• Before you start building:
  
  
  • Ask for advice about how to solve the problem your app would solve.
  
  
  • Ask about the standard name for the kind of thing you want to do; often that's the key to finding things.
  
  
  • Search for existing similar apps, ask on forums if anyone knows of a similar app.
  
  
  • Search for apps on a variety of platforms and styles: scripts, phone apps, desktop CLI apps, desktop GUI apps, GitHub projects, desktop widgets/extensions, docks/launchers, macroes, bookmarklets, add-ons, web pages, CLI shells.
  
  
• Can you do what you need with existing CLI apps ? Make a shell script.
  Linux Shell Script


• Is what you need best done inside an existing GUI app (browser or editor or IDE or image-editor or system file-explorer app) ?
  
  
  • Search the Help and menus and buttons of the app; often they have buried features you don't know about.
  
  
  • Can you use an existing extension/add-on for the existing app ? If your usual app for that kind of processing doesn't support add-ons, maybe switch to an alternative app that does.
  
  
  • Can you use CLI to drive the existing GUI app ? Go to CLI and run the GUI app from there to see options, such as "firefox --help". If the necessary options exist, make a shell script.
    Linux Shell Script
  
  
  • Can you use a macro engine to drive the existing GUI app ?
    Kantu, iMacro, GreaseMonkey.
  
  
  • Can you build a new extension/add-on for the existing app ? If your usual app for that kind of processing doesn't support add-ons, maybe switch to an alternative app that does.
    Building a Firefox Extension
    Building a Thunderbird Extension
    Building a new extension for VSCode
    Nemo file-explorer actions/scripts
  
  
• Can you do what you need by adding a small feature to an existing app ? Find out where that app's source project lives, what language it's built in. File a feature request, or build the new feature yourself.


• Do you need a fairly simple app, a step or two up from a shell script ? Maybe make a one-file Python or PHP app.
  PHP program


• Does your app not need access to the filesystem ? Maybe make a web page, with HTML and CSS and JavaScript.


• If you want to make a text-processing app, and maybe pipe it with other apps, make a CLI app. Write it in C ? Or in Rust ? Or in Node.js (and use Commander.js module) ?


• If you want to make a GUI app:
  
  
  • If you want the app to be very cross-platform, maybe use: Electron, Flutter, Java
  
  
  • If you want the app to be very Linux-native, maybe use GTK or Qt for the GUI framework/toolkit.
    
    Then you can use one of many languages for the app logic. With GTK, you can use C, C++, Python, Rust, Vala, Java, or even JavaScript ? With Qt, same ?
    PyQt
    Java
    
    With GTK, maybe use GNOME Builder ?
    
    Make a Linux App
    
    Don't make your own theme and icons and decorations etc in the app; use the system-wide settings.
    
    If you do want to take it cross-platform, follow the convention for each OS, for things such as where to put config files, name and location of Settings/Preference menu item, etc.
  
  

[Not sure all of this is accurate.]

Higher-level toolkits:

• GTK: Use via C language. Used in the GNOME, Cinnamon, LXDE, Xfce desktop environments.


• Qt: Use via C++, Python languages. Used in the KDE, Unity, LXQt, Lumina desktop environments.


• Swing: Use via Java language.


• Clutter:


• SDL:


• Enlightenment Foundation Libraries (EFL):


• Flutter:

Wikipedia's "List of widget toolkits"
Wikipedia's "List of platform-independent GUI libraries"

Some apps use a lower level: drawing libraries instead of toolkits:

• Cairo: Connects to X Windowing. Used by Firefox browser.


• OpenGL: Connects to Mesa.


• Direct3D:


• Vulkan:

Next level down:

• Xlib or XCB, libraries that connect to X Windowing System.
  X does both window management and rendering.
  Clean Rinse's "The Linux Graphics Stack"


• Mesa.
  Does rendering only ?
  Wikipedia's "Mesa (computer graphics)"


• Wayland.
  Does window management only, uses Mesa for rendering ?
  Wikipedia's "Wayland (display server protocol)"


• Mir.
  Does window management only, can use X, Wayland and/or Mesa.
  Wikipedia's "Mir (software)"

1. [Tried Gitg GUI app, didn't understand it.]
2. [Downloaded and tried to install GitHub extension into VSCode, it failed.]



3. sudo apt-get install git
4. git config --global user.name "Your Name Here"
5. git config --global user.email "your_email@youremail.com"



6. In browser, logged in to GitHub, went to a project I wanted to copy (Microsoft / linkcheckermd), cloned it to my home directory.



7. Renamed "linkcheckermd" directory to "linkcheckerhtml".
8. Deleted the .git stuff under linkcheckerhtml.
9. Edited the source files.



10. On GitHub web page, created new repository in my account named linkcheckerhtml.
11. Set description.
12. Turned off Wiki and Projects. Turned on "Restrict editing to collaborators only", but I think it only applies to the Wiki ?



13. Went to CLI, into linkcheckerhtml directory, and did:
    1. git init
    2. git add README.md
    3. git commit -m "first commit"
    4. git remote add origin https://github.com/BillDietrich/linkcheckerhtml.git
    5. git push -u origin master
       (Had to turn off 2FA for login to work.)
14. From now on, cycle is:
    1. Edit source files.
    2. git add filename (for each file edited)
    3. git commit -m "first commit"
    4. git push -u origin master
    When you operate this way, there is only one branch ("master").
    
    To delete a file, do "git rm filename", then commit and push.
    
    To see status at any time, do "git status".
    
    Starting a new repository from scratch (the wrong way, probably):
    • Created app source code on my disk.
    • Backed it up.
    • In browser, logged into GitHub and created new repo.
    • Went to home directory of project on disk, and did "git init".
    • Edited .git/config to point to new repo on GitHub; added:

      [remote "origin"]
      	url = https://github.com/SOMETHING.git
      	fetch = +refs/heads/*:refs/remotes/origin/*
      [branch "master"]
      	remote = origin
      	merge = refs/heads/master
      

    • Did "git add *", "git commit -m 'initial commit'", "git push --force -u origin master".
    
    
    Starting a new repository from scratch (better):
    • In browser, log into GitHub and create new repo. Set description, initialize with a README, pick a license type (probably MIT).
    • Click on "Clone or Download". See "Clone with HTTPS". Click on the "page" icon at right of the URL to copy the URL.
    • In CLI, cd to Projects folder, then "git clone https://github.com/OWNERNAME/PROJECTNAME.git"
    • CD into the new folder for the project, and add/edit files.
    • Do git adds (git add FILENAME), commit (git commit -m "COMMENT"), push (git push -u origin master).

From a project-owner on GitHub:

"Forking" is just Github's name for making your own clone of someone else's repo on Github. It is a weird name and completely different from forking an open source project (into a new project).

[After pushing changes to a branch on your repo on GitHub] it doesn't matter, you can open a pull request between the original repo's master and your issue branch in your Github repo, or between original repo's master and your repo's master branch.

If you fork an original repo on GitHub to make your own repo on GitHub, then clone your repo on GitHub to your local disk, you now have three repo's. Your files on disk are a repo.

I'm told there are two cases for project management:

• If you have write access to the original project repo:
  
  

  1. Clone the original master branch files on GitHub to disk: login to GitHub web site, go to repo, click big green "Clone or download" button near upper-right. Easiest to click on "Download ZIP".
  2. Build the project on disk, test.
  3. Create a branch (on project's main page in GitHub, click "Branch: Master" pull-down, and type new branch's name; or "git branch issue857").
  4. Have to "checkout" to the branch on disk. Do "git status" to see that you're on branch, not master.
  5. Edit files on disk, test, repeat.
  6. Commit changed files to the branch as you go along, and push them to the GitHub repo, or after it's all working ("git add FILENAMES" and "git commit -a -m 'whatever'" and "git push -u origin issue857").
  7. Get whole thing into a finished state.
  8. When all changes are done and committed and pushed to the branch on GitHub, open a pull request for the branch.
  9. Get approval of the pull request (the changes).
  10. On disk, go back to master branch.
  11. Merge branch into master branch.


• If you don't have write access to the original project repo:
  
  

  1. Fork the whole original repo on GitHub to make your own repo on GitHub: login to GitHub web site, go to repo, click "fork" button near upper-right.
  2. From your repo on GitHub, clone the (master branch) files to disk: login to GitHub web site, go to repo, click big green "Clone or download" button near upper-right. Easiest to click on "Download ZIP".
  3. Build the project on disk, test.
  4. Create a branch (on project's main page in GitHub, click "Branch: Master" pull-down, and type new branch's name; or "git branch issue857").
  5. Have to "checkout" to the branch on disk. Do "git status" to see that you're on branch, not master.
  6. Edit files on disk, test, repeat.
  7. Commit changed files to the branch as you go along, and push them to the GitHub repo, or after it's all working ("git add FILENAMES" and "git commit -a -m 'whatever'" and "git push -u origin issue857").
  8. Get whole thing into a finished state.
  9. When all changes are done and committed to the branch, open a pull request for the branch but to the original GitHub repo.
  10. Owner will approve and merge the pull request (the changes).

# cd into project directory
git ls-files | xargs wc -l
# or:
git ls-files | grep -P ".*(js|html)$" | xargs wc -l
# or:
git ls-files | grep -vE ".*(png|jpg|ico)$" | xargs wc -l
# or:
sudo apt install cloc
cloc $(git ls-files)
#or:
cloc --vcs git

# clone latest commit of project to disk, count, then remove it from disk
git clone --depth 1 https://github.com/OWNERNAME/PROJECTNAME.git
cd PROJECTNAME
cloc --vcs git
cd ..
rm -fr PROJECTNAME

# Diff a single file on disk with same file in master branch:
git diff master -- FILENAME

# Diff all files on disk with same files in master branch:
git diff master --

• Glade:
  
  Available in Mint's Software Manager.
  Too complicated, couldn't figure out how to use it.
  



