Programming - My Awesome Moments

PHP Constant expression contains invalid operations new stdClass Error

I got this PHP error of “Constant expression contains invalid operations”.

This is due to a function variable default value of new stdClass()

public function add(string $name, object $contents = new stdClass()){
/*
function definition
*/
}

public function add(string $name, object $contents = new stdClass()){

function definition

}

This happens on PHP version 8.0.30 on my hosting server.

This errors doesn’t appear on my development laptop which is version 8.2.4.

Solution

I put “null” instead of “new stdClass()” and then set it to new stdClass if the variable is null.

public function add(string $name, object $contents = null){
if($contents == null):
   $contents = new stdClass();
endif;
/* function definition */ }

public function add(string $name, object $contents = null){

if($contents == null):

$contents = new stdClass();

endif;

/* function definition */ }

OpenCV findContours – What it is?

OpenCV findContours detects change in the image color and marked it as contour.

In this example using archery target face, findContours detects the outer circle, yellow circle, bullseye circle, logos on top left and bottom left.

In this case, findContours doesn’t detect the red circle contour.

The Original Image

The Image Gray

The Find Contours Image

Green color is the contours found on the image.

opencv findcontours on archery target face

The OpenCV Python Code

import os
import cv2 as cv
import numpy as np
import matplotlib.pyplot as plt


def findContours():
    root = os.getcwd()
    imgPath = os.path.join(root, 'images/target.jpg')
    img = cv.imread(imgPath)
    #change to GRAY to easily detect the contours
    imgGray = cv.cvtColor(img, cv.COLOR_BGR2GRAY)

    ret, thresh = cv.threshold(imgGray, 127, 255, 0)
    contours, hierarchy = cv.findContours(thresh, cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE)


    imgContours = cv.drawContours(img, contours, -1, (0,255,0), 3)

    plt.figure()
    plt.subplot(121)
    plt.imshow(imgContours)
  
    plt.show()

    

if __name__ == '__main__':    
    print("Start")
    findContours()

import os

import cv2 as cv

import numpy as np

import matplotlib.pyplot as plt

def findContours():

root = os.getcwd()

imgPath = os.path.join(root, 'images/target.jpg')

img = cv.imread(imgPath)

#change to GRAY to easily detect the contours

imgGray = cv.cvtColor(img, cv.COLOR_BGR2GRAY)

ret, thresh = cv.threshold(imgGray, 127, 255, 0)

contours, hierarchy = cv.findContours(thresh, cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE)

imgContours = cv.drawContours(img, contours, -1, (0,255,0), 3)

plt.figure()

plt.subplot(121)

plt.imshow(imgContours)

plt.show()

if __name__ == '__main__':

print("Start")

findContours()

Conclusion

findContours is an easy way to automatically detect an image shape or outline.

References:

OpenCV Python Image Perspective Transform

I wanted to learn OpenCV Perspective Transform. Tutorials that I found on the internet bit complex for me to really understand what it is all about. I have to read few tutorials before really understand it.

In layman term, perspective transform is taking a rectangle area from original image and re-project the cut rectangle to our defined size canvas.

To do this, you just need 4 corner pixel points and perspective transform will do all other pixels calculation automatically based on those 4 pixels points.

The Required Pixel Points

The corner pixels points must follow the order as shown in below image.

This is considered the source pixel points.

The destination points are where you want to re-project those source points into new plane.

The size of destination plane is:

width: 1000 pixels
height: 200 pixels

I just take the source rectangle width and height.

Image Used for the Perspective Transform

I used below image to do the perspective transform.

Code on Perspective Transform

Filename: Main.py

import os
import cv2 as cv
import numpy as np
import matplotlib.pyplot as plt

def perspectiveTransform():
    root = os.getcwd()
    imgPath = os.path.join(root, 'images/restaurant.png')
    img = cv.imread(imgPath)
    img = cv.cvtColor(img, cv.COLOR_BGR2RGB)
   
    src = np.array([[477,539], [1476,748], [428,786], [1520,905]], dtype=np.float32)

    width = 1000
    height = 200

   
    dest = np.array([[0,0], [width,0], [0,height], [width,100]], dtype=np.float32)
    
    transformation = cv.getPerspectiveTransform(src, dest)
    warpedImg = cv.warpPerspective(img, transformation, (width, height))


    plt.figure()
    plt.subplot(121)
    plt.imshow(img)
    plt.plot(src[:,0], src[:,1], 'r.')

    plt.subplot(122)
    plt.imshow(warpedImg)
    plt.plot(dest[:,0], dest[:,1], 'r.')
    plt.show()

