PHP & Web Development Blogs

Today I am going write a blog on how to Monitor Memory and Disk custom metrics and creating alarm in Ubuntu.

To do this, we can use Amazon CloudWatch, which provides a flexible, scalable and reliable solution for monitoring our server.

Amazon Cloud Watch will allow us to collect the custom metrics from our applications that we will monitor to troubleshoot any issues, spot trends, and configure operational performance. CloudWatch functions display alarms, graphs, custom metrics data and including statistics.

Installing the Scripts

Before we start installing the scripts for monitoring, we should install all the dependent packages need to perform on Ubuntu.

First login to your AWS server, and from our terminal, install below packages

sudo apt-get update
sudo apt-get install unzip
sudo apt-get install libwww-perl libdatetime-perl

Now Install the Monitoring Scripts

Following are the steps to download and then unzip we need to configure the Cloud Watch Monitoring scripts on our server:
1. In the terminal, we need to change our directory and where we want to add our monitoring scripts.
2. Now run the below command and download the source:

curl https://aws-cloudwatch.s3.amazonaws.com/downloads/CloudWatchMonitoringScripts-1.2.2.zip -O

3. Now uncompress the currently downloaded sources using the following commands

unzip CloudWatchMonitoringScripts-1.2.2.zip && \

rm CloudWatchMonitoringScripts-1.2.2.zip && \

cd aws-scripts-mon

The directory will contain Perl scripts, because of the execution of these scripts only report memory run and disk space utilization metrics will run in our Ubuntu server.
Currently, our folder will contain the following files:
mon-get-instance-stats.pl - This Perl file is used to displaying the current utilization statistics reports for our AWS instance on which these file scripts will be executed.
mon-put-instance-data.pl - This Perl script file will be used for collecting the system metrics on our ubuntu server and which will send them to the Amazon Cloud Watch.
awscreds.template - This Perl script file will contain an example for AWS credentials keys and secret access key named with access key ID.
CloudWatchClient.pm - This Perl script file module will be used to simplify by calling Amazon Cloud Watch from using other scripts.
LICENSE.txt – This file contains the license details for Apache 2.0.
NOTICE.txt – This file contains will gives us information about Copyright notice.
4. For performing the Cloud Watch operations, we need to confirm that whether our scripts have corresponding permissions for the actions:

If we are associated with an IAM role with our EC2 Ubuntu instance, we need to verify that which will grant the permissions to perform the below-listed operations:

cloudwatch:GetMetricStatistics

cloudwatch:PutMetricData

ec2:DescribeTags

cloudwatch:ListMetrics

Now we need to copy the ‘awscreds.template’ file into ‘awscreds.conf’ by using the command below and which will update the file with details of the AWS credentials.

cp awscreds.template awscreds.conf

AWSAccessKeyId = my_access_key_id

AWSSecretKey = my_secret_access_key

Now we completed the configuration.

mon-put-instance-data.pl

This Perl script file will collect memory, disk space utilization data and swap the current system details and then it makes handling a remote call to Amazon Cloud Watch to reports details to the collected cloud watch data as a custom metrics.

We can perform a simple test run, by running the below without sending data to Amazon CloudWatch

./mon-put-instance-data.pl --mem-util --verify --verbose

Now we are going to set a cron for scheduling our metrics and we will send them to Amazon CloudWatch
1. Now we need to edit the crontab by using below command:

 crontab -e

2. Now we will update the file using the following query which will disk space utilization and report memory for particular paths to Amazon CloudWatch in every five minutes:

*/5 * * * * ~/STORAGE/cloudwatch/aws-scripts-mon/mon-put-instance-data.pl --mem-util --mem-avail --mem-used --disk-space-util --disk-space-avail --disk-space-used --disk-path=/ --disk-path=/STORAGE --from-cron

If there is an error, the scripts will write an error message in our system log.

