Injected scripts

[Mark Dostie]

I use the scripting API quite extensively in my new v3 extension (migrating from a v2) and there seems to be some odd things.

I have a script border.js which gets injected into a tab by the service worker:

chrome.scripting.executeScript( {
                            target: {tabId: tabId},
                            files: ["border.js"],
                            world: chrome.scripting.ExecutionWorld.MAIN,
                        }, function (e) {
                            console.log("Added border.js");                          
                        });

And at one point border.js calls:

chrome.runtime.sendMessage(extensionid, {action: 'openlink', payload: $(this).prop('href')}, function(response) {
            console.log('Openlink message sent');         
        });

To send a message back to the service worker...

The console complains that I need to send the id of the extension. But when I call chrome.runtime.id it is undefined so I need to hard code the extension id.

When I do that (hard-code) the message never arrives at the service worker (background.js) even though I see the "openlink message sent" in the console for the page.

I assume I'm missing something that has changed between v2 and v3 any suggestions?

Thanks,

Mark

[Stefan vd]

Hi there,

The "extensionId" is an optional string. If you want to send it to another Chrome extension.

Can you try it without the "extensionId" in your code:

chrome.runtime.sendMessage({action: 'openlink', payload: $(this).prop('href')}, function(response) {

     console.log('Openlink message sent');        
 });

Source: https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/runtime/sendMessage

Thanks,

Stefan vd

[wOxxOm]

1. When you inject the code into the MAIN world, it is a normal page script, not a content script, i.e. not a part of the extension anymore, so it can't access `chrome.runtime.id`.
   
   
2. In order to send messages from a page via chrome.runtime.sendMessage you need to use "external messaging", but it doesn't support <all_urls>, so if you need that, instead of sendMessage you'll send a CustomEvent DOM event to a normal content script, which will then relay the event's `detail` to the background script via chrome.runtime.sendMessage. There should be googlable examples of doing that. In the future chrome.scripting will allow such MAIN world script to communicate with the content script directly.