PHP & Web Development Blogs

As you all know, Laravel Eloquent Relationships are powerful and easy methods introduced by Laravel for helping developers to reduce the complexity when connecting with multiple tables. While connecting with multiple tables, this method is very easy for developers for creating the application

Here you can see the next three methods of the eloquent relationships:
   
. Has Many Through Relationship
    . One to Many Polymorphic
    . Many to many Polymorphic

HAS MANY THROUGH ELOQUENT RELATIONSHIP

Has many through is a little bit complicated while understanding. I will provide a shortcut method to provide access data of another mode relationship. We will create a user table, post table, and country table and they will be interconnected with each other.

Here we will see Many through relationship will use hasManyThrough() for the relation

Create Migrations

Users table

 Schema::create('users', function (Blueprint $table) {

 $table->increments('id');

 $table->string('name');

 $table->string('email')->unique();

 $table->string('password');

 $table->integer('country_id')->unsigned();

 $table->rememberToken();

 $table->timestamps();

 $table->foreign('country_id')->references('id')->on('countries')

 ->onDelete('cascade');

});

Posts table

Schema::create('posts', function (Blueprint $table) {

 $table->increments('id');

 $table->string("name");

 $table->integer('user_id')->unsigned();

 $table->timestamps();

 $table->foreign('user_id')->references('id')->on('users')

 ->onDelete('cascade');

});

Countries table

Schema::create('countries', function (Blueprint $table) {

 $table->increments('id');

 $table->string('name');

 $table->timestamps();

});

Create Models

Country Model

<?php


namespace App;

use Illuminate\Database\Eloquent\Model;


class Country extends Model

{

 public function posts(){

 return $this->hasManyThrough(

 Post::class,

 User::class,

 'country_id', 
 'user_id', 
 'id', 
 'id' 
 );

 }

}

Now we can retrieve records by

$country = Country::find(1); 

dd($country->posts);

ONE TO MANY POLYMORPHIC RELATIONSHIP

One to many polymorphic relationships used one model belongs to another model on a single file. For example, we will have tweets and blogs, both having the comment system. So we need to add the comments. Then we can manage both in a single table


Here we will use sync with a pivot table, create records, get all data, delete, update, and everything related to one too many relationships.

Now I will show one too many polymorphic will use morphMany() and morphTo() for relation.

Create Migrations

Posts table

Schema::create('posts', function (Blueprint $table) {

 $table->increments('id');

 $table->string("name");

 $table->timestamps();

});

Videos Table

Schema::create('videos', function (Blueprint $table) {

 $table->increments('id');

 $table->string("name");

 $table->timestamps();

});

Comments Table

Schema::create('comments', function (Blueprint $table) {

 $table->increments('id');

 $table->string("body");

 $table->integer('commentable_id');

 $table->string("commentable_type");

 $table->timestamps();

});

Create Models

Post Model

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;


class Post extends Model

{

 

 public function comments(){

 return $this->morphMany(Comment::class, 'commentable');

 }

}

Video Model

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;


class Video extends Model{

 

 public function comments(){

 return $this->morphMany(Comment::class, 'commentable');

 }

}

Comment Model

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Comment extends Model{

 

 public function commentable(){

 return $this->morphTo();

 }

}

Create Records

$post = Post::find(1); 

$comment = new Comment;

$comment->body = "Hi Harikrishnan";

$post->comments()->save($comment);


$video = Video::find(1); 

$comment = new Comment;

$comment->body = "Hi Harikrishnan";

$video->comments()->save($comment);

Now we can retrieve records

$post = Post::find(1); 

dd($post->comments);



$video = Video::find(1); 

dd($video->comments);

MANY TO MANY POLYMORPHIC RELATIONSHIPS

Many to many polymorphic is also a little bit complicated like above. If we have a tweet, video and tag table, we need to connect each table like every tweet and video will have multiple persons to tag. And for each and every tag there will be multiple tweet or videos.

Here we can understand the creating of many to many polymorphic relationships, with a foreign key schema of one to many relationships, use sync with a pivot table, create records, attach records, get all records, delete, update, where condition and etc..


