Develop Reference

browser.downloads.download - images disappearing after download

So I was tinkering with a firefox extension and came across something I can't explain. This extension downloads images from a certain site when a browser action (button) is clicked. Can confirm that the rest of the extension works perfectly and the code below has proper access to the response object.
const downloading = browser.downloads.download({
filename:response.fileName + '.jpg',
url:response.src,
headers:[{name:"Content-Type", value:"image/jpeg"}],
saveAs:true,
conflictAction:'uniquify'
});
const onStart = (id) => {console.log('started: '+id)};
const onError = (error) => {console.log(error)};
downloading.then(onStart, onError);
So the saveAs dialog pops up (filename with file extension populated), I click save, and then it downloads. As soon as the file finishes downloading it disappears from the folder it was saved in. I have no idea how this is happening.
Is this something wrong with my code, Firefox, or maybe a OS security action? Any help would be greatly appreciated.
Extra Information:
Firefox - 95.0.2 (64-bit)
macOS - 11.4 (20F71)

I had the same issue. You have to put download in background, background.js.
Attached sample of Thunderbird addon creates new menu entry in the message list and save raw message to the file on click.
If you look to the manifest.json, "background.js" script is defined in the "background" section. The background.js script is automatically loaded when the add-on is enabled during Thunderbird start or after the add-on has been manually enabled or installed.
See: onClicked event from the browserAction (John Bieling)
manifest.json:
{
"description": "buttons",
"manifest_version": 2,
"name": "button",
"version": "1.0",
"background": {
"scripts": ["background.js"]
},
"permissions": [
"menus","messagesRead","downloads"
],
"browser_action": {
"default_icon": {
"16": "icons/page-16.png",
"32": "icons/page-32.png"
}
}
}
background.js:
async function main() {
// create a new context menu entry in the message list
// the function defined in onclick will get passed a OnClickData obj
// https://thunderbird-webextensions.readthedocs.io/en/latest/menus.html#menus-onclickdata
await messenger.menus.create({
contexts: ["all"],
id: "edit_email_subject_entry",
onclick: (onClickData) => {
saveMsg(onClickData.selectedMessages?.messages);
},
title: "iktatEml"
});
messenger.browserAction.onClicked.addListener(async (tab) => {
let msgs = await messenger.messageDisplay.getDisplayedMessages(tab.id);
saveMsg(msgs);
})
}
async function saveMsg(MessageHeaders) {
if (MessageHeaders && MessageHeaders.length > 0) {
// get MessageHeader of first selected messages
// https://thunderbird-webextensions.readthedocs.io/en/latest/messages.html#messageheader
let MessageHeader = MessageHeaders[0];
let raw = await messenger.messages.getRaw(MessageHeader.id);
let blob = new Blob([raw], { type: "text;charset=utf-8" })
// https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/downloads
await browser.downloads.download({
'url': URL.createObjectURL(blob),
'filename': "xiktatx.eml",
'conflictAction': "overwrite",
'saveAs': false
});
} else {
console.log("No message selected");
}
}
main();

How To Call Chrome Extension Function After Page Redirect?

