Allow showOpenDialog to open local files

[connor4312]

In the demo in https://github.com/microsoft/vscode-internalbacklog/issues/2178#issuecomment-901514989, I had to manually create a file in the web workspace since I couldn't figure out a way to get vscode.window.showOpenDialog to open a file on the user's machine. Rob suggested that adding a file:/// URI as the defaultUri might work, but it doesn't.

Is opening a local file in this way already possible, and if not could we add a way for it to happen, perhaps using the defaultUri as Rob suggested?

[alexr00]

There was some discussion somewhere about whether we should allow extensions to open local files on web which I now cannot find. If I remember correctly, the outcome of the discussion was that we wouldn't allow it for now because:

• we didn't have compelling reason to allow it.
• it was probably almost never what the extension wanted to do and more likely would result from a programming error.

Now we have a real need for it now though. Given the potential for error here, we should consider making the local file option for vscode.window.showOpenDialog opt-in, and not something that could be done by accident. Similar to the availableFilesystems option we have internally:

vscode/src/vs/platform/dialogs/common/dialogs.ts

Lines 101 to 107 in ee1655a

	export interface IPickAndOpenOptions {
	forceNewWindow?: boolean;
	defaultUri?: URI;
	telemetryExtraData?: ITelemetryData;
	availableFileSystems?: string[];
	remoteAuthority?: string | null;
	}

[connor4312]

Sounds good. Let's dive into this more next iteration; Kai would like to get the referenced experience going by the end of this year :)

[connor4312]

Actually with the new approach with embedder-side code in vscode.dev I don't really need this -- I can have a custom command added in the embedder which opens a file and passes it back down. Having an API for this would make it simpler, though, and there may be other use cases, so I'll leave it open.

[connor4312]

I think this will still be eventually needed, but my particular use case is no longer required.

[bpasero]

This seems to work fine for me now?

[alexr00]

@bpasero extension API still can't cause the "Show Local" button to show.

[bpasero]

Ah ok 👍

[alexr00]

Proposal:

vscode/src/vscode-dts/vscode.proposed.showLocal.d.ts

Lines 10 to 18 in 1f4d6ea

	export interface OpenDialogOptions {
	/**
	* Controls whether the dialog allows users to select local files via the "Show Local" button.
	* Extensions that set this to `true` should check the scheme of the selected file.
	*
	* TODO: Workspace extensions already get only `file` scheme URIs back from the dialog. How will we tell the extension that the file is local?
	*/
	allowLocal?: boolean;
	}

[jrieken]

alt name; allowUIResources

[gulshan]

Can the "web/remote" open file view be made available for opening local files also, through a setting?

[alexr00]

It already is! "files.simpleDialog.enable": true

[gulshan]

Did not know that! Thanks.

[connor4312]

The prototype this was for is not the direction we ended up going, so I don't need this any more, but it might be otherwise useful

[alexr00]

@connor4312 , If you're not using it, I'll delete the vscode.proposed file for it.

Do you have another use for this? I haven't heard from any extension authors that need this. I'm inclined to clone as out of scope since I don't foresee us adding this any time soon.

[connor4312]

Not so far