I've a problem with Electron where the app goes blank. i.e. It becomes a white screen. If I open the dev tools it displays the following message.
In ActivityMonitor I can see the number of Electron Helper processes drops from 3 to 2 when this happens. Plus it seems I'm not the only person to come across it. e.g.
Facing "Devtools was disconnected from the page. Once page is reloaded, Devtools will automatically reconnect."
Electron dying without any information, what now?
But I've yet to find an answer that helps. In scenarios where Electron crashes are there any good approaches to identifying the problem?
For context I'm loading an sdk into Electron. Originally I was using browserify to package it which worked fine. But I want to move to the SDKs npm release. This version seems to have introduced the problem (though the code should be the same).
A good bit of time has passed since I originally posted this question. I'll answer it myself in case my mistake can assist anyone.
I never got a "solution" to the original problem. At a much later date I switched across to the npm release of the sdk and it worked.
But before that time I'd hit this issue again. Luckily, by then, I'd added a logger that also wrote console to file. With it I noticed that a JavaScript syntax error caused the crash. e.g. Missing closing bracket, etc.
I suspect that's what caused my original problem. But the Chrome dev tools do the worst thing by blanking the console rather than preserve it when the tools crash.
Code I used to setup a logger
/*global window */
const winston = require('winston');
const prettyMs = require('pretty-ms');
/**
* Proxy the standard 'console' object and redirect it toward a logger.
*/
class Logger {
constructor() {
// Retain a reference to the original console
this.originalConsole = window.console;
this.timers = new Map([]);
// Configure a logger
this.logger = winston.createLogger({
level: 'info',
format: winston.format.combine(
winston.format.timestamp(),
winston.format.printf(({ level, message, timestamp }) => {
return `${timestamp} ${level}: ${message}`;
})
),
transports: [
new winston.transports.File(
{
filename: `${require('electron').remote.app.getPath('userData')}/logs/downloader.log`, // Note: require('electron').remote is undefined when I include it in the normal imports
handleExceptions: true, // Log unhandled exceptions
maxsize: 1048576, // 10 MB
maxFiles: 10
}
)
]
});
const _this = this;
// Switch out the console with a proxied version
window.console = new Proxy(this.originalConsole, {
// Override the console functions
get(target, property) {
// Leverage the identical logger functions
if (['debug', 'info', 'warn', 'error'].includes(property)) return (...parameters) => {
_this.logger[property](parameters);
// Simple approach to logging to console. Initially considered
// using a custom logger. But this is much easier to implement.
// Downside is that the format differs but I can live with that
_this.originalConsole[property](...parameters);
}
// The log function differs in logger so map it to info
if ('log' === property) return (...parameters) => {
_this.logger.info(parameters);
_this.originalConsole.info(...parameters);
}
// Re-implement the time and timeEnd functions
if ('time' === property) return (label) => _this.timers.set(label, window.performance.now());
if ('timeEnd' === property) return (label) => {
const now = window.performance.now();
if (!_this.timers.has(label)) {
_this.logger.warn(`console.timeEnd('${label}') called without preceding console.time('${label}')! Or console.timeEnd('${label}') has been called more than once.`)
}
const timeTaken = prettyMs(now - _this.timers.get(label));
_this.timers.delete(label);
const message = `${label} ${timeTaken}`;
_this.logger.info(message);
_this.originalConsole.info(message);
}
// Any non-overriden functions are passed to console
return target[property];
}
});
}
}
/**
* Calling this function switches the window.console for a proxied version.
* The proxy allows us to redirect the call to a logger.
*/
function switchConsoleToLogger() { new Logger(); } // eslint-disable-line no-unused-vars
Then in index.html I load this script first
<script src="js/logger.js"></script>
<script>switchConsoleToLogger()</script>
I had installed Google Chrome version 79.0.3945.130 (64 bit). My app was going to crash every time when I was in debug mode. I try all the solutions I found on the web but no one was useful. I downgrade to all the previous version:
78.x Crashed
77.x Crashed
75.x Not Crashed
I had to re-install the version 75.0.3770.80 (64 bit). Problem has been solved. It can be a new versions of Chrome problem. I sent feedback to Chrome assistence.