• Pencil:
  
  Pencil Project
  No grid/table tool.
  



• Google Web Designer:
  
  Google Web Designer
  If you don't want Google's repository added to your system, do "sudo touch /etc/default/google-webdesigner" before installing the package.
  It's really just for building ads for mobile.
  



• Akira:
  
  SkySilk's "Akira: A Native Linux App for UI & UX Design"
  

An Electron application is (basically) a web app packaged with a (slightly old) version of the Chrome browser ...

The Electron application has a copy of the Node.js runtime, which allows you to do many of the things that a native desktop application can do, but which the security model of a web browser doesn't allow you to do, including accessing local files, integrating at a lower level with the Operating System.

JavaScript in the "main" JS file (as specified in package.json) is running in the "main process", and JavaScript in the HTML file is running in the "render process". The syntax for connecting to modules is a bit different between the two.

"The DevTools in an Electron browser window can only debug JavaScript that's executed in that window (i.e. the web pages). To debug JavaScript that's executed in the main process you will need to use an external debugger and launch Electron with the --inspect or --inspect-brk switch."
from Electron's "Debugging the Main Process"

Using console.log() in Electron app

Electron's "remote"
Carlos Delgado's "How to execute a function of the main process inside the renderer process in Electron Framework"

Carlos Delgado's "Best tree view jQuery and JavaScript plugins"
npm's "electron tree view"
js-treeview"

sudo npm install -g electron --unsafe-perm=true --allow-root

cd ~/projects
mkdir installproto2
cd installproto2

npm init

npm install js-treeview
npm install load-json-file
npm install systeminformation

Create app.js file:

const {app, BrowserWindow} = require('electron')
const path = require('path')
const url = require('url')

let window = null

// Wait until the app is ready
app.once('ready', () => {
  // Create a new window
  // https://www.electronjs.org/docs/api/browser-window
  window = new BrowserWindow({
    // Set the initial width to 800px
    width: 800,
    // Set the initial height to 600px
    height: 600,
    // Set the default background color of the window to match the CSS
    // background color of the page, this prevents any white flickering
    backgroundColor: "#D6D8DC",
    // Don't show the window until it's ready, this prevents any white flickering
    show: false,
    webPreferences: { devTools: true, nodeIntegration: true }
  })

  // Load a URL in the window to the local index.html path
  window.loadURL(url.format({
    pathname: path.join(__dirname, 'index.html'),
    protocol: 'file:',
    slashes: true
  }))

  // Show window when page is ready
  window.once('ready-to-show', () => {
    window.show()
  })
})

Create index.html file:

<!DOCTYPE html>
<html lang="en-US">
<head>
<title>My app name</title>
<meta charset="UTF-8">

<link rel="stylesheet" href="index.css" />
<link rel="stylesheet" href="./node_modules/js-treeview/dist/treeview.min.css" />

<script>
delete module.exports
</script>

<script src="https://code.jquery.com/jquery-3.2.1.js"></script>
<script src="./window.js" charset="utf-8"></script>

</head>

<body>

<label id="t1filename"></label>
<button id="t1expandAll">Expand All</button>
<button id="t1collapseAll">Collapse All</button>
<br /><br />
<div id="t1tree"></div>

</body>

</html>

Create window.js file:

// "document ready" function:

$(() => {

  const jstreeview = require('js-treeview')
  const loadJsonFile = require('load-json-file')

// https://www.npmjs.com/package/js-treeview
// https://github.com/justinchmura/js-treeview
// https://www.npmjs.com/package/load-json-file


  //
  // Tree Structure
  //

  var t1dataX = [{
    name: 'Vegetables',
    children: []
  }, {
    name: 'Fruits',
    children: [{
      name: 'Apple',
      children: []
    }, {
      name: 'Orange',
      children: []
    }, {
      name: 'Lemon',
      children: []
    }]
  }, {
    name: 'Candy',
    children: [{
      name: 'Gummies',
      children: []
    }, {
      name: 'Chocolate',
      children: [{
        name: 'M & M\'s',
        children: []
      }, {
        name: 'Hershey Bar',
        children: []
      }]
    }, ]
  }, {
    name: 'Bread',
    children: []
  }];

let t1filename = "System-Existing.json";
var t1data = loadJsonFile.sync(t1filename);
$('#t1filename').text(t1filename);

  //
  // Grab expand/collapse buttons
  //
  var t1expandAll = document.getElementById('t1expandAll');
  var t1collapseAll = document.getElementById('t1collapseAll');

  //
  // Create tree
  //

  var t1 = new jstreeview(t1data, 't1tree');
  //$('#t1tree').text("hello");
  //alert("JSON.stringify(t1): " + JSON.stringify(t1));

  //
  // Attach events
  //

  $('#t1expandAll').bind('click', function() {
    //alert("t1expandAll click");
    t1.expandAll();
  });
  $('#t1collapseAll').bind('click', function() {
    //alert("t1collapseAll click");
    t1.collapseAll();
  });


  t1.on('select', function (e) {
    //const text = this.text;
	  //alert('select "' + this.name + '"');
    //alert("select");
    //alert("select: JSON.stringify(e.data): " + JSON.stringify(e.data));
	});
  t1.on('expand', function (e) {
	  // alert('expand');
    //alert("expand: JSON.stringify(e.leaves): " + JSON.stringify(e.leaves));
	  });
  t1.on('collapse', function (e) {
	  // alert('collapse');
    //alert("collapse: JSON.stringify(e.leaves): " + JSON.stringify(e.leaves));
	  });
  t1.on('expandAll', function () {
	  //alert('expand all');
	  });
  t1.on('collapseAll', function () {
	  // alert('collapse all');
	  });

})

Create index.css file:

td.mytree1 {
	border-style: solid;
	border-width: 1px;
	border-collapse: collapse;
	display:table;
	margin:0 auto;
	min-height: 500px;
	min-width: 300px;
	background-color:lightgreen;
}

Edit package.json file:

  "main": "app.js",
  "scripts": {
    "start": "/usr/local/lib/nodejs/node-v10.15.3-linux-x64/lib/node_modules/electron/dist/electron app.js"
  },

Run electron desktop-app:

npm start
# see desktop app window appear !

There can be two steps: packaging, and then making an installer.

There are four ways to do packaging and/or making installer: electron-packager, electron-builder, electron-forge, or manually (bad).

So far, I haven't tried electron-forge or manually, and I've found electron-builder is better than electron-packager.

Manually: Electron's "Application Distribution"

Electron-forge might be best ?
Electron's "Boilerplates and CLIs"
Electron Forge
electron-userland / electron-forge


Packaging the app (if you want to do packaging and making installer separately):

Using electron-packager:

Christian Engvall's "Electron packager tutorial"
electron / electron-packager

npm install electron-packager --save-dev
sudo npm install electron-packager -g
# edit package.json to add a "productName" line

#-------------------------
# build for MacOS:
./node_modules/.bin/electron-packager . --overwrite --platform=darwin --arch=x64 --icon=./icon.icns --prune=true --out=release-builds

#-------------------------
# build for Windows:
./node_modules/.bin/electron-packager . YOURPROJECTNAME --overwrite --asar --platform=win32 --arch=ia32 --icon=./icon.ico --prune=true --out=release-builds --version-string.ProductName="YOURPRODUCTNAME"
# requires WINE !!!

#-------------------------
# build for Linux:
./node_modules/.bin/electron-packager . YOURPROJECTNAME --overwrite --asar --platform=linux --arch=x64 --icon=./icon.png --prune=true --out=release-builds

Making an installer for the app:

If you used electron-packager:

Christian Engvall's "DMG installer for electron app"
Christian Engvall's "Electron Windows installer tutorial"
Christian Engvall's "Electron installer debian package"

# build for MacOS:

npm install electron-installer-dmg --save-dev
sudo npm install electron-installer-dmg -g

./node_modules/.bin/electron-installer-dmg ./release-builds/YOURPRODUCTNAME-darwin-x64/YOURPRODUCTNAME.app YOURPROJECTNAME
# FAILS !!!:    Error: Must be run on OSX
# creates a file called YOURPROJECTNAME.dmg in the root folder of the application

# build for Windows:

npm install --save-dev electron-winstaller
mkdir installers
cd installers
mkdir windows
cd windows
# make file createinstaller.js as described in
# https://www.christianengvall.se/electron-windows-installer/
cd ../..

node installers/windows/createinstaller.js

# build for Linux:

npm install --save-dev electron-installer-debian
sudo npm install -g electron-installer-debian
# create file debian.json as described in
# https://www.christianengvall.se/electron-installer-debian-package/

./node_modules/.bin/electron-installer-debian --src release-builds/YOURPROJECTNAME-linux-x64/ --arch amd64 --config debian.json

Using electron-builder:

electron-builder
electron-userland / electron-builder
Akash Nimare's "A complete guide to packaging your Electron app"

mkdir build
# copy a background.png and icon files into build directory

npm install electron-builder --save-dev

# had to tweak package.json file a lot
# https://www.electron.build/configuration/configuration
# add following to package.json file:
# "build": {
#  "appId": "YOURAPPID",
#  "mac": {
#    "category": "YOURAPPCATEGORY"
#  },
# "win": {
#   "target": "NSIS"
#  }
# },

#-------------------------
# build for MacOS:
./node_modules/.bin/electron-builder --macos default
# failed because it couldn't spawn hdiutil, which apparently runs only on MacOS

#-------------------------
# build for Windows:
# requires WINE !!!

