Upon receiving a message from a content script I want to create a new tab and fill the page it opens dynamically (for now I'm just trying to turn the newly created page red).
eventPage.js:
// ... code that injects another content script, works fine
// Problem code...
chrome.runtime.onMessage.addListener(
function(request, sender, sendResponse)
{
chrome.tabs.create({url: chrome.extension.getURL("blankpage.html")},
turnTabRed);
});
function turnTabRed(tab)
{
chrome.tabs.executeScript(
tab.id,
{code: 'document.body.style.backgroundColor="red"'}
);
}
This successfully creates a new tab and loads blankpage.html (which is just an HTML page with some text) fine, but fails to paint the background colour red. After inserting console.log() statements in various places and fooling around in the debugger, I have ascertained that turnTabRed is being called, tab.id is indeed the ID of the newly created tab and if I call document.body.style.backgroundColor="red" from the console, the background of the new tab turns red. I noticed that if I added
(*)
chrome.tabs.query(
{}, function (tabArr) { for (var i = 0; tabArr[i]; i++)
console.log(tabArr[i].title); });
into the body of turnTabRed the title of the new tab would not be printed into the console, which suggested that the script was being injected too early, so I tried delaying the injection with setTimeout and when that failed, I tried listening for the status-complete event:
function turnTabRed(tab)
{
chrome.tabs.onUpdated.addListener(
function(tabUpdatedId, changeInfo, tabUpdated)
{
if (tabUpdatedId == tab.id && changeInfo.status &&
changeInfo.status == 'complete')
chrome.tabs.executeScript(
tabUpdatedId,
{code: 'document.body.style.backgroundColor="red"'});
});
}
which also failed. Calling (*) after waiting with setTimeout did print the new tab's title along with all the others though.
What's wrong? How can I create a new tab, load an HTML page and then turn its background red?
The problem is that you cannot inject scripts into chrome-extension://* pages (which your blankpage.html is).
For example, change
{url: chrome.extension.getURL("blankpage.html")}
to
{url: "http://www.google.com"}
in your original codeblock and it will change the background to red. As far as I know there is no way around injecting into chrome-extension://* pages (I would assume the reason for this is that it is a giant security concern). I'm not sure what your extension is trying to do, but injecting into a "live" page should work...maybe you can create some API to generate a new "blankpage" on your server whenever the chrome.runtime.onMessage.addListener fires?
EDIT
So you can't inject stuff into chrome-extension://* pages, but you can pass messages to them and use some subset of chrome API's inside those new pages as mentioned below. So using message passing you will be able to do exactly what you want (modify the new page), albeit in a roundabout way. Here is a really simple proof of concept that works for me:
eventPage.js:
chrome.runtime.onMessage.addListener(
function(request, sender, sendResponse)
{
chrome.tabs.create({url: chrome.extension.getURL("blankpage.html")}, turnTabRed);
});
function turnTabRed(tab)
{
chrome.tabs.sendMessage(tab.id, {"action" : "setBackground"});
}
blankpage.js:
chrome.runtime.onMessage.addListener(
function(request, sender, sendResponse) {
if(request.action == "setBackground") document.body.style.background = "red";
});
Related
I have a extension that is doing all kind of stuff with any given website. Everything worked well before i added popup window in purpose to use it as some kind of UI for the extension. After i have found it impossible to get my code run anywhere outside of that popup..
This sample is from my previous unsuccessful try:
HTML is just a start (starts initSession function) and stop button with access to content.js. I'am looking for solution (if there is a one) where i don't have to inject the actual page and could handle this with messages somehow..
content.js:
function initSession() {
window.close(); //popup..
chrome.runtime.sendMessage({
message: 'popup_closed'
}, function(response) {
var response = response.message;
if(response === "ready_to_record")
startRecording();
});
}
function startRecording(){
createListeners();
}
//background.js
chrome.runtime.onMessage.addListener(
function(request, sender, sendResponse, tab) {
if (request.message == "popup_closed")
sendResponse({message: "ready_to_record"});
});
I'm new to Chrome extensions. I know there's lots of similar questions and info out there, but none of it seems to address this problem.
I need my content script to execute on every page that matches *://*.youtube.com/watch?v=*.