Use of Options

--mem-used
The above command will collect the information about used memory and which will send the details of the reports in MBs into the MemoryUsed metrics. This will give us information about the metric counts memory allocated by applications and the OS as used.
--mem-util
The above command will collect the information about memory utilization in percentages and which will send the details of the Memory Utilization metrics and it will count the usage of the memory applications and the OS.
--disk-space-util
The above command will collect the information to collect the current utilized disk space and which will send the reports in percentages to the DiskSpaceUtilization for the metric and for the selected disks.
--mem-avail
The above command will collect the information about the available memory and which will send the reports in MBs to the MemoryAvailable metrics details. This is the metric counts memory allocated by the applications and the OS as used.
--disk-path=PATH
The above command will collect the information and will point out the which disk path to report disk space.
--disk-space-avail
The above command will collect the information about the available disk space and which will send the reports in GBs to the DiskSpaceAvailable metric for the selected disks.
--disk-space-used
The above command will collect the information about the disk space used and which will send the reports in GBs to the DiskSpaceUsed metric for the selected disks.

The PATH can specify to point or any of the files can be located on which are mounted point for the filesystem which needs to be reported.

If we want to points to the multiple disks, then specify both of the disks like below:

--disk-path=/ --disk-path=/home

Setting an Alarm for Custom Metrics

Before we are going to running our Perl Scripts, then we need to create an alarm that will be listed in our default metrics except for the custom metrics. You can see some default metrics are listed in below image:



Once we completed setting the cron, then the custom metrics will be located in Linux System Metrics.

Now we are going to creating the alarm for our custom metrics
1. We need to open the cloudwatch console panel at https://console.aws.amazon.com/cloudwatch/home
2. Now navigate to the navigation panel, we need to click on Alarm and we can Create Alarm.
3. This will open a popup which with the list of the CloudWatch metrics by category.
4. Now click on the Linux System Metrics . This will be listed out with custom metrics you can see in the below pictures






5. Now we need to select metric details and we need to click on the NEXT button. Now we need to navigate to Define Alarm step.



6. Now we need to define an Alarm with required fields

Now we need to enter the Alarm name for identifying them. Then we need to give a description of our alarm.

Next, we need to give the condition with the maximum limit of bytes count or percentage when it notifies the alarm. If the condition satisfies, then the alarm will start trigger.

We need to provide a piece of additional information about for our alarm.

We need to define what are the actions to be taken when our alarm changes it state.

We need to select or create a new topic with emails needed for sending notification about alarm state.
7. Finally, we need to choose the Create Alarm.

So its completed. Now the alarm is created for our selected custom metrics.

Finished!

Now the alarm will be listed out under the selected state in our AWS panel. Now we need to select an alarm from the list seen and we can see the details and history of our alarm.

Models and controllers are one of the most essential programming handlers in the Laravel MVC framework, and both are used vastly for different functional operations. Models in Laravel are created inside the app folder and are mostly used to interact with the database using Eloquent ORM, while the controllers are located inside the directory App/Http/Controllers.

As a programmer, you should have the knowledge how to keep the balance in between the programming usage of Models and controllers. As which one should be more utilized for allowing functional tasks in applications deployed on any PHP MySQL hosting.

What is the Concept of Thin Controller and FAT Models

The concept of the thin controller and fat model is that we do less work in our controllers and more work in our models. Like we use our controllers to validate our data and then pass it to the models. While in models, we define our actual functional logic and main coding operations of the desired application. This code structuring process is also a very basic concept of MVC and also the differentiating factor from the conventional complex programming which we mistakenly ignore sometimes.

Why FAT Controllers Are Bad For Handling Code

Controllers are always meant to be defined short and concise, and it should only be used for receiving requests and return responses to it. Anything else further should be programmed in Models, which is actually made for main functional operations.

Placing functional logic in controllers can be bad for many reasons for your applications deployed on anyhosting for PHP. As it not only makes code structure long but also makes it complex sometimes. Further placing code in Controllers is also not recommended because if same functionality is needed somewhere else in route, then pulling out the whole code from their becomes difficult and so its reusability in the application.

Though Laravel is an MVC framework while developing on laravel, we sometimes ignore this and write mostly all our code including the extending of App\Model and all our functional logic in controller route methods. What we can do here is we can create a sub model of our parent model. For example, our parent model is User then we can create another sub model of username in CustomerModel if you are using the same User model for all types of users. In this model, we will write all the logic related to user type Customer.