My problem was that I was not loading a page such as index.html. Once I loaded problem went away.
parentWindow = new BrowserWindow({
title: 'parent'
});
parentWindow.loadURL(`file://${__dirname}/index.html`);
parentWindow.webContents.openDevTools();
The trick to debugging a crash like this, is to enable logging, which is apparently disabled by default. This is done by setting the environment variable ELECTRON_ENABLE_LOGGING=1, as mentioned in this GitHub issue.
With that enabled, you should see something along the lines of this in the console:
You can download Google Chrome Canary. I was facing this problem on Google Chrome where DevTools was crashing every time on the same spot. On Chrome Canary the debugger doesn't crash.
I also faced the exact same problem
I was trying to require sqlite3 module from renderer side
which was causing a problem but once i removed the request it was working just fine
const {app , BrowserWindow , ipcMain, ipcRenderer } = require('electron')
const { event } = require('jquery')
const sqlite3 = require('sqlite3').verbose(); // <<== problem
I think the best way to solve this (if your code is really really small) just try to remove functions and run it over and over again eventually you can narrow it down to the core problem
It is a really tedious , dumb and not a smart way of doing it , but hey it worked
I encountered this issue, and couldn't figure out why the the DevTool was constantly disconnecting. So on a whim I launched Firefox Developer edition and identified the cause as an undefined variable with a string length property.
if ( args.length > 1 ) {
$( this ).find( "option" ).each(function () {
$( $( this ).attr( "s-group" ) ).hide();
});
$( args ).show();
}
TL;DR Firefox Developer edition can identify these kinds of problems when Chrome's DevTool fails.
After reading the comments above it is clear to me that there is a problem at least in Chrome that consists of not showing any indication of what the fault comes from. In Firefox, the program works but with a long delay.
But, as Shane Gannon said, the origin of the problem is certainly not in a browser but it is in the code: in my case, I had opened a while loop without adding the corresponding incremental, which made the loop infinite. As in the example below:
var a = 0;
while (a < 10) {
...
a ++ // this is the part I was missing;
}
Once this was corrected, the problem disappeared.
I found that upgrading to
react 17.0.2
react-dom 17.0.2
react-scripts 4.0.3
but also as react-scripts start is being used to run electron maybe its just react scripts that needs updating.
Well I nearly went crazy but with electron the main problem I realized I commented out the code to fetch (index.html)
// and load the index.html of the app.
mainWindow.loadFile('index.html');
check this side and make sure you have included it. without this the page will go black or wont load. so check your index.js to see if there's something to load your index.html file :) feel free to mail : profnird#gmail.com if you need additional help
Downgrade from Electron 11 to Electron 8.2 worked for me in Angular 11 - Electron - Typeorm -sqlite3 app.
It is not a solution as such, but it is an assumption of why the problem.
In the angular 'ngOnInit' lifecycle I put too many 'for' and 'while' loops, one inside the other, after cleaning the code and making it more compact, the problem disappeared, I think maybe because it didn't finish the processes within a time limit I hope someone finds this comment helpful. :)
I have stumbled upon the similar problem, My approach is comment out some line that I just added to see if it works. And if that is the case, those problem is at those lines of code.
for(var i = 0;i<objLen; i+3 ){
input_data.push(jsonObj[i].reading2);
input_label.push(jsonObj[i].dateTime);
}
The console works fine after i change the code to like this.
for(var i = 0;i<objLen; i=i+space ){
input_data.push(jsonObj[i].reading2);
input_label.push(jsonObj[i].dateTime);
}
Open your google dev console (Ctrl + shift + i). Then press (fn + F1) or just F1, then scroll down and click on the Restore defaults and reload.
I recently have had a problem when coding using NativeScript.