# If you don't want to install wine through Software Manager:
apt-get install wine
sudo dpkg --add-architecture i386 && apt-get update && apt-get install wine32

# https://www.linuxbabe.com/linux-mint/install-wine-linux-mint-19-1
# Best to install wine-stable from Software Manager (535 MB)
# add /opt/wine-stable/bin to PATH in .profile, log out and in
winecfg
# gave:  0009:err:file:init_redirects cannot open L"C:\\windows" (c000000f)
# but kept going
# wanted to install wine-mono and gecko, but I said cancel to each
# Settings dialog came up, and I chose Windows 10
# Finished, and I ran it again, and Settings dialog came right up, no problems.

./node_modules/.bin/electron-builder --windows nsis
# insisted on an icon at least 256x256

#-------------------------
# build for Linux:
./node_modules/.bin/electron-builder --x64 --linux deb
# insisted on an icon at least 256x256

HTML/CSS:	Bootstrap or Materialize or Foundation
Library everything else uses:	jQuery
UI library or framework:	Library: React or Vue. Framework: Angular (AKA "ng")
	Electron
	electron-builder (packager)
Modules:	Node
Database access:	SQL.js or Electron-store
Database format:	SQLite or MongoDB
OS:	Linux.

HTML/CSS:	Bootstrap (CSS and JS), ng-bootstrap (JS)
Library:	jQuery from ng-bootstrap (JS)
UI framework:	Angular (AKA "ng")
	Electron
	electron-builder (packager)
Modules:	Node
Database access:	SQL.js
Database format:	SQLite
OS:	Linux.

1. Install stuff:
   
   

   
   # if you don't have Node.js, install that
   
   sudo npm install -g @angular/cli@latest
   # got "skipping optional dependency fsevents"
   # apparently fsevents is for running on OSX
   ng --version
   # 3/2019: I got "Angular CLI: 7.3.5"
   
   sudo npm install -g typescript
   # 3/2019: got "typescript@3.3.3333"
   
   sudo npm install -g electron --unsafe-perm=true --allow-root
   # 3/2019: got "electron@4.0.8"
   
   # Name of new app can not have any uppercase letters in it !
   # cd to place where you want app dir to be created, and:
   ng new matrix-dashboard
   # Asked "Would you like to add Angular routing ?"
   #		This allows user to follow URL links to different parts
   #		of the one page of your single-page application
   #		I answered "no"
   # Asked "Which stylesheet format ?"
   #		I picked the default, CSS.
   
   cd matrix-dashboard
   
   # (I didn't realize that ng-bootstrap and ngx-bootstrap
   # are different things.  Having installed ng-bootstrap,
   # I'll stick with it.)
   ng add @ng-bootstrap/schematics
   # see warnings about peers of jquery and popper not found
   #	ignore the warnings
   #	You don't need jQuery / popper to use ng-bootstrap and
   #	you shouldn't install those manually
   # I also saw warnings about peers of angular/common and
   # /core and /forms not found.  Sounds fatal.  But online,
   # someone says as long as the installed version of Angular
   # is higher than the version in the warning, no problem.
   
   # start development server
   ng serve
   # saw messages that server is up and compile succeeded
   # now app is accessible on http://localhost:4200/
   # go there in browser, see default Angular app
   # back to CLI window, ctrl-C to kill server
   
   # add electron as a dev dependency
   npm i -D electron
   # 3/2019: got electron 4.0.8
   
   npm i -D @types/electron
   
   mkdir dist
   mkdir dist/matrix-dashboard
   
   # edit tsconfig.json file to add first line:
   #		/* angular tsconfig.json */
   
   # edit package.json file to add first component:
   #		"comment": "angular package.json file",
   
   mkdir electron
   cd electron
   mkdir dist
   mkdir dist/matrix-dashboard
   

   Directory structure that resulted:

   
   matrix-dashboard/
   	angular json files
   	do "ng build" when in this dir
   	dist/
   		matrix-dashboard/
   			app's angular HTML, JS files
   	e2e/
   		end-to-end tests
   	node-modules/
   		bootstrap
   			CSS, JS files
   		@ng-bootstrap/
   			JS files
   	src/
   		angular CSS, TS, HTML, JSON files
   		app/
   			app's CSS, TS, HTML files
   	electron/
   		TS, JSON files
   		dist/
   

   So, some trickiness going on here:
   

   • The "top-level" app is an Angular web-app, which uses a local server if you run it.
   
   
   • The Angular web-app is using CSS and JS from bootstrap, and JS from @ng-bootstrap.
   
   
   • Inside the electron directory is stuff which grabs the Angular code and node_modules, compiles it, and runs it as a desktop app in the electron framework.
   
   

   Mosh Hamedani's "Angular 4 Tutorial: Angular 4 in 20 minutes"
   Angular's "Workspace and project file structure"
   
   
   


2. Build and run Angular web-app:

   
   # cd to main matrix-dashboard/ dir
   ng serve
   ng generate service file  # one-time thing to add a service
   ng build
   # go to http://localhost:4200/ to see Angular web app running
   # page HTML source is src/app/app.component.html
   
   # ctrl-C to kill Angular server
   

   Structure of the Angular application:
   

   • Really all that should be in the body of src/index.html is

       <app-root>
         <app-yourappsname></app-yourappsname>
       </app-root>"
     

   
   
   • In app.component.ts should be the line:

       selector: 'app-yourappsname'
     

   
   
   • The main page of your app will be in app.component.html.
   
   
   • You can't use deprecated HTML in the pages. That means no "center" tags: use CSS "text-align:center" or "margin:0 auto;". Probably also no "font" or "u" tags, and a bunch of deprecated attributes.
     CodeHelp.co.uk's "What's a deprecated tag / attribute?"
   
   
   
   Places errors could be flagged/shown:
   

   • In your source-code editor as you type.
   
   
   • In the "ng serve" window when it recompiles.
   
   
   • In the page displayed in the browser.
   
   
   • In browser's debug-console for the page displayed in the browser.
   
   

   Edward Jackson's "Debugging Angular CLI Applications in Visual Studio Code"
   
   
   


3. Get electron desktop-app going:
   
   Create electron/index.html file:

   
   <html>
   <head>
   <title>Matrix Dashboard</title>
   </head>
   <body>
   Hello
   </body>
   </html>
   

   Create electron/tsconfig.json file:

   
   /* electron tsconfig.json */
   {
     "compileOnSave": false,
     "compilerOptions": {
       "baseUrl": "./",
       "outDir": "./dist",
       "sourceMap": true,
       "declaration": false,
       "module": "commonjs",
       "moduleResolution": "node",
       "emitDecoratorMetadata": true,
       "experimentalDecorators": true,
       "target": "es5",
       "typeRoots": ["../node_modules/@types"],
       "lib": ["es2018", "dom"]
     }
   }
   

   Create electron/main.ts file:

   
   import { app, BrowserWindow } from "electron";
   //import { Injectable } from "@angular/core";
   //import { ipcMain, IpcRenderer } from "electron";
   import * as path from "path";
   import * as url from "url";
   
   let win: BrowserWindow;
   
   app.on("ready", createWindow);
   
   app.on("activate", () => {
     if (win === null) {
       createWindow();
     }
   });
   
   /*
   ipcMain.on("getFiles", (event, arg) => {
     const files = fs.readdirSync(__dirname);
     win.webContents.send("getFilesResponse", files);
   });
   */
   
   function createWindow() {
     win = new BrowserWindow({ width: 800, height: 600 });
   
     win.loadURL(
       url.format({
         pathname: path.join(__dirname, `/../../dist/matrix-dashboard/index.html`),
         protocol: "file:",
         slashes: true
       })
     );
   
     //win.webContents.openDevTools();
   
     win.on("closed", () => {
       win = null;
     });
   }
   

   Create electron/package.json file (I added the comment):

   
   {
     "comment": "electron package.json file",
     "name": "matrix-dashboard",
     "version": "0.0.0",
     "main": "electron/dist/main.js",
     "scripts": {
       "ng": "ng",
       "start": "ng serve",
       "build": "ng build",
       "test": "ng test",
       "lint": "ng lint",
       "e2e": "ng e2e",
       "electron": "ng build --base-href ./ && tsc --p . && electron ."
     }
   }
   

   Build and run electron desktop-app:

   
   cd electron/
   npm run electron
   # see desktop app window appear !
   



4. Now to use Bootstrap:
   
   Edit Angular's src/styles.css file to add line:

   @import "../node_modules/bootstrap/dist/css/bootstrap.css"
   

   Edit src/app/app.component.html file to add:

   
   a bootstrap thing:<br />
   <select multiple data-role="tagsinput">
     <option value="Amsterdam">Amsterdam</option>
     <option value="Washington">Washington</option>
     <option value="Sydney">Sydney</option>
     <option value="Beijing">Beijing</option>
     <option value="Cairo">Cairo</option>
   </select>
   

   Build and run Angular web-app:

   
   # cd to main matrix-dashboard/ dir
   ng serve
   # go to http://localhost:4200/
   # see Angular web app running with bootstrap-CSS-influenced "select" in page
   

   
   Build and run electron desktop-app:

   
   cd electron/
   npm run electron
   # see new "select" appear in desktop app window
   



5. Now to use ng-bootstrap:
   
   Let's try a simple example widget: Rating.
   