Here morphToMany() and morphedByMany() will be used for many to many polymorphic relationships

Creating Migrations

Posts Table

Schema::create('posts', function (Blueprint $table) {

 $table->increments('id');

 $table->string("name");

 $table->timestamps();

});

Videos Table

Schema::create('videos', function (Blueprint $table) {

 $table->increments('id');

 $table->string("name");

 $table->timestamps();

});

Tags table

Schema::create('tags', function (Blueprint $table) {

 $table->increments('id');

 $table->string("name");

 $table->timestamps();

});

Taggables table

Schema::create('taggables', function (Blueprint $table) {

 $table->integer("tag_id");

 $table->integer("taggable_id");

 $table->string("taggable_type");

});

Creating ModelsPost Model

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Post extends Model

{

 

 public function tags(){

 return $this->morphToMany(Tag::class, 'taggable');

 }

}

Video Model

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Video extends Model

{

 

 public function tags(){

 return $this->morphToMany(Tag::class, 'taggable');

 }

}

Tag Model

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Tag extends Model

{

 

 public function posts(){

 return $this->morphedByMany(Post::class, 'taggable');

 }



 

 public function videos(){

 return $this->morphedByMany(Video::class, 'taggable');

 }

}

Creating Records

$post = Post::find(1); 
$tag = new Tag;
$tag->name = "Hi Harikrishnan";
$post->tags()->save($tag);


$video = Video::find(1); 
$tag = new Tag;
$tag->name = "Vishnu";
$video->tags()->save($tag);


$post = Post::find(1); 
$tag1 = new Tag;
$tag1->name = "Kerala Blasters";
$tag2 = new Tag;
$tag2->name = "Manajapadda";
$post->tags()->saveMany([$tag1, $tag2]);


$video = Video::find(1); 
$tag1 = new Tag;
$tag1->name = "Kerala Blasters";
$tag2 = new Tag;
$tag2->name = "Manajappada";
$video->tags()->saveMany([$tag1, $tag2]);


$post = Post::find(1); 
$tag1 = Tag::find(3);
$tag2 = Tag::find(4);
$post->tags()->attach([$tag1->id, $tag2->id]);


$video = Video::find(1); 
$tag1 = Tag::find(3);
$tag2 = Tag::find(4);
$video->tags()->attach([$tag1->id, $tag2->id]);


$post = Post::find(1); 
$tag1 = Tag::find(3);
$tag2 = Tag::find(4);
$post->tags()->sync([$tag1->id, $tag2->id]);


$video = Video::find(1); 
$tag1 = Tag::find(3);
$tag2 = Tag::find(4);
$video->tags()->sync([$tag1->id, $tag2->id]);

Now we can retrieve records

$post = Post::find(1); 
dd($post->tags);


$video = Video::find(1); 
dd($video->tags)


$tag = Tag::find(1);
dd($tag->posts);


$tag = Tag::find(1);
dd($tag->videos);

Hence we completed all the relationships. In the above blog how has many through relationship, one to many polymorphic relationships and many to many polymorphic are working. This feature is introduced from Laravel 5.0 onwards and till the current version. Without the model, we can’t able to do this relationship. If we are using an eloquent relationship it will be very useful while developing an application.

Recently I was faced with a task to post data from a .csv file to an external REST API. I’m just going to log in to this article about what I did to get the job done.

Let’s start by creating a template for uploading the file. For this article’s sake, lets make the changes in the dashboard.blade.php file.

<form method="post" enctype="multipart/form-data"> @csrf <div class="custom-file"> <input type="file" accept=".csv" name="excel" class="custom-file-input" id="customFile" /> <label class="custom-file-label" for="customFile">Choose file</label	> </div> <div> <button type="submit" class="btn btn-primary btn-sm" style="margin-top: 10px"	>Submit> </div>

</form>

Note : Don’t forget to add enctype=”multipart/form-data”!



Once the user has submitted the file, we need a new router to process the file and send its content to the REST API. Let’s start by creating a Controller.

php artisan make:controller UploadController

Now in the web.php file,

Route::post('/upload', [UploadController::class, 'upload'])->name('upload')->middleware('auth');

In the UploadController.php , create a function named upload. We will be writing all the code inside this function. Also, we need an action for the form.

