Filesystem path APIs

2 years ago by Niels Dossche — view source — reply

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Hi internals

I'd like to start a pre-RFC discussion about filesystem path APIs in PHP.
The reason I bring this up is because of this recent feature request: https://github.com/php/php-src/issues/11258

The feature request is about the following:
We already have some functions to work with paths in PHP, e.g. basename, dirname, realpath.
We do not have some common path APIs that you can find in other languages like: path_join to join paths and path_normalize to normalize paths.

As not everyone may be familiar with such functions, I'll explain them briefly.

Proposed Functions:

path_join(string... $components): string;
This function concatenates the components with a / (or \ on Windows) between them and normalizes the path.
If the resulting path is empty then it'll return "." to indicate the current directory.
You may be wondering "Isn't this just implode?". Not really, it normalizes the path too, which means that components like "." are removed from the path, redundant slashes are removed, and if there are ".." components then they remove the previous component from the path.

It's also not the same thing as calling realpath after doing implode: realpath would not work for non-existent paths and it would allow escaping from the root.
To demo the root escape problem:
path_join("..", "foo"); yields "foo"
Whereas realpath("../foo"); yields the absolute path of the "foo" file one directory up.

Note: This function does not do any I/O.

path_normalize(string $path): string;

This function only does the normalization part described above.
Note: This function also does not do any I/O.

Examples:

// Example usage of path_join
$result = path_join('dir1', 'dir2', '..', 'file.txt'); // Resolves to 'dir1/file.txt'

// Example usage of path_normalize
$normalizedPath = path_normalize('dir1/../dir2'); // Resolves to 'dir2'

I think these would be great additions to PHP as working with paths and files is a core part of any programming language.

Furthermore, languages like Python and runtimes like Node.JS allow to join and normalize paths that are not native to the operating system PHP is running on.
E.g. it's possible to create a Posix-style path (what is used on Linux, macOS, BSD etc) on a Windows system.
This is sometimes necessary in order to construct a path to access a remote file on a Linux server to just give an example.

In PHP we could add functions like (just to give an example):
\Path\Windows\join for Windows paths
\Path\Posix\join for Linux/macOS/Posix paths
\Path\join that automatically chooses one of the above depending on what operating system PHP runs on.
Similar approach for path_normalize.

There could be OOP-style alternatives too, e.g. Rust has a PathBuf struct with methods that are used to build paths.
However if we were to choose this route then we need to be aware that interoperability with existing filesystem functions would be much harder because they all work directly with strings at the moment.

What do you think?

Kind regards
Niels

2 years ago by Ayesh Karunaratne — view source — reply

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There could be OOP-style alternatives too, e.g. Rust has a PathBuf struct with methods that are used to build paths.
However if we were to choose this route then we need to be aware that interoperability with existing filesystem functions would be much harder because they all work directly with strings at the moment.

I think we really could use such an API. I would have liked a more
OOP-style approach, because it can impactfully "consolidate" various
functions into one.
I really like NodeJS Path class (https://nodejs.org/api/path.html),
which I think have done a really nice job at making it simple while
being quite versatile even for remote system paths.

In PHP land, the now-abandoned path-util
(https://packagist.org/packages/webmozart/path-util) library also had
an intuitive API.

2 years ago by Jeffrey Dafoe — view source — reply

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The feature request is about the following:
We already have some functions to work with paths in PHP, e.g. basename,
dirname, realpath.
We do not have some common path APIs that you can find in other languages
like: path_join to join paths and path_normalize to normalize paths.
...
What do you think?

That would be a welcome addition in my book.

-Jeff

2 years ago by Max Semenik — view source — reply

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On Wed, Dec 6, 2023 at 10:20 PM Niels Dossche dossche.niels@gmail.com
wrote:

Hi internals

I'd like to start a pre-RFC discussion about filesystem path APIs in PHP.
The reason I bring this up is because of this recent feature request:
https://github.com/php/php-src/issues/11258

The feature request is about the following:
We already have some functions to work with paths in PHP, e.g. basename,
dirname, realpath.
We do not have some common path APIs that you can find in other languages
like: path_join to join paths and path_normalize to normalize paths.

We have a lot of commonly used functionality that's successfully fulfilled
by Composer packages - does this really have to be core functionality? I
understand the argument about batteries included, but across mainstream
languages you can always find examples of something that sounds like it
should really be there, but it isn't.

--
Best regards,
Max Semenik

2 years ago by Lanre Waju — view source — reply

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So your suggestion for simple file stuff is to download composer?

On Wed, Dec 6, 2023 at 10:20 PM Niels Dossche dossche.niels@gmail.com
wrote:

Hi internals

I'd like to start a pre-RFC discussion about filesystem path APIs in PHP.
The reason I bring this up is because of this recent feature request:
https://github.com/php/php-src/issues/11258

The feature request is about the following:
We already have some functions to work with paths in PHP, e.g. basename,
dirname, realpath.
We do not have some common path APIs that you can find in other languages
like: path_join to join paths and path_normalize to normalize paths.

We have a lot of commonly used functionality that's successfully fulfilled
by Composer packages - does this really have to be core functionality? I
understand the argument about batteries included, but across mainstream
languages you can always find examples of something that sounds like it
should really be there, but it isn't.

2 years ago by Max Semenik — view source — reply

unread

So your suggestion for simple file stuff is to download composer?

Not necessarily, but I'd like to have more discussion of pros and cons.

--
Best regards,
Max Semenik

2 years ago by Pierre Joye — view source — reply

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On Wed, Dec 6, 2023 at 10:20 PM Niels Dossche dossche.niels@gmail.com
wrote:

Hi internals

I'd like to start a pre-RFC discussion about filesystem path APIs in PHP.
The reason I bring this up is because of this recent feature request:
https://github.com/php/php-src/issues/11258

The feature request is about the following:
We already have some functions to work with paths in PHP, e.g. basename,
dirname, realpath.
We do not have some common path APIs that you can find in other languages
like: path_join to join paths and path_normalize to normalize paths.