   Edit src/app/app.component.html file to add:

   
   an ng-bootstrap thing:<br />
   <ngb-rating rate="2"></ngb-rating>
   

   Edit src/app/app.module.ts file to add lines:

   
   import { NgbModule } from '@ng-bootstrap/ng-bootstrap';
   
   // in imports, after BrowserModule:
       NgbModule.forRoot()
   

   Build and run Angular web-app:

   
   # cd to main matrix-dashboard/ dir
   ng serve
   # go to http://localhost:4200/
   # see Angular web app running with new widget in page
   
   # ctrl-C to kill Angular server
   

   Edward Jackson's "Debugging Angular CLI Applications in Visual Studio Code"
   
   Build and run electron desktop-app:

   
   cd electron/
   npm run electron
   # see new widget appear in desktop app window
   



6. Add a new app component that uses ng-bootstrap:
   
   Create src/app/rating-basic.html file containing:

   
   <ngb-rating [(rate)]="currentRate"></ngb-rating>
   <br />
   <pre>Rate: <b>{{currentRate}}</b></pre>
   

   Create src/app/rating-basic.ts file containing:

   
   import {Component} from '@angular/core';
   
   @Component({
     selector: 'ngbd-rating-basic',
     templateUrl: './rating-basic.html'
   })
   export class NgbdRatingBasic {
     currentRate = 8;
   }
   

   Edit src/app/app.component.html file to add:

   
   app component that references an ng-bootstrap thing:<br />
   <ngbd-rating-basic></ngbd-rating-basic>
   

   Edit src/app/app.module.ts file to add lines:

   
   import { NgbdRatingBasic } from './rating-basic';
   
   // in declarations:
       NgbdRatingBasic
   

   Build and run Angular web-app:

   
   # cd to main matrix-dashboard/ dir
   ng serve
   # go to http://localhost:4200/
   # see Angular web app running with new widget in page
   
   # ctrl-C to kill Angular server
   

   Edward Jackson's "Debugging Angular CLI Applications in Visual Studio Code"
   
   Build and run electron desktop-app:

   
   cd electron/
   npm run electron
   # see new widget appear in desktop app window
   

• vscode-angular-html


• vscode-typescript-angular-plugin


• People report problems with vscode-ng-language-service, say it causes a huge performance hit.

7. Add a new app component that is the main window of my application:
   
   Bootstrap - Layout - Overview
   
   
   
   Ran into a nasty problem involving tables and Angular. I had one big table, with a header row generated in one page/component (mdmainwindow), then next rows generated by N calls to a sub-component (mdrow). But Angular passes the tags <sub-component-name> ... </sub-component-name> through to the browser, and since they are encapsulating each row, they made the browser place the whole row (for rows 2-N) into the first column in the bigger table, not what I wanted. Ended up with an L-shaped table ! I'll have to generate the whole table structure in one page, and then call sub-components to fill the contents of each cell in the table.
   
   HTML looked like:

   <table>
     <tr><td>colheader1</td><td>colheader2</td></tr>
     <mdrow>
       <tr><td>data</td><td>data</td></tr>
     </mdrow>
     <mdrow>
       <tr><td>data</td><td>data</td></tr>
     </mdrow>
     <mdrow>
       <tr><td>data</td><td>data</td></tr>
     </mdrow>
   </table>
   

   
   Fixed it by making mdrow into a TypeScript class, not an Angular class, and never putting <mdrow> in HTML.
   
   Later, someone told me I could have fixed it by invoking ("selecting") MDRow via an attribute on another tag (e.g. <tr mdrow>), instead of via an <mdrow> tag:
   "In @Component you've a 'selector' property. It's pretty much a CSS selector. Normally it's like 'mdrow', but it can be also a class selector ".mdrow" or attribute '[mdrow]'."
   
   Got the code working.
   
   Code is too big to show here. But src/app/mdmainwindow.html file contains:

   
   <table class="table-striped table-bordered table-hover table-sm">
   
   <thead class="thead-light">
   <tr>
   <td> </td>
   <td *ngFor="let colname of appareas[ncurrentapparea].columnnames; index as ncolumn" id="{{colname}}">
     {{colname}}
   </td>
   </tr>
   </thead>
   
   <tr *ngFor="let row of rows; index as nrow" id="{{row.name}}">
     <td>{{row.name}}</td>
     <td *ngFor="let colname of appareas[ncurrentapparea].columnnames; index as ncolumn"
           id="cell{{nrow}}-{{ncolumn}}">
       <mdcell [nrow]="nrow" [ncolumn]="ncolumn"></mdcell>
     </td>
   </tr>
   
   </table>
   

   And src/app/mdmainwindow.ts file contains:

   
   export class MDMainWindow implements OnInit {
     @Input() nrows = 0;
     @Input() ncolumns = 0;
   
     rows: Array<MDRow>;
   
     appareas: Array<MDAppArea>;
     ncurrentapparea = 0;
   
     constructor() {
     }
     ngOnInit() {
       this.rows = new Array();
       for (let r = 0; r < this.nrows; r++) {
         var newrow = new MDRow(r,this.ncolumns);
         this.rows.push(newrow);
       }
   
       this.appareas = new Array();
       var aa = new MDAppArea("Standard",this.ncolumns);
       this.appareas.push(aa);
       aa = new MDAppArea("Custom1",this.ncolumns);
       this.appareas.push(aa);
       aa = new MDAppArea("Custom2",this.ncolumns);
       this.appareas.push(aa);
     }
   }
   

• {{name}} is an "interpolation" to fetch the value of "name".


• [name]=value is a "property binding" to send "value" from parent object to "name" property of the child object.


• (name)=method(value) is an "event binding" that calls the component's "method" when the "name" event occurs.


• [(name1)]=name2 is a "two-way binding" where first value of name2 is copied to name1, then any changes to name1 are copied back to name2.

8. Add database connection:
   
   Angular can do HTTP requests, and SQL databases can provide RESTful APIs, where they accept HTTP requests to do operations.
   
   I wanted to use Node's sql.js module and a local SQLite database, following patrickmoffitt / local-sqlite-example. But Angular is in a browser client with no access to filesystem. And the sql.js module throws errors when added to a TypeScript project.
   
   There used to be an Angular "http" module, but it's been replaced by an "HttpClient" module.
   
   Started looking into client/server components:
   
   Sunny Sun's "How to map REST API data using Decorator pattern in Angular 6"
   
   GraphQL seems easier than a RESTful connection ?
   
   Client:
   Apollo's "What is Apollo Client and what does it do?"
   Alexandr Selyanov's "How To Use GraphQL with Angular 2"
   Uri Goldshtein's "GraphQL as a best practice for modern Angular apps?"
   Nikolas Burk's "How to GraphQL - Introduction"
   prisma-labs / graphql-request
   apollographql / apollo-client
   grafoojs / grafoo
   chentsulin / awesome-graphql
   
   Server:
   Mikhail Novikov's "Building a GraphQL Server with Node.js and SQL"
   Sam Hogarth's "Connecting SQLite to GraphQL"
   rexxars / sql-to-graphql
   Jonas Helfer's "Tutorial: How to build a GraphQL server"
   Chimezie Enyinnaya's "How To Set Up a GraphQL Server in Node.js with Apollo Server and Sequelize"
   
   
   Then someone said just use IndexedDB, a database inside the browser.
   
   A complication for me: often there will be two browser profiles, one for daily use and one for web-app testing use. Probably this app will have to "live" in the testing profile.
   MDN's "IndexedDB API
   MDN's "Browser storage limits and eviction criteria
   Wikipedia's "Web storage"
   Works on Firefox, Chrome, Opera.
   Data-size limits not a problem for my app.
   How to backup or copy to another machine ? On Firefox, the DB is under "<profile>/storage/permanent". Or I could create export and import features into my app.
   
   But I see some statements:
   "IndexedDB is a document-oriented database while SQL is relational database ... Avoid using multiple tables in IndexedDB and trying to create joins."
   "SQL is relational database. IndexedDB is an indexed key/value store similar to a document-oriented database."
   
   Wrapper libraries, or DB engines that use IndexdDB for storage:
   SQL-like interface:
   AlaSQL (SQL-like interface)
   Object interface:
   JsStore
   Dexie.js
   NanoSQL
   Lovefield
   
   Firefox uses SQLite to store IndexedDB data, and there's an API directly to SQLite ? Confusing.
   Mozilla's "Performance/Avoid SQLite In Your Next Firefox Feature"
   
   
   Decided to use AlaSQL.
   The AlaSQL Wiki
   
   
   Whoops, better design my database schema first:
   

   Table Name	Row Fields	Example
   projects:	project_id, project_name	Project1
   appareas:	apparea_id, project_id, apparea_name	Standard
   appfunctions:	appfunction_id, project_id, apparea_id, appfunction_name	Login
   activities:	activity_id, project_id, activity_name, role_id, client_id	Learn app
   cells:	cell_id, project_id, appfunction_id, activity_id	Learn app / Login
   tools:	tool_id, tool_name, tool_path_type, tool_path	Burp Suite
   cellpaths:	cellpath_id, cell_id, cellpath_type, path_name, path_type, path, toolid, args	app.com/login.html or docs/doc1.md
   roles:	role_id, role_name	Admin
   clients:	client_id, client_name, devicetype_id, browsertype_id, ostype_id	PFL
   devicetypes:	devicetype_id, devicetype_name	PC
   browsertypes:	browsertype_id, browsertype_name	Firefox
   ostypes:	ostype_id, ostype_name	Windows

   
   Before I changed to AlaSQL, I started to do:
   
   SQLite Home Page
   Create a new file mdschema.sql:

   CREATE TABLE "projects" (
   	 "project_id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
   	 "project_name" TEXT(255,0) NOT NULL
   );
   CREATE INDEX "project_name_index" ON projects ("project_name" COLLATE NOCASE ASC);
   INSERT INTO `projects` VALUES
   	(NULL, "Default");
   
   CREATE TABLE "appareas" (
   	 "apparea_id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
   	 "project_id" INTEGER NOT NULL,
   	FOREIGN KEY(project_id) REFERENCES projects(project_id),
   	 "apparea_name" TEXT(255,0) NOT NULL
   );
   CREATE INDEX "apparea_name_index" ON appareas ("apparea_name" COLLATE NOCASE ASC);
   INSERT INTO `appareas` VALUES
   	(NULL, (SELECT project_id FROM projects WHERE project_name = "Default"), "Standard");
   

   
   

   npm install alasql
   # gave "3 vulnerabilities found"
   

   Create a new file mdsql.ts (only partial code shown):

   import alasql from 'alasql';
   
   ...
   
     alasql("SET AUTOCOMMIT ON");
     alasql("DROP localStorage DATABASE matrixdashboard");
     alasql("CREATE localStorage DATABASE matrixdashboard");
     alasql("ATTACH localStorage DATABASE matrixdashboard AS matrixdashboard");
     alasql("USE matrixdashboard");
   
   ...
   
     var res = alasql('CREATE TABLE projects ( \
                     project_id INT NOT NULL PRIMARY KEY AUTOINCREMENT, \
                     project_name  TEXT(255,0) NOT NULL \
                     )');
   
   ...
   
     var res = alasql('INSERT INTO projects (?,?)',[0,new_project_name]);
   
   ...
   
     var res = alasql("SELECT * FROM projects WHERE project_id=" + project_id);
   
   ...
   
     var res = alasql('CREATE TABLE appareas ( \
                     apparea_id INT NOT NULL PRIMARY KEY AUTOINCREMENT, \
                     project_id INT REFERENCES projects(project_id), \
                     apparea_name  TEXT(255,0) NOT NULL \
                     )');
   

   Every time I start up "ng serve", the very first compile fails with "alasql no default export". Change the source in some tiny way, recompiles, the compile sucseeds, while STILL saying "alasql no default export".
   