<form method="post" action="{{route('upload')}}" enctype="multipart/form-data">

Now inside the upload function, we need to get the submitted file and parse its contents.

Get the submitted file,

$file = $request->file('excel');

Parse the submitted file,

if (($handle = fopen($file, "r")) !== FALSE) { while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) { ..... }

}

We will be using a dummy REST API to create users — https://reqres.in/api/users. This is the request body required to create a user.

{ "name": "test", "job": "test"

}

Keeping this in mind, we will create a sample .csv template to be submitted. The fields need to be two, namely Name and Job.



We need to send the values from this file as the request body to the API. So let’s add the code to loop through the content of this file.

if (($handle = fopen($file, "r")) !== FALSE) { while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) { Http::post('https://reqres.in/api/users', [ 'name' => $data[0], 'job' => $data[1], ]); }

}

This will create each student for each row of the file. But we don’t need to send the data of the first row of the file.

Full code:

public function upload(Request $request){ $file = $request->file('excel'); if($file){ $row = 1; $array = []; if (($handle = fopen($file, "r")) !== FALSE) { while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) { if($row > 1){ Http::post('https://reqres.in/api/users', [ 'name' => $data[0], 'job' => $data[1], ]); array_push($array,$data[0]); } $request->session()->flash('status', 'Users '.implode($array,", ").' created successfully!'); $row++; } } }else{ $request->session()->flash('error', 'Please choose a file to submit.'); } return view('dashboard');

}

This will post the data starting from the second row of the file, display a success message once the users are created, and an error message if the submit button is clicked without choosing a file.

Full template:

<div class="container max-w-7xl mx-auto sm:px-6 lg:px-8" style="width: 50%"> @if (session('status')) <div class="alert alert-success"> {{ session('status') }} </div> @endif @if (session('error')) <div class="alert alert-error"> {{ session('error') }} </div> @endif <form action="{{route('upload')}}" method="post" enctype="multipart/form-data"> @csrf <div class="custom-file"> <input type="file" accept=".csv" name="excel" class="custom-file-input" id="customFile" /> <label class="custom-file-label" for="customFile">Choose file</label> </div> <div> <button type="submit" class="btn btn-primary btn-sm" style="margin-top: 10px">Submit</button> </div> </form>

</div>

That’s it, thanks for reading :)

Welcome back! If you're new to this series have a look at Part 1 here

Today we are going to beef things up a bit and we will focus on the backend and some key CMS functionality.

It's time to get excited, this is where you'll start to see your barebones structure morph into something extraordinary!

Tired of my intro? That's ok! Let's jump into it!

Getting the DB on board

Before we delve into this, it's imperative that we take a minute and plan things out.

The database tables that are vital to any CMS are the menu, the user table, and the content table.

Our menu table will start of as follows:

CREATE TABLE 'mydbname'.'menus' ( 'ID' INT(11) NOT NULL AUTO_INCREMENT , 'menuname' VARCHAR(100) NOT NULL , 'item' VARCHAR(50) NOT NULL , 'itemlink' VARCHAR(100) NOT NULL , PRIMARY KEY ('ID')) ENGINE = MyISAM COMMENT = 'menu table';

Let's break this down a bit.

In the SQL above, we're creating a new table called menus.

Essentially our structure looks like this:

ID | Menuname | Item | Itemlink

Our ID field is our unique identifier (our PRIMARY KEY).

Tip: Remember, you can use raw SQL or a tool like PhpMyAdmin to create your db tables/execute SQL queries.

Next up is our user table.

CREATE TABLE 'mydbname'.'users' ( 'ID' INT(11) NOT NULL AUTO_INCREMENT , 'username' VARCHAR(100) NOT NULL , 'password' VARCHAR(50) NOT NULL , 'email' VARCHAR(100) NOT NULL , PRIMARY KEY ('ID')) ENGINE = MyISAM COMMENT = 'user table';

Visually represented this structure looks like this:

ID | Username | Password | Email

Our ID field is our unique identifier.

And finally, our content table modifications. You probably remember creating a rudimentary content table in Part 1 of the series.

ALTER TABLE 'mydbname'.'content' ADD content_type VARCHAR(50);

Yep, you guessed right, in the above statement we are altering our content table and adding a new field called content type.

