Chrome extensions: Using chrome.tabs and chrome.contextMenus - google-chrome-extension

I am attempting to create a chrome extension that scrubs a URL and opens the URL in a new tab. However I keep getting the same error as this (content_script error). I've followed instructions, but I believe I just don't understand where I'm going wrong. Here is the full code:
manifest.json
{
"name": "Link scrub",
"description": "Removes redirectors from links",
"version": "0.1",
"permissions": ["contextMenus", "tabs"],
"background_page" : "background.html"
"content_scripts": [{
"js" : ["linkscrub.js"]
}];
}
linkscrub.js
chrome.contextMenus.create({
"title" : "Link Trap",
"type" : "normal",
"contexts" : ["link"],
"onclick" : modifyLink
});
function modifyLink(info, tab) {
chrome.extension.sendRequest({
"nurl" = info.linkURL,
function(response) {
console.log("linkscrub failed: " + response.farewell)
}
});
}
background.html
<script>
chrome.extension.onRequest.addListener(
function(request, sender, sendResponse) {
link = "";
link = sender.nurl;
link = link.match("url=\b(.*?)&link");
chrome.tabs.create({
"url": link,
"selected" : false
});
if(chrome.extension.lastError)
sendResponse({farewell : chrome.extension.lastError.message});
else
sendResponse({farewell : "Success")};
});
<script>

It throws error because you cannot use chrome.contextMenus.* API inside a content script.
You don't need a content script for this task, just move everything from linkscrub.js into your background page (also you won't be needing those requests).

Related

Chrome Extension: Unchecked runtime.lastError: Could not establish connection. Receiving end does not exist

Recently, it is reported that the context menu of my app is vanished. If you remove the app and reinstall it, it works. But the vanishment happens again.
I found an error. I'm not sure if the error causes the vanishment of the context menu. But I'd like to fix this matter, because all I found is this.
This app shows texts you select in a page. When you select texts in an ordinaly page and click browser action button, it works without error. But if you try it on Google Docs, you will get error "Unchecked runtime.lastError: Could not establish connection. Receiving end does not exist".
I'm afraid I don't know what to do with this. And I might have two problems. It'll be great help if you could give me some advice.
[manifest.js]
{
"manifest_version": 2,
"name": "Test Chrome Extension",
"short_name": "Test",
"version": "1.0",
"description": "This is a test.",
"icons": {
"128": "128.png"
},
"content_scripts": [{
"matches": ["<all_urls>"],
"js": ["googleDocsUtil.js", "content_scripts.js"]
}],
"background": {
"scripts": ["background.js"],
"persistent": true
},
"browser_action": {
"default_icon": {
"48": "48.png"
},
"default_title": "Test Chrome Extension"
},
"permissions": [
"contextMenus",
"tabs",
"background",
"http://*/*",
"https://*/*"
]
}
[background.js]
chrome.contextMenus.create({
type: 'normal',
id: 'testchromeextension',
title: 'Test Chrome Extension',
contexts:['selection']
});
chrome.contextMenus.onClicked.addListener(function(info,tab){
if( info.menuItemId == 'testchromeextension' ){
var selectedText = info.selectionText.replace(/ /g, "\n");
doSomething(selectedText);
}
});
chrome.browserAction.onClicked.addListener( function(tab) {
chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
chrome.tabs.sendMessage(tabs[0].id, {method: "getSelection"}, function(response) {
doSomething(response.data);
});
});
});
function doSomething(selectedText) {
console.log(selectedText);
}
[content_scripts.js]
chrome.runtime.onMessage.addListener( function(request, sender, sendResponse) {
if (request.method == "getSelection") {
var post_val = window.getSelection().toString();
if ( !post_val ) {
var googleDocument = googleDocsUtil.getGoogleDocument();
post_val = googleDocument.selectedText;
}
sendResponse({data: post_val});
}
});
I believe this error is caused when you update the local version of an extension and then try to use the extension with its old/not-updated source code.
The fix: after you reload your local extension at chrome://extensions/, make sure you refresh the page you're using the extension on. You should no longer see the error.

In Chrome Extension development, how do I pass a variable from background.js to a content script that embedded as a script node?

