I am trying to communicate with a google chrome extension using JavaScript. I have succeeded in calling the extension from my code. But can't read the response back to my application.
I have written the calling function like this.
function extensionCall(){
var event = document.createEvent('Event');
event.initEvent('EXTENSION_READ_EVENT');
document.dispatchEvent(event);
}
And the code inside the extension is
document.addEventListener("EXTENSION_READ_EVENT", function (data) {
chrome.runtime.sendMessage("test", function (response) {
});
});
chrome.extension.onMessage.addListener(function (msg, sender, sendResponse) {
if (msg.action == 'EXTENSION_DATA') {
try {
readExtension($.parseJSON(msg.response));
}
catch (e) {
var error = "error" + e;
}
}
});
And I am expecting the response here..
function readExtension(val){
console.log(val);
}
But unfortunately, I am not getting any response from the extension.
How can I access the data to my application?
Related
In my Chrome extension, I'm trying to exchange data between an internal web page of the extension chrome-extension://myExtensionId/path/to/web/page.html and content scripts.
So, in order to make this data persistent among different content scripts, I'm trying to save it as global variables in the extension's background! I do so using message passing.
My problem is:
When I try to send a response back from the background I get this error:
Error in event handler for (unknown): TypeError: sendResponse is not a
function
I followed the documentation's examples and this is my attempt:
In the scriptOfTheInternalPage.js :
var message = {
'order': 'setData',
'varName': 'myArray',
'data': myArray
};
extPort.postMessage(message, function (response) {
console.log('response:\n', JSON.stringify(response));
});
In background.js :
var globals = {
'myArray': [],
...
};
chrome.runtime.onConnect.addListener(function (port) {
port.onMessage.addListener(
function (message, sender, sendResponse) {
console.log(
'the port received this message:\n', JSON.stringify(message), '\n',
(sender.tab) ? ' from tab #' + sender.tab.id : ' from the extension!'
);
if (message.order === 'setData') {
globals[message.varName] = message.data;
sendResponse({'response': 'data saved!'}); //<=====
}
return true; //<=== tried to return true here as well;
});
});
Does this error means I should create a brand new function outside of the onMessage event listener?
I'm confused! What am I missing?
Port's onMessage event listeners do not have the same signature as runtime.onMessage. You don't get sender and sendResponse parameters, only the message. Returning true has no effect either.
To reply to a message, you need to use the port itself. This is covered by examples:
port.onMessage.addListener(function(msg) {
if (msg.joke == "Knock knock")
port.postMessage({question: "Who's there?"});
}
So you do need an onMessage listener on both sides, and some way to track requests (unique ID?) if several can be made.
I am getting a trouble about passing message inside background page of chrome extension.
In content page
I send a message and wait for a response from background page:
chrome.runtime.sendMessage({"name": "Calling"}, function (response) {
console.log(response);
});
In background page
I have an event listener to listen message from content page:
chrome.runtime.onMessage.addListener(
function (request, sender, sendResponse) {
if (request.name == "Calling") {
doTask().then(function (message) {
sendResponse(message);
});
return true; // Make respond asynchronously
}
}
);
Inside "Calling" event Listener, i call the function doTask() which return a promise:
var doTask = function(){
return new Promise(function (resolve) {
chrome.runtime.sendMessage({"name": "DoTask"}, function (response) {
resolve(response);
});
});
};
Inside doTask() i send another message "DoTask", and wait for response.
chrome.runtime.onMessage.addListener(
function (request, sender, sendResponse) {
if (request.name == "DoTask") {
var message = "Task has done!";
sendResponse(message);
return true; // Make respond asynchronously
}
}
);
I expect "Task has done!" will be printed in content page, but nothing appears! When debugging i realize "DoTask" event listener cannot receive any message.
What wrong here? Thank you.
P/S: I make sure that all scripts are injected in manifest.json
I am trying to send a message from a content script to my background script. When the background receives the message it sends data back to the content script in the callback.
My popup also has a listener for messages from the content script, but does not respond to a message meant for the background script.
Then content is receiving an undefined back from the callback, which I think is caused by the popup receiving the message but not responding.
The reference says:
Note: If multiple pages are listening for onMessage events, only the
first to call sendResponse() for a particular event will succeed in
sending the response. All other responses to that event will be
ignored.
So surely I should only get the response from my background script.
My content script does this:
function notifyReady() {
chrome.runtime.sendMessage({
type: 'ACTIVITY_HISTORY_READY'
},
function (response) {
console.log(">>>>Response: ", response);
if (response.type == 'HISTORY_DATA') {
processLog(response);
}
});
}
My background script listens like this:
chrome.runtime.onMessage.addListener(function (msg, sender, sendResponse) {
console.log("received " + msg.type);
if (msg.type = 'ACTIVITY_HISTORY_READY' && historyData) {
if (historyData) {
sendResponse({
type: "HISTORY_DATA",
position: historyData.position,
company: historyData.company
});
historyData = '';
} else {
sendResponse({
type: "NO_DATA"
});
}
}
});
And the listener in my popup is:
chrome.runtime.onMessage.addListener(function (msg, sender, sendResponse) {
if (msg.type == 'JOB_DETAILS') {
sendResponse("OK!");
document.getElementById('position').value = msg.position;
document.getElementById('company').value = msg.company;
document.getElementById('url').value = sender.tab.url;
}
});
if (msg.type = 'ACTIVITY_HISTORY_READY' && historyData) {
note that if historyData is falsey you are not sending any response. The else branch of the second if can never be taken.
