How to define $mysqli once in a class?

[audiodef]

I have a class that goes like so:

Code: Select all

class Radio{
	function mysqlConnect(){
		global $host,$user,$password,$database;

		$mysqli = new mysqli($host,$user,$password,$database);
		if (mysqli_connect_errno()) {
		    printf("Connect failed: <p>%s</p>", mysqli_connect_error());
		    exit();
		}
		
		return $mysqli;
	}
	function doSomething(){
		$mysqli=$this->mysqlConnect();
		...
		$mysqli->close();
	}
	function doSomethingElse(){
		$mysqli=$this->mysqlConnect();
		...
		$mysqli->close();
	}
	function doYetAnotherThing(){
		$mysqli=$this->mysqlConnect();
		...
		$mysqli->close();
	}
}

I can't help but think there must be a more efficient way to do this - in other words, not have to define $mysqli and then close the connection inside each function. How would I do that?

[Mad Merlin]

Use a constructor and class members...

Code: Select all

class Radio
{
	private $mysqli;

	function __construct()
	{
		$this->mysqli = new mysqli($host, $user, $password, $database);
	}

	function something()
	{
		$this->mysqli->query(...);
		...
	}

	...
}

The constructor is called once when the object is instantiated, and the member variables are stored in the object.

[audiodef]

I thought it would have to do with a constructor, but I didn't know exactly how to implement it. Thanks!

I now notice a lot of these:

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Warning: mysqli::close(): Couldn't fetch mysqli in /var/www/synthetronica/htdocs/radio/class_radio.php on line 112 

Unless I remove $this->mysqli->close(); from the end of each function. Also, if the same function is called twice or more in one block, mysqli->close() at the end of the function seems to interfere. Where should mysqli->close() be placed?

[Jeffrey0]

Also, if the same function is called twice or more in one block, mysqli->close() at the end of the function seems to interfere. Where should mysqli->close() be placed?

PHP automatically closes connections when the mysqli object is garbage collected, so there's no real need to close it manually with exception of a few very special cases.

Otherwise, you'd call it in your __destruct destructor. The destructor gets called when there's no references to your Radio instance left anymore.

Code: Select all

class Demo {
  function __construct() {
    echo 'hi!';
  }
  function __destruct() {
    echo 'bye!';
  }
}

function make_a_demo() {
  $test = new Demo(); // hi!
}
make_a_demo();
// the $test from make_a_demo is gone now - bye! gets printed

$otherTest = new Demo(); // hi!
// end of the script - the destructor gets called here but it might be too late to actually send any text over to the browser

[audiodef]

Thanks, I appreciate that.

I doubt I have any special cases requiring me to call close(), but what would those be?