Our new table structure now looks like this:

ID | Title | Content | Author | Content Type

Planning to Add to the Backend

Next , we're going to add a menu section, an add user section, and we'll also modify our content section.

Let's do this! reate a file called menus.php in your backend folder.

Next, code a HTML form to save your menu data.

The form needs the following fields:

Menu Name (we called this menuname in our db table).

Menu Item Name (we called this item in our db table).

Menu Link (we called this itemlink in our db table).

Try to follow Part 1 to do this on your own.

If you get a little stuck, that's ok. You can also follow the example below:

<form method="post" action="<?php $_SERVER['PHP_SELF'];?>"/>

<input type="text" name="menuname" class="mytextbox" placeholder="Menu Name" required />

<input type="text" name="item" class="mytextbox" placeholder="Item" required />

<input type="text" name="itemlink" class="mytextbox" placeholder="Item Link" required />

<input type="submit" value="Save Menu Item" name="savemenu" class="mybutton"/>

</form>
 

Notice the use of CSS classes? The gravy!

This will come in handy in our next tutorial.

Next, let's add the form processing code as we need to save these fields to the database. Remember to use the sanitization technique you learned in Part 2.

Add this above your <form> tag.

<?php

if(isset($_POST['savemenu'])){

include('../includes/conn.php');

if ($letsconnect->connect_error) {

die("Your Connection failed: " . $letsconnect->connect_error);

}else{

$menuname = $letsconnect ->real_escape_string($_POST['menuname']);

$item = $letsconnect -> real_escape_string($_POST['item']);

$itemlink = $letsconnect->real_escape_string($_POST['itemlink']);

$sql = "INSERT INTO menus(menuname,item,itemlink) VALUES ('".$menuname."', '".$item."', '".$itemlink."')";

if (mysqli_query($letsconnect, $sql)) {

echo "Your data was saved successfully!";

} else { echo "Error: " . $sql . "" . mysqli_error($letsconnect);

} $letsconnect->close();

}

}

?>

Ok phew, the menu data capturing section is done.

Let's move on to the user data capturing section, and modify the content capturing screen.

Repeat the steps above and create these two screens. Remember to keep an eye out for our database field names that we defined earlier! If you get stuck, look at the end result below:

Create adduser.php in your backend folder.

Create your data capturing form.

<form method="post" action="<?php $_SERVER['PHP_SELF'];?>"/>

<input type="text" name="username" class="mytextbox" placeholder="Username" required/>

<input type="password" name="password" class="mytextbox" placeholder="Password" required />

<input type="email" name="email" class="mytextbox" placeholder="Email" required />

<input type="submit" value="Save Menu Item" name="saveuser" class="mybutton"/>

</form>

Add your PHP processing code, remember the security!

Add this above your <form> tag.

<?php

if(isset($_POST[‘saveuser])){

include('../includes/conn.php');

if ($letsconnect->connect_error) {

die("Your Connection failed: " . $letsconnect->connect_error);

}else{

$menuname = $letsconnect -> real_escape_string($_POST[‘username']);

$item = $letsconnect -> real_escape_string($_POST[‘password']);

$itemlink = $letsconnect -> real_escape_string($_POST[‘email']);

$sql = "INSERT INTO menus(username,password,email) VALUES ('".$username."', '".$password."', '".$email."')";

if (mysqli_query($letsconnect, $sql)) {

echo "Your data was saved successfully!";

} else { echo "Error: " . $sql . "" . mysqli_error($letsconnect);

} $letsconnect->close();

}

}

?>

Please note that I will be covering Password security in the tutorials that follow.

Make sure that you are using your localhost server to complete this tutorial series. Do not publish your work until you complete this series.

Lastly, let's move to our content capturing screen which is currently found in index.php in the backend folder.

