Message passing in Chrome Extension

StackOverflow https://stackoverflow.com/questions/14268694

質問

I am quite confused about the what are counted as chrome extension view, which directly linked to what function I can use for passing messages between different components.

Let me just describe what I am trying to do first;

My background.html creates Desktop Notifications based on some events received from a node.js server through socket.io.

When the user clicks on the notification, I want to create a new tab pointing to a html within my extension (/src/view/token.html), and then send some data from the background.js (where my socket.io codes are) to the new tab. And I want to do this through message passing.

So, basically, i am doing

 var notification = webkitNotifications.createNotification(image, title, content);
 notification.onclick(function(e){

    chrome.tabs.create({url: "/src/view/tokens.html"}, function(tab){
        //just to make sure the tab is activated..
        chrome.tabs.onUpdated.addListener(function(tabId){
            if(tabId == tab.id) {
                chrome.tabs.sendMessage({data: whatever_data}, tabId); 
            }
        });
    });

 });

Now my problem is in my tokens.js (loaded in tokens.html), I try to listen for the message using:

chrome.extension.onMessage.addListener(function (msg, _, sendResponse) {
console.log(msg);
});

but I am getting "Uncaught TypeError: Cannot read property 'onMessage' of undefined:, so I assume that I don't have access to chrome.extension in the tokens.html???

I tried this with popup page (browser action popup) and option page, and they all worked just fine. So, I guess the view I created is just not a chrome extension page?

Now I am confused... 1) What are considered as chrome extension pages that have access to the chrome.* API 2) How should I implement what I want to do?

Thanks!

役に立ちましたか？

解決

Problems in your code

  • chrome.tabs.sendMessage() wrong Invocation pattern
  • As complete code is not shared, i assume permissions are given to all pages, because manifest don't generate warnings for some set of values.
  • notification.onclick(function creates Uncaught TypeError: Property 'onclick' of object #<Notification> is not a function error

Chrome.tabs.sendMessage

Invocation form of chrome.tabs.sendMessage({data: whatever_data}, tabId); should be chrome.tabs.sendMessage(tabId,{"data": "whatever_data"}); (Tab id followed by message).

notification.onclick(function

Use notification.onclick = (function( assign handler to onclick property (because it is not a function)

After fixing above problems i got your script running.

manifest.json

Registered background scripts and given all permissions needed.

{
    "name": "Message Passing",
    "description": "This is used as a message passing",
    "version": "1",
    "manifest_version": 2,
    "background": {
        "scripts": [
            "background.js"
        ]
    },
    "permissions": [
        "notifications",
        "tabs"
    ]
}

background.js

Modified code to eliminate errors

//Created Notification
var notification = webkitNotifications.createNotification("icon.jpg", "title", "content");
//Added onclick property
notification.onclick = (function (e) {
    //Created new tab
    chrome.tabs.create({
        url: "/src/view/notification.html"
    }, function (tab) {
        //just to make sure the tab is activated..
        chrome.tabs.onUpdated.addListener(function (tabId) {
            if (tabId == tab.id) {
                //Send Mesage
                chrome.tabs.sendMessage(tabId, {
                    "data": "whatever_data"
                });
            }
        });
    });
});
notification.show();

notification.html

Ensure there is no inline script or <script> tag to comply with CSP.

<html>

    <head>
        <script src="notification.js">

        </script>
    </head>

    <body>
        <p>This is a notification</p>
    </body>

</html>

notification.js

Used your script with no changes!

chrome.extension.onMessage.addListener(function (msg, _, sendResponse) {
    console.log(JSON.stringify(msg));
});

Output

You can see message(s) being received in your new tab.

enter image description here

References

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