November 27, 2024
First of all, let's find out what responsive design is. Responsive Web Design (RWD) is an approach to web design that enables websites to automatically adjust and optimize the user experience across a variety of devices, including desktops, tablets, and mobile phones. In today’s digital age, having a responsive website is crucial.
November 26, 2024
In the world of front-end development, managing state is important for creating scalable and easy-to-maintain applications. As Vue.js grows in popularity, developers look for tools that make their work easier. That’s where Pinia comes in—a modern state management library made for Vue 3. In this blog post, we’ll explain Pinia, its main features, how it compares to Vuex, and how it can help you in your Vue.js projects.
Pinia is a state management library that serves as a lightweight and easy-to-use alternative to Vuex, the main state management tool for Vue.js. Pinia is designed for Vue 3 and uses the Composition API, making it a more modern choice for developers. It offers many features that meet the needs of today’s web development.
Pinia stands out because it is simple to use. The API is designed to be user-friendly so that developers can create their stores with very little code. This makes it easy for both new and experienced developers to get started quickly.
Pinia is built specifically for Vue 3, meaning it works perfectly with the Composition API. This gives developers more flexibility in how they structure their applications and makes state management fit better within Vue.
As TypeScript becomes more common in projects, Pinia offers great support for it. This ensures that developers can catch errors before the code runs, which leads to stronger applications.
With Pinia, managing the global state is simple. You can create stores that hold your application’s state and access them from any component, making it easier to manage data without passing it through many layers.
Pinia allows the use of plugins, which means developers can add more features as needed. This makes Pinia adaptable for various projects.
While Vuex has been the main choice for state management in Vue.js, Pinia offers some advantages that make it a good alternative:
To start using Pinia, you’ll first need to install it in your Vue 3 project:
npm install pinia
Once installed, you can create a store like this:
import { defineStore } from 'pinia';
export const useMainStore = defineStore('main', {
state: () => ({
count: 0,
}),
actions: {
increment() {
this.count++;
},
},
});
You can then use this store in your components:
<template>
<div>
<p>{{ count }}</p>
<button @click="increment">Increment</button>
</div>
</template>
<script setup>
import { useMainStore } from '@/stores/main';
const store = useMainStore();
const { count, increment } = store;
</script>
Pinia is a big step forward in state management for Vue.js applications. With its easy-to-use API, strong TypeScript support, and smooth integration with Vue 3, it’s a great choice for developers who want to simplify their work.
While Vuex has been helpful for many years, Pinia’s simplicity and performance make it a strong alternative. Whether you’re working on a small project or a large one, Pinia can help you manage state more effectively.
If you haven’t tried Pinia yet, now is a great time to explore what it can do for your Vue.js projects!
November 26, 2024
Design patterns are tried-and-tested solutions to common software design problems. With the advent of modern C++ (C++11 and later), these patterns can be implemented more elegantly and efficiently, taking advantage of language features like lambda functions, smart pointers, and threading support. In this article, we'll explore three popular design patterns—Singleton, Observer, and Factory Pattern—and see how they can be applied using modern C++.
The Singleton pattern ensures that a class has only one instance and provides a global point of access to it.
Using C++11's thread-safe static initialization, the Singleton pattern becomes simpler and safer to implement.
Results:
static local variable ensures thread-safe initialization.The Observer pattern allows an object (subject) to notify multiple dependent objects (observers) about changes in its state.
Using std::function and std::vector makes it easier to manage observers and their callbacks.
Results:
std::function allows for flexible observer callbacks.The Factory pattern provides an interface for creating objects without specifying their concrete classes.
With smart pointers and std::unordered_map, factories in modern C++ can be made both safe and efficient.
Results:
std::make_unique ensures memory safety and exception handling.std::unordered_map and lambdas make product registration intuitive.Modern C++ features such as smart pointers, lambda expressions, and thread-safe static initialization significantly enhance the implementation of traditional design patterns. They not only make the code more concise and readable but also reduce common pitfalls like memory leaks and thread-safety issues.
Exploring design patterns with modern C++ is an excellent way to understand the power of the language while adhering to best practices in software engineering. By combining these patterns with the features introduced in C++11 and beyond, developers can write more robust, efficient, and maintainable code.
References:
https://www.geeksforgeeks.org/singleton-pattern-c-design-patterns/
https://www.geeksforgeeks.org/factory-method-pattern-c-design-patterns/
https://www.geeksforgeeks.org/observer-pattern-c-design-patterns/
November 26, 2024
Multithreading is an important aspect of modern software development, enhancing performance and optimizing the use of system resources. In the C++ programming language, the ability to create and manage threads is facilitated by the standard library std::thread. In this article, we will explore the basic concepts of multithreading in C++, along with its practical applications and the benefits it offers.
Multithreading is a technique that allows a program to perform multiple tasks simultaneously, utilizing CPU cores and system resources.
Today, many applications use multithreading, such as image processing and data handling applications. In C++, threads are created through the standard C++ library, std::thread. Each thread in C++ is executed independently and can perform different tasks.
Using multithreading to design and develop applications based on C++ offers many benefits, including:
For a programming language that can leverage many resources like C++, using multithreading is extremely beneficial. This is especially true in the development of applications related to embedded systems, where hardware resources are often significantly limited. Additionally, multithreading is used in image processing and analysis, where it can speed up image rendering and maximize computer resources.
For complex computations such as creating 3D images or simulating systems, using multithreading can make the computation and simulation processes faster.