I am working on building a Javascript (in-browser) Instagram bot. However, I ran into a problem.
If you run this script, the first function will be called and the page will be redirected to "https://www.instagram.com/explore/tags/samplehashtag/" and the second function will be called immediately after (on the previous URL before the page changes to the new URL). Is there a way to make the second function be called after this second URL has been loaded completely?
I have tried setting it to a Window setInterval() Method for an extended time period, window.onload and a couple of other methods. However, I can't seem to get anything to work. Any chance someone has a solution?
This is my first chrome extension and my first real project, so I may be missing something simple..
manifest.json
{
"name": "Inject Me",
"version": "1.0",
"manifest_version": 2,
"description": "Injecting stuff",
"homepage_url": "http://danharper.me",
"background": {
"scripts": [
"background.js"
],
"persistent": true
},
"browser_action": {
"default_title": "Inject!"
},
"permissions": [
"https://*/*",
"http://*/*",
"tabs"
]
}
inject.js
(function() {
let findUrl = () => {
let hashtag = "explore/tags/samplehashtag/";
location.replace("https://www.instagram.com/" + hashtag);
}
findUrl();
})();
background.js
// this is the background code...
// listen for our browerAction to be clicked
chrome.browserAction.onClicked.addListener(function(tab) {
// for the current tab, inject the "inject.js" file & execute it
chrome.tabs.executeScript(tab.ib, {
file: 'inject.js'
});
});
chrome.tabs.onUpdated.addListener(function(tabId, changeInfo, tab) {
chrome.tabs.executeScript(tab.ib, {
file: 'inject2.js'
});
});
inject2.js
(function() {
if (window.location.href.indexOf("https://www.instagram.com/explore/tags/samplehashtag/") != -1){
let likeAndRepeat = () => {
let counter = 0;
let grabPhoto = document.querySelector('._9AhH0');
grabPhoto.click();
let likeAndSkip = function() {
let heart = document.querySelector('.glyphsSpriteHeart__outline__24__grey_9.u-__7');
let arrow = document.querySelector('a.coreSpriteRightPaginationArrow');
if (heart) {
heart.click();
counter++;
console.log(`You have liked ${counter} photographs`)
}
arrow.click();
}
setInterval(likeAndSkip, 3000);
//alert('likeAndRepeat Inserted');
};
likeAndRepeat();
}
})();

It is not clear from the question and the example, when you want to run your function. But in chrome extension there is something called Message Passing
https://developer.chrome.com/extensions/messaging
With message passing you can pass messages from one file to another, and similarly listen for messages.
So as it looks from your use case, you can listen for a particular message and then fire your method.
For example
background.js
chrome.runtime.sendMessage({message: "FIRE_SOME_METHOD"})
popup.js
chrome.runtime.onMessage.addListener(
function(request) {
if (request.message == "FIRE_SOME_METHOD")
someMethod();
});
EDIT
Also if you want to listen for the URL changes, you can simply put a listener provided as in the documentation.
chrome.tabs.onUpdated.addListener(function(tabId, changeInfo, tab) {
console.log('updated tab');
});

OAuth for GAPI - Avoid Authentication and Authorization after initial sign in for Javascript