   Got things working, creating a database, using it, closing it, opening it. But when I quit out of Firefox and launched it again, the database was gone.
   
   Messed around in FF's storage settings, ended up clearing all storage, and that destroyed everything ! Anything I do in alasql gives "There is no any AlaSQL databases in localStorage" error message. Restarted "ng serve" and FF, tried loads of code combinations, always get that error. Gave up and filed a bug report on GitHub.
   
   An hour later, situation on my machine is fixed. Maybe I forgot to try just starting with a CREATE after it got into this state ? I quit everything, did "npm remove alasql", then "npm install alasql", DROP still gave the error if it was the first operation, but CREATE as first operation worked. And now the database is persistent across quit/relaunch of Firefox, too. I must have gotten the storage into some weird state or something.
   
   Tried building in Electron, and that "alasql no default export" error made the build fail every time. Back to Angular, and tried to eliminate it. Tried all kinds of variations of the import statement in mdsql.ts and the declare/export statements in node_modules/alasql/dist/alasql.d.ts, but no luck.
   
   Then started looking at compiler options, and found something. Added

   "allowSyntheticDefaultImports": true
   

   to src/tsconfig.app.json, and that killed the error, but caused uses of "alasql.databases.*" to fail (can import using either "import alasql from 'alasql';" or "import * as alaSQLSpace from 'alasql';", same behavior with either). I can do without "alasql.databases.*", I think. Holding my breath to see if anything else breaks. Build and run in Electron works.
   
   Started wiring the database further into my app. Reached a point where I was beating my head against a problem for half an hour, finally noticed compile-time errors from "ng serve", and realized it was using an old copy of one of the source files. Restarted it and app worked. Also, if you change a JSON config file, best to kill "ng serve" and restart it.
   
   Built in electron, and app fails with "alasql.min.js: It looks like you are using the browser version of AlaSQL. Please use the alasql.fs.js file instead.".
   
   Tried adding following to electron/package.json file, later (without "../") in angular.json file, but no change:

     "fileReplacements": [
       {
         "replace": "../node_modules/alasql/dist/alasql.min.js",
         "with": "../node_modules/alasql/dist/alasql.fs.js"
       }
     ],
   

   In the app under electron, select View/ToggleDeveloperTools menu item (or ctrl-shift-I) to see console log and errors.
   
   Got the app to run, despite the "alasql.fs.js" error message. And got another message in the console: "This window has node integration enabled by default. In Electron 5.0.0, node integration will be disabled by default. To prepare for this change, set {nodeIntegration: true} in the webPreferences for this window ...". Fixed it; in electron/main.ts, change:

     win = new BrowserWindow({ width: 800, height: 600 });
   

   to:

     win = new BrowserWindow({ width: 800, height: 600, webPreferences: {nodeIntegration: true} });
   

   
   Hey, the database is persistent under Electron ! I was trying to get to that point. I don't see where it's being stored, though; no new files have popped up in the development tree, that I can see. I thought it would not be persistent, because Electron provides a fresh copy of Chromium engine every time it starts ?
   
   Later, found out my database keys are not auto-incrementing. Strange. Looking in Github, found this issue was reported over 3 years ago and still not fixed. Bummer. And still seeing occasional hiccups where AlaSQL gives errors opening the database or a table of it.
   
   Decided to switch from AlaSQL to Dexie.

   npm remove alasql
   

   Later was told "Please remember that any interaction with localstorage is async, so you risk running into problems if you don't handle the async behavour. I recommend the promise notation from Async" So probably I was doing that wrong.


9. Switch to Dexie:
   
   

   npm install dexie --save
   npm install webpack -g
   

   Took a few hours to get things to compile, had to rework various constructors and such. And then started the battle with Promises; I like synchronous code, but for this I have to use asynchronous.
   
   Took a while just to get opening the database to work properly. Then I had to rework the code a couple of times to get Promises working and data going in and out. Then I still ended up with startup not working: NgInit() requests all the data, but then the HTML code executes before the data has arrived, blowing up everything. Consulting with people online, and they're saying I have to learn about more Angular things, resolvers and services and such. Beginning to think I shouldn't use Angular.
   
   Yes, the more they explain "reactive programming" to me, the more I think I want nothing to do with it. I'll have to try a different approach.

1. Starting, with NetBeans and Swing:
   
   Downloaded incubating-netbeans-10.0-bin.zip
   Extracted it to /usr/local/share
   apt install ant
   At CLI, run /usr/local/share/netbeans/bin/netbeans
   
   Followed Saleem Gul and Tomas Pavek's "Introduction to GUI Building":
   Created new project of type Java / Java Application, unchecking "Create Main Class".
   IDE downloaded and installed an extension manager.
   IDE activated Java SE.
   
   Created a quick GUI in Swing and ran it:
   In Projects window, right-click on main project's node and choose New / Other.
   In the New File dialog box, choose the Swing GUI Forms category and the JFrame Form file type.
   Set <projectname>UI as the class name.
   Enter my.<projectname> as the package.
   Files are created and GUI builder opens.
   Drag and drop GUI items, when done select Run / Run Project menu item.
   


2. Get SQLite and JDBC driver:
   
   (There also is "Java DB / Derby", but it seems more complicated than SQLite. Apache Derby)
   
   Followed SQLite Tutorial's "Getting started with SQLite":
   Download Linux binary version of SQLite from https://www.sqlite.org/download.html (it's only about 2 MB)
   Extracted it to /usr/local/share
   cd /usr/local/share/sqlite-tools-linux-x86-3270200
   sqlite3
   type ".quit" to quit
   
   Download SQLite Studio from https://sqlitestudio.pl/index.rvt
   Set Execute permission on the file
   Double-click it to run it
   Installed in /opt/SQLStudio
   Tried it, decided it's better to create database from inside the IDE.
   
   Followed SQLite Tutorial's "SQLite Java: Connect To The SQLite Database Using SQLite JDBC Driver":
   Went to https://bitbucket.org/xerial/sqlite-jdbc/downloads/ and downloaded sqlite-jdbc-3.27.2.1.jar
   Moved JAR file into my project folder
   In NetBean IDE with your project open:
   Select main project node and click on Services tab
   Right-click on Drivers and select New Driver ...
   Specify JAR file
   
   Set up for app to connect through JDBC to database:
   In Services tab, right-click on SQLite driver and select Connect Using ...
   For "JDBC URL" use connection string jdbc:sqlite:matrixdashboard.sqlite3
   Click Finish
   See database appear in next area below Drivers.
   "KDE Wallet" dialog opens up; NetBeans IDE wants to store database login credentials in a secure way (even though there are no credentials).
   Click Cancel two or three times to get rid of dialog.
   


3. Connect app through JDBC to database:
   
   tutorialspoint's "JDBC - Sample, Example Code"
   mkyong's "Java JDBC Tutorials"
   
   Created table definitions: under Services / JDBC, right-click on Tables and select Create Table ...
   But there seems to be no way to write those definitions into the database, they're just used by the IDE.
   
   In NetBeans IDE, tried right-clicking on main project node and selecting New / Entity classes from database ...
   Interesting code got created, but not quite useful.
   
   Telosys does automatic code-generation from an existing database.
   Laurent Guerin's "Telosys : the concept of lightweight model for code-generation"
   After installing the CLI version, have to edit CFG file to set editor.
   But the documentation is incredibly cryptic, apparently you need a .dbcfg file which I have no idea how to get.
   Gave up on it.
   
   Finally started copying/writing code to connect to database. Took a bit of trial-and-error to get the connect working, key steps were:
   • In NetBeans IDE, right-click on Libraries, select Add JAR/Folder, add sqlite JAR.
   • In code, use driver class name "org.sqlite.JDBC".
   • In code, use connection URL "jdbc:sqlite:matrixdashboard.sqlite3".
   Got the code working, database to table etc.
   
   Some quirks of NetBeans IDE:
   
   
   • Somehow, the main "form" file disappears from the project, so the "Design" button disappears. File still was on disk, so just did an Open File on it, and Design button came back.
   
   
   • In Design mode, can't do GUI design of components that are not top-level ? Found the answer: have to right-click on your main package icon, select New... For modal dialog, select JPanel Form.
   
   
   • But Design mode imposes some restriction: one source file for each UI element (form) you design. So if you have four dialogs which are very similar, figure out a way to design it once, in one class, and use code to hide/reveal/enable/disable elements in the form.
   
   
   • Javadocs: Go to Tools / Java Platforms, for JDK 10 select Javadoc tab. Click on Add URL button, add url "http://docs.oracle.com/javase/10/docs/api/". Now you can right-click on Java classes and see the docs for it.
   