We have a lot of commonly used functionality that's successfully fulfilled
by Composer packages - does this really have to be core functionality?

if any of them could be a easy win, relative path resolver without checking
its existence would be one. It is available internally but the existence
check option is not exposed.

2 years ago by Dusk — view source — reply

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if any of them could be a easy win, relative path resolver without checking
its existence would be one. It is available internally but the existence
check option is not exposed.

Are you thinking of realpath()? That also expands symbolic links, which wouldn't be desirable for abstract path manipulation.

2 years ago by David CARLIER — view source — reply

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Hi Niels,

Hi internals

I'd like to start a pre-RFC discussion about filesystem path APIs in PHP.
The reason I bring this up is because of this recent feature request:
https://github.com/php/php-src/issues/11258

The feature request is about the following:
We already have some functions to work with paths in PHP, e.g. basename,
dirname, realpath.
We do not have some common path APIs that you can find in other languages
like: path_join to join paths and path_normalize to normalize paths.

As not everyone may be familiar with such functions, I'll explain them
briefly.

Proposed Functions:

path_join(string... $components): string;
This function concatenates the components with a / (or \ on Windows)
between them and normalizes the path.
If the resulting path is empty then it'll return "." to indicate the
current directory.
You may be wondering "Isn't this just implode?". Not really, it normalizes
the path too, which means that components like "." are removed from the
path, redundant slashes are removed, and if there are ".." components then
they remove the previous component from the path.

It's also not the same thing as calling realpath after doing implode:
realpath would not work for non-existent paths and it would allow escaping
from the root.
To demo the root escape problem:
path_join("..", "foo"); yields "foo"
Whereas realpath("../foo"); yields the absolute path of the "foo" file one
directory up.

Note: This function does not do any I/O.

path_normalize(string $path): string;

This function only does the normalization part described above.
Note: This function also does not do any I/O.

Examples:
// Example usage of path_join
$result = path_join('dir1', 'dir2', '..', 'file.txt'); // Resolves to
'dir1/file.txt'

// Example usage of path_normalize
$normalizedPath = path_normalize('dir1/../dir2'); // Resolves to 'dir2'
I think these would be great additions to PHP as working with paths and
files is a core part of any programming language.

Seems like it, is there an argument to be made to, let's say, in the
performance side ?

2 years ago by Niels Dossche — view source — reply

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Hi David

I think these would be great additions to PHP as working with paths and files is a core part of any programming language.
Seems like it, is there an argument to be made to, let's say, in the performance side ?

A native implementation is going to be faster than an implementation in userspace.
However, I don't think that matters because the performance is likely dominated by the I/O you do after constructing a path.
You'd need to construct a large number of paths before you notice anything I guess.

Cheers
Niels

2 years ago by David CARLIER — view source — reply

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Hi David
I think these would be great additions to PHP as working with paths
and files is a core part of any programming language.

Seems like it, is there an argument to be made to, let's say, in the
performance side ?

A native implementation is going to be faster than an implementation in
userspace.
However, I don't think that matters because the performance is likely
dominated by the I/O you do after constructing a path.
You'd need to construct a large number of paths before you notice anything
I guess.

Cheers
Niels

Very true, so what would be the argument beside having those as "builtins"
as opposed to external components ?

2 years ago by Niels Dossche — view source — reply

unread

Hi David
I think these would be great additions to PHP as working with paths
and files is a core part of any programming language.

Seems like it, is there an argument to be made to, let's say, in the
performance side ?

A native implementation is going to be faster than an implementation in
userspace.
However, I don't think that matters because the performance is likely
dominated by the I/O you do after constructing a path.
You'd need to construct a large number of paths before you notice anything
I guess.

Cheers
Niels
Very true, so what would be the argument beside having those as "builtins"
as opposed to external components ?

Mainly for convenience reasons and a correct implementation provided by PHP.
Many functions in PHP are not strictly necessary because they can be implemented in userland.
They're only there for convenience reasons. Where to draw the line is difficult.
To me they complement the realpath(), dirname(), basename() functions.

2 years ago by Erick de Azevedo Lima — view source — reply

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I'm in favor for this. I think that, since you already have a built-in file
API, adding useful functions is always good. I use \str_starts_with and
\str_ends_with a lot in my code. In Laravel, which is the most used
Framework these days, you have the \Illuminate\Supports\Str::startsWith and
\Illuminate\Supports\Str::endsWith, but it did stop the implementation of
those functions in the core and I'm glad for it.

Best regards,
Erick

Em sáb., 9 de dez. de 2023 às 13:21, Niels Dossche dossche.niels@gmail.com
escreveu:

On Fri, 8 Dec 2023 at 16:10, Niels Dossche dossche.niels@gmail.com
wrote:
Hi David
I think these would be great additions to PHP as working with paths
and files is a core part of any programming language.

Seems like it, is there an argument to be made to, let's say, in the
performance side ?

A native implementation is going to be faster than an implementation in
userspace.
However, I don't think that matters because the performance is likely
dominated by the I/O you do after constructing a path.
You'd need to construct a large number of paths before you notice
anything
I guess.

Cheers
Niels
Very true, so what would be the argument beside having those as
"builtins"
as opposed to external components ?
Mainly for convenience reasons and a correct implementation provided by
PHP.
Many functions in PHP are not strictly necessary because they can be
implemented in userland.
They're only there for convenience reasons. Where to draw the line is
difficult.
To me they complement the realpath(), dirname(), basename() functions.

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