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Showing 21 to 25 of 39 blog articles.
8667 views · 5 years ago
Underclocking a Website

For those of you not familiar with the concept of underclocking: it's the opposite of overclocking, that is, you don't speed up CPU but instead slow it down..

What for?

Ask the underclockers, I'm totally not sure. Actually, hanging around the Web these days leaves a feeling that nearly every website out there must have been underclocked, but most of the time it's about tons of unnecessary images, megabytes of javascript (of which hardly a hundred kilobytes gets actually executed), and all that. In this post I will, however, tell you about a server-side approach to underclocking, with a help of our good old friend - the MySQL Database Server.

Today I had a nice chat in my client's development telegram channel. The two other devs, R** and V**, were making a switch of the old image API app to a new MySQL server. A couple of days before that, we have discussed a plan, it was as dumb as possible, just as I like it. Super-simple clear steps that a five-year-old can make. Switch to readonly mode (stop uploads), dump DB, restore the dump on the new server, update database connection details, turn off readonly mode. What could possibly go wrong?

Nothing. Except that it did go wrong. The app that I'm talking about, is a really ancient piece of what is gently called "legacy". Once the app was back to normal again, we noticed a significant slowdown on every page that made use of images. Before that point, I never got to that app and/or its database. I logged in to the MySQL console, and started investigating, at the same point chatting with colleagues.

Me: Is that really important that the tables are MyISAM? It's 2018, you know.. There are dozens of queries in queue waiting for table-level locks.

R**: Are they MyISAM? Really?

Me: Yes.. Any objection against converting them to InnoDB? With the current state of the website, with all those tons of Gateway Timeouts, it's not going to make it worse if I do it right now..


    . minutes later:

Me: Nah, it didn't help a lot.. But, looking at the SHOW PROCESSLIST output, I see something weird. What, do you think, this query does? SELECT LAST_INSERT_ID() FROM images? 

R**: ehh... Gets you the last AUTO_INCREMENT id from images table?

Me: Let's play another good news bad news joke.. Good news: you're right, it gets you the last AUTO_INCREMENT id. Bad news: it's not for table, it's for the session. Worse news: this query gets you the last AUTO_INCREMENT id and does it exactly as many times as there are rows in the images table. how many are there?

R**: about 8mln. #@%&! It's sending 8mln rows on every image upload, through the network!

Me: Bingo! 8mln rows, with one and the same integer value in all of them.

R**: Ouch... Aaaand... Before today, it was not an issue. Because the database was on the same server as the application..

Me: Exactly, it used the loopback interface, and now it's using ehternet, which, apparently, doesn't have a super good bandwidth. We don't have a gigabit channel between servers, do we?

R**: No, it's 100 Mbit

Me: Are you fixing the query, BTW?

R**: yeah, man, deploying it...


Another 10 minutes later, problem is gone, performance is back to normal.

What conclusions can one make from this story?

I can think of two at least:
First: never underestimate legacy code. The ways it can move to bite you in the ass, are mysterious.
Second: if you're working with MySQL or another RDBMS, learn SQL, learn the specific SQL dialect you're using and learn how to trouble shoot issues. In this case, I did not need to look in the PHP code at all in order to help my fellow colleagues out. You can also generalize this principle as "you have to know the tools you're using".

Happy optimizing, folks! Comments appreciated!
8458 views · 3 years ago
Laravel Eloquent Relationship Part 2

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.
7588 views · 5 years ago
Now that the Thanksgiving and Black Friday are left behind, we're all back at our desks, some of us having PHPStorm open for the whole day. In this post, I'll say a few words on this beautiful IDE, PHPUnit and XDebug.
You know that unit tests are essential, don't you? So do the PHPStorm developers. This industry-standard level IDE has tons of capabilities for integrating test frameworks and debuggers into your project. Even if you use VMs or containers to run your development environment, chances are they got you covered!

Blind Pew from Treasure Island

I often see even experienced PHP programmers debugging their code with var_dump(), which is obviously not the best way to do it. If you see the code for the first time, if you work with legacy code - step-by-step interactive debugging is the way to go. Sometimes it can save you hours of old school var_dumping.

As of unit tests, I often hear that it's good enough to run tests from the terminal. I even know a guy who runs watch phpunit /path/to/test while developing: this way the test is run every 2 seconds, you switch to the terminal whenever you want to see the latest results and that's it. However, there are certain advantages in running tests from the IDE. First, it's super-handy to launch a test method, test class or a whole folder with tests, just by pressing a hotkey. Second, the test results appear right there, in PHPStorm, with failures and their stack traces, every entry clickable and takes you directly to the file:line where a nasty thing happened. I also find the ability to run a debugger for a unit test, extremely attractive. Test fails, you click on a trace entry, get to a problematic line, place a break point, re-run the test in debug mode - and there you go.