    

if __name__ == '__main__':    
    print("Start")
    perspectiveTransform()

import os

import cv2 as cv

import numpy as np

import matplotlib.pyplot as plt

def perspectiveTransform():

root = os.getcwd()

imgPath = os.path.join(root, 'images/restaurant.png')

img = cv.imread(imgPath)

img = cv.cvtColor(img, cv.COLOR_BGR2RGB)

src = np.array([[477,539], [1476,748], [428,786], [1520,905]], dtype=np.float32)

width = 1000

height = 200

dest = np.array([[0,0], [width,0], [0,height], [width,100]], dtype=np.float32)

transformation = cv.getPerspectiveTransform(src, dest)

warpedImg = cv.warpPerspective(img, transformation, (width, height))

plt.figure()

plt.subplot(121)

plt.imshow(img)

plt.plot(src[:,0], src[:,1], 'r.')

plt.subplot(122)

plt.imshow(warpedImg)

plt.plot(dest[:,0], dest[:,1], 'r.')

plt.show()

if __name__ == '__main__':

print("Start")

perspectiveTransform()

To run the program, type at the terminal

python3 Main.py

1	python3 Main.py

Folder Structure:

Reference

OpenCV Perspective Transform Youtube

How To Install WordPress in Docker using Docker Compose

I follow How to install WordPress in Docker Tutorial and found it has error in its docker-compose.yml file. Besides, it didn’t tell how to access phpMyAdmin and WordPress.

I am completely newbie on Docker so it took me time to really understand.

For that reason, I copy the tutorial and improve and simplify it. So it is easier for newcomer to Docker.

How To Install WordPress in Docker Using Docker Compose?

Create a folder for your project

mkdir dockerwordpress

1	mkdir dockerwordpress

Create a docker-compose.yml file inside your folder

touch docker-compose.yml

1	touch docker-compose.yml

Copy this Configuration to Your docker-compose.ymlversion: '3.9'

services:
  mysql:
    image: mysql:8.0
    volumes:
      - mysql_data:/var/lib/mysql
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: root
      MYSQL_DATABASE: wordpress
      MYSQL_USER: wordpress
      MYSQL_PASSWORD: wordpress

  phpmyadmin:
    image: phpmyadmin/phpmyadmin
    depends_on:
      - mysql
    environment:
      PMA_HOST: mysql
      PMA_PORT: 3306
      PMA_ARBITRARY: 1
    restart: always
    ports:
      - 8183:80

  wordpress:
    depends_on:
      - mysql
    image: wordpress:latest
    ports:
      - "8020:80"
    restart: always
    environment:
      WORDPRESS_DB_HOST: mysql:3306
      WORDPRESS_DB_USER: wordpress
      WORDPRESS_DB_PASSWORD: wordpress
      WORDPRESS_DB_NAME: wordpress
    volumes:
      - ./wordpress:/var/www/html

volumes:
  mysql_data: {}

Copy this Configuration to Your docker-compose.ymlversion: '3.9'

services:

mysql:

image: mysql:8.0

volumes:

- mysql_data:/var/lib/mysql

restart: always

environment:

MYSQL_ROOT_PASSWORD: root

MYSQL_DATABASE: wordpress

MYSQL_USER: wordpress

MYSQL_PASSWORD: wordpress

phpmyadmin:

image: phpmyadmin/phpmyadmin

depends_on:

- mysql

environment:

PMA_HOST: mysql

PMA_PORT: 3306

PMA_ARBITRARY: 1

restart: always

ports:

- 8183:80

wordpress:

depends_on:

- mysql

image: wordpress:latest

ports:

- "8020:80"

restart: always

environment:

WORDPRESS_DB_HOST: mysql:3306

WORDPRESS_DB_USER: wordpress

WORDPRESS_DB_PASSWORD: wordpress

WORDPRESS_DB_NAME: wordpress

volumes:

- ./wordpress:/var/www/html

volumes:

mysql_data: {}

Run The Docker WordPress Installation

Run Docker Compose Command Same Location as Your docker-compose.yml

docker-compose up -d

1	docker-compose up -d

docker - wordpress run compose up — docker – wordpress run compose up

Access WordPress

http://localhost:8020/

1	http://localhost:8020/

Run the usual WordPress Installation

Database Configuration:

Database name: wordpress
Username: wordpress
Password: wordpress

Testing Your WordPress Installation in Docker

Check at phpMyAdmin

http://localhost:8183/

1	http://localhost:8183/

Server: <leave it empty>
Username: WordPress
Password: WordPress

docker phpmyadmin username and password wordpress

Check Inserted Data

docker - new post successfully inserted in database — docker – new post successfully inserted in database

Last Note

With this docker-compose configuration you can’t access to your local file system. So this another thing I need to find the solution.

Python Unit Test Error: AttributeError has no attribute test

I got AttributeError: has no attribute ‘test’ when I run python unit test.