So now let's take an example of my existing blog creating comment system with laravel and vuejs. In that article, you can see I have made so much mess in my controller methods. Mostly, I have written all my comments logic in my methods, so to shorten that let's clean them in this article. Inside app folder, I will create a new file with name CommentModel.php. Inside this file, I will write my whole logic for comment functions. This is my basic file:

<?php
namespace App;

use App\Comment;
use App\CommentVote;
use App\CommentSpam;
use App\User;
use Auth;

class CommentModel
{


}

?>

Right now it contains no function but has the reference of all my models which I required for this model. Let's first add a function namedgetallcomments passing$pageId as a parameter inside it. The function will get all the comments for the given page:

public function getAllComments($pageId)
 {
 $comments = Comment::where('page_id',$pageId)->get();

 $commentsData = [];


 foreach ($comments as $key) {
 $user = User::find($key->users_id);
 $name = $user->name;
 $replies = $this->replies($key->id);
 $photo = $user->first()->photo_url;
 $reply = 0;
 $vote = 0;
 $voteStatus = 0;
 $spam = 0;
 if(Auth::user()){
 $voteByUser = CommentVote::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();
 $spamComment = CommentSpam::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();


 if($voteByUser){
 $vote = 1;
 $voteStatus = $voteByUser->vote;
 }

 if($spamComment){
 $spam = 1;
 }
 }


 if(sizeof($replies) > 0){
 $reply = 1;
 }

 if(!$spam){
 array_push($commentsData,[
 "name" => $name,
 "photo_url" => (string)$photo,
 "commentid" => $key->id,
 "comment" => $key->comment,
 "votes" => $key->votes,
 "reply" => $reply,
 "votedByUser" =>$vote,
 "vote" =>$voteStatus,
 "spam" => $spam,
 "replies" => $replies,
 "date" => $key->created_at->toDateTimeString()
 ]);
 } 


 }
 $collection = collect($commentsData);
 return $collection->sortBy('votes');
 }

Now I will create another function namedreplies which takes$commentId as a parameter. The function is more or less programmed in the same manner as the upper function get all comments.

protected function replies($commentId)
 {
 $comments = Comment::where('reply_id',$commentId)->get();
 $replies = [];



 foreach ($comments as $key) {
 $user = User::find($key->users_id);
 $name = $user->name;
 $photo = $user->first()->photo_url;

 $vote = 0;
 $voteStatus = 0;
 $spam = 0; 


 if(Auth::user()){
 $voteByUser = CommentVote::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();
 $spamComment = CommentSpam::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();

 if($voteByUser){
 $vote = 1;
 $voteStatus = $voteByUser->vote;
 }

 if($spamComment){
 $spam = 1;
 }
 }
 if(!$spam){


 array_push($replies,[
 "name" => $name,
 "photo_url" => $photo,
 "commentid" => $key->id,
 "comment" => $key->comment,
 "votes" => $key->votes,
 "votedByUser" => $vote,
 "vote" => $voteStatus,
 "spam" => $spam,
 "date" => $key->created_at->toDateTimeString()
 ]);
 }




 }


 $collection = collect($replies);
 return $collection->sortBy('votes');
 }

Now lets create a functioncreate comment which passes$array as a parameter in it:

public function createComment($arary)
 {
 $comment = Comment::create($array);


 if($comment)
 return [ "status" => "true","commentId" => $comment->id ];
 else
 return [ "status" => "false" ]; 
 }

Similarly, Now I will create all the function for comment in myCommentModel, so that all the functions gets accumulated in one model.

<?php
namespace App;

use App\Comment;
use App\CommentSpam;
use App\CommentVote;
use App\User;
use Auth;

class CommentModel
{
 public function getAllComments($pageId)
 {
 $comments = Comment::where('page_id', $pageId)->get();

