Make a link from Electron open in browser - javascript

Is there any (simple/built-in way) to open a new browser (I mean default OS browser) window for a link from Electron instead of visiting that link inside your Electron app ?

You can simply use :
require("shell").openExternal("http://www.google.com")

EDIT: #Arjun Kava's answer is much better these days.
This answer is quite old and assumes you have jQuery.
const shell = require('electron').shell;
// assuming $ is jQuery
$(document).on('click', 'a[href^="http"]', function(event) {
event.preventDefault();
shell.openExternal(this.href);
});

mainWindow.webContents.on('new-window', function(e, url) {
e.preventDefault();
require('electron').shell.openExternal(url);
});
Requires that you use target="_blank" on your anchor tags.

My code snippet clue accordingly to the depreciations in Electron version ^12.0.0
const win = new BrowserWindow();
win.webContents.setWindowOpenHandler(({ url }) => {
// config.fileProtocol is my custom file protocol
if (url.startsWith(config.fileProtocol)) {
return { action: 'allow' };
}
// open url in a browser and prevent default
shell.openExternal(url);
return { action: 'deny' };
});

To make all Electron links to open externally in the default OS browser you will have to add an onclick property to them and change the href property so it doesn't load anything in the Electron app.
You could use something like this:
aTags = document.getElementsByTagName("a");
for (var i = 0; i < aTags.length; i++) {
aTags[i].setAttribute("onclick","require('shell').openExternal('" + aTags[i].href + "')");
aTags[i].href = "#";
}
But make sure the entire document has loaded before doing this otherwise it is not going to work.
A more robust implementation would look like this:
if (document.readyState != "complete") {
document.addEventListener('DOMContentLoaded', function() {
prepareTags()
}, false);
} else {
prepareTags();
}
function prepareTags(){
aTags = document.getElementsByTagName("a");
for (var i = 0; i < aTags.length; i++) {
aTags[i].setAttribute("onclick","require('shell').openExternal('" + aTags[i].href + "')");
aTags[i].href = "#";
}
return false;
}
Remember that if you load external files you will have to make them go through this process as well after they are fully loaded.

Some handy solutions can be found in this gist.
By listening on the body, the following solutions will work on <a> tags that may not yet exist when the JavaScript runs, but only appear in the DOM at a later time.
This one by luizcarraro requires jQuery:
$('body').on('click', 'a', (event) => {
event.preventDefault();
require("electron").shell.openExternal(event.target.href);
});
You can change the selector to target only certain links, e.g. '#messages-view a' or 'a.open-external'.
Here is an alternative without any library (derived from zrbecker's):
document.body.addEventListener('click', event => {
if (event.target.tagName.toLowerCase() === 'a') {
event.preventDefault();
require("electron").shell.openExternal(event.target.href);
}
});
Consult the gist for more examples.

I use this method with Electron v.13.
We intercept the user's navigation (window.location) and open the URL in the default browser.
See the doc : https://www.electronjs.org/docs/latest/api/web-contents#event-will-navigate
const { shell } = require('electron');
window.webContents.on('will-navigate', function (e, url) {
e.preventDefault();
shell.openExternal(url);
});

On tsx syntax (Electron):
import { shell } from "electron";
shell.openExternal("http://www.google.com")

In the view component use simple a link:
<a href="https://google.com" target="_blank" rel="noreferrer">
<button type="button">
button title
</button>
</a>
And in file public/electron.js add default behavior for all a link navigations:
function createWindow() {
...
// Open urls in the user's browser
win.webContents.setWindowOpenHandler((edata) => {
shell.openExternal(edata.url);
return { action: "deny" };
});
}

To open an external link in an Electron's Project you will need the module Shell (https://www.electronjs.org/docs/api/shell#shell) and the method openExternal.
But if you are looking for an abstract way to implement that logic is by creating a handler for a custom target to your target attribute.
const {shell} = require('electron');
if (document.readyState != "complete") {
document.addEventListener('DOMContentLoaded', function() {
init()
}, false);
} else {
init();
}
function init(){
handleExternalLinks();
//other inits
}
function handleExternalLinks(){
let links = document.getElementsByTagName('a')
let a,i = 0;
while (links[i]){
a = links[i]
//If <a target="_external">, so open using shell.
if(a.getAttribute('target') == '_external'){
a.addEventListener('click',(ev => {
ev.preventDefault();
let url = a.href;
shell.openExternal(url);
a.setAttribute('href', '#');
return false;
}))
}
console.log(a,a.getAttribute('external'))
i++;
}
}