The cause of the error is due to file naming that has ‘filename.test.py’. So I change into test_filename.py then it works!

wan@Wans-MacBook-Pro-2 python % python3 -m unittest post_request.test.py
E
======================================================================
ERROR: test (unittest.loader._FailedTest.test)
----------------------------------------------------------------------
AttributeError: module 'post_request' has no attribute 'test'

----------------------------------------------------------------------
Ran 1 test in 0.000s

FAILED (errors=1)

wan@Wans-MacBook-Pro-2 python % python3 -m unittest post_request.test.py

======================================================================

ERROR: test (unittest.loader._FailedTest.test)

----------------------------------------------------------------------

AttributeError: module 'post_request' has no attribute 'test'

----------------------------------------------------------------------

Ran 1 test in 0.000s

FAILED (errors=1)

Import SQL File into MySQL in XAMPP from Command Line in MacOS

To import SQL file in XAMPP MySQL, first has to go to XAMPP MySQL bin then do the command standard Mysql import command line.

XAMPP Path in MacOS

/Applications/XAMPP/bin

1	/Applications/XAMPP/bin

Command in Terminal

./mysql -u <username> -p <database_name> < <sql_file>

1	./mysql -u <username> -p <database_name> < <sql_file>

Example:

./mysql -u wanrazali -p property_price_trends < /Users/wanrazalimatsah/Downloads/Original/hd_postmeta.sql

1	./mysql -u wanrazali -p property_price_trends < /Users/wanrazalimatsah/Downloads/Original/hd_postmeta.sql

Selenium – This version of ChromeDriver only supports Chrome version error on Ubuntu for version higher than 114

I use Selenium web driver to scrap some website data that I need for my property analysis. In this case I use chromedriver.

When I want to run it after I upgraded my Chrome browser on Ubuntu I found this error.

This version of ChromeDriver only supports Chrome version 114

1	This version of ChromeDriver only supports Chrome version 114

My steps to resolve this

1) Check my Chrome browser version and found it is 123.

2) Check my chromedriver version by typing

chromedriver --v

1	chromedriver --v

I found my version is 114 not same as my browser.

3) Check the location of the chrome driver by typing

echo $PATH

1	echo $PATH

In my case I found my chrome driver at /usr/local/sbin

4) Download the latest chromedriver at

Google Chrome Driver for version after version 114

5) After extracting the latest chromedriver, replace the old one.

Ensure you download the right chrome driver which is highlighted in blue.

mv [latest chromedriver file] [location of current chromedriver]

1	mv [latest chromedriver file] [location of current chromedriver]

Then when I run back my program, it works!

Access XAMPP 8.2.4 MySQL via Command Line in MacOS

You can access XAMPP 8.2.4 MySQL via command line in MacOS by following these steps.

1. Go to XAMPP 8.2.4 MySQL folder in MacOS

/Applications/XAMPP/xamppfiles/bin/

1	/Applications/XAMPP/xamppfiles/bin/

2. Type This Command

./mysql -u username -p

1	./mysql -u username -p

If successful, XAMPP will connect to MariabDB instead of MySQL

You can double check by getting all databases in the MariaDB.

show databases;

1	show databases;

macos xampp 8.2.4 mysql access via command line

Typescript Factory Pattern without Switch or If Else

Factory pattern is a well known creator pattern. Problem with factory pattern is whenever there is a new concrete class that will be instantiate by the creator class (that have factory method), you have to add new ‘case’ in a switch or if / else.

So this violate the Open Close Principle which states open for extensions but close for modifications.

Code below using typescript, but the concept is same for other programming language.

Factory Pattern with Switch or If Else

 public static create(shape: string): Shape{
        switch(type){
            case 'circle':
                return new Circle();

            case 'rectangle':
                return new Rectangle();

            case 'triangle':
                return new Triangle()
                       
            default:
                throw Error(`Shape is not supported`);

        }
   }

public static create(shape: string): Shape{

switch(type){

case 'circle':

return new Circle();

case 'rectangle':

return new Rectangle();

case 'triangle':

return new Triangle()

default:

throw Error(`Shape is not supported`);

}

If you want to add Square shape, we need to add another case in the factory.

case 'square': 
  return new Square()

1 2	case 'square': return new Square()

The concept is the same with If Else

So I need to open my factory class every time there is a new shape to be add in.