 $commentsData = [];

 foreach ($comments as $key) {
 $user = User::find($key->users_id);
 $name = $user->name;
 $replies = $this->replies($key->id);
 $photo = $user->first()->photo_url;
 $reply = 0;
 $vote = 0;
 $voteStatus = 0;
 $spam = 0;
 if (Auth::user()) {
 $voteByUser = CommentVote::where('comment_id', $key->id)->where('user_id', Auth::user()->id)->first();
 $spamComment = CommentSpam::where('comment_id', $key->id)->where('user_id', Auth::user()->id)->first();

 if ($voteByUser) {
 $vote = 1;
 $voteStatus = $voteByUser->vote;
 }

 if ($spamComment) {
 $spam = 1;
 }
 }

 if (sizeof($replies) > 0) {
 $reply = 1;
 }

 if (!$spam) {
 array_push($commentsData, [
 "name" => $name,
 "photo_url" => (string) $photo,
 "commentid" => $key->id,
 "comment" => $key->comment,
 "votes" => $key->votes,
 "reply" => $reply,
 "votedByUser" => $vote,
 "vote" => $voteStatus,
 "spam" => $spam,
 "replies" => $replies,
 "date" => $key->created_at->toDateTimeString(),
 ]);
 }

 }
 $collection = collect($commentsData);
 return $collection->sortBy('votes');
 }

 protected function replies($commentId)
 {
 $comments = Comment::where('reply_id', $commentId)->get();
 $replies = [];

 foreach ($comments as $key) {
 $user = User::find($key->users_id);
 $name = $user->name;
 $photo = $user->first()->photo_url;

 $vote = 0;
 $voteStatus = 0;
 $spam = 0;

 if (Auth::user()) {
 $voteByUser = CommentVote::where('comment_id', $key->id)->where('user_id', Auth::user()->id)->first();
 $spamComment = CommentSpam::where('comment_id', $key->id)->where('user_id', Auth::user()->id)->first();

 if ($voteByUser) {
 $vote = 1;
 $voteStatus = $voteByUser->vote;
 }

 if ($spamComment) {
 $spam = 1;
 }
 }
 if (!$spam) {

 array_push($replies, [
 "name" => $name,
 "photo_url" => $photo,
 "commentid" => $key->id,
 "comment" => $key->comment,
 "votes" => $key->votes,
 "votedByUser" => $vote,
 "vote" => $voteStatus,
 "spam" => $spam,
 "date" => $key->created_at->toDateTimeString(),
 ]);
 }

 }

 $collection = collect($replies);
 return $collection->sortBy('votes');
 }

 public function createComment($arary)
 {
 $comment = Comment::create($array);

 if ($comment) {
 return ["status" => "true", "commentId" => $comment->id];
 } else {
 return ["status" => "false"];
 }

 }

 public function voteComment($commentId, $array)
 {
 $comments = Comment::find($commentId);
 $data = [
 "comment_id" => $commentId,
 'vote' => $array->vote,
 'user_id' => $array->users_id,
 ];

 if ($array->vote == "up") {
 $comment = $comments->first();
 $vote = $comment->votes;
 $vote++;
 $comments->votes = $vote;
 $comments->save();
 }

 if ($array->vote == "down") {
 $comment = $comments->first();
 $vote = $comment->votes;
 $vote--;
 $comments->votes = $vote;
 $comments->save();
 }

 if (CommentVote::create($data)) {
 return true;
 }

 }

 public function spamComment($commentId, $array)
 {
 $comments = Comment::find($commentId);

 $comment = $comments->first();
 $spam = $comment->spam;
 $spam++;
 $comments->spam = $spam;
 $comments->save();

 $data = [
 "comment_id" => $commentId,
 'user_id' => $array->users_id,
 ];

 if (CommentSpam::create($data)) {
 return true;
 }

 }
}
?>

Now we have all our required methods inCommentModel. So now let's clean upCommentController which is currently bit complex and lengthy in code structure. As right nowCommentController look like this:

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Http\Requests;
use App\Comment;
use App\CommentVote;
use App\CommentSpam;
use App\User;
use Auth;

class CommentController extends Controller
{


 
 public function index($pageId)
 {
 $comments = Comment::where('page_id',$pageId)->get();