To run an Electron project in your actual browser (Chrome, Mozilla, etc), add this to your script are external script:
aTags = document.getElementsByTagName("a");
for (var i = 0; i < aTags.length; i++) {
aTags[i].setAttribute("onclick","require('shell').openExternal('" + aTags[i].href + "')");
aTags[i].href = "#";
}

Related

How to detect a window url change? [duplicate]

How can I check if a URL has changed in JavaScript? For example, websites like GitHub, which use AJAX, will append page information after a # symbol to create a unique URL without reloading the page. What is the best way to detect if this URL changes?
Is the onload event called again?
Is there an event handler for the URL?
Or must the URL be checked every second to detect a change?
I wanted to be able to add locationchange event listeners. After the modification below, we'll be able to do it, like this
window.addEventListener('locationchange', function () {
console.log('location changed!');
});
In contrast, window.addEventListener('hashchange',() => {}) would only fire if the part after a hashtag in a url changes, and window.addEventListener('popstate',() => {}) doesn't always work.
This modification, similar to Christian's answer, modifies the history object to add some functionality.
By default, before these modifications, there's a popstate event, but there are no events for pushstate, and replacestate.
This modifies these three functions so that all fire a custom locationchange event for you to use, and also pushstate and replacestate events if you want to use those.
These are the modifications:
(() => {
let oldPushState = history.pushState;
history.pushState = function pushState() {
let ret = oldPushState.apply(this, arguments);
window.dispatchEvent(new Event('pushstate'));
window.dispatchEvent(new Event('locationchange'));
return ret;
};
let oldReplaceState = history.replaceState;
history.replaceState = function replaceState() {
let ret = oldReplaceState.apply(this, arguments);
window.dispatchEvent(new Event('replacestate'));
window.dispatchEvent(new Event('locationchange'));
return ret;
};
window.addEventListener('popstate', () => {
window.dispatchEvent(new Event('locationchange'));
});
})();
Note, we're creating a closure, to save the old function as part of the new one, so that it gets called whenever the new one is called.
In modern browsers (IE8+, FF3.6+, Chrome), you can just listen to the hashchange event on window.
In some old browsers, you need a timer that continually checks location.hash. If you're using jQuery, there is a plugin that does exactly that.
Example
Below I undo any URL change, to keep just the scrolling:
<script type="text/javascript">
if (window.history) {
var myOldUrl = window.location.href;
window.addEventListener('hashchange', function(){
window.history.pushState({}, null, myOldUrl);
});
}
</script>
Note that above used history-API is available in Chrome, Safari, Firefox 4+, and Internet Explorer 10pp4+
window.onhashchange = function() {
//code
}
window.onpopstate = function() {
//code
}
or
window.addEventListener('hashchange', function() {
//code
});
window.addEventListener('popstate', function() {
//code
});
with jQuery
$(window).bind('hashchange', function() {
//code
});
$(window).bind('popstate', function() {
//code
});
EDIT after a bit of researching:
It somehow seems that I have been fooled by the documentation present on Mozilla docs. The popstate event (and its callback function onpopstate) are not triggered whenever the pushState() or replaceState() are called in code. Therefore the original answer does not apply in all cases.
However there is a way to circumvent this by monkey-patching the functions according to #alpha123:
var pushState = history.pushState;
history.pushState = function () {
pushState.apply(history, arguments);
fireEvents('pushState', arguments); // Some event-handling function
};
Original answer
Given that the title of this question is "How to detect URL change" the answer, when you want to know when the full path changes (and not just the hash anchor), is that you can listen for the popstate event:
window.onpopstate = function(event) {
console.log("location: " + document.location + ", state: " + JSON.stringify(event.state));
};
Reference for popstate in Mozilla Docs
Currently (Jan 2017) there is support for popstate from 92% of browsers worldwide.
With jquery (and a plug-in) you can do
$(window).bind('hashchange', function() {
/* things */
});
http://benalman.com/projects/jquery-hashchange-plugin/
Otherwise yes, you would have to use setInterval and check for a change in the hash event (window.location.hash)
Update! A simple draft
function hashHandler(){
this.oldHash = window.location.hash;
this.Check;
var that = this;
var detect = function(){
if(that.oldHash!=window.location.hash){