   
   • To generate a Javadocs file for your new classes, go to Run / Generate javadoc (yourprojectname).
   
   
   Put the code into GitHub: BillDietrich / MatrixDashboard

• Zip the project's dist folder into a ZIP archive. (The dist folder might also contain a lib folder, which you would also need to include.)
• Rename ZIP file to JAR file ?
• On CLI: java -jar <jar_name>.jar

> Why do you think Java is a bad choice?

Lots of reasons.

Java is an old language. It has many problems with it that are never fixed, especially with respect to security. They just let the problems continue from one version to the next.

Java was not designed with security in mind: many parts of it are not secure by default (examples: all the XML parsers are vulnerable to XXE by default, the deserialization vulnerabilities, the crypto, etc). The Java Cryptography Architecture is a disaster. Very few developers can write Java crypto code securely because the architecture assumes the developer is expert in crypto (none are) and warns that it is the developer's responsibility to achieve such expertise before using it (the exact opposite approach of NaCl). The Java documentation is generally poor quality. You get a vague, half-useful explanation of many API methods in the sunny day case, with no explanation of what explanation of what happens if not-so-friendly data is sent in. There are so many little gotchas in the language that are not explained, and are left for the developer or security-reviewer to figure out on their own. For example, Google the dangers of seeding SecureRandom or specifying a default SecureRandom provider, and really there are many, many obscure examples like this.

There are lots of other problems with Java other than security. For example it did not support unsigned ints because one of the people who created it thought it was too complicated (ironically, signed ints are more complicated than unsigned). Java generally takes a lot more code to do simple things than modern languages do. Worst of all, they are now trying to get people to pay for Java SE. And don't forget that fight with Google for Google using the APIs in Android -- Java was originally free for everybody, and then Oracle tried to find a way to get money for it by changing the rules.

Back in the 1990s, Java was wonderful. It gave us an escape from the horrible crap that Microsoft was trying to force on everybody else. It was free. It had functionality built into it that other languages did not support. It had the elegance of C with added features, yet avoided the complexities of C++. That was good for back then, but the bar for software language expectations today is much higher than it was back then in the 20th century.

Since then, times have changed enormously. Nowadays Microsoft is giving us great software (.Net core) that we can use anywhere to escape the horrible mess of Java. Microsoft languages now tend to be secure by default, well documented, and easy to use. Microsoft has gone forward, whereas Java in general (especially Oracle Java) is going backwards if anywhere.

So we don't just complain about Java because it is the cool thing to do. We complain because we have lived through the torture for too many years.

I myself whose career largely involves secure code review and guidance know that I will always be in demand as long as languages like Java are around. But if I were to write production software today, Java is one of the last languages I would consider using. It's just awful.

snap install flutter

# to build Linux desktop apps:
flutter channel dev
flutter upgrade
flutter config --no-analytics
flutter config --enable-linux-desktop
flutter config
# now have 924 MB installed under ~/snap/flutter

snap install flutter-gallery

Install Flutter extension in editor such as VSCode (search for "Flutter" extension, install, restart editor, then run "Flutter Doctor").

cd ~/projects
flutter create flutt2

In VSCode, open folder flutt2.
Open file lib/main.dart, see code.
F5 to run.
Select environment "Dart & Flutter".
App may take 30 seconds or longer to appear.
App window may not paint until you move the mouse.

Code looks like this:

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: 'Flutter Demo',
        theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

My First App using Flutter Framework

I made Android app using Flutter framework in 20 days. This is related to Telegram channels, groups, stickers and Bots.

...

I have 4 years experience in programming (php) but 0% experience in app or Java. I was able to learn flutter and dart in one week from YouTube videos. Just check 2 or 3 videos from below playlist, you will find if it is easy or not.
The Net Ninja's "Flutter Tutorial for Beginners"

This is the easiest framework i found to make an app. One of the advantages is same source code will work for both Android and iOS.

# use app "Qt 4 Designer" to edit JSONitor.ui file to manage UI
designer JSONitor.ui

# process JSONitor.ui file to create JSONitorUI.py file
pyuic5 JSONitor.ui -o JSONitorUI.py

# run application
python3 JSONitor.py

for ind, filename in enumerate(["System-Existing.json", "System-New.json"]):
    logger.debug('initUI: ind {}'.format(ind))
    logger.debug('initUI: filename {}'.format(filename))
    if filename and os.path.isfile(filename):
        self.currentTextPane = ind


import Utilities.JSONTools as jst
jsc = jst.JSONConverter(logger)
sampleJSON = jsc.getDict(text)

itemModel = StandardItemModel()
if sampleJSON:
    itemModel.populateTree(sampleJSON, itemModel.invisibleRootItem())

JavaScript traditionally only runs in internet browser as a client application.

Node is basically just a so-called runtime environment which allows JavaScript to be executed outside of the browser. Aditionally it provides tools for filesystem access and other low-level stuff that doesn't exist in normal "browser" JavaScript as well as a package manager, which ends up making JavaScript a pretty powerful and versatile programming language.

# went to https://nodejs.org/en/download/
# downloaded "Linux Binaries (x64)" tar.xz file

# followed instructions at https://github.com/nodejs/help/wiki/Installation
VERSION=v10.15.3
DISTRO=linux-x64
sudo mkdir -p /usr/local/lib/nodejs
sudo mv node-$VERSION-$DISTRO.tar.xz /usr/local/lib/nodejs
cd /usr/local/lib/nodejs
sudo tar -xJvf node-$VERSION-$DISTRO.tar.xz
sudo rm node-$VERSION-$DISTRO.tar.xz

# added following to .bash_profile and .zshrc
# Nodejs
VERSION=v10.15.3
DISTRO=linux-x64
export PATH=/usr/local/lib/nodejs/node-$VERSION-$DISTRO/bin:$PATH

sudo ln -s /usr/local/lib/nodejs/node-$VERSION-$DISTRO/bin/node /usr/bin/node
sudo ln -s /usr/local/lib/nodejs/node-$VERSION-$DISTRO/bin/npm /usr/bin/npm
sudo ln -s /usr/local/lib/nodejs/node-$VERSION-$DISTRO/bin/npx /usr/bin/npx

# tested installation using
cd ~
node -v
npm version
npx -v

sudo npm uninstall npm -g
sudo rm -fr /usr/local/lib/nodejs
sudo rm -rf /usr/local/{lib/node{,/.npm,_modules},bin,share/man}/npm*
cd ~
grep -s nodejs ~/.*
# edit matched files to remove *nodejs* from PATH

# went to https://nodejs.org/en/download/current/
# downloaded "Linux Binaries (x64)" tar.xz file

# followed instructions at https://github.com/nodejs/help/wiki/Installation
# But I'm not sure why the version number in the instruction is old
NODEVERSION=v13.11.0
NODEDISTRO=linux-x64
sudo mkdir -p /usr/local/lib/nodejs
sudo mv node-$NODEVERSION-$NODEDISTRO.tar.xz /usr/local/lib/nodejs
cd /usr/local/lib/nodejs
sudo tar -xJvf node-$NODEVERSION-$NODEDISTRO.tar.xz
sudo rm node-$NODEVERSION-$NODEDISTRO.tar.xz


# Added following to user's .profile and ALSO to /root/.profile
# Nodejs
NODEVERSION=v13.11.0
NODEDISTRO=linux-x64
export PATH=/usr/local/lib/nodejs/node-$NODEVERSION-$NODEDISTRO/bin:$PATH

# log out and back in, or
. ~/.profile

# tested installation using
cd ~
node -v
npm version
npx -v

# install web-ext so can develop Firefox extensions
sudo su - root
npm install -g npm
npm install --global web-ext
ctrl-D to get out of SU shell
web-ext --version

https://nodejs.org/dist/latest-v13.x/docs/api/

npm audit
npm prune --dry-run

# ???
depcheck
npm-check
# double-check before removing anything listed as "not used"

Ruby is comparable to Python, although maybe more object-oriented, and slower ?
"Ruby isn't compiled so ruby developers have to give away their source code for desktop apps."

Tutorials Point's "Ruby Tutorial"
GeeksforGeeks' "Ruby For Beginners"

Using a text-editor, create a file mytest.rb:

# comment here
n = 100
puts "Hello World #{n}"

ruby mytest.rb

"WxRuby: cross-platform GUI toolkit that is native-looking on whatever platform you are on."

"The standard graphical user interface (GUI) for Ruby is Tk." from Tutorials Point's "Ruby - Tk Guide"

Rails is a MVC web application framework running on the Ruby programming language.
I think Rails is for database-centric web apps: you have a database and the web app lets users read and modify it, using app logic etc.
Rails Guides' "Getting Started with Rails"
Mehdi Farsi's "Learn Ruby on Rails"



When installing Ruby on Rails, there are some choices: RVM or rbenv or from source or from Ubuntu repos, and sqlite3 or MySQL or PostgreSQL or MariaDB database.