 $commentsData = [];




 foreach ($comments as $key) {
 $user = User::find($key->users_id);
 $name = $user->name;
 $replies = $this->replies($key->id);
 $photo = $user->first()->photo_url;
 $reply = 0;
 $vote = 0;
 $voteStatus = 0;
 $spam = 0;
 if(Auth::user()){
 $voteByUser = CommentVote::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();
 $spamComment = CommentSpam::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();


 if($voteByUser){
 $vote = 1;
 $voteStatus = $voteByUser->vote;
 }

 if($spamComment){
 $spam = 1;
 }
 }


 if(sizeof($replies) > 0){
 $reply = 1;
 }

 if(!$spam){
 array_push($commentsData,[
 "name" => $name,
 "photo_url" => (string)$photo,
 "commentid" => $key->id,
 "comment" => $key->comment,
 "votes" => $key->votes,
 "reply" => $reply,
 "votedByUser" =>$vote,
 "vote" =>$voteStatus,
 "spam" => $spam,
 "replies" => $replies,
 "date" => $key->created_at->toDateTimeString()
 ]);
 } 


 }
 $collection = collect($commentsData);
 return $collection->sortBy('votes');
 }

 protected function replies($commentId)
 {
 $comments = Comment::where('reply_id',$commentId)->get();
 $replies = [];



 foreach ($comments as $key) {
 $user = User::find($key->users_id);
 $name = $user->name;
 $photo = $user->first()->photo_url;

 $vote = 0;
 $voteStatus = 0;
 $spam = 0; 


 if(Auth::user()){
 $voteByUser = CommentVote::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();
 $spamComment = CommentSpam::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();

 if($voteByUser){
 $vote = 1;
 $voteStatus = $voteByUser->vote;
 }

 if($spamComment){
 $spam = 1;
 }
 }
 if(!$spam){


 array_push($replies,[
 "name" => $name,
 "photo_url" => $photo,
 "commentid" => $key->id,
 "comment" => $key->comment,
 "votes" => $key->votes,
 "votedByUser" => $vote,
 "vote" => $voteStatus,
 "spam" => $spam,
 "date" => $key->created_at->toDateTimeString()
 ]);
 }




 }


 $collection = collect($replies);
 return $collection->sortBy('votes');
 }

 
 public function store(Request $request)
 {
 $this->validate($request, [
 'comment' => 'required',
 'reply_id' => 'filled',
 'page_id' => 'filled',
 'users_id' => 'required',
 ]);
 $comment = Comment::create($request->all());
 if($comment)
 return [ "status" => "true","commentId" => $comment->id ];
 }

 
 public function update(Request $request, $commentId,$type)
 {
 if($type == "vote"){


 $this->validate($request, [
 'vote' => 'required',
 'users_id' => 'required',
 ]);

 $comments = Comment::find($commentId);
 $data = [
 "comment_id" => $commentId,
 'vote' => $request->vote,
 'user_id' => $request->users_id,
 ];

 if($request->vote == "up"){
 $comment = $comments->first();
 $vote = $comment->votes;
 $vote++;
 $comments->votes = $vote;
 $comments->save();
 }

 if($request->vote == "down"){
 $comment = $comments->first();
 $vote = $comment->votes;
 $vote--;
 $comments->votes = $vote;
 $comments->save();
 }

 if(CommentVote::create($data))
 return "true";
 }

 if($type == "spam"){


 $this->validate($request, [
 'users_id' => 'required',
 ]);

 $comments = Comment::find($commentId);


 $comment = $comments->first();
 $spam = $comment->spam;
 $spam++;
 $comments->spam = $spam;
 $comments->save();

 $data = [
 "comment_id" => $commentId,
 'user_id' => $request->users_id,
 ];

 if(CommentSpam::create($data))
 return "true";
 }
 }

 
 public function destroy($id)
 {
 }
}?>

After cleaning up the controller it will look much simpler and easy to understand like this:

<?php

namespace App\Http\Controllers;

use App\CommentModel;
use Illuminate\Http\Request;

class CommentController extends Controller
{

 private $commentModel = null;
 private function __construct()
 {
 $this->commentModel = new CommentModel();
 }

 
 public function index($pageId)
 {
 return $this->commentModel->getAllComments($pageId);
 }

 
 public function store(Request $request)
 {
 $this->validate($request, [
 'comment' => 'required',
 'reply_id' => 'filled',
 'page_id' => 'filled',
 'users_id' => 'required',
 ]);
 return $this->commentModel->createComment($request->all());
 }

 
 public function update(Request $request, $commentId, $type)
 {
 if ($type == "vote") {

 $this->validate($request, [
 'vote' => 'required',
 'users_id' => 'required',
 ]);

 return $this->commentModel->voteComment($commentId, $request->all());
 }

 if ($type == "spam") {

 $this->validate($request, [
 'users_id' => 'required',
 ]);

 return $this->commentModel->spamComment($commentId, $request->all());
 }
 }

}
?>

Wrap Up!