I have created a chrome extension that reads email, does something and create tasks using google client API for javascript.
I am using chrome identity for authentication and authorization.
The extension works as expected. However, it keeps asking for sign every once in a while. What I want is to authorize the user in the background script so that they don't need to do it over and over again, after the initial authentication and authorization.
What I have done so far:
I read that I need a refresh token to avoid this. However, refresh tokens are expected to be exchanged and stored on the server side and not client side (which wouldn't work because the background script is doing the job here which is client side)
Using gapi.auth.authorize with immediate true. That gives error regarding external visibility. When I read else, they suggested using it inside a server. I am not sure how can I do that in a chrome extension.
Turn interactive to false in getAuthToken, which starts giving error 401 due to authentication problem after the access token expires.
Following is the code I am using for authentication and authorization, with function onGoogleLibraryLoaded being called after loading the google api's client js file.
var signin = function (callback) {
chrome.identity.getAuthToken({interactive: true}, callback);
};
function onGoogleLibraryLoaded() {
signin(authorizationCallback);
}
var authorizationCallback = function (data) {
gapi.auth.setToken({access_token: data});
gapi.client.load('tasks', 'v1')
gapi.client.load('gmail', 'v1', function () {
console.log("Doing my stuff after this ..")
});
};
UPDATE:
As per the suggestion in the answer, I made some changes to the code. However, I am still facing the same issue. Following is the updated code snippet
jQuery.loadScript = function (url, callback) {
jQuery.ajax({
url: url,
dataType: 'script',
success: callback,
async: false
});
}
//This is the first thing that happens. i.e. loading the gapi client
if (typeof someObject == 'undefined') $.loadScript('https://apis.google.com/js/client.js',
function(){
console.log("gapi script loaded...")
});
//Every 20 seconds this function runs with internally loads the tasks and gmail
// Once the gmail module is loaded it calls the function getLatestHistoryId()
setInterval(function() {
gapi.client.load('tasks', 'v1')
gapi.client.load('gmail', 'v1', function(){
getLatestHistoryId()
})
// your code goes here...
}, 20 * 1000); // 60 * 1000 milsec
// This is the function that will get user's profile and when the response is received
// it'll check for the error i.e. error 401 through method checkForError
function getLatestHistoryId(){
prevEmailData = []
var request = gapi.client.gmail.users.getProfile({
'userId': 'me'
});
request.execute(function(response){
console.log("User profile response...")
console.log(response)
if(checkForError(response)){
return
}
})
}
// Now here I check for the 401 error. If there's a 401 error
// It will call the signin method to get the token again.
// Before calling signin it'll remove the saved token from cache through removeCachedAuthToken
// I have also tried doing it without the removeCachedAuthToken part. However the results were the same.
// I have left console statements which are self-explanatory
function checkForError(response){
if("code" in response && (response["code"] == 401)){
console.log(" 401 found will do the authentication again ...")
oooAccessToken = localStorage.getItem("oooAccessTokenTG")
console.log("access token ...")
console.log(oooAccessToken)
alert("401 Found Going to sign in ...")
if(oooAccessToken){
chrome.identity.removeCachedAuthToken({token: oooAccessToken}, function(){
console.log("Removed access token")
signin()
})
}
else{
console.log("No access token found to be remove ...")
signin()
}
return true
}
else{
console.log("Returning false from check error")
return false
}
}
// So finally when there is 401 it returns back here and calls
// getAuthToken with interactive true
// What happens here is that everytime this function is called
// there is a signin popup i.e. the one that asks you to select the account and allow permissions
// That's what is bothering me.
// I have also created a test chrome extension and uploaded it to chrome web store.
// I'll share the link for it separately.
var signin = function (callback) {
console.log(" In sign in ...")
chrome.identity.getAuthToken({interactive: true}, function(data){
console.log("getting access token without interactive ...")
console.log(data)
gapi.auth.setToken({access_token: data});
localStorage.setItem("oooAccessTokenTG", data)
getLatestHistoryId()
})
};
Manifest goes like this:
{
"manifest_version": 2,
"name": "Sign in Test Extension ",
"description": "",
"version": "0.0.0.8",
"icons": {
"16": "icon16.png",
"48": "icon48.png",
"128": "icon128.png"
},
"content_security_policy": "script-src 'self' 'unsafe-eval' https://apis.google.com; object-src 'self'",
"browser_action": {
"default_icon": "icon.png",
"default_popup": "popup.html"
},
"permissions": [
"identity",
"storage"
],
"oauth2": {
"client_id": "1234.apps.googleusercontent.com",
"scopes": [
"https://www.googleapis.com/auth/gmail.readonly"
]
},
"background":{
"scripts" : ["dependencies/jquery.min.js", "background.js"]
}
}
Anyone else facing the same issue?

I am also using the identity API for google authorization in my chrome extension. I used to get the 401 status when my google token expired. So I added a check that if I am getting 401 status response of my request, then I will again authorize and get the token (it will happen in background) and continue my work.
Here is an example from my background.js
var authorizeWithGoogle = function() {
return new Promise(function(resolve, reject) {
chrome.identity.getAuthToken({ 'interactive': true }, function(result) {
if (chrome.runtime.lastError) {
alert(chrome.runtime.lastError.message);
return;
}
if (result) {
chrome.storage.local.set({'token': result}, function() {
resolve("success");
});
} else {
reject("error");
}
});
});
}
function getEmail(emailId) {
if (chrome.runtime.lastError) {
alert(chrome.runtime.lastError.message);
return;
}
chrome.storage.local.get(["token"], function(data){
var url = 'https://www.googleapis.com/gmail/v1/users/me/messages/id?alt=json&access_token=' + data.token;
url = url.replace("id", emailId);
doGoogleRequest('GET', url, true).then(result => {
if (200 === result.status) {
//Do whatever from the result
} else if (401 === result.status) {
/*If the status is 401, this means that request is unauthorized (token expired in this case). Therefore refresh the token and get the email*/
refreshTokenAndGetEmail(emailId);
}
});
});
}
function refreshTokenAndGetEmail(emailId) {
authorizeWithGoogle().then(getEmail(emailId));
}
I don't need to log in again and again manually. The google token is refreshed automatically in the background.

