Programming - My Awesome Moments

WordPress Error Establishing A Database Connection

Suddenly this morning around 11AM, 16th August 2021, my awesomegrasp.com is not reachable with error message of error establishing a database connection.

From cPanel, I check my database is still up and running.
Database username and password is correct.
My other website is still running (means my hosting is up and running as it i shared hosting).

Error Explanation at wp-admin

I go to wp-admin and the page said one of the tables is broken and to fix it I need to enable below code at wp-configs.php:

define('WP_ALLOW_REPAIR', true);

1	define('WP_ALLOW_REPAIR', true);

wordpress error establishing a database connection - wp allow repair — wordpress error establishing a database connection – wp allow repair

Run Repair Tables

After enabled WP_ALLOW_REPAIR, I run repair tables.

wordpress error establishing a database connection - repair database — wordpress error establishing a database connection – repair database

WordPress List Down The Repair Status

wordpress error establishing a database connection - database repair results — wordpress error establishing a database connection – database repair results

Remove WP_ALLOW_REPAIR

After remove WP_ALLOW_REPAIR, my website is up again.

My worry whether this is possible hacks in my wordpress installation.

Chart.js version 3.5 Examples

I was using Chart.js v2++ for quite some time, and I found it difficult to migrate to version 3.5 as lack of examples.

So I created JS Fiddle to ease the development using Chart.js version 3.5.

I created examples on

Line Chart – Multi Axis
Combo Bar & Line Chart – Multi Axis
Radar Chart

You can easily understand from the JS Fiddle on the chart data and options.

Line Chart – Multi Axis

chart js version 3.5 lines chart multi axis

JSFiddle – Line Chart Multi Axis

Combo Bar & Line Chart – Multi Axis

JSFiddle – Combo Bar & Line Chart – Multi Axis

Radar Chart

JSFiddle – Radar Chart

Python Circular Import Error if Import CSV or Pandas read_csv

I faced issue of circular import error when import CSV or pandas to read cvs file.
My python file name is csv.py

To rectify this is very easy. Ensure your file name is not CSV. If file name is CVS it will cause circular import.

Circular Import when file name is csv.py

python import csv or pandas cause circular import

No more circular import error when file name change to csv-reader.py

python import csv or pandas caused circular import if file name is csv

NodeJS How To Have Unique Array of Objects

I want to have unique array of objects. So if I add an object, any objects which have same values won’t be added twice.
So I try use Set() data structure.

Adding Object directly to Set()

const d1 = {ID: 1, distance: 2}
const d2 = {ID: 1, distance: 3}
const d3 = {ID: 1, distance: 2}

const set1 = new Set()
set1.add(d1)
set1.add(d2)
set1.add(d3)

console.log("size set1: ", set1.size)

for(const item of set1.values()){
    console.log("item ", item)
}

const d1 = {ID: 1, distance: 2}

const d2 = {ID: 1, distance: 3}

const d3 = {ID: 1, distance: 2}

const set1 = new Set()

set1.add(d1)

set1.add(d2)

set1.add(d3)

console.log("size set1: ", set1.size)

for(const item of set1.values()){

console.log("item ", item)

}

Output

[LOG]: "size set1: ",  3 
[LOG]: "item ",  {
  "ID": 1,
  "distance": 2
} 
[LOG]: "item ",  {
  "ID": 1,
  "distance": 3
} 
[LOG]: "item ",  {
  "ID": 1,
  "distance": 2

[LOG]: "size set1: ", 3

[LOG]: "item ", {

"ID": 1,

"distance": 2

}

[LOG]: "item ", {

"ID": 1,

"distance": 3

}

[LOG]: "item ", {

"ID": 1,

"distance": 2

Conclusion:

As you can see, the Set result is 3. It should be 2. So it doesn’t work

Adding a stringify Object to Set()

const d1 = {ID: 1, distance: 2}
const d2 = {ID: 1, distance: 3}
const d3 = {ID: 1, distance: 2}


const set2 = new Set()
set2.add(JSON.stringify(d1))
set2.add(JSON.stringify(d2))
set2.add(JSON.stringify(d3))

console.log("size set 2: ", set2.size)

for(const item of set2.values()){
    console.log("item ", item)
}

const d1 = {ID: 1, distance: 2}

const d2 = {ID: 1, distance: 3}

const d3 = {ID: 1, distance: 2}

const set2 = new Set()

set2.add(JSON.stringify(d1))

set2.add(JSON.stringify(d2))

set2.add(JSON.stringify(d3))

console.log("size set 2: ", set2.size)

for(const item of set2.values()){

console.log("item ", item)

}

Output:

[LOG]: "size set 2: ",  2 
[LOG]: "item ",  "{"ID":1,"distance":2}" 
[LOG]: "item ",  "{"ID":1,"distance":3}"

[LOG]: "size set 2: ", 2

[LOG]: "item ", "{"ID":1,"distance":2}"

[LOG]: "item ", "{"ID":1,"distance":3}"

Conclusion:

The Set size is 2 with no duplicate values.