So Isn't it looking much cleaner and simpler to understand now? This is what actually a thin controller and fat model looks like. We have all our logic related to Comment system programmed in ourCommentModel and our controller is now just used to transfer data from the user to our model and returning the response which is coming from our model.

So this is how the structuring of the thin controller and fat model is made. Give your thoughts in the comments below.

To say that we have been hard at work here at Nomad PHP, or that I'm excited about these three announcements would be a tremendous understatement. Over the past several months, behind the scenes, we've been working to bring even more features and benefits to Nomad PHP - these have already included unlimited streaming of all past meetings and access to PHP Architect.

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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);
 }
 }

Hey There,
I am expecting you are familiar with PHP. In this post I will be using the Laravel framework to create a small blog system. I am showing here very simple steps to create blogs, If you want this complete code then please message me.
What are major Prequisites for Laravel:
* PHP version >= 5.6
* Composer should be installed in system

Create a project with name tiny_blog with following command

composer create-project laravel/laravel --prefer-dist tiny_blog

enter into the laravel project

cd tiny_blog

create a migration file using following artisan command
<pre>php artisan make:migration create_blog_table</pre>
After this command you will found a new file created in database/migrations folder in your project, Just edit the file having 'create_blog_table' appended in its name

Now replace following code to create table schema with function up(), So now the method will look like following:

public function up()
{
 Schema::create('blogs', function (Blueprint $table) {
$table->increments('id');
$table->integer('user_id');
$table->string('category');
$table->string('title');
$table->text('description');
$table->timestamps();
});

}

replace following snippet with down method, it will look like following:

public function down()
 {
 Schema::dropIfExists('blogs');
 }

Its time to run the migration file we have created

php artisan migrate

After running,It will create the blogs table in database.Now time to create form and insert data into the table

Laravel itsef provide authentication , use following artisan command :

php artisan make:auth

Now start Larvel:

php artisan serve

it will start the laravel development server at http://127.0.0.1:8000

Now if you run that url the basic default ui will be created and login & register link you can see in Top right position of header

You can register and login now.this feature is provided by authentication module.
Now we need to create a controller for manage blogs with following command:

php artisan make:controller BlogController

will create a file namedBlogController.php in** app/HTTP/controllers** folder location

Now we need to create a Model also, use following command

php artisan make:model Blog

will create a file namedBlog.php in app folder location

Now in Controller we need to create a method for create blogs and available that method in Routes to access it via url. Just editroutes/web.php file and add the following line

Route::get('blog/create','BlogController@createBlog');

/create/blog/ will be url route that land on Blog Controller's createBlog method using get method.

Now before running this route just go to the app/Http/Controllers folder and Edit BlogController.php file and Add the createBlog method in that class as following

public function createBlog()
{
 return view('blog.create');
}

This code will try to load the view from/resources/views/blog/create.blade.php

In Laravel blade is a template engine. As we had not created the view file yet, so we need to create a blog folder inside/resources/views/ folder then inside blog folder create a file create.blade.php with following form

@extends('layouts.app')

@section('content')
<div class="container">
@if ($errors->any())
 <div class="alert alert-danger">
 <ul>
 @foreach ($errors->all() as $error)
 <li>{{ $error }}</li>
 @endforeach
 </ul>
 </div><br />
@endif
 <div class="row">
 <form method="post" action="{{url('blog/create')}}">
 <div class="form-group">
 <input type="hidden" value="{{csrf_token()}}" name="_token" />
 <label for="title">Title:</label>
 <input type="text" class="form-control" name="title"/>
 </div>
 <div class="form-group">
 <label for="title">Category/Tags:</label>
 <input type="text" class="form-control" name="category"/>
 </div>
 <div class="form-group">
 <label for="description">Description:</label>
 <textarea cols="10" rows="10" class="form-control" name="description"></textarea>
 </div>
 <button type="submit" class="btn btn-primary">Submit</button>
 </form>
 </div>
</div>
@endsection