So this is what I believe would be the answer to my question.
Few important things to know
Chrome sign in is not same as gmail sign in. You could have UserA signed into chrome, while you plan to use the chrome extension with UserB. chrome.identity.getAuthToken won't work in that case, because it looking for the user signed into chrome.
For using other google accounts i.e. the one not signed into chrome, you would need to use chrome.identity.launchWebAuthFlow. Following are the steps you can use. I am referring the example given here (Is it possible to get an Id token with Chrome App Indentity Api?)
Go to google console, create your own project > Credentials > Create Credentials > OAuthClientID > Web Application. On that page in the field Authorized redirect URIs, enter the redirect url in the format https://.chromiumapp.org. If you don't know what chrome extension ID is, refer this (Chrome extension id - how to find it)
This would generate a client id that would go into your manifest file. Forget about any previous client id you might have created. Let's say in our example the client id is 9999.apps.googleusercontent.com
Manifest file:
{
"manifest_version": 2,
"name": "Test gmail extension 1",
"description": "description",
"version": "0.0.0.1",
"content_security_policy": "script-src 'self' 'unsafe-eval' https://apis.google.com; object-src 'self'",
"background": {
"scripts": ["dependencies/jquery.min.js", "background.js"]
},
"browser_action": {
"default_icon": "icon.png",
"default_popup": "popup.html"
},
"permissions": [
"identity",
"storage"
],
"oauth2": {
"client_id": "9999.apps.googleusercontent.com",
"scopes": [
"https://www.googleapis.com/auth/gmail.readonly",
"https://www.googleapis.com/auth/tasks"
]
}
}
Sample code for getting user's info in background.js
jQuery.loadScript = function (url, callback) {
jQuery.ajax({
url: url,
dataType: 'script',
success: callback,
async: false
});
}
// This is the first thing that happens. i.e. loading the gapi client
if (typeof someObject == 'undefined') $.loadScript('https://apis.google.com/js/client.js',
function(){
console.log("gapi script loaded...")
});
// Every xx seconds this function runs with internally loads the tasks and gmail
// Once the gmail module is loaded it calls the function getLatestHistoryId()
setInterval(function() {
gapi.client.load('tasks', 'v1')
gapi.client.load('gmail', 'v1', function(){
getLatestHistoryId()
})
// your code goes here...
}, 10 * 1000); // xx * 1000 milsec
// This is the function that will get user's profile and when the response is received
// it'll check for the error i.e. error 401 through method checkForError
// If there is no error i.e. the response is received successfully
// It'll save the user's email address in localstorage, which would later be used as a hint
function getLatestHistoryId(){
var request = gapi.client.gmail.users.getProfile({
'userId': 'me'
});
request.execute(function(response){
console.log("User profile response...")
console.log(response)
if(checkForError(response)){
return
}
userEmail = response["emailAddress"]
localStorage.setItem("oooEmailAddress", userEmail);
})
}
// Now here check for the 401 error. If there's a 401 error
// It will call the signin method to get the token again.
// Before calling the signinWebFlow it will check if there is any email address
// stored in the localstorage. If yes, it would be used as a login hint.
// This would avoid creation of sign in popup in case if you use multiple gmail accounts i.e. login hint tells oauth which account's token are you exactly looking for
// The interaction popup would only come the first time the user uses your chrome app/extension
// I have left console statements which are self-explanatory
// Refer the documentation on https://developers.google.com/identity/protocols/OAuth2UserAgent >
// Obtaining OAuth 2.0 access tokens > OAUTH 2.0 ENDPOINTS for details regarding the param options
function checkForError(response){
if("code" in response && (response["code"] == 401)){
console.log(" 401 found will do the authentication again ...")
// Reading the data from the manifest file ...
var manifest = chrome.runtime.getManifest();
var clientId = encodeURIComponent(manifest.oauth2.client_id);
var scopes = encodeURIComponent(manifest.oauth2.scopes.join(' '));
var redirectUri = encodeURIComponent('https://' + chrome.runtime.id + '.chromiumapp.org');
// response_type should be token for access token
var url = 'https://accounts.google.com/o/oauth2/v2/auth' +
'?client_id=' + clientId +
'&response_type=token' +
'&redirect_uri=' + redirectUri +
'&scope=' + scopes
userEmail = localStorage.getItem("oooEmailAddress")
if(userEmail){
url += '&login_hint=' + userEmail
}
signinWebFlow(url)
return true
}
else{
console.log("Returning false from check error")
return false
}
}
// Once you get 401 this would be called
// This would get the access token for user.
// and than call the method getLatestHistoryId again
async function signinWebFlow(url){
console.log("THE URL ...")
console.log(url)
await chrome.identity.launchWebAuthFlow(
{
'url': url,
'interactive':true
},
function(redirectedTo) {
if (chrome.runtime.lastError) {
// Example: Authorization page could not be loaded.
console.log(chrome.runtime.lastError.message);
}
else {
var response = redirectedTo.split('#', 2)[1];
console.log(response);
access_token = getJsonFromUrl(response)["access_token"]
console.log(access_token)
gapi.auth.setToken({access_token: access_token});
getLatestHistoryId()
}
}
);
}
// This is to parse the get response
// referred from https://stackoverflow.com/questions/8486099/how-do-i-parse-a-url-query-parameters-in-javascript
function getJsonFromUrl(query) {
// var query = location.search.substr(1);
var result = {};
query.split("&").forEach(function(part) {
var item = part.split("=");
result[item[0]] = decodeURIComponent(item[1]);
});
return result;
}
Feel free to get in touch with me if you have any questions. I have spent quite a few days joining these dots. I wouldn't want someone else to do the same.