I've tried using the above value and *://*.youtube.com/* as the match property, but neither works supposedly due to the way YouTube handles requests. I've also tried using the onhashchange event, but of course YouTube doesn't use anchors in their URLs. I've read about webRequest, but I don't need the function to be called when somebody is scrolling through the comments and the page loads more comments.
All I need is a way to call my content script when the URL changes. How exactly can I accomplish this?
Additionally, I cannot load the content script at document_start because the extension scrapes the HTML and parses it.
I had the same issue and this is what I did. I added a background script to listen to all changes
chrome.tabs.onUpdated.addListener((tabId, changeInfo, tab) => {
if (changeInfo.url) {
chrome.tabs.sendMessage(tabId, {
message: 'hello',
url: changeInfo.url
});
}
});
Then in my content script, I listen to it and reload the URL
chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {
if (request.message === 'hello') {
const { url } = request;
chrome.location.replace(url);
}
});
Creating browser extension where I have to open new tab from background.js and pass JSON data to this new tab. In new tab I am manipulating/rendering DOM using passed JSON data.
Below is part of my background.js where I create new tab with custom URL and send JSON data object
....
var analyticsUrl = chrome.extension.getURL("analytics.html");
chrome.tabs.create({ url: analyticsUrl, selected: true }, sendDataToAnalytics);
function sendDataToAnalytics(tab)
{
console.log(JSON.stringify(txnDataJSON));
chrome.tabs.sendMessage(tab.id, {"action" : "renderChartsTxns", "txns" : JSON.stringify(txnDataJSON)});
}
....
My custom analytics.html page has
<script src="analytics.js" type="text/javascript"></script>
And analytics.js looks like below
chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {
if(request.action == "renderChartsTxns")
{
// JSON parsing and analytics.html DOM processing
});
Problem is, my analytics.js listener is never receiving any messages. I've confirmed that background.js is sending JSON message as expected (using background page debugging)
BTW, analytics.js/html are not registered as part of manifest.json file but these files are part of extension package.
I did this setup today morning and everything was working properly for few hours (was able to receive JSON data in analytics.js), not sure what changed later and I lost message receiving in analytics.js (for debugging I tried clearing browser cache, uninstall and reinstalled chrome and much more but no luck yet!)
The callback of chrome.tabs.create returns as soon as the tab is created, not after it fully loads.
As such, you have a race condition: your message is potentially sent before the listener is initialized. Since it's a race condition, it can sometimes work.
The correct logic here would be to send a message requesting data from the newly opened tab, and use sendResponse to pass that data from the background.
// analytics.js
chrome.runtime.sendMessage({"action" : "getTxns"}, function(txns) {
// Process the data
});
// background.js
// Register this before opening the tab
chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {
if(request.action == "getTxns") {
sendResponse(txnDataJSON); // No need to serialize yourself!
}
});
(I have already read this and it didn't work, and I've done a lot of searching and experimentation to no avail.)
I am writing a Chrome extension (BigConsole) with the goal of building a better Console tab for the Chrome developer tools. This means I would like to execute user-input code in the context of the page with access to the DOM and other variables on the page. To do this, the communication is structured as follows:
devtools creates a panel where the user writes code
When the user wants to execute code from the panel, the panel sends a message to a background script with the code
The background script receives the message/code from panel and passes it on to the content script which is injected into the page
The content script receives the message/code from the background script and injects a script element into the page which then runs the code
The result of the script on the page is then posted back to the content script with window.postMessage
The content script listens for the message/result from the page and passes it on to the background script
The background script receives the message/result from the content script and passes it on to the panel
The panel receives the message/result from the background script and inserts it into the log of results
Whew.