alert("HASH CHANGED - new has" + window.location.hash);
that.oldHash = window.location.hash;
}
};
this.Check = setInterval(function(){ detect() }, 100);
}
var hashDetection = new hashHandler();
Add a hash change event listener!
window.addEventListener('hashchange', function(e){console.log('hash changed')});
Or, to listen to all URL changes:
window.addEventListener('popstate', function(e){console.log('url changed')});
This is better than something like the code below because only one thing can exist in window.onhashchange and you'll possibly be overwriting someone else's code.
// Bad code example
window.onhashchange = function() {
// Code that overwrites whatever was previously in window.onhashchange
}
this solution worked for me:
function checkURLchange(){
if(window.location.href != oldURL){
alert("url changed!");
oldURL = window.location.href;
}
}
var oldURL = window.location.href;
setInterval(checkURLchange, 1000);
None of these seem to work when a link is clicked that which redirects you to a different page on the same domain. Hence, I made my own solution:
let pathname = location.pathname;
window.addEventListener("click", function() {
if (location.pathname != pathname) {
pathname = location.pathname;
// code
}
});
Edit: You can also check for the popstate event (if a user goes back a page)
window.addEventListener("popstate", function() {
// code
});
Best wishes,
Calculus
If none of the window events are working for you (as they aren't in my case), you can also use a MutationObserver that looks at the root element (non-recursively).
// capture the location at page load
let currentLocation = document.location.href;
const observer = new MutationObserver((mutationList) => {
if (currentLocation !== document.location.href) {
// location changed!
currentLocation = document.location.href;
// (do your event logic here)
}
});
observer.observe(
document.getElementById('root'),
{
childList: true,
// important for performance
subtree: false
});
This may not always be feasible, but typically, if the URL changes, the root element's contents change as well.
I have not profiled, but theoretically this has less overhead than a timer because the Observer pattern is typically implemented so that it just loops through the subscriptions when a change occurs. We only added one subscription here. The timer on the other hand would have to check very frequently in order to ensure that the event was triggered immediately after URL change.
Also, this has a good chance of being more reliable than a timer since it eliminates timing issues.
Although an old question, the Location-bar project is very useful.
var LocationBar = require("location-bar");
var locationBar = new LocationBar();
// listen to all changes to the location bar
locationBar.onChange(function (path) {
console.log("the current url is", path);
});
// listen to a specific change to location bar
// e.g. Backbone builds on top of this method to implement
// it's simple parametrized Backbone.Router
locationBar.route(/some\-regex/, function () {
// only called when the current url matches the regex
});
locationBar.start({
pushState: true
});
// update the address bar and add a new entry in browsers history
locationBar.update("/some/url?param=123");
// update the address bar but don't add the entry in history
locationBar.update("/some/url", {replace: true});
// update the address bar and call the `change` callback
locationBar.update("/some/url", {trigger: true});
To listen to url changes, see below:
window.onpopstate = function(event) {
console.log("location: " + document.location + ", state: " + JSON.stringify(event.state));
};
Use this style if you intend to stop/remove listener after some certain condition.
window.addEventListener('popstate', function(e) {
console.log('url changed')
});
The answer below comes from here(with old javascript syntax(no arrow function, support IE 10+)):
https://stackoverflow.com/a/52809105/9168962
(function() {
if (typeof window.CustomEvent === "function") return false; // If not IE
function CustomEvent(event, params) {
params = params || {bubbles: false, cancelable: false, detail: null};
var evt = document.createEvent("CustomEvent");
evt.initCustomEvent(event, params.bubbles, params.cancelable, params.detail);
return evt;
}
window.CustomEvent = CustomEvent;
})();
(function() {
history.pushState = function (f) {
return function pushState() {
var ret = f.apply(this, arguments);
window.dispatchEvent(new CustomEvent("pushState"));
window.dispatchEvent(new CustomEvent("locationchange"));
return ret;
};
}(history.pushState);
history.replaceState = function (f) {
return function replaceState() {
var ret = f.apply(this, arguments);
window.dispatchEvent(new CustomEvent("replaceState"));
window.dispatchEvent(new CustomEvent("locationchange"));
return ret;
};
}(history.replaceState);