We will be changing this to a more professional dashboard in the tutorials that follow!
Our current file looks like this:

<html>

<head><title>Backend - Capture Content</title></head>

<body>

<?php

if(isset($_POST['savedata'])){

include('../includes/conn.php');

if ($letsconnect->connect_error) {

die("Your Connection failed: " . $letsconnect->connect_error);

}else{

$title = $letsconnect -> real_escape_string($_POST['title']);

$content = $letsconnect -> real_escape_string($_POST['content']);

$author = $letsconnect -> real_escape_string($_POST['author']);

$sql = "INSERT INTO content (title,content,author) VALUES ('".$title."', '".$content."', '".$author."')";

if (mysqli_query($letsconnect, $sql)) {

echo "Your data was saved successfully!";

} else { echo "Error: " . $sql . "" . mysqli_error($letsconnect);

} $letsconnect->close();

}

}

?>

<form action="<?php $_SERVER[‘PHP_SELF'];?>" method="post">

<input type="text" name="title" placeholder="Content Title here" required/>

<textarea name="content">Content Here</textarea>

<input type="text" name="author" placeholder="Author" required/>

<input type="submit" value="Save My Data" name="savedata"/>

</form>

</body>

</html>

We need to modify this slightly to include our new field, content_type.

Add the input field in your <form> above the submit button.

<input type="text" name="content_type" placeholder="Content Type" required/>;

Next, add the content_type to the sanitization lineup.

$content_type = $letsconnect->real_escape_string($_POST['content_type']);

Lastly, store this variable to the database by modifying the $sql.

$sql = "INSERT INTO content (title,content,author,content_type) VALUES ('".$title."', '".$content."', '".$author."', '".$content_type."')";

Conclusion

Chopping and changing is not always as daunting. Find a rhythm. There are many ways to make cumbersome coding a breeze and we will delve into that in the tutorials to come.

Challenge

Think of ways to test what we just did through retrieving and echoing data from the database.

Next Up: #CodeWithMe Part 5 Building a good base Continued

Hi Guys,

I am sharing you a standalone class for managing a session based cart system. In this class I have provided multiple methods for adding, updating and deleting the products. and By using this class you may manage multiple cart objects with different data only you need to pass a different key in constructor of that class.

Let me share you the How can we use that Class:

Include The cart class

require 'PhpKart.class.php';

Create a Cart Object initializing the Cart base key name, by using different keys we can manage multiple cart data in a same project , like main cart or wishlist

$obj1 = new PhpKart("MainCart");

Here Maincart is the keyname in which $obj1 insert/modify/delete the data

Adding any product inside cart

$obj1->add_to_cart($product_id=123,$quantity=2,$product_information=array("product_name"=>"Tomato","Price"=>20));

Where parameter1 is product, id,parameter 2 is quantity, and Parameter 3 is product information Array

Now If we want to update the quantity in product_id=123 with quantity 5 then use following:

$obj1->add_to_cart($product_id=123,$quantity=5);

Here we did not pass the information array again because no matter you pass or not if the product information is already added in the cart then if won't be affected So no ned to pass this, only pass product id and its Quantity

If we want to add another product:

$obj1->add_to_cart($product_id=145,$quantity=3,$product_information=array("product_name"=>"Potato","Price"=>30));

Now we have a case what if our product is already having some quantity and we want to increase into it or decrease into it, Then to retrieve the already added product information, using AlreadyExists method by passing product id,it will return array if it exists and it will return boolean false if not exists:

$already_exists=$obj1->AlreadyExists($product_id=145); 
if($already_exists !== false )
{
print_r($already_exists);
}

If we want to remove any product from cart:

$obj1->remove_from_cart($product_id=145);

If we want to get all products from the current cart

print_r( $obj1->getAllItems() );

It will return you an array with all the items exist in the current cart

Getting all item's count inside the current cart

echo $obj1->getTotalItems(); 

If we want to get calculate total amount in the current cart

echo $obj1->getCartTotalAmount($priceKeyName='Price')

Note: In the above snippet we need to provide teh same key name which we have used for product price in project information array at the time of adding items in cart array, and need to take the same key name in all the products inserting in Same Cart

If we want to clear/reset the current cart then use following:

$obj1->clear_cart(); 

Now if we want to save some other user interested items separately which use likes but don't want to buy now so that items can be Add into wishlist So we need to create new object with different cart ket name and that list will be manage separately using it's object. Like Following:

Create new Object by passing different Key

$obj2=new PhpKart("MyWishlist"); 

