Option to enable localStorage in WebView panels

[jdgarcia]

I am currently using the vscode.previewHtml command to display a web app in VS Code (via iframe) which uses localStorage to store persisting state, and I am currently trying to convert it to use the new Webview API, in order to take advantage of the new retainContextWhenHidden option. I noticed however that while accessing localStorage works fine when using vscode.previewHtml, it is disabled in panels that use the Webview API.

I saw that a persistence API is currently being worked on (#49022), but in order to even use that, I would have to wrap all my localStorage gets/sets in async functions that check to see if localStorage is accessible, and if it isn't, use message passing between the iframe and the webview in order to use getState/setState inside the webview.

That would be doable but it's definitely not ideal.

This comment seems to imply that it is disabled intentionally but is something that can potentially be enabled.

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Webview: Failed to read the localStorage property from Window (#48464)

[mjbvz]

It's disabled because we serve webview using data uris: https://stackoverflow.com/questions/37379254/how-to-save-data-to-the-browser-with-data-url/37541068

[formulahendry]

Do we have plan to enable this? I meet with the same issue on https://marketplace.visualstudio.com/items?itemName=formulahendry.vscode-node-red extension. Currently, we are using vscode.previewHtml but want to use retainContextWhenHidden in new WebView API. However, localStorage is not enabled..

[mjbvz]

@formulahendry You should not need local storage. See the new persistence APIs instead

[formulahendry]

Hi @mjbvz , in my extension, I embed https://www.npmjs.com/package/node-red (which is just a localhost website) into the webview. I have no control of node-red npm package to not to use local storage.. Any suggestion would be appreciated. Thanks!

[jrieken]

It a WebView, not a WebBrowser ;-) I don't think we can isolate local storage of web views with the local storage VS Code is using That would be cross pollution that's generally undesirable for us.

[formulahendry]

If we have no plan to support that in WebView, do we have plan to make vscode.previewHtml not re-render when switching? I really need the page to be retained. 😢

[mjbvz]

No. You should use a webview. The old html preview is deprecated and will not receive new features

[formulahendry]

OK, so seems like I need to wait for localStorage to be enabled in WebView.

[vscodebot]

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