window.addEventListener("popstate", function() {
window.dispatchEvent(new CustomEvent("locationchange"));
});
})();
While doing a little chrome extension, I faced the same problem with an additionnal problem : Sometimes, the page change but not the URL.
For instance, just go to the Facebook Homepage, and click on the 'Home' button. You will reload the page but the URL won't change (one-page app style).
99% of the time, we are developping websites so we can get those events from Frameworks like Angular, React, Vue etc..
BUT, in my case of a Chrome extension (in Vanilla JS), I had to listen to an event that will trigger for each "page change", which can generally be caught by URL changed, but sometimes it doesn't.
My homemade solution was the following :
listen(window.history.length);
var oldLength = -1;
function listen(currentLength) {
if (currentLength != oldLength) {
// Do your stuff here
}
oldLength = window.history.length;
setTimeout(function () {
listen(window.history.length);
}, 1000);
}
So basically the leoneckert solution, applied to window history, which will change when a page changes in a single page app.
Not rocket science, but cleanest solution I found, considering we are only checking an integer equality here, and not bigger objects or the whole DOM.
Found a working answer in a separate thread:
There's no one event that will always work, and monkey patching the pushState event is pretty hit or miss for most major SPAs.
So smart polling is what's worked best for me. You can add as many event types as you like, but these seem to be doing a really good job for me.
Written for TS, but easily modifiable:
const locationChangeEventType = "MY_APP-location-change";
// called on creation and every url change
export function observeUrlChanges(cb: (loc: Location) => any) {
assertLocationChangeObserver();
window.addEventListener(locationChangeEventType, () => cb(window.location));
cb(window.location);
}
function assertLocationChangeObserver() {
const state = window as any as { MY_APP_locationWatchSetup: any };
if (state.MY_APP_locationWatchSetup) { return; }
state.MY_APP_locationWatchSetup = true;
let lastHref = location.href;
["popstate", "click", "keydown", "keyup", "touchstart", "touchend"].forEach((eventType) => {
window.addEventListener(eventType, () => {
requestAnimationFrame(() => {
const currentHref = location.href;
if (currentHref !== lastHref) {
lastHref = currentHref;
window.dispatchEvent(new Event(locationChangeEventType));
}
})
})
});
}
Usage
observeUrlChanges((loc) => {
console.log(loc.href)
})
I created this event that is very similar to the hashchange event
// onurlchange-event.js v1.0.1
(() => {
const hasNativeEvent = Object.keys(window).includes('onurlchange')
if (!hasNativeEvent) {
let oldURL = location.href
setInterval(() => {
const newURL = location.href
if (oldURL === newURL) {
return
}
const urlChangeEvent = new CustomEvent('urlchange', {
detail: {
oldURL,
newURL
}
})
oldURL = newURL
dispatchEvent(urlChangeEvent)
}, 25)
addEventListener('urlchange', event => {
if (typeof(onurlchange) === 'function') {
onurlchange(event)
}
})
}
})()
Example of use:
window.onurlchange = event => {
console.log(event)
console.log(event.detail.oldURL)
console.log(event.detail.newURL)
}
addEventListener('urlchange', event => {
console.log(event)
console.log(event.detail.oldURL)
console.log(event.detail.newURL)
})
for Chrome 102+ (2022-05-24)
navigation.addEventListener("navigate", e => {
console.log(`navigate ->`,e.destination.url)
});
API references WICG/navigation-api
Look at the jQuery unload function. It handles all the things.
https://api.jquery.com/unload/
The unload event is sent to the window element when the user navigates away from the page. This could mean one of many things. The user could have clicked on a link to leave the page, or typed in a new URL in the address bar. The forward and back buttons will trigger the event. Closing the browser window will cause the event to be triggered. Even a page reload will first create an unload event.
$(window).unload(
function(event) {
alert("navigating");
}
);
window.addEventListener("beforeunload", function (e) {
// do something
}, false);
You are starting a new setInterval at each call, without cancelling the previous one - probably you only meant to have a setTimeout
Enjoy!
var previousUrl = '';
var observer = new MutationObserver(function(mutations) {
if (location.href !== previousUrl) {
previousUrl = location.href;
console.log(`URL changed to ${location.href}`);
}
});
Another simple way you can do this is by adding a click event, through a class name to the anchor tags on the page to detect when it has been clicked, then you can now use the window.location.href to get the url data which you can use to run your ajax request to the server. Simple and Easy.