Now we need to add a additional route to handle the post request on blog/create route, Just edit routes/web.php file and just add following line in last:

Route::post('blog/create','BlogController@saveBlog'); 

post route to handle the form post on route blog/create


Now create a method name saveBlog to save the user input data in the form

 public function saveBlog(Request $request)
 {
 $blog = new Blog();
 
 $this->validate($request, [
 'title'=>'required',
'category'=>'required',
 'description'=> 'required'
 ]);
 
 $blog->createBlog($request->all());
 return redirect('blog/index')->with('success', 'New blog has been created successfully :)'); }

Notice This method is using Blog object that we don't know that where it comes from? , So to make above code working we need to include the model which we created earlier need to include in our controller file So use following code to include it before the class created.

use App\Blog;

Now following line shows that there is a method named createBlog in Model(app/Blog.php), but in actual it is not there:

$blog->createBlog($data);

So go to the file app/Blog.php and Edit it and inside the class add following method:

 public function createBlog($data)
{

$this->user_id = auth()->user()->id;
$this->title = $data['title'];
$this->description = $data['description'];
$this->category = $data['category'];
$this->save();
return 1;
}

Now the creation of blog task has been done , Its time to show the created Entries So just create a route blog/index in routes/web.php

Route::get('blog/index','BlogController@showAllBlogs');

get route blog/index to show all the created blogs by current user


Now just add a method in controller

public function showAllBlogs()
 {
 $blogs = Blog::where('user_id', auth()->user()->id)->get();
 
 return view('blog.index',compact('blogs'));
 }

This method requires to create a index view in blog folder , So create a file named index.blade.php in /resources/views/blog/ folder with following code

@extends('layouts.app')

@section('content')
<div class="container">
 @if(\Session::has('success'))
 <div class="alert alert-success">
 {{\Session::get('success')}}
 </div>
 @endif
 <a type="button" href="{{url('blog/create')}}" class="btn btn-primary">Add New Blog</a>
 <br>
 <table class="table table-striped">
 <thead>
 <tr>
 <td>ID</td>
 <td>Title</td>
 <td>Category</td>
 <td>Description</td>
 <td colspan="2">Action</td>
 </tr>
 </thead>
 <tbody>
 @foreach($blogs as $blog)
 <tr>
 <td>{{$blog->id}}</td>
 <td>{{$blog->title}}</td>
 <td>{{$blog->category}}</td>
 <td>{{$blog->description}}</td>
 <td>Edit</td>
 <td>Delete</td>
 </tr>
 @endforeach
 </tbody>
 </table>
<div>
@endsection

Now all code is ready but we need to add 1 line of code to prevent the blog controller without authentication or without login

just add the following constructor method in BlogController class

 public function __construct()
 {
$this->middleware('auth');
 }

this constructor method will call very first when user will try to access any of BlogController class method, and the middleware will check whether user is logged in then only it will allow to access that method otherwise it will redirect to login page automatically.


After It Run your Code and you will able to create and listing your created blogs/articles. but the Edit and Delete links are not working right now, If you want that also working then please comment here or message me. If we get multiple requests then definitely i will write its part 2 article


Thanks very much for reading this blog, if you have any doubt about it then let me know in comments or by messaging me.

Following is the final code for BlogController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Blog;



class BlogController extends Controller
{
 public function __construct()
 {
 $this->middleware('auth');
 }

 public function createBlog()
{
 return view('blog/create');
}


public function saveBlog(Request $request)
 {
 $blog = new Blog();
 
 $this->validate($request, [
 'title'=>'required',
'category'=>'required',
 'description'=> 'required'
 ]);
 
 $blog->createBlog($request->all());
 return redirect('blog/index')->with('success', 'New blog has been created successfully :)');
 }

 public function showAllBlogs()
 {
 $blogs = Blog::where('user_id', auth()->user()->id)->get();
 
 return view('blog.index',compact('blogs'));
 }

}