"Receiving end does not exist" when passing message to injected content script

In an add-on for Firefox, I'm trying to inject code from a background script into a tab and then pass a message to it. Unfortunately, the content script seems to add the listener only after the message has already been sent, resulting in in error. What am I missing? Here is my sample code:
manifest.json:
{
"description": "Test background to content message passing",
"manifest_version": 2,
"name": "Background content message passing",
"version": "0.1.0",
"default_locale": "en",
"applications": {
"gecko": {
"id": "bcm#example.com",
"strict_min_version": "51.0"
}
},
"permissions": [
"contextMenus",
"<all_urls>"
],
"background": {
"scripts": ["background.js"]
}
}
background.js:
"use strict";
const {contextMenus, i18n, runtime, tabs} = browser;
contextMenus.onClicked.addListener(function(info, tab) {
if (info.menuItemId == "bgd-cnt-msg") {
tabs.executeScript(tab.id, {
file: "/content.js",
})
.then(runtime.sendMessage({"result": 42}))
.then(console.log("Debug: runtime message sent"))
.catch(console.error.bind(console));
}
});
contextMenus.create({
id: "bgd-cnt-msg",
title: "Test message passing",
contexts: ["all"],
documentUrlPatterns: ["<all_urls>"]
});
content.js
"use strict";
console.log("Debug: executing content script");
browser.runtime.onMessage.addListener(function (message) {
console.log("Debug: received message %O", message);
});
console.log("Debug: added listener");
The result of selecting the the context menu entry is
Debug: runtime message sent background.js:11:15
Debug: executing content script content.js:3
Debug: added listener content.js:9
Error: Could not establish connection. Receiving end does not exist. undefined
I.e., the context scripts executes after the message to the tab is sent. How can I add the listener before sending the message?
As suggested by #Thắng, I changed my code to use tabs.sendMessage instead of runtime.sendMessage:
contextMenus.onClicked.addListener(function(info, tab) {
if (info.menuItemId == "bgd-cnt-msg") {
tabs.executeScript(tab.id, {
file: "/content.js",
})
.then(tabs.sendMessage(tab.id, {"result": 42}))
.then(console.log("Debug: runtime message sent"))
.catch(console.error.bind(console));
}
});
Now the error is reported a little earlier:
Debug: runtime message sent background.js:11:15
Error: Could not establish connection. Receiving end does not exist. undefined
Debug: executing content script content.js:3
Debug: added listener content.js:9
Thanks to #Thắng, who provided a working solution, I fixed my code to not only use tabs.sendMessage but also pass functions for the callbacks:
contextMenus.onClicked.addListener(function(info, tab) {
if (info.menuItemId == "bgd-cnt-msg") {
tabs.executeScript(tab.id, {
file: "/content.js",
})
.then(function () { tabs.sendMessage(tab.id, {"result": 42}) })
.then(function () { console.log("Debug: runtime message sent") })
.catch(console.error.bind(console));
}
});
With an additional fix in content.js
browser.runtime.onMessage.addListener(function (message) {
console.log("Debug: result is " + message.result);
});
I now get
Debug: executing content script content.js:3
Debug: added listener content.js:9
Debug: runtime message sent background.js:11:15
Debug: result is 42 content.js:6

