CODEWITHSUNDEEP
javascriptgoogle-chromegoogle-chrome-extensionwebpage-screenshot
Chris
Chris

Reputation: 68

captureVisibleTab returning undefined

captureVisibleTab [docs] doesn't appear to be working for me in my Google Chrome extension, I've been trying to get it running in a browser action based extension but the image returned is undefined every time. I then downloaded the example created by Google and this also doesn't appear to work, returning either undefined or white.png (a blank white image) as the image src.

I've tried setting permissions to "tabs", "<all_urls>" in the manifest.json files for both projects. I have Google Chrome 37.

I've been trying to find an answer but I don't see any solid information out there, is there a bug, and is there a fix for it? If there's no fix are there any alternatives?

Thanks, Christian.

Edit: I should probably make this part more clear. I downloaded the Google example, installed it, ran the extension on code.google.com, and a blank image was returned see screenshot.

Upvotes: 1

Views: 1492

Answers (1)

Rob W
Rob W

Reputation: 348972

There are two bugs at play here:

  1. chrome.tabs.captureVisibleTab requires the <all_urls> permission (crbug.com/339703).
  2. chrome.tabs.onUpdated is never triggered for extension pages in newly opened extension tabs (crbug.com/411225).

The work-around for the first bug is to declare <all_urls> in the permissions section of the manifest file; the work-around for the second bug is to not use the chrome.tabs.onUpdated event to detect whether a tab is updated, but use message passing or chrome.runtime.getBackgroundPage to get the data-URL of the screenshot in the newly opened extension page. (note that you cannot use the webNavigation instead of the tabs API to detect new tabs, because chrome-extension:-URLs are hidden from the webNavigation API).

Upvotes: 2

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