RVM and PostgreSQL on Ubuntu:
HowtoForge's "How to Install Ruby on Rails on Ubuntu 20.04 LTS"

Multiple choices:
Go Rails' "Install Ruby On Rails on Ubuntu 20.04 Focal Fossa"
Raj's "How To Install Ruby On Rails On Ubuntu 20.04"



I installed rbenv / MariaDB on Ubuntu 20.04 following Raj's "How To Install Ruby On Rails On Ubuntu 20.04":

sudo apt update

sudo apt install -y curl gnupg2 dirmngr git-core zlib1g-dev build-essential libssl-dev libreadline-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt1-dev libcurl4-openssl-dev software-properties-common libffi-dev

wget -qO- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.3/install.sh | bash
# close terminal and re-open it
nvm install node
node -v   # get 14.n.n
npm -v    # get 6.14.n

curl -sL https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
sudo apt update && sudo apt install -y  yarn

cd
git clone https://github.com/rbenv/rbenv.git ~/.rbenv
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(rbenv init -)"' >> ~/.bashrc
exec $SHELL

git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build
echo 'export PATH="$HOME/.rbenv/plugins/ruby-build/bin:$PATH"' >> ~/.bashrc
exec $SHELL
du -sh .rbenv

rbenv install 2.7.1
du -sh .rbenv
rbenv global 2.7.1
ruby -v   # get 2.7.1

gem install bundler
du -sh .rbenv

gem install rails
du -sh .rbenv     # 270M
rails -v

sudo apt install -y mariadb-server mariadb-client
sudo apt install -y libmariadb-dev

sudo mysql -u root -p
# At MariaDB prompt:
CREATE USER 'myuser'@'localhost' IDENTIFIED BY 'mypassword';
GRANT ALL PRIVILEGES ON *.* TO 'myuser'@'localhost';
exit

gem install mysql2

# Create new application:
cd ~/projects
rails new myrailsapp1 -d mysql
du -sh myrailsapp1    # 132M
cd myrailsapp1

# Edit config/database.yml to change username and password to values you chose:
default: &default
  adapter: mysql2
  encoding: utf8mb4
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  username: myuser
  password: mypassword
  socket: /var/run/mysqld/mysqld.sock

rake db:create

# Start the application:
rails server -b 0.0.0.0

# Open in browser:
http://localhost:3000
# See app's web page.
# Close page in browser.
ctrl+C to stop app running

# Main HTML page of app seems to be app/views/layouts/application.html.erb
https://www.tutorialspoint.com/ruby-on-rails/rails-directory-structure.htm
https://dev-yakuza.github.io/en/ruby-on-rails/folder-structure/

# Too complicated for me.
cd ~/projects
rm -fr myrailsapp1
gem uninstall mysql2
sudo apt remove libmariadb-dev
sudo apt remove mariadb-server mariadb-client
gem uninstall rails

sudo apt install rustc
rustc --version

fn main() {
    println!("Hello, world!");
}

rustc mytest.rs 
./mytest

https://github.com/mozilla/multi-account-containers and related/derived extensions.

Original project was called "test pilot".

Some resources:

https://discourse.mozilla.org/c/test-pilot/containers (but most recent activity is 8 months ago)

https://wiki.mozilla.org/Security/Contextual_Identity_Project/Containers (but seems outdated/proposal)

https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/contextualIdentities is the missing piece.

Import/export config: issues 1427, 1409, 1420, 1282 in https://github.com/mozilla/multi-account-containers

I want to make an extension that has no UI other than a Settings page.
Started with https://github.com/mdn/webextensions-examples/tree/master/favourite-colour
https://github.com/mdn/webextensions-examples/tree/master/contextual-identities
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/downloads/download

Did:
Copied example code from github.
Changed names etc in code.

sudo bash
npm install --global web-ext
ctrl-D to get out of SU shell
/usr/local/lib/nodejs/node-v10.15.3-linux-x64/bin/web-ext --version

Created repo https://github.com/BillDietrich/ContainersExportImport

In extension project directory:

/usr/local/lib/nodejs/node-v10.15.3-linux-x64/bin/web-ext run --pref privacy.userContext.enabled=true --pref privacy.firstparty.isolate=false --pref privacy.firstparty.isolate.restrict_opener_access=false

In browser running add-on, to see console.log() messages, you don't want web console, you want add-on debugging console. Type about:debugging in the address bar. See your add-on listed. Click the "debug" link for it. A separate window/process will open, showing the output. Click on "console" and enable "persist logs". Then manipulate your add-on. https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Debugging

Got the code working (I think) in debug environment.

To sign the extension for permanent but private (unlisted) use, went to Developer Hub - API Credentials. Logged in wth Firefox account. Clicked on the "Generate new credentials" button to get API keys. Copied the keys.

Then in CLI, in add-on project directory:

/usr/local/lib/nodejs/node-v10.15.3-linux-x64/bin/web-ext sign --api-key=<JWT issuer> --api-secret=<JWT secret>

Got success, it returned a validation ID, and created a .web-extension-id file and a web-ext-artifacts directory. Inside that directory is the .xpi file.

In Firefox, type "about:addons" in address bar (or do alt-T, a) (or do ctrl-shft-a), see add-ons page. Click on "gear" pull-down menu, select "Install add-on from file" menu item. Navigate to web-ext-artifacts directory and select your add-on's .xpi file.

Go to Developer Hub - My Add-ons and log in to see list of your add-ons.

alert() works in debug mode but is a bit broken in "real mode" ? The text and button appear, but no box around them, and they're a bit separated. Supposed to use Notifications, not alert(), in "real mode".

Type "about:profiles" in the address bar to manage profiles or choose a profile. Click on "Launch profile in new browser" button for new/test profile.

To publish to the world:
Tweak descriptions and settings and versions:
Start at https://addons.mozilla.org/en-US/firefox/
Log in.
Go to https://addons.mozilla.org/en-US/developers/
Locate your add-on and click on its "Edit Product Page".
Click on "Manage Status & Versions"
Publish:
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Distribution/Submitting_an_add-on
https://addons.mozilla.org/en-US/developers/addons

Was confused about how to change from self-distributed to AMO (public to world). Got this info: "When you submit a new version on the website, the top of the first page in the submission flow is labeled 'Where to Host'. You should see a button or link there that allows you to change the setting to hosted on the site. You can change that setting every time you submit, depending on what you need."

So, make changes and commit and push them.
Do NOT sign the extension to make XPI file.
Add files to a ZIP file: icons, manifest, package, README, LICENSE, source files:

zip archivename.zip file1 file2 ...
zip containersexportimportVERSION.zip background.js icon*.png LICENSE.md manifest.json options.* package.json README.md
zip decentraleyessimpler1.3.zip background.js icon*.png LICENSE.md manifest.json options.* package.json README.md

Login at https://addons.mozilla.org/en-US/firefox/
Go to https://addons.mozilla.org/en-US/developers/addons
Click on link for the add-on
Do NOT click on "upload new version", instead click on "View All".
Click on "Upload a New Version" button.
Click on "Upload a New Version" button.
Under "Where to Host Version", click on "change" link.
Upload ZIP file.
Click on "Sign add-on" button.
Icon did not get picked up, had to edit that setting later.

If there are errors/warnings about the content of your add-on when you try to publish, you can see same list of errors/warnings by running "web-ext lint" locally.

MDN's "Developing extensions for Firefox for Android"

To just quickly try your extension in an Android phone:

1. On computer, create .xpi file.
2. On phone, enable Developer Options.
3. On phone, enable Android USB Debugging.
4. Connect computer to phone via USB cable.
5. On computer CLI, do "adb devices" to see that connection is good.
6. On computer CLI, do "adb push filename.xpi /mnt/sdcard/" to copy file to phone.
7. On phone, launch Firefox for Android browser.
8. In Firefox, browse to file:///mnt/sdcard
9. You may have to Allow access to files by Firefox.
10. See list of filenames.
11. Tap on filename.xpi link.
12. In Firefox, click Allow on warnings.

David Rousset's "Creating One Browser Extension For All Browsers: Edge, Chrome, Firefox, Opera, Brave And Vivaldi"
MDN's "Porting a Google Chrome extension"
MDN's "Building a cross-browser extension"
MDN's "Chrome incompatibilities"
mozilla / webextension-polyfill

To just quickly try your extension in Chrome:

1. In Chrome, type "chrome://extensions" in address bar.
2. Enable "Developer Mode" (button in upper-right).
3. Click on "Load unpacked", and choose the extension's project folder.
4. See a box for your extension in the Extensions page.
5. If there is a red "Errors" button for your extension, click it.

Useful snippet to allow use of "browser" in Chrome:

window.browser = (function () {
  return window.msBrowser ||
    window.browser ||
    window.chrome;
})();

But, for me, there are too many differences between Firefox and Chrome, I gave up:

• Various manifest.json differences; requires two separate files.
• Permission "browser_specific_settings" not supported in Chrome.
• Chrome doesn't support Promises (maybe use mozilla / webextension-polyfill).

https://addons.thunderbird.net/en-US/thunderbird/addon/new-account-types/
https://addons.thunderbird.net/en-US/thunderbird/addon/teclib/
https://github.com/gooselinux/thunderbird
I want to add WhatsApp integration into TB. Chat accounts (e.g. Twitter) seem to be formatted as one integrated timeline from all users, which is not how WhatsApp works. Maybe I want to model it after a newsgroup integration ?

https://developer.mozilla.org/en-US/docs/Mozilla/Thunderbird/MailNews_fakeserver
http://test.xennanews.com/
https://www.ngprovider.com/free-newsgroup-server.php

Or maybe I could just have WhatsApp appear as a button on the top, like "Chat", and open as an HTML window in the main pane ?

Thunderbrowse
https://bitbucket.org/alta8888/browseintab/wiki/Home

Config setting general.useragent.override lets you set user-agent string ?
Boolean compatMode.firefox should work too, but doesn't work with WhatsApp parsing for some reason.

#!/usr/bin/env sh

# this is a comment

echo "hello"

read -p 'OK? ' dummyvar

chmod a+x mytest.sh
./mytest.sh

zenity --info --title="mytest.sh running" --text="the mytest.sh script is running"

#!/usr/bin/env python3

# this is a comment

if __name__ == '__main__':
  print('hello')

# for Linux Mint, no installation needed, Zenity is installed by default.

# For Win10, https://github.com/maravento/winzenity
# Download https://github.com/maravento/winzenity/raw/master/zenity.zip
# and copy the EXE file inside it to the same folder where ipwatch.py is located..