Update: I am sorry that I wasn't clear about my case. The content script is not literally content script but a js file embedded into the page via the createElement method.
It's something like:
// this is "content.js"
var scriptElement = document.createElement('script');
scriptElement.src = 'chrome-extension://' + chrome.runtime.id + '/js/page-inject.js';
(document.head || document.documentElement).appendChild(scriptElement);
I want to use it in "page-inject.js", not the "content.js"
I thought it was very simple but failed after hours of retrying and searching.
I have a background.js like this:
chrome.tabs.query({active: true, currentWindow: true},
function(tabs) {
chrome.tabs.executeScript(tabs[0].id, {
code: 'window.my_var = 123'
}, function() {
chrome.tabs.executeScript(tabs[0].id, {file: 'js/content.js'});
});
});
After this, when I type "window.my_var" in the console of that page. It's not working. The wanted "123" is not showing up.
If I replace the code: 'window.my_var = 123' to alert(123), it works. But what I need is just to pass a variable from my background script (background.js) to the web page that my extension injected into.
Is there anything wrong with my try?
As #wOxxOm already pointed out you how to see the variable inject using the chrome.tabs.executeScript in the web page console by changing the Top in the console.
There is another way you can easily pass values from background to content script using messaging.
Se below a simple example:
manifest.json
{
"name": "test",
"version": "0.0.1",
"manifest_version": 2,
"description": "Test ",
"background": {
"scripts": [
"background.js"
]
},
"browser_action": {
"default_title": "Test "
},
"permissions": [
"*://*/*",
"tabs"
], "content_scripts" : [{
"matches" : ["*://*/*"],
"js" : ["content.js"]
}]
}
background.js
chrome.browserAction.onClicked.addListener(function(){
chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
chrome.tabs.sendMessage(tabs[0].id, {data: "some value"});
});
});
content.js
chrome.extension.onMessage.addListener(handleMessage);
function handleMessage(request) {
console.log(request.data);
}
chrome.extension.getBackgroundPage() will return the global window object of the background page. You can access scripts and any data in the background worker.
Example
const backgroundDOMWindow = chrome.extension.getBackgroundPage();
const myGlobalVariable = backgroundDOMWindow.window['myGlobalVariable'];
Adding script to global background object "background.js"
document.write(
'<script src="main.js"></script>'+
'<script src="main2.js"></script>'
);

Chrome extension : Is it possible to keep extension open on reload?

I'm building an google extension that inserts html in page and shows a menu on browser action icon click and I don't find way to keep my extension open when I reload the page. So on every reload, we have to active it again from Browser Action icon.
Below the manifest file
{
"background": {
"scripts": ["background.js"]
},
"browser_action": {
"default_icon": "img/icone.png",
"default_title": "show menu"
},
"icons" : {
"128" : "img/icone_128.png",
"48" : "img/icone_48.png",
"32" : "img/icone_32.png",
"24" : "img/icone_24.png",
"16" : "img/icone_16.png"
},
"manifest_version": 2,
"name": "p|layer",
"version": "1.0.4",
"content_scripts": [
{
"matches": [ "<all_urls>"],
"css":["css/grid.css", "css/font-awesome.min.css"],
"js":["js/jquery-1.11.1.min.js","js/jquery-ui.js", "js/jquery.nicefileinput.min.js"]
}
],
"web_accessible_resources": [
"fonts/fontawesome-webfont.woff"
],
"permissions": [ "activeTab"]
}
script (background.js) injecting contentscript
chrome.browserAction.onClicked.addListener(function (tab) { //Fired when User Clicks ICON
chrome.tabs.executeScript(tab.id,
{"file": "js/contentscript.js"},
function () { // Execute your code
console.log("Script Executed .. "); // Notification on Completion
});
chrome.tabs.insertCSS(tab.id, {file: "css/grid.css"});
chrome.tabs.insertCSS(tab.id, {file: "css/font-awesome.min.css"});
chrome.tabs.insertCSS(tab.id, {file: "css/slider.css"});
});
any help will be appreciated
So, from the comments the problem was inferred: your button click activates your content script, but a page reload clears it. Assuming you want the button click to act as a toggle:
1) Always inject the content script / CSS, but don't show the UI immediately:
"content_scripts": [
{
"matches": [ "<all_urls>"],
"css": ["css/grid.css", "css/font-awesome.min.css", "css/slider.css"],
"js": [
"js/jquery-1.11.1.min.js", "js/jquery-ui.js",
"js/jquery.nicefileinput.min.js", "js/contentscript.js"
]
}
],
2) Keep track of "activated" tabs:
var activeTabs = {};
chrome.browserAction.onClicked.addListener( function(tab){
var active;
if(activeTabs[tab.id]){
delete activeTabs[tab.id];
active = false;
} else {
activeTabs[tab.id] = true;
active = true;
}
/* (part 3) */
});
chrome.tabs.onRemoved.addListener( function(tabId){
delete activeTabs[tabId];
});
chrome.tabs.onReplaced.addListener( function(newTabId, oldTabId){
if(activeTabs[oldTabId]) activeTabs[newTabId] = true;
delete activeTabs[oldTabId];
});
3) Use messaging to show/hide UI:
Content script:
chrome.runtime.onMessage.addListener( function(message. sender, sendResponse){
if(message.showUI) showUI();
if(message.hideUI) hideUI();
});
Background script:
chrome.browserAction.onClicked.addListener( function (tab) {
var active;
/* (part 2) */
if(active) {
chrome.tabs.sendMessage(tab.id, {showUI: true});
} else {
chrome.tabs.sendMessage(tab.id, {hideUI: true});
}
});
Additional robustness can be added for the cases of extension reload, but that's the gist of it.

