qufighter / localfilebrowser Goto Github PK

While looking for a way to easily preview local images I found your extension. Although it doesn't do what I want, I reviewed the code and have some suggestions.

file:// permission - improve usability

1. The extension requires file:/// access in order to be functional, and you're getting 1-star reviews because people can't be bothered to read your description that explicitly lists this requirement. I suggest to use chrome.extension.isAllowedFileSchemeAccess to check whether the extension has file access, and if not prompt the user for permission (e.g. by opening a new tab).
2. To complement the above suggestion, add the webNavigation permission (you already have the tabs permission, so there is no permission warning) and use the chrome.webNavigation.onBeforeNavigate event to detect navigations to file://-URLs, and show the permission request when the extension lacks the file permission.

Here is an example (for local PDF files): https://github.com/mozilla/pdf.js/blob/64a409b539bf7974aa695dec82fa414cfcb777ac/extensions/chromium/pdfHandler.js#L191-L215

Note that the above example replaces the tab with an extension page because the extension assumes that Chrome is not able to open the PDF file without the extension. In your case, you probably want to open a new tab instead (chrome.tabs.create).

Fix fragile rotation logic

It seems that you're fighting against the same origin policy in localfiles.user.js and background.js to rotate pictures. The current "solution" is to repeatedly move the image around, capture a screenshot of the tab and assemble the images later. This is fragile, I tested it on one image and it did not work.

I suggest to use XMLHttpRequest with responseType='blob' (from the content script, localfiles.user.js), then get a same-origin URL using URL.createObjectURL(blob), and then directly load this image in an new Image() for straightforward manipulation on a canvas.

This would be much faster than your current method and also less error-prone.