PHP 5 OOP question

compbry15

Hello all,

I am kind of new to PHP, but I have a heavy background in programming. Most of my development has been in C/C++, with a little bit of Perl. From an OOP point of view, I am very used to the rule that all created objects must be destroyed. What I am trying to understand in PHP is how this works? Please tell me if I am far off with the following example:

Ok so lets say I have a blog website where people can post a blog, then people can post comments to the blog. So I have a file Blog.php, which describes a Blog class. When someone goes to post a new blog, I would do something like first set up the variables, such as $body, $title, $etc, $etc... then when they hit submit, do:

$myBlog = new Blog( pass all those variables);

$myBlog->store(); // store new blog to DB

At this point I would move on to some other page, like displaying of the blog or whatever...the user may return to the home page...or if later down the road someone wants to view a blog I could do something like:

$viewBlog = new Blog( ID of the blog to get);
$viewBlog->get(); // sets all the variables of the blog from the DB
$viewBlog->display() // echo all the information to the page in some formatted way

Then, maybe they want to create a comment, I could create a new comment object, with the BlogID of the current blog being viewed, store the comment to the DB, etc etc. Then it would be easy to do:

$viewBlog->getAllComments(); // loop through and display all comments linked to blog

I think you get the picture. Throughout all of this, no object is ever destroyed, they just like float off into nothingness lol. Is this OK practice in PHP? Is this whole scenario even possible in PHP?

I look forward to, and appreciate your insight.

Thanks

Bryan

halojoy

yes,
it is a perfect use of a class (object oriented programming)

A Class makes sense when you want to have collection of functions
that will use the same stuff, same rawmaterial
and treat these variables in a nubmber of ways

You can not store data from one php page to another, in the class.
But your class can be configured to store/read data in a file or a database.
Then each time a page creates an object
you can have a main function, that runs automatically
and get you blog articles from file/db.

Let say your 'viewblog.php' uses this:

<?php

include( 'blog.class.php' ); //loads the class script

// create a new object
$viewBlog = new Blog(); // will call main function and get data from file/db

$viewBlog->display( 10 ); // will display 10 last entries

?>

the 'blog.class.php' could be

<?php

class Blog{

//class variables
$articles = array();
$datafile = 'myblogarticles.txt';

function Blog(){
// here is the main 'constructor' function
// a function with same name as the class
// this will autorun when a 'new' object is created from some page

// read my file '$datafile' into '$articles' variable

} // end main Blog function

function display( $number ){
//display last '$number' of articles
for( $i=0; $i <$number; $i++){
echo $articles[$i];
echo '<br>';
}
} // end display funtion

function newentry(){
// submit a new blog article
} // end newentry function

function editentry(){
// edit an article
}

function delentry(){
// delete an article
}

} // END CLASS

?>

compbry15

Cool, thanks for the reply. It's good to here that that is how it works. I'm looking forward to starting the development of this project now that I know I can do some real OOP. Some of the pre-made software I have looked at, like Blogs and CMS's, are so script-like its not even funny.

So, there is no real need to delete an object, since the reference to it automatically is deleted upon the completion of the script?

NogDog

Not sure if this is what you are asking, but all objects are automatically destroyed by PHP when they are no longer referenced or the script terminates (as are all other variables). This of course is different from the persistence of objects across different PHP script instantiations, where you might be persisting an object via the database or via the filesystem as a session variable.

ahundiak

compbry15 wrote:
Cool, thanks for the reply. It's good to here that that is how it works. I'm looking forward to starting the development of this project now that I know I can do some real OOP. Some of the pre-made software I have looked at, like Blogs and CMS's, are so script-like its not even funny.

So, there is no real need to delete an object, since the reference to it automatically is deleted upon the completion of the script?

Yep. No need to be worried about garbage collection in PHP. Think of each http request as starting a brand new program with fresh memory.

Unless of course your script is dealing with umteen thousands of objects within a single request. In that case, you might need to explicitly destroy unneeded objects to prevent running out of memory.