Chrome Extension Send Message From Background.js to Content Script

I have read the documentation on how to do Send Message From background javascript file(main.js) to Content Script (content.js) but I cannot get the onMessage to open my alert.
Manifest.json
{
"name": "Example",
"version": "1.0.1",
"manifest_version" : 2,
"description": "Example Description",
"background" : {
"scripts" : ["main.js"]
},
"page_action" : {
"default_icon": {
"19": "icons/19.png",
"38": "icons/38.png"
},
"default_title" : "Example Title"
},
"content_scripts": [{
"matches": ["<all_urls>"],
"js": ["lib/jquery-1.8.3.min.js","scripts/content.js"],
"run_at": "document_idle",
"all_frames": false
}],
"permissions": [
"tabs",
"geolocation"
],
"icons": {
"16": "icons/16.png",
"48": "icons/48.png",
"128": "icons/48.png"
}
}
Background javascript file (main.js)
chrome.tabs.query({active: true, currentWindow: true}, function(tabs){
chrome.tabs.sendMessage(tabs[0].id, {action: "SendIt"}, function(response) {});
});
Content javascript file (content.js)
chrome.extension.onMessage.addListener(function(msg, sender, sendResponse) {
if (msg.action == 'SendIt') {
alert("Message recieved!");
}
});
Thanks to the insight of #Teepeemm I have included a tab load complettion before sending message to content script.
WAIT FOR TAB TO BE FULLY LOADED
chrome.tabs.onUpdated.addListener(function (tabId, changeInfo, tab) {
if (changeInfo.status == 'complete') {
chrome.tabs.query({active: true, currentWindow: true}, function(tabs){
chrome.tabs.sendMessage(tabs[0].id, {action: "SendIt"}, function(response) {});
});
}
});
Sidenote: chrome.extension.onMessage is deprecated, you should be using chrome.runtime.onMessage - although I don't believe this will solve your problem.
I remember that I had an issue injecting a minified jquery file using content scripts. Try to use an un-minified version (ie jquery-1.8.3.js). Once you have done that, also add jquery-1.8.3.js to web_accessible_resources in your manifest file. (Read about that here)
If it still doesn't work, my last suggestion would be to add "<all_urls>" to the permissions array in your manifest.
If you have each script announce its presence (I prefer console.log to alert), you see that the background script runs once (on installation or startup), while the content script runs with each new page. This means that you'll want to have some external event trigger the message. Something like
chrome.pageAction.onClicked.addListener(function(tab) {
chrome.tabs.sendMessage(tab.id,{action:"SendIt"});
});
And don't forget to call chrome.pageAction.show(tabId); as appropriate.

Inserting code into a Confluence page programmatically using a Chrome content script