You should remove historyData from the first if. The popup code has nothing to do with this.
I'm trying to get some user configs from the background page of my chrome extension to the content script (or popup) but I'm having some problems, I think the problem is that chrome.storage.sync.get is async, I tried using callbacks but I also read that callbacks can't return the value so I have no idea how to solve this.
Here's kinda how the code looks:
popup.js:
(function() {
chrome.runtime.sendMessage({
message: "loadconfig"
}, function(response) {
console.log(response);
if (response.status === 'success') {
console.log(response);
} else {
console.log(response.except);
}
});
})();
background.js
(function() {
chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {
switch (request.message) {
case "loadconfig":
sendResponse(loadStuff());
break;
default:
sendResponse({
reply: null
});
break;
}
});
function loadStuff() {
var to_return_configs = {
blocked_characters: '',
good_post: ''
};
var function_status = 'failed';
var exception = '';
var blocked_characters_parsed, good_post_parsed;
try {
var to_get = ["blocked_characters_saved", "good_post_saved"];
chrome.storage.sync.get(to_get, function(result) {
to_get.forEach(function(got) {
if (got === "good_post_saved") {
to_return_configs.good_post = result[got];
}
if (got === "blocked_characters_saved") {
to_return_configs.blocked_characters = result[got];
}
});
});
exception = '';
function_status = 'success';
} catch (err) {
exception = String(err);
function_status = 'failed';
}
var to_return = {
status: function_status,
configs: to_return_configs,
except: (exception)
};
return to_return;
}
})();
The problem here is that when I'm looking at the popup.js console, "blocked_characters" and "good_post" are both empty.
How can I solve this?
You do not need Message API for communication between Popup and Background. Popup in chrome extension can directly call methods of Background .
You can do something like this
BG = chrome.extension.getBackgroundPage();
And then you can call BG.loadStuff() in your popup js.
From within loadStuff, you can pass a callback which can return data to you. So it should look like
BG.loadStuff(function(items) {
console.log(items);
});
background.js
function loadStuff(cb) {
chrome.storage.sync.get(null, function(superObj) {
cb.call(null, superObj);
});
}
For more understanding, read these
http://blog.papersapp.com/chrome-development-parent-and-child-windows/
https://stackoverflow.com/a/17276475/816213
https://stackoverflow.com/a/17378016/816213
sendResponse(function) becomes invalid when the event listener returns, unless you return true from the event listener to indicate you wish to send a response asynchronously (this will keep the message channel open to the other end until sendResponse is called). See the reference: onMessage.
Because sendResponse is called asynchronously in chrome.storage.sync.get's callback, you need to return true from the onMessage listener to prevent the function from being invalidated. Code similar is Like:
chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {
if (request.message === 'loadconfig') {
sendResponse(loadStuff());
return true;
}
return false;
});
I'm so close to finishing my Chrome extension. I have one or two things to do. One of them is sending a message from the content script to the background script. I wrote the following, but it doesn't quite what I want.
content.js
var a=document.getElementsByTagName('a');
for (i=0,len=a.length;i<len;i++) {
a[i].addEventListener('contextmenu', function() {
var linkTitle = this.getAttribute('title').trim();
var linkUrl = this.getAttribute('href');
if ((linkTitle != null) && (linkTitle.length > 0)) {
chrome.extension.sendMessage({action:'bookmarkLink', 'title':linkTitle, 'url': linkUrl}, function(msg) {
alert('Messages sent: '+action+' and '+linkTitle+' also '+linkUrl);
});
}
});
};
background.js
chrome.contextMenus.create({'title': 'Add to mySU bookmarks', 'contexts': ['link'], 'onclick': mySUBookmarkLink});
function mySUBookmarkLink(info, tab) {
chrome.extension.onMessage.addListener(function(msg, sender, sendResponse) {
if (msg.action == 'bookmarkLink') {
chrome.storage.sync.set({'title': msg.linkTitle, 'url': msg.linkUrl}, function(msg) {
alert('Saved '+msg.linkTitle+' to bookmarks');
});
}
});
};
My problems are:
In the first code block, it alerts Saved undefined to bookmarks as soon as I right click on the link, while as I understand it should only send a message on right click and the second code block should alert Saved to bookmarks when I click on the context menu. What am I missing or doing wrong?
I may not have used parameters correctly (I am fairly new to extension development and Javascript in general). Do the above look okay?
Thank you in advance,
K.
It's chrome.runtime.sendMessage and chrome.runtime.onMessage rather than chrome.extension.
There used to be chrome.extension.sendRequest and chrome.extension.onRequest which have been deprecated in favor of the chrome.runtime API methods mentioned above.
See Chrome Extensions - Message Passing
it's JSON-serializable messaging, where first pair is for recognition, and then followed by pairs of
key: value.
You pull the value from received message by calling it's key.
is should be:
alert('Saved '+msg.title+' to bookmarks');
or even better:
function mySUBookmarkLink(info, tab) {
chrome.extension.onMessage.addListener(function(msg, sender, sendResponse) {
if (msg.action == 'bookmarkLink') {
var receivedValue = msg.title; //pull it out first, for better overview
chrome.storage.sync.set({'title': msg.title, 'url': msg.url}, function(msg) {
alert('Saved '+receivedValue+' to bookmarks');
});
}
});
};