rghvdberg / php-practice

The PHP Practitioner

• https://laracasts.com/series/php-for-beginners
• start a server with php -S localhost:8888

Step 3: Variables

• commands operations end with ;
• variables start with $
  • $var
• period . is used for concatenation
  • echo 'Hello ,' . $var;
• double quotes for printing the variable in a string
  • echo "Hello , $var";
• curly braces can be used for better readability
  • echo "Hello, {$var}";

---

Step 4: PHP and HTML

• a file with 100% php has no php closing tag ?>
• $_GET['var'] gets the value of a key value pair in the url
  • with url http://localhost:8888?var=foo , $_GET['var'] will return foo
• htmlspecialchars(); Convert special characters to HTML entities
  • useful for making sure no html is parsed in $_GET , aka sanitize
• use <?= as a shorthand for <?php echo
• end css statements with ;
• comment out html with <!-- this is a comment -->

---

Step 5: Separate Logic From Presentation

• require <file.php> loads an external php file
  • allows separation of logic and rendering

---

Step 6: Understanding Arrays

• $myArray[] defines an empty array

• assign values

  $myArray=[  
   'item1',
   'item2'
   ]

• loop over array

  <?php foreach($myArray as $item){
    // do stuff 
  }
  ?>

  • or

  <?php foreach($myArray as $item) : ?>
  // do stuff
  <?php endforeach; ?>

---

Step 7: Associative Arrays

• key value pairs use arrow =>
  • $myArray['key'=>'value]
• add key/value to existing array $myArray['newKey']='newValue'
• add value to non associative array myArray[]='newValue'
• remove key/value unset(myArray['key'])
• dump variable info with var_dump($myVar)
• die('message') stops execution
  • e.g. die(var_dump($myVar))

---

Step 8: Booleans

• boolean values true / false
  • e.g. $completed = true;
• ternary operator $condition ? 'do this when true' : 'do this when false';
• ucwords('uppercase the first character of each word in a string')

---

Step 9: Conditionals

• <?php 
    if (condition) {
      // do stuff
    }
    else {
      // do stuff
      }
  ?>

• or

  <?php if(condition) : ?>
    // do html stuff
  <?php endif; ?>

• with else

  <?php if(condition) : ?>
    //do html stuff
  <?php else : ?>
    // do other html stuff
  <?php endif; ?>

• use ! for not

  • ! true == false

• https://www.w3schools.com/charsets/ref_utf_dingbats.asp

---

Step 10 : Functions

• function functionName($arg){
    // do stuff
    
    // optionally return
    $returnValue = true;
    
    return $returnValue;
  }

---

Step 11 : MySQL 101

• using mariadb instead of mysql ;-)
• cd into step_11
  • docker compose up -d
  • docker compose exec db mariadb -uroot
• sql commands end with ;
• some commands

  • show databases;

  • create database mytodos;

  • use mytodos;

  • create table todos (id integer PRIMARY KEY AUTO_INCREMENT,
                        description  text NOT NULL,
                        completed boolean NOT NULL);

  • show tables;
    +------------------+
    | Tables_in_mytodo |
    +------------------+
    | todos            |
    +------------------+
    1 row in set (0.016 sec)
    

  • describe todos;
    +-------------+------------+------+-----+---------+----------------+
    | Field       | Type       | Null | Key | Default | Extra          |
    +-------------+------------+------+-----+---------+----------------+
    | id          | int(11)    | NO   | PRI | NULL    | auto_increment |
    | description | text       | NO   |     | NULL    |                |
    | completed   | tinyint(1) | NO   |     | NULL    |                |
    +-------------+------------+------+-----+---------+----------------+
    3 rows in set (0.097 sec)

  • drop table table_name;

  • insert new record

    • insert into todos (description, completed ) values('Go to the store', false);

  • show records

    • select * from todos;
      +----+-----------------+-----------+
      | id | description     | completed |
      +----+-----------------+-----------+
      |  1 | Go to the store |         0 |
      +----+-----------------+-----------+
      1 row in set (0.001 sec)

---

Step 12 : Classes 101

• define a class with class
• properties
  • protected $prop
  • can also be 'private' and 'public'
• constructor public function __construct($prop)
• access member functions and properties with $this->prop
  • note that prop gets no $
• create new object with new
  • new myClass('property');
    • constructors can take arguments

---

Step 13 : Intro to PDO

• https://www.php.net/manual/en/book.pdo.php

• connect to database with

  • SQLite: PDO("sqlite:path_to_db);
  • MySQL: PDO('mysql:host=172.21.0.2;dbname=mytodos', 'root', '');

• query in two parts

  • prepare('QUERY_STRING')
  • execute()

---

Step 14 : PDO Refactoring and Collaborators

• split and move different functions over different files
• static function : use function without instantiating a class
• NOTE: php files can return value (see bootstrap.php)

---

Step 15 : Hide Your Secret Passwords

• move database configurations in config.php

---

Step 16 : Make a Router

• restructure code in core / controllers / views
• $_SERVER['REQUEST_URI'] returns URI
• static function Router::load($var)
  • create new Router object with $router = new static;
  • can't return $this because it's a static object
  • use return $router

---