Multiple messages from main script to contentscript

Question

I am using the code below to get file-size of a remote file inside a Firefox Addon being developed using Mozilla Addon SDK.

main.js

// Import the page-mod API
var pageMod = require("sdk/page-mod");
// Import the self API
var self = require("sdk/self");


// Create a page mod
pageMod.PageMod({
    include : "*.example.com",
    contentScriptFile : [self.data.url("content.js"), self.data.url("jquery.min.js"), self.data.url("contentloaded.js")],
    contentScriptWhen : "ready",
    attachTo: ["top", "existing"],
    onAttach : startListening,
    contentScriptOptions : {
        iconWait : self.data.url("wait.gif"),
        iconFinished : self.data.url("done.png"),
    }
});

function startListening(worker) {


    worker.port.on("GetSize", function (data) {

        // Handle the message
        let getReq = require("sdk/request").Request({
                url : data[0],
                onComplete : function (response) {
                    reply = [response.headers["Content-Length"], data[1]];
                    //console.log("Send linkID : " + reply[1]);
                    worker.port.emit('receiveSize', reply);
                }
            }).head();
    });


}

This works perfectly but the the DisplaySize function gets called multiple times for the same request.

content.js

function checkURL(url, linkID) {

    data = [url, linkID];
    self.port.emit("GetSize", data);
    self.port.on("receiveSize", DisplaySize);
    console.log("Inside checkURL For linkID : " + linkID); //<--This displays only once for each request

}

function DisplaySize(data) {


    console.log("Inside DisplaySize For linkID : " + data[1]); //<--But this thrice

}

What am I missing here?

nmaier · Accepted Answer · 2015-02-11 16:29:15Z

1

Each time you call port.on a new message listener is added. Only call it once.

function checkURL(url, linkID) {
    data = [url, linkID];
    self.port.emit("GetSize", data);
    console.log("Inside checkURL For linkID : " + linkID);
}

function DisplaySize(data) {
    console.log("Inside DisplaySize For linkID : " + data[1]);
}
self.port.on("receiveSize", DisplaySize);

answered Feb 11, 2015 at 16:29

nmaier

33.3k5 gold badges67 silver badges79 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Stacked Over a year ago

This solved it, however if I navigate to other pages (via Ajax) the previous message listener are still active resulting in same behavior. How to fix that?

Stacked Over a year ago

nmaier any suggestions on how to get this fixed?

Collectives™ on Stack Overflow

Multiple messages from main script to contentscript

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related