I am trying to develop a Chrome extension to open Office documents stored in Confluence in a new tab using the IE Tab extension.
In the 'View Page Attachment' screen, there is an 'Edit in Office' link for Office file attachments. The link has a click event that creates a new instance of a URLLauncher, which is used to open the document. This feature is not supported in Chrome, so I want to add my own URLLauncher prototype into the web page to make it work.
In short, this is my idea:
Create a Chrome extension with a content script that injects a URLLauncher prototype into the 'View Page Attachment' page (I don't know if this is the right approach, so I am open to suggestions).
When the user clicks on the 'Edit in Office' link, the URLLauncher.open method opens the file attachment in a new tab by calling the IE Tab extension.
I can see the 'Hi there!' alert every time I load a web page, and that confirms that content.js is being injected. Nevertheless, the URLLauncher is not available in the web page. I think this is because the global window object of the content script is distinct from the page/extension's global namespace (i.e., window.URLLauncher is undefined). How could I reorganize my code to overcome this obstacle?
These are my files:
manifest.json
{
"manifest_version": 2,
"background": {
"scripts": [
"background.js"
]
},
"content_scripts": [ {
"js": [ "content.js" ],
"matches": [ "<all_urls>" ]
} ],
"description": "This is a test extension",
"permissions": [
"tabs", "http://*/*", "https://*/*"
],
"name": "Test extension",
"version": "1.0.0"
}
background.js
chrome.tabs.executeScript(null, {
code: "document.body.appendChild(document.createElement('script')).src='" +
chrome.extension.getURL("content.js") + "';"
}, null);
chrome.runtime.onMessage.addListener(
function(request, sender, sendResponse) {
console.log(sender.tab ?
"from a content script:" + sender.tab.url :
"from the extension");
if (request.id == "doUrlLaunch") {
chrome.tabs.create({ url: request.nUrl, selected: true });
sendResponse({result: "goodbye"});
}
}
);
content.js
var prefixUrl = 'chrome-extension://hehijbfgiekmjfkfjpbkbammjbdenadd/iecontainer.html#url=';
alert('Hi there!');
function URLLauncher() {
}
URLLauncher.prototype = {
open : function(urlStr) {
var newUrl = prefixUrl + 'https://host.com' + encodeURI(urlStr);
chrome.runtime.sendMessage({id: "doUrlLaunch", nUrl: newUrl}, function(response) {
});
}
}
Thanks in advance.
UPDATE 1
I edited the files following the instructions given by Rob W and this page ('Message Passing'); now the code is injected in the page itself, but a major problem still remains. The actual JS code sends a message to the content script, but the message is not caught by the listener, so the new tab is not created and the callback function does not receive a response; the error message I got: Error in event handler for (unknown): TypeError: Cannot read property 'success' of undefined.
These are the updated files:
manifest.json
{
"manifest_version": 2,
"content_scripts": [ {
"js": [ "content.js" ],
"matches": [ "<all_urls>" ]
} ],
"web_accessible_resources": [ "script.js" ],
"description": "This is a test extension",
"permissions": [
"tabs", "http://*/*", "https://*/*"
],
"name": "Test extension",
"version": "1.0.0",
"externally_connectable": {
"ids": ["*"],
"matches": ["*://*.hostname.com/*"]
}
}
content.js
var s = document.createElement('script');
s.src = chrome.extension.getURL("script.js");
s.onload = function() {
this.parentNode.removeChild(this);
};
(document.head||document.documentElement).appendChild(s);
chrome.runtime.onMessage.addListener(
//Unreachable code!
function(request, sender, sendResponse) {
console.log(sender.tab ?
"from a content script:" + sender.tab.url :
"from the extension");
if (request.id == "doUrlLaunch") {
chrome.tabs.create({ url: request.nUrl, selected: true });
sendResponse({result: "goodbye"});
}
}
);
script.js
var prefixUrl = 'chrome-extension://hehijbfgiekmjfkfjpbkbammjbdenadd/iecontainer.html#url=';
function URLLauncher() {
}
URLLauncher.prototype = {
open : function(urlStr) {
var newUrl = prefixUrl + 'https://hostname.com' + encodeURI(urlStr);
chrome.runtime.sendMessage({id: "doUrlLaunch", nUrl: newUrl}, function(response) {
if (!response.success)
console.log('Something went wrong...');
});
}
}
Not sure if you're still interested in an answer, but in your edited files your problem is where your listener sits.
chrome.runtime.sendMessage does not reach content scripts; it is intended for extension pages. Message passing to content scripts works through chrome.tabs.sendMessage, but this is irrelevant for this task.
Content scripts can't call chrome.tabs as they do not have the required API access.
A solution would be to call a background script, that can receive those messages and can call the required API.
Therefore, you need a third script, taking out this code from content.js:
// background.js
chrome.runtime.onMessage.addListener(
function(request, sender, sendResponse) {
console.log(sender.tab ?
"from a content script:" + sender.tab.url :
"from the extension");
if (request.id == "doUrlLaunch") {
chrome.tabs.create({ url: request.nUrl, selected: true });
sendResponse({result: "goodbye"});
}
}
);
And modify your manifest:
"background": { "scripts": [ "background.js" ] },

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