function getData(range, columnMap) {
  const dataValues = range.getValues();
  const mapEntries = Object.entries(columnMap)

  return dataValues.map((row) => Object.fromEntries(mapEntries.map((colMap) => [colMap[0], row[colMap[1]]])))
}

Example:

You have a sheet with data from A1:D*** (*** is last row), with the field mappings :

• first col is product_code
• second col is total
• fourth col is rank1

So the code of main function is

function main(){
  // Get the sheet you want
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheets()[0];
  var lastRow = sheet.getLastRow();
  var dataRange = sheet.getRange("A1:D" + (lastRow));
  
  var data = getData(dataRange, {
    "product_code": 0,
    "total": 1,
    // skip third column
    "rank1": 3,
  })

  console.log(data)
}

The DOM event handling go through 2 phrases : Capture and Bubble (with support of preventDefault, stopPropagation, stopImmediatePropagation methods to modify behavior)

Try the demo here : https://svelte.dev/repl/99d1edbf7bd9426384be2c7763d2e872?version=4.2.0

<script>
	const onClickEle = (e) => {
		console.log((new Date()).toISOString() + " : Clicked " + e.currentTarget.tagName)
	}
</script>

<h5>Default (bubble)</h5>
<div on:click={onClickEle}>
	<button on:click={onClickEle}>Click here!</button>
</div>

<h5>Default (bubble with stopPropagation)</h5>
<div on:click={onClickEle}>
	<button on:click|stopPropagation={onClickEle}>Click here!</button>
</div>

<h5>Parent capture</h5>
<div on:click|capture={onClickEle}>
	<button on:click={onClickEle}>Click here!</button>
</div>

<h5>Parent capture stopPropagation</h5>
<div on:click|capture|stopPropagation={onClickEle}>
	<button on:click={onClickEle}>Click here!</button>
</div>

<h5>Self (ele = event target)</h5>
<div on:click|self={onClickEle}>
	<button on:click={onClickEle}>Click here!</button>
</div>

<style>
		div { padding: 10px 30px; background: gray; cursor: pointer; display: inline }
</style>

moduleA.js

export const message = "Hello from moduleA!";

moduleB.js

import { message } from './moduleA.js';
console.log(message);

app.html

<script type="module" src="moduleB.js"></script>

// Print console log "Hello from moduleA!"

So moduleB.js acts like a module entry-point, it loads all dependencies deeply to run it-self, so you only need add script tag point to it.

Reactivity in Svelte works via assignment of variable, so we have this as example

let todos = [];

// Don't work
todos.push({id: 1, name: 'cleaning'})
todos.push({id: 2, name: 'coding'})

// Work
todos = [...todos, {id: 1, name: 'cleaning'}]

// or this even work as tricky way
todos.push({id: 1, name: 'cleaning'})
todos = todos

Why ? I don't know in internal system how it implement, but I think because Svelte works as a compiler, so it triggers the update when it see the assignment variable line.

Different with another frameworks, they work based on proxy object

Object.prototype.groupBy = function(cb) {
  const groupByCategory = this.reduce((group, item) => {
    const category = cb(item);
    group[category] = group[category] ?? [];
    group[category].push(item);
    return group;
  }, {});

  return groupByCategory;
}

// Example
const people = [{"name":"John","age":28},{"name":"Alice","age":24},{"name":"Michael","age":32},{"name":"Emily","age":29},{"name":"David","age":27},{"name":"Sophia","age":38}];

const by_first_age_period = people.groupBy((person) => Math.floor(person.age / 10) * 10 + '+');

console.log(by_first_age_period);

[abc*="something"] means select element has attribute abc, and its value contains "something" string

Example :

/* Warning all admin link is red text color */
a[href*="/admin/"] {
	color: red;
}

• HTTP 307 : Temporary redirect, keep METHOD and BODY
• HTTP 308 : Permanent redirect, keep METHOD and BODY

vs

• HTTP 301 : Permanent redirect, fallback to GET method
• HTTP 302 : Temporary redirect, fallback to GET method

Many examples, articles and repository use insecure config in port mapping Docker.