Overall Conclusion

So you can use Set but first stringifiy the objects than convert back the string to object by using JSON.parse() function

You can try thecoding yourself here:
Typescript Playground

Git Command For Initial Push

Useful Git commands for initial push.

In below example I use <https://gitlab.com/lvlaxpt/to-delete.git>. So change this to your Git URL.

Git global setup

git config --global user.name "your@mail.com"
git config --global user.email "your@mail.com"

1 2	git config --global user.name "your@mail.com" git config --global user.email "your@mail.com"

Create a new repository

git clone https://gitlab.com/lvlaxpt/to-delete.git
cd to-delete
touch README.md
git add README.md
git commit -m "add README"
git push -u origin master

git clone https://gitlab.com/lvlaxpt/to-delete.git

cd to-delete

touch README.md

git add README.md

git commit -m "add README"

git push -u origin master

Push an existing folder

cd existing_folder
git init
git remote add origin https://gitlab.com/lvlaxpt/to-delete.git
git add .
git commit -m "Initial commit"
git push -u origin master

cd existing_folder

git init

git remote add origin https://gitlab.com/lvlaxpt/to-delete.git

git add .

git commit -m "Initial commit"

git push -u origin master

Push an existing Git repository

cd existing_repo
git remote rename origin old-origin
git remote add origin https://gitlab.com/lvlaxpt/to-delete.git
git push -u origin --all
git push -u origin --tags

cd existing_repo

git remote rename origin old-origin

git remote add origin https://gitlab.com/lvlaxpt/to-delete.git

git push -u origin --all

git push -u origin --tags

Pull From Existing Repository

cd existing_folder
git init
git remote add origin https://gitlab.com/lvlaxpt/to-delete.git
git pull origin master

cd existing_folder

git init

git remote add origin https://gitlab.com/lvlaxpt/to-delete.git

git pull origin master

Godot MultiPlayer Lobby Tutorial Part 1

I want to do a multiplayer games but it is hard to really understand how it works.

I did refer the official tutorial from Godot here. but I still can’t understand it then I read the code example of multiplayer bomber.

From the multi player bomber, I just extracted when a lobby is created by Host and then a Player joins the lobby.

I did this to simplify the GDScript so I can focus on understanding its inner working.

Besides I add additional print() to see which function is called first and understand their sequence. To know the sequence I added timestamp when the function is called.

Example:

print("game state - register player() ", id, " time stamp: ", OS.get_system_time_msecs())

1	print("game state - register player() ", id, " time stamp: ", OS.get_system_time_msecs())

I also rearrange the scripts into different folder to reflect its purposes and change gamestate.gd to GameState.gd

Print at Critical Functions To Detect Functions Calling Sequence

scripts/global/GameState.gd

print(“game state – connected_ok()”, ” time stamp: “, OS.get_system_time_msecs())
print(“game state – player connected(). ID: “, id, ” time stamp: “, OS.get_system_time_msecs())
print(“game state – register player() “, id, ” time stamp: “, OS.get_system_time_msecs())

scripts/lobby/lobby.gd

print(“game state – register player() “, id, ” time stamp: “, OS.get_system_time_msecs())
print(“lobby – refresh_lobby() Players: “, players, ” time stamp: “, OS.get_system_time_msecs())
print(“lobby – _on_connect_success()”, ” time stamp: “, OS.get_system_time_msecs())

A Player Joins As Host @ Server

When a player joins as host, below is the print output.

Launch The Application

Run the application via command line (I’m using Linux)
Then click Host

Godot Multiplayer Lobby - starting game — Godot Multiplayer Lobby – starting game

Host / Server output:

As you can see, no network signals (network_peer_connected & connected_to_server) are emitted during the network server connections.

Godot Multiplayer Lobby - print output — Godot Multiplayer Lobby – print output

A Player Joins as Client

When a player joins as client, below is the print output.

Godot Multiplayer Lobby - starting as player @ client — Godot Multiplayer Lobby – starting as player @ client

Host / Server output:

Godot Multiplayer Lobby - server print output when a player joins as client — Godot Multiplayer Lobby – server print output when a player joins as client

Player / Client output:

Godot Multiplayer Lobby - print output as player @ client — Godot Multiplayer Lobby – print output as player @ client

Print Output Timestamp Sequence

I rearrange the print out timestamp based on which comes first. Below is the result.