For all those integrations, you will first need to setup the PHP interpreter for the project: Configuring PHP Development Environment. You will find both local and remote interpreter setups. "Local" is the PHP that you have on your workstation, the host machine. "Remote" can be pretty much everything: SSH if your Dev environment runs on a shared sandbox for all developers, docker or docker-compose if you run it using docker containers.

Next step - creating PHPUnit configuration. Go toSettings -> Languages and Frameworks -> PHP -> Test Frameworks. Follow this guide, it has much more information which will be more up-to-date than this post.Don't forget to set Path Mappings for your remote environments! That is, you probably have your project in, say, $HOME/projects/cool-project, but inside a docker or on a remote host it might be located at /app or /var/www, then you have to let PHPStorm know about this.

Once you're done with PHPUnit setup, you can finally run your tests! The default shortcut on my Linux machine isCtrl+Shift+F10 (shortcuts are usually different on Mac though). Place a cursor inside a test method, press the shotcut: PHPStorm will launch PHPUnit withthat particular test method! When the cursor in a scope of test class but not inside a test method - the whole test class will be run. And, you also can select a whole folder with tests, in the project tree and run it, ain't that cool?

A small tip for the docker-compose lovers. When I first set PHPStorm integration with docker-compose and ran the tests, I was quite surprised (unpleasantly) to see that myphp-fpm service that I was connecting to, is gone after the test process is finished. Took me some time to figure out that it's PHPStorm's expected behavior. It stops the target service after it's done testing. A workaround I started to use is as follows: I just add another service calledphpunit which uses a php-fpm or php-cli image, and is not needed by anything except unit testing in PHPStorm.

Now to debugging.


Debugging is like being the detective in a crime movie where you are also the murderer. Filipe Fortes a.k.a. @fortes


Obviously, your PHP interpreter in development environment will need a debugger extension in order for you to debug interactively. PHPStorm support the two most widely used options: XDebug and Zend Debugger. When using docker I usually make a separate Dockerfile for development, using production image as base, then add development tools,XDebug being the most important. Honestly, I've never usedZend Debugger, so have little to tell about its' nuances.

Got an extension? Go to Debugging Ultimate Guide! Debugger settings in PHPStorm are atSettings -> Languages and Frameworks -> PHP -> Debug. Most of the time you don't need to change them.Again, a note for docker-compose users. There is an XDebug setting that allow debugger to resolve the client (PHPStorm) IP address:xdebug.remoteconnect_back_. That's a disappointment but those will not work, at least with a default docker-compose setup. Thing is, all containers in a compose stack are running behind a network proxy provided by docker-compose. That is, the REMOTE_ADDR for all the containers will always be the IP of proxy. A workaround:

* disablexdebug.remoteconnect_back_;
* add.user.ini to the application root folder with the following contents:xdebug.remotehost = 192.168.X.X_ (your machine's IP address in the LAN). It's generally a good idea to exclude.user.ini from VCS control.

As a conclusion: if you still usevardump()_ to debug, stop living in the stone age, upgrade your knowledge and become more productive! If you don't write unit tests, start doing it. If your managers say it's a waste of time, tell them that it's coding without tests that is a waste of time. And, if you find this post of any use, or have an opinion, or a question - please do comment!
6883 views · 5 years ago
Custom extension to Laravel Application class

Hello folks! This post is for those of you using Laravel. This beautiful framework makes web development super-easy compared to most of competitors. In the heart of Laravel is the Application class, which is responsible for bootstrapping, registering services and also serves as a dependency injection container. What I do with my Laravel apps, is that I take a slight detour from the common path by adding a custom Application class. While this is not really necessary, I find this approach nice, and will try to share my thought below.

It's normal practice in Laravel world to build all kinds of objects like this:

$cache = app("cache");


I find it a bit confusing to call app("cache"") and expect a Cache\Repository instance as result. If I pass the result of this call to a function that requires a Cache\Repository as parameter, I will probably have a code inspection warning from IDE. Moreover, if I want proper autocompletion, I will have to add additional comment:


$cache = app("cache");


This is where a custom application class might be handy:

namespace App;
class MyApp extends Application
{
public function cacheRepository(): Repository
{
return $this->make(Repository::class);
}
}


This way I get a TypeError in case of a misconfiguration, and I have a type-hint which allows the IDE to recognize the return value. Bye-bye nasty comment lines and IDE warnings! I make a method per service, with type-hints, like dbConnection() or viewFactory() - works really well for me!