how to remember clicked href and redirect to it javascript

My home page has a couple of links: one for English version and the other for French version. Something like this:
<a class="ensite" href="/en">English</a>
<a class="ensite" href="/fr">French</a>
I want to use JavaScript to remember the last choice made by visitors and when they come again, they don't have to choose the language one more time because I want them to be autoredirected to the preferred language using cookies.
P.S. the visitors are strangers, not registered users. I want to store cookies in visitors' browsers, not in the database. Please, help me by providing me with the full solution.
Gelerally, the idea is: set handlers on links and upon clicking save preferred version into localStorage. Then every time user loads any page of your site, just check, whether the url contains the language context ("en"/"fr") the user chose before. If yes - do nothing, user opened the right version; if not - redirect him to the previously saved version. The following is a Vanilla approach (not properly tested). You will have to tweak it (attachEvent etc.) or use jQuery library to implement similar ideas in a shorter and more cross-browser way.
<a class="ensite" href="/en">English</a>
<a class="ensite" href="/fr">French</a>
JS:
function LanguageManager(selector) {
this.langLinks = document.querySelectorAll(selector);
}
LanguageManager.prototype.setHandler = function() {
var self = this;
this.langLinks.forEach(function(langLink) {
langLink.addEventListener("click", self.handler, false);
});
}
LanguageManager.prototype.redirect = function() {
var link = storageManager.restoreDataFromStorage();
if(link && !~window.location.href.indexOf(link)) window.location.href = link;
}
LanguageManager.prototype.handler = function() {
var e = event || window. event;
var elem = e.target || e.srcElement;
if(e.preventDefault) e.preventDefault(); else e.returnValue = false;
storageManager.saveDataToStorage(elem.href);
location.href = elem.href;
}
function StorageManager() {
this.storageName = "languageVersion";
this.storageData = null;
}
StorageManager.prototype.isStorageAvailable = function(type) {
try {
var storage = window[type], x = '__storage_test__';
storage.setItem(x, x);
storage.removeItem(x);
return true;
} catch(e) { return false; }
}
StorageManager.prototype.saveDataToStorage = function(data) {
if(!this.isStorageAvailable('localStorage')) {
this.storageData = data;
return false;
}
try {
localStorage.setItem(this.storageName, JSON.stringify(data));
return this.storageName;
} catch(e) {
this.storageData = data;
return false;
}
}
StorageManager.prototype.restoreDataFromStorage = function() {
if(this.storageData) return this.storageData;
return JSON.parse(localStorage.getItem(this.storageName));
}
var storageManager = new StorageManager();
var languageManager = new LanguageManager(".ensite");
languageManager.setHandler();
languageManager.redirect();
Also notice, that there may be issues depending on how you implement language contexts on your site. You can start with my code on your own and tweak it or find someone else to get this properly done.
Just tested this, it works perfect.
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<a class="ensite" href="" onclick ="localStorage.setItem('language','en')">English</a>
<a class="ensite" href="" onclick = "localStorage.setItem('language','fr')">French</a>
<script>
$(document).ready(function(){
var language = (localStorage.getItem('language') == null)? 'en' : localStorage.getItem('language');
console.log(language);
})
</script>

How to add back button event in Universal Windows App without using WinjS Library?

