How can I access webpage data in a browser extension?

[olgerm]

I am trying to make a browser extension. Tutorial (https://developer.mozilla.org/en-US/Add-ons) from mozilla webpage teaches to make these in javascript, but is it possible to make browser extension in some other programming language?

How can I get URL of the tab user is watching. I tried browser.tabs.query({active: true, currentWindow: true},function(tabs){var URL = tabs[0].url;}) but it always makes variable URL equal to "undefined". Maybe because this script tries to get URL of extension's sidebar.

How can get data from webpage with given URL to further process it in same browser extension?

 

[FactChecker]

Is it possible that you are testing it in a development tool that gives you an active window where your call will not work? Here is a similar example that will work for a normal user but not when tested in the development tool. (see the first answer in https://stackoverflow.com/questions...turn-the-tabs-url-when-called-using-requirejs )

 

[olgerm]

Is it possible that you are testing it in a development tool that gives you an active window where your call will not work?

I am not using development tools. I load it as temporary add-on in Firefox to test it. It also makes variable URL equal to "undefined" if active tab is not about:debugging .

 

[olgerm]

I tried URL=window.location.href; ,but it makes variable URL equal to "moz-extension://f0458eeb-2d31-4334-756d-d126f42534d6/sidebar.html" . It seems to be trying to get sidebars URL.

 

[FactChecker]

It sounds like the sidebar part of the window is active and you need to force the active window to be the main one with the web page of interest. Maybe you can make the web page window active if you know the browser tab name. This is beyond my knowledge base and I will have to leave this for others who know more about it.

 

[jack action]

How can I get URL of the tab user is watching. I tried browser.tabs.query({active: true, currentWindow: true},function(tabs){var URL = tabs[0].url;}) but it always makes variable URL equal to "undefined". Maybe because this script tries to get URL of extension's sidebar.

Have you tried 'lastFocusedWindow' instead of 'currentWindow'?

browser.tabs.query(
    {
        active: true,
        lastFocusedWindow: true
    },
    function(tabs){
        var URL = tabs[0].url;
    }
)

ref.:

• How can I get the URL of the current tab from a Google Chrome extension?
• How to fetch URL of current Tab in my chrome extension using javascript

 

[olgerm]

Have you tried 'lastFocusedWindow' instead of 'currentWindow'?

Yes. It still made variable URL equal to "undefined".

 

[olgerm]

I tried esrirequest (https://developers.arcgis.com/javascript/3/jsapi/esri.request-amd.html) to solve the second problem, but seems that I cannot require it. I got error "require is not defined".

 

[olgerm]

I could open, the page I want data from, in IFRAME tag, but same-origin-policy does not let the extensions javascript to get data from the IFRAME.

 

[olgerm]

I tried

lehe_URL=window.content.location.href;

, but got error:

Permission denied to access property "location"

Is it because same-origin-policy? I read from https://stackoverflow.com/questions/11849945/how-does-same-origin-policy-apply-to-browser-extensions that same-origin-policy doesn't apply to browser extensions. Then why did I get that error?

I got answer to my second question. I used XMLHttpRequests.

 

[stoomart]

I tried

lehe_URL=window.content.location.href;

, but got error:

Permission denied to access property "location"

Is it because same-origin-policy? I read from https://stackoverflow.com/questions/11849945/how-does-same-origin-policy-apply-to-browser-extensions that same-origin-policy doesn't apply to browser extensions. Then why did I get that error?

I got answer to my second question. I used XMLHttpRequests.

I'm not a developer, but you may be running into some new security features of the newer multi-process Firefox:

https://developer.mozilla.org/en-US/Firefox/Multiprocess_Firefox
https://developer.mozilla.org/en-US/Firefox/Multiprocess_Firefox/Message_manager

 

[jim mcnamara]

I think stoomart is correct - mozilla has a "love to hate" relationship with regard to browser addons or extensions, and with java as well. Chrome also has similar protections.

 

[olgerm]

What should I do to access window.content.location.href? Add some permission into manifest.json?

 

[stoomart]

What should I do to access window.content.location.href? Add some permission into manifest.json?

You should start here to determine if your code is affected by the changes:

https://developer.mozilla.org/en-US/Add-ons/Working_with_multiprocess_Firefox