I also thought that, if I have a custom class, then all the custom setup that normally you have in bootstrap/app.php, should reside in that custom class:

namespace App;
class MyApp extends Application
{
public function __construct()
{
define('LARAVEL_START', microtime(true));
define("APP_ROOT", realpath(__DIR__ . "/../"));
parent::__construct(APP_ROOT);
$this->setUp();
}
private function setUp()
{
$this->singleton(
Contracts\Http\Kernel::class,
\App\Http\Kernel::class
);
}
}


Then your bootstrap/app.php becomes just this:

return new \App\MyApp;


The Laravel app() function will also return an instance of MyApp from now on. However, it's @phpdoc says it returns \Illuminate\Foundation\Application, so for better clarity, I also added my own accessor method:

namespace App;
class MyApp extends Application
{
public static function app(): self
{

$ret = parent::getInstance();
return $ret;
}
}


I tend to limit the use of global/static functions and methods, but sometimes it can be handy, and whenever I need an instance of MyApp, I just call MyApp::app(). The IDE wil be aware of the return type due to the type-hint, so I get everything I want for clean and clear development.

With your projects in Laravel, you may or may not want to follow this particular advice, but just be aware that extending a framework built-in classes for your team's comfort, is definitely something that can make your life easier. See you around, don't forget to leave comments!
6685 views · 1 months ago


In modern software architecture, developers are constantly exploring new paradigms to enhance the performance, scalability, and maintainability of their applications. One such architectural pattern gaining popularity is Command Query Responsibility Segregation (CQRS). CQRS separates the responsibility of handling read and write operations, offering numerous benefits in complex systems. In this article, we'll delve into CQRS and explore its implementation in PHP.

What is CQRS?


CQRS, coined by Greg Young, is an architectural pattern that segregates the responsibility for handling read and write operations in a system. In traditional CRUD-based architectures, the same model is often used for both reading and writing data. However, CQRS advocates for a clear distinction between commands (write operations that modify state) and queries (read operations that retrieve data).

Key Concepts of CQRS:
   

. Command: Commands represent actions that modify the state of the system. They encapsulate the intent to perform an operation, such as creating, updating, or deleting data.
   
. Query: Queries retrieve data from the system without modifying its state. They are read-only operations used to fetch information for presentation or analysis.
   
. Command Handler: Responsible for processing commands by executing the necessary business logic and updating the system's state accordingly.
   
. Query Handler: Handles queries by retrieving data from the appropriate data source and returning the results to the caller.
   
. Separate Models: CQRS often involves maintaining separate models for commands and queries. This allows each model to be optimized for its specific use case, leading to improved performance and scalability.

Implementing CQRS in PHP:


Implementing CQRS in PHP involves structuring your application to separate command and query responsibilities effectively. Here's a high-level overview of how to implement CQRS in PHP:

1. Define Commands and Queries:


Start by defining the commands and queries your application will support. Commands should encapsulate actions that modify state, while queries should retrieve data.

class CreateProductCommand {
public $name;
public $price;
}

class GetProductQuery {
public $productId;
}


2. Create Command and Query Handlers:


Next, implement handlers for processing commands and queries. Command handlers execute the necessary business logic to fulfill the command, while query handlers retrieve data based on the query criteria.

class CreateProductCommandHandler {
public function handle(CreateProductCommand $command) {
}
}

class GetProductQueryHandler {
public function handle(GetProductQuery $query) {
}
}


3. Use Separate Models:


Maintain separate models for commands and queries to optimize each for its specific purpose. This separation allows you to design models tailored to the needs of write and read operations.

class Product {
public $name;
public $price;
}

class ProductView {
public $name;
public $price;
}


4. Wiring Everything Together:


Finally, wire up your command and query handlers to the appropriate endpoints or controllers in your application. Dispatch commands to their respective handlers and invoke query handlers to retrieve data.

$command = new CreateProductCommand();
$command->name = "Example Product";
$command->price = 99.99;

$handler = new CreateProductCommandHandler();
$handler->handle($command);

$query = new GetProductQuery();
$query->productId = 123;

$handler = new GetProductQueryHandler();
$product = $handler->handle($query);


Benefits of CQRS in PHP:


-Improved Scalability: Separating read and write operations allows you to scale each independently based on demand.

-Enhanced Performance: Optimizing models and handlers for specific tasks can lead to improved performance and responsiveness.

-Simplified Maintenance: Clear separation of concerns makes the codebase easier to understand, maintain, and extend over time.

-Flexibility: CQRS enables flexibility in choosing the most suitable data storage and retrieval mechanisms for different use cases.

Conclusion:


CQRS is a powerful architectural pattern that offers numerous advantages for building complex and scalable PHP applications. By segregating command and query responsibilities, developers can achieve better performance, scalability, and maintainability in their systems. While implementing CQRS in PHP requires careful planning and design, the benefits it provides make it a compelling choice for projects requiring high performance and flexibility.

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