CLIENT
game state - player connected(). ID: 1 time stamp: 1618724339580 - netwoork (rpc to register player())
game state - connected_ok() time stamp: 1618724339580 - emit connection succeed 
lobby - _on_connect_success() time stamp: 1618724339580- from signal connection_succeed connect  hide 

SERVER
game state - player connected(). ID: 741208717 time stamp: 1618724339596 - netwoork (rpc to register player())
game state - register player() 741208717 time stamp: 1618724339597 - emit "player_list_changed
lobby -  refresh_lobby() Players: [p2] time stamp: 1618724339597

CLIENT
game state - register player() 1 time stamp: 1618724339613
lobby -  refresh_lobby() Players: [wanrazali] time stamp: 1618724339613

CLIENT

game state - player connected(). ID: 1 time stamp: 1618724339580 - netwoork (rpc to register player())

game state - connected_ok() time stamp: 1618724339580 - emit connection succeed

lobby - _on_connect_success() time stamp: 1618724339580- from signal connection_succeed connect hide

SERVER

game state - player connected(). ID: 741208717 time stamp: 1618724339596 - netwoork (rpc to register player())

game state - register player() 741208717 time stamp: 1618724339597 - emit "player_list_changed

lobby - refresh_lobby() Players: [p2] time stamp: 1618724339597

CLIENT

game state - register player() 1 time stamp: 1618724339613

lobby - refresh_lobby() Players: [wanrazali] time stamp: 1618724339613

Notes:
The timestamp here differs from screenshots as I did this article in few days, hence the difference in timestamps.

Sequence Diagram

From the “Print Output Timestamp Sequence”, I developed the sequence diagram for better visualization.

Key Take Aways

A put “remote” if the function is called by rpc_id() or any functions called via rpc
Functions within the same entity e.g Client or Server are executed first.
Function called via rpc() is executed after all functions within same entity is executed.
Even function triggered via emit signal is executed first before rpc()

Resources:

Sample code

I want to do a simple board game. Lots of things, I don’t really understand, example the input events. I read the Godot documentation on Input Event but they didn’t provide any project example besides the code.

For beginner, it is not straight forward. So I share the project Input Event example based on the Godot documentation example.

Steps To Do

1. Create Godot Project

2. Create New Input Map

– Click Project -> Project Settings

– Choose Input Map tab

– Find ui_right and choose the right key on your keyboard
– Then click OK
– Do the same with ui_left

3. Test it, by pressing the keys on your game.

– The text will appear on the output screen

godot - output screen — godot – output screen

Add Custom Input Map – Mouse Left Button Click

1. Go to project -> Project Settings

2. Type ui_mouse_left_button_click (you can give any name)

godot - add new input map — godot – add new input map

3. Click Add

4. Add left button event to the Input Map

godot - mouse left button click input map — godot – mouse left button click input map

godot – added mouse left button click

Godot 3.2.3 Inheritance GDScript Call Parent Function

Lets say you want to have two GDscripts where the ChildScript.gd will call ParentScript.gd.

From there, you want the ChildScript.gd to call its parent function.

Create Class Inheritance

You first create inheritance in GDScript by calling “extends”.

extends "res://gdscript-filename.gd"

#example
extends "res://Parent.gd"

extends "res://gdscript-filename.gd"

#example

extends "res://Parent.gd"

Call Parent Function . Use dot “.” to call parent function

#function example, where child calls parent function
.getText()

1 2	#function example, where child calls parent function .getText()

Download Godot Project Example

In this example, when “Press Me” button is clicked. The label will change to “Parent Child” where “Parent” is return value from parent function while child is from child function.

godot-3-2-3 inheritance call parent function

You can download here the project example.

Godot Button Signal Tutorial

I’m still new to games development using Godot engine.

I follow the button signal tutorial on Godot website. I created the project for easy reference for others because at the website they don’t provide the Godot project that you can immediately play.

Full GDScript from the tutorial

# Declare member variables here. Examples:
# var a = 2
# var b = "text"


# Called when the node enters the scene tree for the first time.
func _ready():
	#pass # Replace with function body
	get_node("Button").connect("pressed", self, "_on_Button_pressed")


# Called every frame. 'delta' is the elapsed time since the previous frame.
#func _process(delta):
#	pass


func _on_Button_pressed():
	# pass # Replace with function body.
	get_node("Label").text = "HELLO!"

# Declare member variables here. Examples:

# var a = 2

# var b = "text"

# Called when the node enters the scene tree for the first time.

func _ready():

#pass # Replace with function body

get_node("Button").connect("pressed", self, "_on_Button_pressed")

# Called every frame. 'delta' is the elapsed time since the previous frame.

#func _process(delta):

# pass

func _on_Button_pressed():

# pass # Replace with function body.

get_node("Label").text = "HELLO!"

Download Godot Button Signal Project

You can download the button signal Godot project here, if you want to run the tutorial.

In case the button signal tutorial is broken link for what soever reasons, I have converted the web page into PDF.

Hope it helps beginner games developer like me.

PHP is not running after upgrade MacOS Big Sur on Apple Macbook Pro M1

Another problem I always face after upgrading MacOS where PHP is not running anymore. I have to google to find solution. Now I decided to write step by step tutorial so easy for my future reference and hopefully can help others who face the same thing.

1) My phpMyAdmin instead of showing login page, it displays its PHP code.

2) Uncomment PHP Module

Open httpd.conf

nano /etc/httpd.conf

1	nano /etc/httpd.conf

Find php by typing

ctrl + w and type php

1	ctrl + w and type php

Remove # to uncomment the PHP module.

Save the changes by typing

ctrl + x then type Y

1	ctrl + x then type Y

3) Restart Apache

sudo apachectl restart

1	sudo apachectl restart

4) Refresh the PHP page