This is example in official document of Docker

https://docs.docker.com/engine/reference/run/#detached--d

$ docker run -d -p 80:80 my_image nginx -g 'daemon off;'

or

from 12.2k stars repo in Github

https://github.com/chatwoot/chatwoot/blob/develop/docker-compose.yaml#L89

    ports:
      - '5432:5432'

This mapping config means you will proxy all traffic from the container port to the docker host (your dev machine) with binding 0.0.0.0. It means if you don't have a firewall or accidently open all ports, your contaier data will be public in the Local Network (so danger if you use in public places like coffee shops)

So remember to add the IP, which you wanted to bind in docker host (or have a network firewall ON)

    ports:
      - '127.0.0.1:5432:5432'
      - '172.17.0.1:5432:5432'

By default, all docker container using DNS server from docker host, so if you want to overwrite the specific hostnames ip address, try the flag --add-host [hostname]:[ip]

$ docker run -it --add-host db1:1.2.3.4 --add-host db2:2.3.4.5 alpine cat /etc/hosts
127.0.0.1       localhost
::1     localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
1.2.3.4 db1
2.3.4.5 db2
172.17.0.2      0bdcf2fb2216

If you use docker-compose, then add the extra-hosts param below the service you want

    extra_hosts:
      - "crm.dev:host-gateway"
      - "db1:1.2.3.4"

Bonus : host-gateway mean the ip address of the gateway of network container in, often be the docker host!

Last day I updated my Laravel app from version 8 to 9, all my scheduled command in Console Kernel has run in another environment like "production". Which causes my system didn't work as expected.

Example, I have 2-3 enviroment which I run cronjob like

* * * * * php artisan schedule:run --env=hello
* * * * * php artisan schedule:run --env=world

But all sub scheduled commands has been run with "production" instead of "hello" or "world"

So this is my fix, I created a lambda function which pass current environment to the child command.

class Kernel extends ConsoleKernel
{
    protected function schedule(Schedule $schedule)
    {
        // Added 2 lines to get lamda function
        $env = app()->environment();
        $schedule_command = fn ($cmd) => $schedule->command($cmd, ['--env' => $env]);

        // Then schedule using new lambda function
        $schedule_command('check_product_stock')->everyTenMinutes();
        $schedule_command('run_job_queue')->everyMinute();
        $schedule_command('clean_old_data')->dailyAt('00:25');
    }

    protected function commands()
    {
        $this->load(__DIR__ . '/Commands');

        require base_path('routes/console.php');
    }
}

Enjoy ! :) Hope it works for you !

In case you use google/apiclient package to connect to Google API services, remember to cleaning unused services after deploying to production.

So let me show you why

First, lets counting number of classes of Google API services inside composer autoload classmap file (Composer use this file as a mapping to lazyload your needed class)

$ cat vendor/composer/autoload_classmap.php | grep 'Google' | wc -l
15436
$ du -h vendor/composer/autoload_classmap.php
3.5M    vendor/composer/autoload_classmap.php

As you can see, it has almost 15k classes having Google in class namespace. And your autoload_classmap.php has 3.5Mb in size (so large)

So, let cleaning unused services (by keeping only services you need)

Editing your composer.json file by adding "pre-autoload-dump" in scripts and "google/apiclient-services" in extra, like below (replace services you need like Drive, Youtube, Sheets, etc..)

{
    "scripts": {
        "pre-autoload-dump": "Google\\Task\\Composer::cleanup"
    },
    "extra": {
        "google/apiclient-services": [
            "Drive",
            "YouTube",
	    "Sheets"
        ]
    }
}

Finally, run composer dump-autoload again and see the result

$ cat vendor/composer/autoload_classmap.php | grep 'Google' | wc -l
383
$ du -m vendor/composer/autoload_classmap.php
1.3M    vendor/composer/autoload_classmap.php

Class map reduce from 15k to 400 lines, and size from 3.5M to 1.3M ! Such an optimize !

Beware : If you add services after cleaning, try to run rm -r vendor/google/apiclient-services && composer update to redownloading all services classes.

Laravel 9 uses "Spatie/Ignition" as default error handling pages , which is beatiful but bloated within add-on service like Flare.