Factory Pattern without Switch & If / Else

There are 3 main classes

1) Factory class
– it will import the shape class files in the folder /shapes
– instantiate the object based on shape type

2) Shape abstract class
– abstract method of getType()

3) Shape concrete class
– implement the getType() to tell what type is the shape e.g round
– located in /shapes folder

The concrete class Shape will implement a function to tell it is what kind of Shape.

class abstract Shape{
    public abstract getType(): string;
}

class Round extends Shape{
    public getType(): string{
        return 'round'
    }
}

class abstract Shape{

public abstract getType(): string;

}

class Round extends Shape{

public getType(): string{

return 'round'

}

The factory class will import all the shape file path and instantiate the object when call by user class.

import * as fs from 'fs';
import * as path from 'path';

/** Class representing a FieldFactory. 
*/
export default class ShapeFactory{

    private static instance: ShapeFactory;
    private fieldTypeClass: Map<string, string>;

    constructor(){
        this.fieldTypeClass = new Map<string, string>();
    }

    //i use singleton to load once the file paths
    public static async getInstance(): Promise<ShapeFactory>{
        if (!this.instance) {
            this.instance = new ShapeFactory();
            await this.instance._loadFieldPaths();
        }

        return this.instance;          
    }

    public async create(type: string): Promise<Shape>{

            if(!this.fieldTypeClass.has(type)){
                throw Error(`Shape is not supported.`)
            }
    
            const filenameFilePath = this.fieldTypeClass.get(type);

            const main = await import(filenameFilePath);
            
            //instantiate new shape
            return new main.default();
    }

    protected async _loadFieldPaths(){
        const directoryPath = path.join(__dirname, 'fields');
       
        const fileNames = fs.readdirSync(directoryPath);

        for(const fileName of fileNames){
            const main = await import(directoryPath + '/' + fileName);
            const app = new main.default();
            // console.log('type ', app.getType())
            this.fieldTypeClass.set(app.getType(), directoryPath + '/' + fileName);
 
        }
    } 
   
}//class

import * as fs from 'fs';

import * as path from 'path';

/** Class representing a FieldFactory.

export default class ShapeFactory{

private static instance: ShapeFactory;

private fieldTypeClass: Map<string, string>;

constructor(){

this.fieldTypeClass = new Map<string, string>();

}

//i use singleton to load once the file paths

public static async getInstance(): Promise<ShapeFactory>{

if (!this.instance) {

this.instance = new ShapeFactory();

await this.instance._loadFieldPaths();

}

return this.instance;

}

public async create(type: string): Promise<Shape>{

if(!this.fieldTypeClass.has(type)){

throw Error(`Shape is not supported.`)

}

const filenameFilePath = this.fieldTypeClass.get(type);

const main = await import(filenameFilePath);

//instantiate new shape

return new main.default();

}

protected async _loadFieldPaths(){

const directoryPath = path.join(__dirname, 'fields');

const fileNames = fs.readdirSync(directoryPath);

for(const fileName of fileNames){

const main = await import(directoryPath + '/' + fileName);

const app = new main.default();

// console.log('type ', app.getType())

this.fieldTypeClass.set(app.getType(), directoryPath + '/' + fileName);

}

}//class

How To Use It?

const round = await ShapeFactory.getInstance().create('round')

1	const round = await ShapeFactory.getInstance().create('round')

Impact

It requires async / await because needs to load dynamically the shape class.

This factory pattern can’t be used in a constructor.

How To Install PHP MySQL & Apache on MacOS Ventura on MacBook Pro M1

In my previous post, I was unable to install PHP & MySQL. This time after 2 years, I tried again but still fail, so I decided to use XAMPP to install PHP & MySQL and Apache on MacOS Ventura and it works!

But I had to disable default installed apache2 and change MySQL default port at XAMPP before MySQL and Apache2 can run on XAMPP.

How To Install PHP, MySQL & Apache using XAMPP

1. Download and install XAMPP

Mount the xampp dmg and run it. If you face unknown publish then do Control + Click on the XAMPP installer then run it again.

2. Follow the step by step instruction in installing XAMPP

Just follow the instructions.

3. Run the servers

If you unable to run the MySQL & Apache web server than follow below solution.

xampp macos ventura - mysql and apache webserver unable to start — xampp macos ventura – mysql and apache webserver unable to start

If you can run MySQL change it default ports. I use 3316 instead of default 3306.

xampp macos ventura - change the default port to 3316 — xampp macos ventura – change the default port to 3316

I tried to stop mysql service but MacOS informed no MySQL service was running. Only by changing MySQL default port it works.

xampp macos ventura - mysql not running — xampp macos ventura – mysql not running

If you can’t run the apache2 server, stop default apache2 server by typing at the terminal.

sudo apachectl stop

1	sudo apachectl stop

Then run again Apache Web Server at XAMPP.

xamp macos ventura - apache webserver now running — xamp macos ventura – apache webserver now running

4. Test PHP & MySQL by accessing PhpMyAdmin

If you can access phpMyAdmin and create table or user from phpMyAdmin then your XAMPP installation works!

xampp macos ventura - access localhost and click phpmyadmin — xampp macos ventura – access localhost and click phpmyadmin

xamp macos ventura - successful installed php and mysql now can access phpmyadmin — xamp macos ventura – successful installed php and mysql now can access phpmyadmin