I tried using Map() object as a Collection, but its set() method seems not to work.
I use the following snippet :
var r = new Map();
r.set("one", "two");
console.dir(r);
It however outputs an empty Map(), and I do not know why...
For your convenience, here is a link to a NativeScript PlayGround: https://play.nativescript.org/?template=play-ng&id=evhIxX&v=2
I inserted the snippet inside home.components.ts
Thanks alot!
LMy
Actually it works, if you try r.get("one") then you will see two in console.
May be console.dir does not handle Map as expected. You may report that in the GitHub project.
I am currently working on selenium using ruby.
Is there any way to focus on a new window from an application?
Thanks!
I'm not aware of Ruby, but this what you can do in JAVA. See if you can implement similar logic in RUBY.
String parentHandle= driver.getWindowHandle();//Return parent window handle
for (String handle : driver.getWindowHandles()) {
driver.switchTo().window(handle);
}
driver.close(); // close newly opened window
driver.switchTo().window(parentHandle); // switch back to the parent window
Unfortunately, I cannot leave comments, or else I would point you to both of these websites:
API examples: http://docs.seleniumhq.org/docs/03_webdriver.jsp -> ruby option
API docs: http://seleniumhq.github.io/selenium/docs/api/rb/Selenium/WebDriver/Window.html
http://seleniumhq.github.io/selenium/docs/api/rb/Selenium/WebDriver/Driver.html
Here is a direct translation of the code by abhijeet in case you are wondering how it may look like in ruby.
parent_handle = driver.window_handle
driver.window_handles.each do |handle|
driver.switch_to.window handle
end
driver.close
driver.switch_to.window(parent_handle)
I'm tyring to call the method checkCurrentDictionary() of nsIEditorSpellCheck from within an add-on. The relevant code I use is:
var editorSpellCheck = Cc["#mozilla.org/editor/editorspellchecker;1"].createInstance(Ci.nsIEditorSpellCheck);
editorSpellCheck.checkCurrentDictionary();
This immediately crashes the Fx. What is going wrong here?
So this probably has something to do with the fact that nsIEditorSpellCheck is not a scriptable interface.
Basically, a scriptable interface is one that can be used from JavaScript.
If you want to access the spell check service you can do something like:
let editor = editableElement.editor;
if (!editor) {
let win = editableElement.ownerDocument.defaultView;
editor = win.QueryInterface(Ci.nsIInterfaceRequestor).
getInterface(Ci.nsIWebNavigation).
QueryInterface(Ci.nsIInterfaceRequestor).
getInterface(Ci.nsIEditingSession).
getEditorForWindow(win);
}
if (!editor)
throw new Error("Unable to find editor for element " + editableElement);
(The above is from http://dxr.mozilla.org/mozilla-central/source/editor/AsyncSpellCheckTestHelper.jsm which is MPL).
Then you can use the InlineSpellCheck.jsm to do some crazy stuff.
I'm not sure what you want to do though, so perhaps you should ask that more specific question as a new question.
I'm developing an extension for Joomla!; at the moment I'm trying to make it 3.0 compatible - as with 3.0 the logging changed a little (*). Building on the answer from this related question, my current code looks like this:
JLog::addLogger(array(
'text_file' => 'plg_system_myplg.log.php'
));
JLog::add('blah blah log msg');
The problem is that the log also goes to the messages which are shown to the user - this I want to prevent, I want the log msg only to go to the log file. I think it has to do with the "category" that JLog::add takes as a 3rd (optional) parameter, but I have no idea what to pass there?
Can anybody tell me how to hide the messages / or tell me if I'm on the right way with the categories and what value I should use?
Thanks!
(*) It actually changed already with 1.7 as far as I gathered so far, but the old method of calling addEntry on the return of JLog::getInstance(...) seems to have been removed from 2.5 to 3.0.