So if you want to get back the good-old "Whoops" error pages, this tutorial is for you :D

First, we remove "spatie/ignition" from composer packages

$ composer remove "spatie/laravel-ignition"

Then, add 3 lines in the boot function of AppServiceProvider

use Illuminate\Contracts\Foundation\ExceptionRenderer;
use Illuminate\Foundation\Exceptions\Whoops\WhoopsExceptionRenderer;

class AppServiceProvider extends ServiceProvider {
    public function boot()
    {
        // Add 3 lines below between boot function
        if (config('app.debug')) {
            $this->app->bind(ExceptionRenderer::class, WhoopsExceptionRenderer::class);
        }
    }
}

And last but not least, open the config/app.php then add to this line to array config (try to replace the name of Editor you use in this list )

    ...
    'editor' => 'vscode'
    ...

Now try to add this line to second line in web.php route file to test

$x = 1 / 0;

By default, the document root of a domain in DirectAdmin (DA) has the format

/home/[your_username]/domains/[your_domain]/public_html

But in case you have to run modern PHP app like Laravel or Symfony framework (they use child public directory as their docroot). In some case, using .htaccess file to rewrite is a hacky way to solve problem (or this is the option when you don't have Admin account of DA)

So, if you have an Admin account, try this

Open menu Server Manager > Custom HTTPD Configurations, then click on your domain httpd config file, then click CUSTOMIZE

In the large textbox, add this line (remind to replace username and domain) to

|?DOCROOT=/home/[your_username]/domains/[your_domain]/public_html/public|

Click SAVE to save modification. Then go to Service Monitor and reload your webservers (Nginx, Apache or OpenLiteSpeed)

Yo! Back to my #TIL

Today, I find out a way to insert fastly current date or current time to a cell. It makes you faster 3-5 seconds and reduce confusing about what the time is?

• To insert current date : press Ctrl + :
• To insert current time : press Ctrl + Shift + :

Excel (Spreadsheets) never dies !

TLDR;

Use JSON.parse("[your data in json string]") if your data is big (>10KB for instance)

Short Explaination :

JSON.parse parses a string to object, so it has many strict requirements than Javascript parses the source code (more syntax, more context)

Long Explaination :

https://www.youtube.com/watch?v=ff4fgQxPaO0

NGINX is well known as a simple and good web server right now, but not everyone knows that NGINX can act like a TCP-UDP loadbalancer. So you won't need to install HAProxy when you need a LoadBalancer.

This feature is released on NGINX 1.9+. So you can setup it by this rule

stream {
	upstream backend1 {
		server s1.backend1.com:12345;
		server s2.backend1.com:12345;
	}
	server {
		listen 54321;
		proxy_pass backend1;
	}
	upstream backend2 {
		server s1.backend2.com:7777;
		server s2.backend2.com:7777;
		server s3.backend2.com:7777;
	}
	server {
		listen 8888 udp; # add udp keyword if you want UDP server
		proxy_pass backend2;
	}
}

To learn more, click here : https://docs.nginx.com/nginx/admin-guide/load-balancer/tcp-udp-load-balancer/

Sometimes, you ran into issues that apt update package list so slow or even can not connect to the destination server.

You can change the default list into new one near your country. Get example : if you live in ASIA, choose the Singapore or Japan mirror instead of main mirror. you just change the "archive.ubuntu.com" and "security.ubuntu.com" to "[country_code].archive.ubuntu.com" in file list /etc/apt/sources.list

Then run sudo apt update to test your new mirror :)

TIP : you can generate the new source list file based on this online tool : https://repogen.simplylinux.ch/generate.php

As default, docker runs your container as root user (uid=0). Although docker isolates your filesystem to protect docker host, but running processes as root is redundant and increasing attacking surface. Even it can make its written files having root owner, which can mess your docker-host filesystem permission.

