntry for a specific
path, however when I try, I get the following diagnostic:

>>> os.DirEntry('snap')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: cannot create 'posix.DirEntry' instances

Does anyone have an idea for why this limitation and how to go around it.

At this moment I don't consider pathlib very usefull, it lacks the
follow_symlinks parameter in the is_dir, is_file, ... methods.

--
Antoon Pardon.

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Re: making your own DirEntry. [ In reply to ]

python-list at python

Dec 22, 2023, 12:39 PM

Post #2 of 6 (190 views)

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Antoon,

On 12/23/23 01:00, Antoon Pardon via Python-list wrote:
> I am writing a program that goes through file hierarchies and I am mostly
> using scandir for that which produces DirEntry instances.
>
> At times it would be usefull if I could make my own DirEntry for a specific
> path, however when I try, I get the following diagnostic:
>
>>>> os.DirEntry('snap')
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> TypeError: cannot create 'posix.DirEntry' instances
>
>
> Does anyone have an idea for why this limitation and how to go around it.
>
> At this moment I don't consider pathlib very usefull, it lacks the
> follow_symlinks parameter in the is_dir, is_file, ... methods.

Can't recall ever trying this.

The manual (https://docs.python.org/3/library/os.html#os.DirEntry)
suggests that a DirEntry is one of those Python data-constructs which it
creates, but we may only use: "cannot create".

Secondly, that a DirEntry object consists of a lot more than the
directory-name, eg its path.

Thirdly, that os.scandir() deals (only) with concrete directories -
unlike pathlib's ability to work with both the real thing and abstract
files/dirs.

Why create a DirEntry? Why not go directly to os.mkdir() or whatever?

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Re: making your own DirEntry. [ In reply to ]

python-list at python

Dec 23, 2023, 1:48 AM

Post #3 of 6 (187 views)

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Op 22/12/2023 om 21:39 schreef DL Neil via Python-list:
> Antoon,
>
>
> On 12/23/23 01:00, Antoon Pardon via Python-list wrote:
>> I am writing a program that goes through file hierarchies and I am
>> mostly
>> using scandir for that which produces DirEntry instances.
>>
>> At times it would be usefull if I could make my own DirEntry for a
>> specific
>> path, however when I try, I get the following diagnostic:
>>
>>>>> os.DirEntry('snap')
>> Traceback (most recent call last):
>> File "<stdin>", line 1, in <module>
>> TypeError: cannot create 'posix.DirEntry' instances
>>
>>
>> Does anyone have an idea for why this limitation and how to go around
>> it.
>>
>> At this moment I don't consider pathlib very usefull, it lacks the
>> follow_symlinks parameter in the is_dir, is_file, ... methods.
>
>
> Can't recall ever trying this.
>
>
> The manual (https://docs.python.org/3/library/os.html#os.DirEntry)
> suggests that a DirEntry is one of those Python data-constructs which
> it creates, but we may only use: "cannot create".
>
> Secondly, that a DirEntry object consists of a lot more than the
> directory-name, eg its path.
>
> Thirdly, that os.scandir() deals (only) with concrete directories -
> unlike pathlib's ability to work with both the real thing and abstract
> files/dirs.
>
>
> Why create a DirEntry? Why not go directly to os.mkdir() or whatever?

Because I have functions with DirEntry parameters.

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Re: making your own DirEntry. [ In reply to ]

python-list at python

Dec 23, 2023, 2:30 AM

Post #4 of 6 (185 views)

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On 12/23/23 10:48, Antoon Pardon wrote:
> Op 22/12/2023 om 21:39 schreef DL Neil via Python-list:
>> Why create a DirEntry? Why not go directly to os.mkdir() or whatever?
>
> Because I have functions with DirEntry parameters.
>

Python is duck-typed, so it's quite likely that if you pass something
that *looks like* a DirEntry - has the same variables and methods - it
will work. If it walks like a DirEntry and quacks like a DirEntry, it's
a DirEntry.
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Re: making your own DirEntry. [ In reply to ]

python-list at python

Dec 23, 2023, 3:34 AM

Post #5 of 6 (186 views)

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> On 23 Dec 2023, at 09:48, Antoon Pardon via Python-list <python-list@python.org> wrote:
>
> Because I have functions with DirEntry parameters.

I would duck-type a class I control to be my DirEnrry in this situation.
Would also help you when debugging as you can tell injected DirEntry from "real" DirEntry.

Barry

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Re: making your own DirEntry. [ In reply to ]

python-list at python

Dec 23, 2023, 4:21 AM

Post #6 of 6 (186 views)

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Op 23/12/2023 om 12:34 schreef Barry Scott:
>
>
>> On 23 Dec 2023, at 09:48, Antoon Pardon via Python-list
>> <python-list@python.org> wrote:
>>
>> Because I have functions with DirEntry parameters.
>
> I would duck-type a class I control to be my DirEnrry in this situation.
> Would also help you when debugging as you can tell injected DirEntry
> from "real" DirEntry.
>
Yes that seems to be, the way to go.

--
Antoon Pardon
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