Edit: Think I found a way now; using:
JLog::addLogger(array(
'text_file' => 'plg_system_myplg.log.php',
JLog::ALL,
'myplg'
));
JLog::add('blah blah log msg', JLog::INFO, 'myplg');
all my log entries go only into my log file (and not to the messages shown to the user). However, I also get a few deprecation warnings - one about my code, but also some unrelated ones:
WARNING deprecated JAccess::getActions is deprecated. Use JAccess::getActionsFromFile or JAcces::getActionsFromData instead.
WARNING deprecated JSubMenuHelper::getEntries() is deprecated. Use JHtmlSidebar::getEntries() instead.
WARNING deprecated JSubMenuHelper::getFilters() is deprecated. Use JHtmlSidebar::getFilters() instead.
WARNING deprecated JSubMenuHelper::getAction() is deprecated. Use JHtmlSidebar::getAction() instead.
Not sure what to make of those - why do they appear in my log file, shouldn't they go to the default error.log file instead of my file ?
This is what I am using, works for Joomla 1.5 - 3.2:
if(version_compare(JVERSION,'1.7.0','ge')) {
jimport('joomla.log.log'); // Include the log library (J1.7+)
$priorities = JLog::ALL ^ JLog::WARNING; // exclude warning (because of deprecated)
// In J3.0 we need to ensure that log messages only go to our file, thus use the categories (already supported in J2.5)
if(version_compare(JVERSION,'2.5.0','ge')) {
$logCategory = 'com_mycomponent';
JLog::addLogger(array('text_file' => $logFileName), $priorities, $logCategory);
JLog::add($msg, JLog::INFO, $logCategory);
}else{
JLog::addLogger(array('text_file' => $logFileName), $priorities);
JLog::add($msg, JLog::INFO);
}
} else {
// Joomla! 1.6 and 1.5
jimport('joomla.error.log'); // Include the log library
$log = &JLog::getInstance($logFileName);
$log->addEntry(array('comment' => $msg, 'level' => 'INFO'));
}
This shows the trick for gettring of the deprecated messages.
And yes, you have to include a category for your messages to ensure they are not showing up as system messages.
Use
new JException('Something happened');
This will only add it to debug log but will not show anything.
It seems, that Joomla 3.0 has no default logger enabled. The same in Joomla 3.0.3. Nothing turns logging on by default - even Debug mode.
Finally I think I have solved my issue with unrelated log entries showing up.
A close look at the API documentation of the addLogger function revealed that the third parameter, $categories, is supposed to be an array of categories for which this log will be used.
This is in contradiction to the version of http://docs.joomla.org/Using_JLog that is current at the time of this writing, where a single category is given instead of an array.
Changing my call to addLogger to use an array, like this:
JLog::addLogger(array(
'text_file' => 'plg_system_myplg.log.php',
JLog::ALL,
array('myplg')
));
And keeping my fingers crossed that this will fix the issue!
Edit: unfortunately even this still doesn't solve my issue - still got unrelated entries :(.
I found the answer.. hope this script make you understand.. I already built as function . this code work on joomla 3. hope work in joomla 2
<?php
function logWrite($level, $values, $file='%s.php',$path='',$showOnTop=0,
$option='',$component=''){
/****
jlog Joomla 3.4
created by:gundambison (2015.04.26).
THX: hbit#stackoverflow
****/
jimport('joomla.log.log');
$level=strtoupper($level);
//You can change this com_name
$component= $component==''? 'com_gundambison': $component;
$date= date("Ymd");
$filename= sprintf($file, $date);
$format= $option=='' ?"{TIME}\t{CLIENTIP}\t{CATEGORY}\t{MESSAGE}": $option;
// create options and text
$txt = is_array($values)? json_encode($values): $values;
$options = array('text_file' => $filename,'text_entry_format'=>$format );
$options['text_file_path']=$path==''?'logs': $path;
JLog::addLogger ($options);
/*
if you want the error to show in your page. just see the different
*/
if($showOnTop==1){
JLog::add("$txt");
}
else{
JLog::add("$level\t$txt",$level,$component);
}
}