This is example that show docker runs as root

$ docker run --rm alpine sleep 30

and open another terminal to check this

$ ps xau | grep 'sleep'
khanhic+ 15552  0.5  0.4 1264452 49280 pts/1   Sl+  17:37   0:00 docker run --rm alpine:3.9 sleep 30
root     15610  0.6  0.0   1520     4 ?        Ss   17:37   0:00 sleep 30
khanhic+ 15876  0.0  0.0  23076  1024 pts/2    S+   17:37   0:00 grep --color=auto sleep

You can see that the process sleep 30 is running as root with pid = 15610

To control which user docker container runs as, you can use the --user [userid]:[groupid] argument

Example

$ docker run --rm --user 1000:1000 alpine sleep 30

Then you will get this result

$ ps xau | grep 'sleep'
khanhic+ 16275  2.0  0.4 1411916 50124 pts/1   Sl+  17:41   0:00 docker run --rm --user 1000:1000 alpine:3.9 sleep 30
khanhic+ 16336  1.5  0.0   1520     4 ?        Ss   17:41   0:00 sleep 30
khanhic+ 16403  0.0  0.0  23076   984 pts/2    S+   17:41   0:00 grep --color=auto sleep

TIP : you can set a environment variable by add this line to ~/.bash_profile or ~/.bashrc

export DOCKER_UID="$(id -u ${USER}):$(id -g ${USER})"`

then use docker command like docker run --user $DOCKER_UID ....

When you use a load balancer stay in front of your app, and use SSL Passthrough mode. You will never get real IP of client, because Load balancer works like a TCP load balancer, which means it can not add extra HTTP headers into encrypted traffic from client when it doesn't handle SSL termination.

So if you use 1 domain or wildcard subdomains, it's better if you use SSL Termination mode.

To export data from MySQL by specified query to CSV file, you can use this command

$ mysql -B -u username -p database_name -h dbhost -e "SELECT * FROM table_name;" | sed "s/'/\'/;s/\t/\",\"/g;s/^/\"/;s/$/\"/;s/\n//g"

Tip from : https://stackoverflow.com/a/25427665

To run a shell command in all hosts, you can use the module name raw and provide shell command to module args.

Example:

• To list all CPU model name of hosts

$ ansible all -m raw -a "cat /proc/cpuinfo | grep 'model name'"

Alpine linux becomes the most base image for docker images because it's lightweight and handful package manager apk. Sometimes, you create an image that downloads the binary file but can not execute it. It shows something like this:

/entrypoint.sh: line ***: [your binary]: not found

The problem is your binary built within shared libraries, so it can't run without shared libraries dependencies. To findout which libraries is missing, use this

$ ldd [your binary path]

This is sample result

/usr/local/bin # ldd hugo
        /lib64/ld-linux-x86-64.so.2 (0x7fa852f2a000)
        libpthread.so.0 => /lib64/ld-linux-x86-64.so.2 (0x7fa852f2a000)
Error loading shared library libstdc++.so.6: No such file or directory (needed by hugo)
        libdl.so.2 => /lib64/ld-linux-x86-64.so.2 (0x7fa852f2a000)
        libm.so.6 => /lib64/ld-linux-x86-64.so.2 (0x7fa852f2a000)
Error loading shared library libgcc_s.so.1: No such file or directory (needed by hugo)
        libc.so.6 => /lib64/ld-linux-x86-64.so.2 (0x7fa852f2a000)

So we need to install libstdc++ and libc6-compat before run the binary

RUN apk add --no-cache libstdc++ libc6-compat

Sometimes you want to manipulate the HTML DOM elements inside as a string, then you found a lot of HTML parser or DOM library from the Internet (but it supports only NodeJS). How to do it in a browser ?

The answer is "jQuery is your best friend in browser environment" :)

Then you try this :

const content = jQuery('<p><strong>Hello</strong></p><p>from</p><p><strong>KhanhIceTea</strong></p>');
content.find('p > strong').each(function(i, ele) {
    $(ele).css('color', 'red');
});
console.log(content.html());

What you expected

<p><strong style="color: red;">Hello</strong></p><p>from</p><p><strong style="color: red;">KhanhIceTea</strong></p>

But the console print

<strong>Hello</strong>

SURPRISE !?? JQUERY SUCKS ?