This is my main.js
(function () {
"use strict";
//No need of WinJS
var activation = Windows.ApplicationModel.Activation;
var roaming = Windows.Storage.ApplicationData.current.roamingSettings;
// For App Start Up
Windows.UI.WebUI.WebUIApplication.addEventListener("activated", function (args) {
if (args.detail[0].kind === activation.ActivationKind.launch) {
if (roaming.values["currentUri"]) {
if (roaming.values["UserName"])
{
localStorage.setItem("UserName", roaming.values["UserName"]);
window.location.href = roaming.values["currentUri"];
}
}
}
});
// For App Suspension
Windows.UI.WebUI.WebUIApplication.addEventListener("suspending", function (args) {
roaming.values["currentUri"] = window.location.href;
roaming.values["UserName"] = localStorage.getItem("UserName");
});
// For Resuming App
Windows.UI.WebUI.WebUIApplication.addEventListener("resuming", function (args) {
var roam = Windows.Storage.ApplicationData.current.roamingSettings;
if (roam) {
if (roam.values["currentUri"]) {
localStorage.setItem("UserName", roam.values["UserName"]);
window.location.href = roam.values["currentUri"];
}
}
}, false);
// not working backpressed event
Windows.UI.WebUI.WebUIApplication.addEventListener("backpressed", function (args) {
// to do
}, false);})();
I need to add back key press event for windows phone without using winjs library?
Can anyone suggest me?
I am using ms-appx-web context in my app. I dont want to use winjs library.
I need to add back key press event for windows phone without using winjs library?
The backpressed event should be attached to Windows.Phone.UI.Input.HardwareButtons but not Windows.UI.WebUI.WebUIApplication.
If you refer to HardwareButtons.BackPressed and HardwareButtons, you will find the backpressed event is used like this:
var hardwareButtons = Windows.Phone.UI.Input.HardwareButtons;
function onBackPressed(eventArgs) { /* Your code */ }
// addEventListener syntax
hardwareButtons.addEventListener("backpressed", onBackPressed);
hardwareButtons.removeEventListener("backpressed", onBackPressed);
And since you are not making a Single Page Application. This event should be attached on every new page's JS codes.
Update: If you want to know your current device programmatically, you can use the following if-statement:
if (deviceInfo.operatingSystem.toLowerCase() == "windowsphone")
{
//do your windows phone logic
} else if (deviceInfo.operatingSystem.toLowerCase() == "windows")
{
//do your windows logic
}
I used this-
var flag = Windows.Foundation.Metadata.ApiInformation.isTypePresent("Windows.Phone.UI.Input.HardwareButtons");
if (flag) {
var hardwareButtons = Windows.Phone.UI.Input.HardwareButtons;
hardwareButtons.addEventListener("backpressed", onBackPressed);
}
It worked for me well!

Clicking links with WebdriverIO

I have a web page that I am trying to test via Webdriver I/O. My question is, how do I click a couple of links via a test? Currently, I have the following:
var webdriverio = require('webdriverio');
var client = webdriverio.remote(settings).init()
.url('http://www.example.com')
.elements('a')
.then(function(links) {
for (var i=0; i<links.value.length; i++) {
console.log('Clicking link...');
var link = links.value[i].ELEMENT;
link.click().then(function(result) {
console.log('Link clicked!');
});
}
})
;
When the above gets executed, I get an error that says "click is not a function" on link. When I print link to the console, it looks like JSON, which would make sense since the documentation says that the elements function returns WebElement JSON objects. Still, I'm just trying to figure out how to click this link.
How does one do such?
Thanks!
You need elementIdClick
http://webdriver.io/api/protocol/elementIdClick.html
Here is an example
var settings = {
desiredCapabilities: {
browserName: 'firefox',
},
};
var webdriverio = require('webdriverio');
var client = webdriverio.remote(settings).init()
.url('http://www.example.com')
.elements('a')
.then(function(links) {
for (var i=0; i<links.value.length; i++) {
console.log('Clicking link...');
var link = links.value[i].ELEMENT;
client.elementIdClick(link).then(function(result) {
console.log('Link clicked!');
});
}
});
Result of the above code will be
Clicking link...
Link clicked!
Hello there you could do directly this though:
it clicks all elements a on the page
var client = webdriverio.remote(settings).init()
.url('http://www.example.com')
.click('a')
.end()
);
you could you a selector to target specific a elements
example:
.click("article .search-result .abstract .more")