In background script, you need to let it know it should send the message to which tab, so don't use runtime.sendMessage for this.
var sending = chrome.tabs.sendMessage(
tabId, // integer
message, // any
options // optional object
)
See more here (for webExtensions but also compatible with Chrome): https://developer.mozilla.org/en-US/Add-ons/WebExtensions/API/tabs/sendMessage
Your fully working extension here (you may need to change all the browser.* to chrome.*):
https://drive.google.com/file/d/1KGf8tCM1grhhiC9XcHOjsrbBsIZGff3e/view?usp=sharing

Chrome Extension - Channels Not Working

I am trying to create a channel to my Google App Engine (Python) server, and there seems to be a problem but I am unsure why. When the user toggles the extension, it authenticates the user. If successful, the server replies with a channel token which I use to create the channel. When I authenticate the user, alert("a") appears, but alert("b") does not which makes me believe there is a problem with the line var channel = new goog.appengine.Channel(msg.token);, but the console does not report an error.
I have also copied the javascript code from here and placed it in my manifest as oppose to putting <script type="text/javascript" src="/_ah/channel/jsapi"></script> in background.html.
//script.js
function authenticate(callback) {
var url = "https://r-notes.appspot.com/init/api/authenticate.json?username=" + username + "&password=" + password;
$.post(url, function(data) {
if (data.status == "200") {
channelToken = data.channeltoken;
if (callback) {
callback();
}
var port = chrome.extension.connect({name: "myChannel"});
port.postMessage({token: channelToken});
port.onMessage.addListener(function(msg) {
console.log(msg.question);
});
}
});
}
//background.html
chrome.extension.onConnect.addListener(function(port) {
port.onMessage.addListener(function(msg) {
alert("a"); //pops up
var channel = new goog.appengine.Channel(msg.token);
alert("b"); //does not pop up
console.log(channel); //display error ' Error in event handler for 'undefined': ReferenceError: goog is not defined '
var socket = channel.open()
socket.onopen = function() {
// Do stuff right after opening a channel
console.log('socket opened');
}
socket.onmessage = function(evt) {
// Do more cool stuff when a channel message comes in
console.log('message recieved');
console.log(evt);
}
});
});
//manifest.json
{
"name": "moot",
"description": "Clicking on the moot button will display a sidebar!",
"version": "0.2.69",
"background_page": "html/background.html",
"browser_action": {
"default_icon": "img/icon_64.png",
"default_title": "moot"
},
"content_scripts": [
{
"matches": ["<all_urls>"],
"js": ["js/channelApi.js",
"js/script.js", "js/mootsOnSidebar.js", "js/mootsOnPage.js", "js/authenticate.js", "js/otherFunctions.js",
"js/jquery/jquery-1.7.1.js", "js/jquery/jquery.mCustomScrollbar.js", "js/jquery/jquery-ui.min.js",
"js/jquery/jquery.autosize.js", "js/jquery/jquery.mousewheel.min.js", "js/jquery/jquery.easing.1.3.js",
"js/channel.js"],
"css": ["css/cssReset.css", "css/sidebar.css", "css/onPageCreate.css", "css/onPageExists.css", "css/scrollbar.css", "css/authenticate.css"]
}
],
"permissions": [
"tabs", "contextMenus", "http://*/*", "https://*/"
],
"icons": {
"16": "img/icon_16.png",
"64": "img/icon_64.png"
}
}
EDIT - After doing console.log(channel), I discovered the error ' Error in event handler for 'undefined': ReferenceError: goog is not defined '. I am unsure why I receive this error as I did include the required javascript file as I followed this post.

So the solution is that you need to include the file <script type="text/javascript" src="https://talkgadget.google.com/talkgadget/channel.js"></script> in a HTML page. I placed this on the first row of background.html.
My mistake was saving a local copy of channel.js, and refer to it in manifest.json.
I'm now going to place a copy of channel.js on my server, and refer to my server's copy. I don't think there will be any issues with that.

Make a console log for the value of msg direct between alert("a") and var channel = ...
and inspect the value.