Nope ! The reason is simple, DOM data structure is a tree. And, any tree has a root, right ??? Now you understand the problem ? Then we fix it below

const html_content = '<p><strong>Hello</strong></p><p>from</p><p><strong>KhanhIceTea</strong></p>';
// Wrap all elements into one root element (div)
const content = jQuery('<div />').append(html_content);
// or const content = jQuery('<div>' + html_content + '</div>');
content.find('p > strong').each(function(i, ele) {
    $(ele).css('color', 'red');
});
console.log(content.html());

When you need to debug the docker host of your docker server inside macOS. You can connect to its tty screen by

$ screen ~/Library/Containers/com.docker.docker/Data/vms/0/tty

Then type ENTER to enter the screen and start debugging docker host.

To disconnect the screen, press "Ctrl + A > Ctrl + " and confirm "yes".

If you are in console of developer tool and you want to know what the function does, you can view its source by:

1. call .toSource() of variable or function name in Firefox

Example :

>> function hello(name) { return "Hello " + name; }

>> hello.toSource();
<- "function hello(name) { return \"Hello \" + name; }"

2. click 'show function definition' in Chrome

Cron is a UNIX service that helps user run command periodically. And crontab is simple tool to setup cron job as user, just type in the command crontab -e then setup your cron schedule.

Btw, sometimes you want to run the cronjob every seconds (5, 10 or 20 seconds), but crontab only support every minute. How to achieve your goal without using another tool ?

I got an idea that we can use the sleep command to make it done. So this is solution.

This below is crontab rule that run command every 10 seconds.

* * * * * [command]
* * * * * sleep 10 && [command]
* * * * * sleep 20 && [command]
* * * * * sleep 30 && [command]
* * * * * sleep 40 && [command]
* * * * * sleep 50 && [command]

It's simple, right ? ;)

I often use telnet and netcat to debug my TCP server and client. But these tool only support plain connection, mean every data transfer between server and client is unencrypted and unsafe.

So if you want to achieve the same result through secure connection (SSL or TLS), use this command

$ openssl s_client -host example.com -port 443
$ # or short syntax
$ openssl s_client -connect example.com:443

I made a function named telnets in .bash_profile to make it easier to use

function telnets() {
	openssl s_client -host "$1" -port "$2"
}

then I just type this on bash shell within same syntax of telnet

$ telnets github.com 443

TIP: To hide detail of certificates, add -quiet flag into command

More info, check openssl s_client -h

Today my team met a weird bug on Safari browsers (on all Apple devices), that input losts its focus after you type first character.

First, we thought it's javascript bug so we wasted a lot of time for debugging the behaviour of input. But nothing works !

So we continued searching on Google, then we found this wonderful answer

The root issues caused by one CSS overrided -webkit-user-select to none, so we have to prevent it by add this line to end of CSS file

input, input:before, input:after {
	-webkit-user-select: initial !important;
	-khtml-user-select: initial !important;
	-moz-user-select: initial !important;
	-ms-user-select: initial !important;
	user-select: initial !important;
} 

Hope it helpful for you next time ! :D

Time before, I often meet the situation that I forgot the parameters pass to a function (so I have to searching the API docs to read via Google). This progress can take you huge time if it repeats many times.

So I think one way to debug the parameters without reading API docs, that is pass console.log as a callback function parameter.

Examples :

[3,9,27].forEach(console.log);
// So you will get
// 3 0
// 9 1
// 27 2
// Then you know , first parameter is item, second parameter is indexed key

jQuery.ajax('/data.json').done(console.log).fail(console.error);

Sometimes, you have a interval timer to retrieve new data updates from AJAX requests. But even the response status code of response is 304 (no body), the browser will treat it as 200 response and copy the cached body from browser cache to response body. So it will trigger the re-rederning UI components.

The way we can detect it is via its response headers list.

This example is using fetch API (which is supported in major browsers nowaday)

fetch('https://some.thing/has/data')
.then(function (res) {
	if (res.headers.get('status') == '304 Not Modified') {
		return null;
	}
	return res.json();
})
.then(function (data) {
	if (data == null) return;

	// Render your data below
	renderUI(data);
});