Firefox add-on pageshow event fires before worker able to receive messages

I'm writing a firefox plugin and keeping track of each page's workers in an array. Apart from a bit of fancy footwork required to manage this array (as described here https://bugzilla.mozilla.org/show_bug.cgi?id=686035 and here Addon SDK - context-menu and page-mod workers) everything is working properly. One issue I'm having is that when listening to the tabs pageshow event (or the worker's own pageshow event for that matter), the callback seems to fire before the worker is actually ready. When retrieving the page's corresponding worker in the callback and using it to try to send a message to the content script, I'm receiving the error The page is currently hidden and can no longer be used until it is visible again. Normally, I'd just use a setTimeout and grit my teeth, but this isn't available for add-ons. What's a suitable workaround? The code for the main part of the add-on is below:
var { ToggleButton } = require('sdk/ui/button/toggle');
var panels = require('sdk/panel');
var tabs = require('sdk/tabs');
var self = require('sdk/self');
var pageMods = require('sdk/page-mod');
var ss = require('sdk/simple-storage');
var workers = [];
ss.storage.isPluginActive = ss.storage.isPluginActive || false;
var button = ToggleButton({
id: 'tomorrowww',
label: 'Tomorowww',
icon: {
'16': './icon-16.png',
'32': './icon-32.png',
'64': './icon-64.png'
},
onChange: handleButtonChange
});
var panel = panels.Panel({
contentURL: self.data.url('panel.html'),
contentScriptFile: self.data.url('panel-script.js'),
onHide: handlePanelHide,
width: 342,
height: 270
});
panel.port.on('panel-ready', handlePanelReady);
panel.port.on('plugin-toggled', handlePluginToggled);
panel.port.on('link-clicked', handleLinkClicked);
pageMods.PageMod({
include: ['*'],
contentScriptFile: [self.data.url('CancerDOMManager.js'), self.data.url('content-script.js')],
contentStyleFile: self.data.url('content-style.css'),
onAttach: function (worker) {
addWorker(worker);
sendActiveState(ss.storage.isPluginActive);
}
});
// move between tabs
tabs.on('activate', function () {
sendActiveState();
});
// this actually fires before the worker's pageshow event so isn't useful as the workers array will be out of sync
//tabs.on('pageshow', function () {
// sendActiveState();
//});
function addWorker (worker) {
if(workers.indexOf(worker) > -1) {
return;
}
worker.on('detach', handleWorkerDetach);
worker.on('pageshow', handleWorkerShown);
worker.on('pagehide', handleWorkerHidden);
workers.push(worker);
}
function handleWorkerDetach () {
removeWorker(this, true);
}
function handleWorkerShown () {
addWorker(this);
// back / forward page history
// trying to send the state here will trigger the page hidden error
sendActiveState();
}
function handleWorkerHidden () {
removeWorker(this);
}
function removeWorker (worker, removeEvents) {
var index = workers.indexOf(worker);
removeEvents = removeEvents || false;
if(index > -1) {
if(removeEvents) {
worker.removeListener('detach', handleWorkerDetach);
worker.removeListener('pageshow', handleWorkerShown);
worker.removeListener('pagehide', handleWorkerHidden);
}
workers.splice(index, 1);
}
}
function getWorkersForCurrentTab () {
var i;
var tabWorkers = [];
i = workers.length;
while(--i > -1) {
if(workers[i].tab.id === tabs.activeTab.id) {
tabWorkers.push(workers[i]);
}
}
return tabWorkers;
}
function handlePanelReady () {
setActive(ss.storage.isPluginActive);
}
function setActive (bool) {
ss.storage.isPluginActive = bool;
panel.port.emit('active-changed', bool);
sendActiveState();
}
function sendActiveState () {
var tabWorkers = getWorkersForCurrentTab();
var i = tabWorkers.length;
while(--i > -1) {
tabWorkers[i].port.emit('toggle-plugin', ss.storage.isPluginActive);
}
}
function handleButtonChange (state) {
if(state.checked) {
panel.show({
position: button
});
}
}
function handlePanelHide () {
button.state('window', {checked: false});
}
function handleLinkClicked (url) {
if(panel.isShowing) {
panel.hide();
}
tabs.open(url);
}
function handlePluginToggled (bool) {
if(panel.isShowing) {
panel.hide();
}
setActive(bool);
}
try using contentScriptWhen: "start" in the page-mod
I was dealing with a similar problem. I think I have it working the way I want now by putting the listener in the content script instead of the addon script. I listen for the event on the window, I then emit a message from my content script to my addon script, my addon script then sends a message back to the content script with the information needed from the addon script.
In my code, I am working on update the preferences in the content script to ensure that the tab always has the most up to date settings when they are changed, only the addon script can listen to the prefs change event.
This particular snippet will listen for when the page is navigated to from history (i.e., back or forward button), will inform the addon script, the addon script will get the most up to date preferences, and then send them back to a port listening in the content script.
Content script:
window.onpageshow = function(){
console.log("onpageshow event fired (content script)");
self.port.emit("triggerPrefChange", '');
};
Addon Script (e.g., main.js:
worker.port.on("triggerPrefChange", function() {
console.log("Received request to triggerPrefChange in the addon script");
worker.port.emit("setPrefs", prefSet.prefs);
});
Since the event is being fired from the DOM event, the page must be shown. I am not sure if listening to the pageshow event in the addon script is doing what we think.

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