Add a new item to $obj2 object containing the items user want to add in his/her wishlist

$obj2->add_to_cart($product_id=159,$quantity=8,$product_information=array("product_name"=>"Baby Toy","Price"=>100));

Show the total cart Amount

echo $obj2->getCartTotalAmount("Price"); 

Full Source Code

Following is the full code for that cart managing Class . Just create a file named PhpKart.class.php and add following code in it:

<?php 
if(!session_id()){
 @session_start();
}


class PhpKart{

private $cart_key;

public function __construct($CartkeyName)
{
$this->cart_key=$CartkeyName;
}
public function add_to_cart($product_id,$quantity='1',$product_information=array())
{
$_SESSION[$this->cart_key][$product_id]['product_id']=$product_id;
$_SESSION[$this->cart_key][$product_id]['quantity']=$quantity;
if(!isset($_SESSION[$this->cart_key][$product_id]['product_information']) && !empty($product_information)){
$_SESSION[$this->cart_key][$product_id]['product_information']=$product_information;
}
}
public function remove_from_cart($product_id)
{
unset($_SESSION[$this->cart_key][$product_id]);
}
public function clear_cart()
{
unset($_SESSION[$this->cart_key]);
}
public function getTotalItems()
{
return count($_SESSION[$this->cart_key]);
}
public function getCartTotalAmount($price_key_name)
{
$total=0;
foreach($_SESSION[$this->cart_key] as $row)
{
$total += ($row['product_information'][$price_key_name]*$row['quantity']);
}

return $total;
}
public function AlreadyExists($product_id)
{
 if (isset($_SESSION[$this->cart_key][$product_id]))
 {
	return $_SESSION[$this->cart_key][$product_id];
 }
 else
 {
	return false;
 }
}
public function getAllItems()
{
return $_SESSION[$this->cart_key];
}


}

?>

Every time I see this

$users = [new User(), new User()];

I see a lost opportunity to use Iterator.

Why Iterators?

Collections are an awesome way to organize your previously no-named array. There is a couple of reasons why you should use iterators. One of reason stays for behavior, you can specify exact behavior on standard calls such as next, current, valid etc. Other reason could be that you want to ensure that collection contains an only specific type of an object.

Understand a suffer from using an array of unknown value types.
Very common in the PHP world arrays are used to store all kind of data, in many dimensions in many nested forms. Arrays introduced infinite flexibility to the developer, but because of that, they become very evil.

Example:

- Your function (getUsers) returns an array of User objects.
- Another function (setUsersToActiveState) using getUsers output array and set all users active status to true.
- setUsersToActiveState loop through the array and expect to call a specific method on array item. For example, the method name is getActiveStatus.
- If given array is an array of desired objects which have a callable method getActiveStatus, all fine. But if not exception will be thrown.
- How we can ensure that given array is always an array of objects of a specific type?

public function getUsers(): array
{
 
 return $userArray;
}

public function setUsersToActiveState()
{
 $users = $this->getUsers();
 
 foreach ($users as $user) {
 if(!$user->getActiveStatus()) {
 $user->setActiveStatus(true);
 }
 }
}

There immediately two problems occurred.
    . One is the problem of type. Our IDE doesn't know what's inside array of $users, so because of that IDE can't suggest us how to use $user element. (I put this comment block above foreach, it works for phpStorm and I guess for some other IDEs)
    . Your colleagues! How they possibly know what's inside array if there is no any hint.
    . Bonus problem, getUsers can return literally any array and there won't be warning in the system.

Solution

class UsersCollection implements \IteratorAggregate
{
 
 private $users = [];

 public function getIterator() : UserIterator
 {
 return new UserIterator($this);
 }

 public function getUser($position)
 {
 if (isset($this->users[$position])) {
 return $this->users[$position];
 }

 return null;
 }

 public function count() : int
 {
 return count($this->users);
 }

 public function addUser(User $users)
 {
 $this->users[] = $users;
 }
}

class UserIterator implements \Iterator
{
 
 private $position = 0;

 
 private $userCollection;

 public function __construct(UsersCollection $userCollection)
 {
 $this->userCollection = $userCollection;
 }

 public function current() : User
 {
 return $this->userCollection->getUser($this->position);
 }

 public function next()
 {
 $this->position++;
 }

 public function key() : int
 {
 return $this->position;
 }

 public function valid() : bool
 {
 return !is_null($this->userCollection->getUser($this->position));
 }

 public function rewind()
 {
 $this->position = 0;
 }
}

Tests

Off course there is the tests to ensure that our Collection and Iterator works like a charm. For this example I using syntax for PHPUnit framework.