Right now, when the user tries to run the code, nothing happens. I put a bunch of console.log()s into the code but nothing appears in the console. My main question is, what have I done wrong here with the message passing that results in nothing happening? Alternatively, I would love to be told that I am making this way too complicated and there is a better way of doing things. Simplified code below...
panel.js:
window.onload = function() {
var port = chrome.runtime.connect({name: "Eval in context"});
// Add the eval'd response to the console when the background page sends it back
port.onMessage.addListener(function (msg) {
addToConsole(msg, false);
});
document.getElementById('run').addEventListener('click', function() {
var s = document.getElementById('console').value;
try {
// Ask the background page to ask the content script to inject a script
// into the DOM that can finally eval `s` in the right context.
port.postMessage(s);
// Outputting `s` to the log in the panel works here,
// but console.log() does nothing, and I can't observe any
// results of port.postMessage
}
catch(e) {}
});
};
background.js:
chrome.runtime.onConnect.addListener(function (port) {
// Listen for message from the panel and pass it on to the content
port.onMessage.addListener(function (message) {
// Request a tab for sending needed information
chrome.tabs.query({'active': true,'currentWindow': true}, function (tabs) {
// Send message to content script
if (tab) {
chrome.tabs.sendMessage(tabs[0].id, message);
}
});
});
// Post back to Devtools from content
chrome.runtime.onMessage.addListener(function (message, sender) {
port.postMessage(message);
});
});
content.js:
// Listen for the content to eval from the panel via the background page
chrome.runtime.onMessage.addListener(function (message, sender) {
executeScriptInPageContext(message);
});
function executeScriptInPageContext(m) { alert(m); }
As pointed out by Alex, here's a typo in your code which prevents it from working.
Drop your current code and use chrome.devtools.inspectedWindow.eval to directly run the code and parse the results. This simplifies your complicated logic to:
devtools creates a panel where the user writes code
devtools runs code
devtools handles result
PS. There is a way to manipulate the existing console, but I recommend against using it, unless it's for personal use. Two different ways to do this are shown in this answer.
I've checked numerous questions regarding message passing in a Chrome extension but I haven't found much specifically relating to this.
I'm using the chrome.devtools* APIs and I'm having trouble sending messages between content scripts when the developer toolbar is docked. Everything works fine when it is not docked i.e. floating.
Here's a brief example of what I'm doing.
devtools.js
chrome.devtools.panels.create("myExtension", "img/icon.png",
"/panel.html", function(extensionPanel) {
var myData; //this variable gets manipulated before a user
//clicks on the panel
extensionPanel.onShown.addListener(function(panelWindow) {
chrome.extension.sendMessage({greeting: "update my data", data: myData}, function(response) {});
});
});
Then in my background script (eventPage.js) I listen for this message and pass it on to panel.js
chrome.extension.onMessage.addListener(function(request, sender, sendResponse) {
if (request.greeting == "update my data"){
chrome.tabs.sendMessage(sender.tab.id, {greeting: "show data", showResource: request.data}, function(response) {});
}
});
And then finally I listen for the 'show data' call in my panel.js (which is loaded from panel.html)
chrome.extension.onMessage.addListener(function(request, sender, sendResponse) {
if (request.greeting == "show data") {
//do stuff with my data here
});
Essentially, I need to pass messages between devtools.js to panel.js but the only way to do it is by using the background script as an intermediary.
devtools.js -> background.js -> panel.js.
This actually works fine as long as the dev tools panel is not docked to the window. When it is docked I get an error because sendMessage() won't except a tab id of -1, which is what sender.tab.id equals when the dev tools are docked to the window. I also tried using chrome.tabs.connect - long lasting connections - but ran into the same problem.
I also just found out recently how to do this.
A technique used by "Google Pagespeed" is to get the tab id of the inspected window and pass it back and forth between the extension and background using a port.
Whenever you want to send the extension a message, you look for the tab id and get its port.
panel.js
// get the inspected windows tab id from the panel
var tabId = chrome.devtools.inspectedWindow.tabId;
// create the port
var port = chrome.extension.connect({name: 'connection'});
// keep track of the port and tab id on the background by
// sending the inspected windows tab id
port.postMessage(['connect', tabId])
eventPage.js
var activeListeners = {};
chrome.extension.onConnect.addListener(function(port) {
port.onMessage.addListener(function(message) {
if (message[0] === 'connect') {
// get the tab id
var tabId = message[1];
// save the reference to the port
activeListeners[tabId] = port;
// make sure we clean up after disconnecting (closing the panel)
activeListeners[tabId].onDisconnect.addListener(function() {
delete activeListeners[tabId];
});
}
});
});
This is not a very thorough explanation but I hope you get the point.