Storing directory handles does not work

[sirinsidiator]

I just added support for the File System Access API to one of my projects and since it's not available in Firefox I'm really glad I found this extension. Thanks for making this!

However I found several issues where this extension does not behave like how Chrome does, which I'd like to report.

I'm trying to keep a directory handle stored between page visits, but sadly it seems the extension currently does not support this.
After loading the handle from the IndexDB it is missing all its functions (queryPermission, requestPermission, entries). In Chrome the same code works just fine.

[ichaoX]

Hi, there are two experimental solutions to this issue.

1. Enable CLONE_ENABLED in the options page, for example:

    API_ENABLED: !!self.isSecureContext,
-    CLONE_ENABLED: ['vscode.dev'].includes(location.hostname),
+    CLONE_ENABLED: ['vscode.dev','sir.insidi.at'].includes(location.hostname),
    WORKER_ENABLED: ['vscode.dev'].includes(location.hostname),

2. Enable EXPORSE_NAMESPACE in the options page, and call the parseHandle method. for example:

+    EXPORSE_NAMESPACE: true,
};

let parseHandle = (handle) => {
    if (!self.__fs || !self.__fs.parseHandle) return handle;
    return self.__fs.parseHandle(handle);
};

[sirinsidiator]

Adding the entry to CLONE_ENABLED worked. Thanks for the hint.

Maybe you can make it so the config is updated automatically when the user gives permission, or add some sort of UI to easily do this? Not sure why this extra step is needed, but it's certainly not something regular users will be able to accomplish on their own.

[ichaoX]

Because CLONE_ENABLED has side effects, it is not enabled by default.
For example: ('isSameEntry' in {}) === true.

[sirinsidiator]

Ah. Then it makes sense.
Maybe a workaround this issue could be a function that I can call in my script to manually restore the handle when I load it from the db? Probably not ideal, but better than having users fiddle around with the config.

[ichaoX]

Ah. Then it makes sense. Maybe a workaround this issue could be a function that I can call in my script to manually restore the handle when I load it from the db? Probably not ideal, but better than having users fiddle around with the config.

You may want to enable EXPORSE_NAMESPACE by default.

let parseHandle = (handle) => {
    if (!self.__fs || !self.__fs.parseHandle) return handle;
    return self.__fs.parseHandle(handle);
};

[sirinsidiator]

That works, but I'm not sure I like having that enabled by default for all pages. Maybe you could make it so it is only exposed when there are active permissions for the current page (in other words when the "File System Access" button is shown in the address bar)?
A simple checkbox in the panel that opens when pressing that button to quickly toggle the setting would also be cool.

Btw there is a typo in EXPORSE_NAMESPACE. Should be either EXPORT_NAMESPACE or EXPOSE_NAMESPACE.

[ichaoX]

If it is only made public when permissions are gained, it will not be possible to try to recover the first permission directly from the stored handle.

Maybe something like what __VUE_DEVTOOLS_GLOBAL_HOOK__ does.

The default __fs namespace should probably be changed to something like __FILE_SYSTEM_TOOLS__.

If there is a better way to implement CLONE_ENABLED that would be great.

[ichaoX]

Starting with v0.9.2, the default namespace has been changed from __fs to __FILE_SYSTEM_TOOLS__.
The default setting will contain EXPOSE_NAMESPACE: true,.

If you want to change the namespace to fs you can do this:

-    EXPOSE_NAMESPACE: true,
+    EXPOSE_NAMESPACE: 'fs',

[sirinsidiator]

Thanks! I just installed the latest version, reset the config to default and updated my script and it all works like a charm.

I also looked a bit into how the issue could be resolved without the need for support by a website, but the only idea that would work is to wrap all the different apis that could potentially load a stored file system handle. Which would probably be a horror to maintain and risks causing unexpected bugs in other peoples websites. So likely not a good idea.

I'll consider this unsolvable for now and take the current solution as the best possible one until something changes in Firefox. Feel free to close the issue if you want.