How do I convert my functions to a class? - php

Question

I am trying to get into the world of OOP and therefore building my first class out of some file handler functions. I am having a hard time understanding the whole idea of objects and methods, and I am not quite sure if I did it the right way, though the output is as expected.
I would appreciate your help with the following example. How could I add a method to it the right way?
class.File.php
class File {
public $file = '';
public $data = '';
public function __construct($file = '') {
$this->file = $file;
}
function put($create = false) {
// Check if file is writeable and put content, won't create new file unsless $create is set to true
if($create == false) {
is_writable($this->file) ? file_put_contents($this->file, $this->data, LOCK_EX) : exit;
} else {
file_put_contents($this->file, $this->data);
}
}
}
example call
$f = new File();
$f->file = "/www/htdocs/somehost/folder/data/helloworld.txt";
$f->data = "Hello world";
$f->put('true');

Answer 1

Object is the concrete entity of the real world. That has properties and behaviour (methods).
What are the properties of the concrete file? It is a name, permissions, a date of creation, etc. All properties should be hidden from real world.
What behaviour can the file have? Read content, rewrite content, append content, rename, delete, change permissions, etc. All that you do with the file. Note it is better to have two methods "rewrite content" and "append content" than one "put" with arguments. Because these are different actions on the file.
So let's write the class File.
class File
{
private $name;
private $permissions;
// name and permissions are mandatory because file cannot exist without these properties
public function __construct($name, $permissions)
{
$this->name = $name;
$this->permissions = $permissions;
}
public function read()
{
// you can check if the file exists
return file_get_contents($this->name);
}
// may also named `put`
public function write($content)
{
file_put_contents($this->name, $content);
}
public function append($content)
{
file_put_contents($this->name, $content, FILE_APPEND);
}
public function rename($name)
{
$this->name = $name;
}
}
Any checks (if file exists, if file is writeble) is concrete implementation, not about OOP.
PS
You can read this article http://www.yegor256.com/2014/09/16/getters-and-setters-are-evil.html about getters and setters.