# https://www.linux.org/threads/zenity-gui-for-shell-scripts.9802/
# https://en.wikipedia.org/wiki/Zenity

import subprocess

# in Linux, do a (non-modal) notification, so no wait for user action
subprocess.call(['zenity','--notification','--text',sMsg])
# on Linux, see output as notifications in system tray

# in Win10, only modal-dialog choices are available with WinZenity
# open a modal dialog, so no more checking until user sees the dialog and closes it
subprocess.call(['zenity','--info','--text',sMsg])

# https://plyer.readthedocs.io/en/latest/#
# https://github.com/kivy/plyer
# no way to have notification remain permanently

# do "pip3 install plyer" or "pip install plyer"

from plyer import notification

# in Linux, notifications appear both on desktop (briefly) and in tray

notification.notify(title='SOMETITLE', message=sMsg, app_name='SOMEAPPNAME', timeout=8*60*60)

# https://docs.python.org/2/library/syslog.html

import syslog

syslog.syslog(sMsg)

# to see output:
#   sudo journalctl --pager-end
# or
#   sudo journalctl | grep ipwatch

# https://stackoverflow.com/questions/51385195/writing-to-windows-event-log-using-win32evtlog-from-pywin32-library
# https://www.programcreek.com/python/example/96660/win32evtlogutil.ReportEvent
# https://docs.microsoft.com/en-us/windows/win32/eventlog/event-logging-elements
# https://rosettacode.org/wiki/Write_to_Windows_event_log#Python

# do "pip install pywin32"

import win32evtlogutil
import win32evtlog

win32evtlogutil.ReportEvent(
                            "APPNAME",
                            #7040,       # event ID  # https://www.rapidtables.com/convert/number/decimal-to-binary.html
                            1610612737,  # event ID  # https://www.rapidtables.com/convert/number/decimal-to-binary.html
                            eventCategory=1,
                            eventType=win32evtlog.EVENTLOG_INFORMATION_TYPE,
                            strings=[sMsg],
                            data=b"")

# to see output: run Event Viewer application.

import signal       # https://docs.python.org/3/library/signal.html

# Not sure why this is needed, but it is, otherwise signal will make process exit.
# And sometimes this is not called, even though the signal came in to the main loop.
def handler(signum, frame):
    #print('Signal handler called with signal', signum)
    return

# Not sure why this is needed, but it is, otherwise signal will make process exit.
signal.signal(signal.SIGUSR1, handler)

# Create file to tell sender that it can send signals to us now.
# If we allowed it to send signal before this point, a signal would make this app exit.
gsAliveFilename = "/tmp/serverisup"
fileAlive = open(gsAliveFilename, 'w+')

# SIGUSR1 == 10 in major archs
# send does:  pkill --signal SIGUSR1 -f server.py

objSignal = signal.sigtimedwait({signal.SIGUSR1}, gnSleep)
if objSignal == None:
   print('sleep timed out')
else:
   print('received signal '+str(objSignal.si_signo))

fileAlive.close()
try:
    os.remove(gsAliveFilename)
except:
    i = 1   # placeholder

python3 -m pip install mypy
mypy yourprogram.py

# change:
def greeting(name):
# to:
def greeting(name: str) -> str:

# change:
def greet_all(names):
# to:
from typing import List
def greet_all(names: List[str]):

# change:
my_global_dict = {}
# to:
my_global_dict: Dict[int, float] = {}   # Python 3.6+
or:
my_global_dict = {}  # type: Dict[int, float]   # any version of Python

#!/usr/bin/env php
<?php

/*
  this is a comment
*/

echo "hello";

?>

php -r 'phpinfo();' | more

# if that fails, do:
sudo apt-get install php-cli

chmod a+x mytest.php
./mytest.php

# if you remove the "#!/usr/bin/env php" line and don't do the chmod:
php -f mytest.php

sudo apt-get install php-gd

#!/usr/bin/env perl -w

# this is a comment

print "hello\n";

perl -v

# if that fails, do:
sudo apt-get install perl

chmod a+x mytest.pl
./mytest.pl

# if you remove the "#!/usr/bin/env perl" line and don't do the chmod:
perl mytest.pl

# to install a needed module:
# https://www.ostechnix.com/how-to-install-perl-modules-on-linux/
make -v
sudo cpan
install MODULENAME
# Expect a TON of operations and output the first time you do this.
# Installing XML::RSS set off half an hour of building on my machine,
# and created 260M of stuff under ~/.local/share/.cpan, maybe more elsewhere.
# Tried to install XML::Atom::Entry, which set off another 5-10 minutes and then failed.
exit

script to generate system status into a file:
- list of browser profiles and extensions and certs
- default browser
- browser home page
- microcode checksum
- BIOS checksum
- /etc/passwd checksum
- /etc/groups checksum
- kernel version
- active network listeners
- VPN status
- IP address
- DNS settings
- MAC address of router (Arpwatch ?)
- dir list of /bin, /usr/bin, ...
- filesystem dirty bits
- list of PCI devices: lspci
- list of SCSI/SATA devices: lsscsi
- dmidecode
- env has changed
- who is logged on right now (w)
- iptables rules
- list of cron jobs
- shell profiles for users
- file explorer extensions
- source editor extensions
- home/.ssh/known_hosts
- /etc/init/*

script to call that script, then diff results with previous results

send alerts to:
- pushbullet (https://unix.stackexchange.com/questions/381821/how-can-i-send-notifications-alerts-using-the-linux-terminal)
- journal (logger -p user.info this is the message")
- email

Started building it.

Then someone pointed me to SysConfCollect (SCC)

Best if your script file /FULLPATH/SCRIPTNAME.sh is NOT under /home, because if user's home directory is encrypted or not mounted, script will be inaccessible.

Create file /etc/systemd/system/YOURSERVICENAME.service:

[Unit]
Description=MY DESCRIPTION HERE
#After=network.target
After=network-online.target
Before=graphical.target
Before=multi-user.target

[Service]
Type=simple
ExecStart=/FULLPATH/SCRIPTNAME.sh

[Install]
WantedBy=multi-user.target

Create file /home/FULLPATH/SCRIPTNAME.sh:

Set permission and enable the service:

chmod a+x /FULLPATH/SCRIPTNAME.sh
sudo systemctl enable YOURSERVICENAME
sudo systemctl status YOURSERVICENAME
sudo systemctl start YOURSERVICENAME
sudo systemctl status YOURSERVICENAME

After system boot:

sudo journalctl | grep YOURSERVICENAME

#!/usr/bin/env bash

echo "script test1.sh executed" `date` >~/test1.log.txt
echo "arguments " $* >>~/test1.log.txt
echo "env:" >>~/test1.log.txt
printenv >>~/test1.log.txt

zenity --info --title="test1.sh running" --text="the test1.sh script is running"

chmod a+x ~/.local/share/nemo/scripts/test1.sh

#!/usr/bin/php
#!/usr/bin/env php
# second form is more portable than the first form

Put a file "autorun.sh" on a USB stick that is EXT4 format (MSDOS format does not work). Set execute permission on the file. When attach the drive, get a prompt asking if want to run the file, click Run.

Trickier, more flexible ways:

From Ask Ubuntu question:

Find the *.mount name for your drive:

systemctl list-units -t mount | grep media
# insert your device
systemctl list-units -t mount | grep media
# find the added name

Create file /etc/systemd/system/YOURSERVICENAME.service:

[Unit]
Description=MY SCRIPT TRIGGERED WHEN DRIVE XXX INSERTED
Requires=media-YOURMEDIALABEL.mount
After=media-YOURMEDIALABEL.mount

[Service]
ExecStart=/home/FULLPATH/SCRIPTNAME.sh

[Install]
WantedBy=media-YOURMEDIALABEL.mount

Create file /home/FULLPATH/SCRIPTNAME.sh:

Set permission and enable the service:

chmod a+x /home/FULLPATH/SCRIPTNAME.sh
sudo systemctl enable YOURSERVICENAME.service

"If the service is failed somehow (for example, the script is not executable), your mount point will change to OLDMOUNTPOINTNAME1 next time you mount the USB device. To fix this issue, execute 'sudo systemctl reset-failed'".

Another way: using udevadm and creating a file in /etc/udev/rules.d/. But using systemd (above) is better because the systemd service won't trigger until after the filesystem is mounted.

Another way: Nemo file-explorer in Mint has Edit / Preferences / Behavior / Media Handling / "Prompt or autorun/autostart programs when media are inserted" check-box. But I don't see how to specify a program. If I turn off that option, no Nemo window is opened when I attach a USB drive, even though the "automatically open a folder" option still is checked. See Nemo file-explorer actions/scripts

In Nautilus file-explorer under Edit / Preferences / Media you can choose "other action" and then "custom command". https://github.com/Alfcx/linux-mint-nemo-actions https://linuxconfig.org/how-to-extend-the-gnome-nautilus-file-manager-with-custom-scripts

In Ubuntu, Activities / Details: https://help.ubuntu.com/stable/ubuntu-help/files-autorun.html

An important point made by some people: we really should stop using the C language (created in 1972-3). It is not memory-safe and type-safe, doesn't have the concepts of exceptions (it always just does something and keeps going), heap, strings. Unfortunately, the Linux kernel and much of the user-space code is written in it. This leads to tens of thousands of bugs in Linux today, including security vulnerabilities. Maybe C is appropriate for very low-level system programming, as an alternative to assembly language. But for apps and services and modules, not.
John Regehr's "A Guide to Undefined Behavior in C and C++"
Alex Gaynor's "Modern C++ Won't Save Us"
Ian Barland's "Why C and C++ are Awful Programming Languages"
Quora thread "Is C that bad of a programming language?"
Catalin Cimpanu's "Chrome: 70% of all security bugs are memory safety issues"

What is better, and a reasonable evolution from C ? Probably Rust
But: Drew DeVault's "Rust is not a good C replacement"

Cross-compiler that runs on Linux and makes an EXE for Windows: MinGW ("sudo apt install mingw-w64").