class UsersCollectionTest extends TestCase
{
 
 public function testUsersCollectionShouldReturnNullForNotExistingUserPosition()
 {
 $usersCollection = new UsersCollection();

 $this->assertEquals(null, $usersCollection->getUser(1));
 }

 
 public function testEmptyUsersCollection()
 {
 $usersCollection = new UsersCollection();

 $this->assertEquals(new UserIterator($usersCollection), $usersCollection->getIterator());

 $this->assertEquals(0, $usersCollection->count());
 }

 
 public function testUsersCollectionWithUserElements()
 {
 $usersCollection = new UsersCollection();
 $usersCollection->addUser($this->getUserMock());
 $usersCollection->addUser($this->getUserMock());

 $this->assertEquals(new UserIterator($usersCollection), $usersCollection->getIterator());
 $this->assertEquals($this->getUserMock(), $usersCollection->getUser(1));
 $this->assertEquals(2, $usersCollection->count());
 }

 private function getUserMock()
 {
 }
}


class UserIteratorTest extends MockClass
{
 
 public function testCurrent()
 {
 $iterator = $this->getIterator();
 $current = $iterator->current();

 $this->assertEquals($this->getUserMock(), $current);
 }

 
 public function testNext()
 {
 $iterator = $this->getIterator();
 $iterator->next();

 $this->assertEquals(1, $iterator->key());
 }

 
 public function testKey()
 {
 $iterator = $this->getIterator();

 $iterator->next();
 $iterator->next();

 $this->assertEquals(2, $iterator->key());
 }

 
 public function testValidIfItemInvalid()
 {
 $iterator = $this->getIterator();

 $iterator->next();
 $iterator->next();
 $iterator->next();

 $this->assertEquals(false, $iterator->valid());
 }

 
 public function testValidIfItemIsValid()
 {
 $iterator = $this->getIterator();

 $iterator->next();

 $this->assertEquals(true, $iterator->valid());
 }

 
 public function testRewind()
 {
 $iterator = $this->getIterator();

 $iterator->rewind();

 $this->assertEquals(0, $iterator->key());
 }

 private function getIterator() : UserIterator
 {
 return new UserIterator($this->getCollection());
 }

 private function getCollection() : UsersCollection
 {
 $userItems[] = $this->getUserMock();
 $userItems[] = $this->getUserMock();

 $usersCollection = new UsersCollection();

 foreach ($userItems as $user) {
 $usersCollection->addUser($user);
 }

 return $usersCollection;
 }

 private function getUserMock()
 {
 }
}

Usage

public function getUsers(): UsersCollection
{
 $userCollection = new UsersCollection();
 
 foreach ($whatIGetFromDatabase as $user) {
 $userCollection->addUser($user);
 }
 return $userCollection;
}

public fucntion setUsersToActiveState()
{
 $users = $this->getUsers();

 foreach ($users as $user) {
 if(!$user->getActiveStatus()) {
 $user->setActiveStatus(true);
 }
 }
}

As you can see setUsersToActiveState remains the same, we only do not need to specify for our IDE or collagues what type $users variable is.

Extending functionalities

Believe or not you can reuse this two objects and just change names of variables to fit most of the needs. But if you want any more complex functionality, than feel free to add it in iterator or collection.

Example 1

For example, let's say that userCollection accepts only users with age more than 18. Implementation will happen in UsersCollection class in the method addUser.

 public function addUser(User $users)
 {
 if ($user->getAge() > 18) {
 $this->users[] = $users;
 } 
 }

Example 2

You need to add bulk users. Then you can expand your userCollection with additional method addUsers and it might look like this.

 public function addUsers(array $users)
 {
 foreach($users as $user) {
 $this->addUser(User $users);
 }
 }