In C++, threads are managed by the std::thread class. To use this class, you need to include the thread header file. To create a thread, we use the statement: std::thread thread_obj(callable);
When executing the above statement, a thread will be created and will execute the [callable] function. The [callable] can be any of the five ways:
The above is an example to help you use basic multithreading. When using multithreading, you should pay attention to the following points to avoid data conflicts between threads:
Multithreading in C++ is an important technique for optimizing performance and efficiently utilizing system resources. However, using multithreading also requires solid knowledge of synchronization methods and resource management. I hope this article has provided you with an overview of this topic and encouraged you to further explore multithreading in C++.
November 20, 2024
Event handling is a critical aspect of modern programming, especially in interactive applications such as GUI software, games, and real-time systems. While C++ lacks built-in event-handling mechanisms, its flexibility allows developers to design efficient systems or leverage powerful libraries like Qt and wxWidgets.
This guide will take you through the essentials of event handling in C++, covering fundamental concepts and practical implementations.
Event handling involves responding to actions or events within a program. Examples of events include:
Unlike some other programming languages with built-in support for event handling, C++ requires developers to design their own systems or utilize external libraries.
An event represents an action or signal triggered by a user or the system, such as:
MouseClickEvent).KeyPressEvent).An event listener monitors and detects specific events, taking appropriate actions when they occur.
An event handler is the function or code block executed in response to an event.
Callback functions are one of the simplest methods for handling events in C++.
Example:
Explanation:
onButtonClick is the event handler function.triggerEvent invokes the callback function when the event occurs.The Observer Pattern is a design pattern where one object (Observer) reacts to changes or events from another object (Subject).
Example:
Explanation:
Game engines like Unreal Engine (built with C++) use event-driven models to handle user inputs and game logic.
Libraries such as Qt, wxWidgets, and FLTK enable developers to create responsive graphical applications with event handling.
Event handling is a foundational concept in programming, enabling applications to react dynamically to user or system actions. While C++ lacks native support, you can utilize strategies like callback functions, the Observer Pattern, or libraries like Qt to implement robust systems.
November 20, 2024
What is database deadlock?
|
<?php
function place_order($order_id) {
$max_retries = 3;
$retry_count = 0;
while ($retry_count < $max_retries) {
try {
// Attempt to deduct item quantity from inventory
deduct_inventory($order_id);
// Attempt to update order status
update_order_status($order_id, 'Processed');
echo "Order $order_id placed successfully.";
return;
} catch (DeadlockException $e) {
echo "Deadlock detected. Retrying order $order_id";
sleep(1); //Set delay time before retrying
$retry_count++;
}
}
echo "Failed to place order $order_id after $max_retries retries.";
}
function deduct_inventory($order_id) {
// Deduct item quantity from inventory
// This operation may encounter a deadlock due to concurrent access
}
function update_order_status($order_id, $status) {
// Update order status in the database
// This operation may encounter a deadlock due to concurrent access
}
place_order(1001);
?>
|
November 20, 2024
composer require league/flysystem-aws-s3-v3
AWS_ACCESS_KEY_ID=your-access-keyAWS_SECRET_ACCESS_KEY=your-secret-keyAWS_DEFAULT_REGION=your-regionAWS_BUCKET=your-bucket-name
use Illuminate\Support\Facades\Storage;public function uploadFile(Request $request){ if ($request->hasFile('file')) { $file = $request->file('file'); $path = $file->store('uploads', 's3'); // 'uploads' is the folder in your bucket // Make the file publicly accessible Storage::disk('s3')->setVisibility($path, 'public');
return "File uploaded to: " . $path; } return "No file selected.";}
$url = Storage::disk('s3')->url('uploads/your-file-name.jpg');return $url;
Storage::disk('s3')->delete('uploads/your-file-name.jpg');
November 20, 2024
If you are using AWS services, specifically EC2 and S3. In the usual way, if you want to access from EC2 to S3 to read and write data, you need to use two pieces of information: the access key and secret key.
These two pieces of information are usually stored in the source code or somewhere on the EC2 instance. This approach carries a risk of information leakage, and if hackers obtain these keys, it could result in a loss of data on S3 bucket.
If you do not want to hardcode these keys, you can use an IAM role to grant the necessary permissions to the EC2 instance to access the S3 bucket.
To set this up, you would create an IAM role with permissions to access the S3 bucket and then attach that role to the EC2 instance. Afterward, the EC2 instance can use the role’s temporary security credentials to access the S3 bucket.
Here are the detailed steps to do it.
Step 1: Create an IAM Role for the EC2 Instance
1. Access IAM on the AWS Console.
2. Go to Roles and click Create Role.
3. In the Trusted entity section, select AWS service and select EC2 because this role will be assigned to an EC2 instance.
4. In the Permissions section:
- Select AmazonS3FullAccess or create a separate policy if you want to allow access to only a specific bucket.
- If you want to create your own policy, you can select Create policy and use the following JSON to specify access to a specific bucket:
| { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": [ "s3:PutObject", "s3:GetObject" ], "Resource": "arn:aws:s3:::your-bucket-name/*" } ] } |
5. Confirm and name the role, for example EC2S3AccessRole.
Step 2: Assign IAM Role to EC2 Instance
1. Go to EC2 Console and select the instance you want to assign permissions to.
2. On the Actions tab, select Security > Modify IAM role.
3. Select the EC2S3AccessRole role you created in the step above and confirm.
Step 3: Example upload images from EC2 to S3
With the IAM Role assigned, the EC2 instance will have access to S3 without using the Access Key or Secret Key. Here is an example Python code to upload images from EC2 to S3:
1. Install boto3 if not already present:
| pip install boto3 |
2. Write Python code to upload images to S3:
|
import boto3 # Initialize S3 client # Define bucket and file name # Upload file |
Note:
- IAM Role ensures access only from the assigned EC2 instance without using a direct key.
- If you need more specific permissions, adjust the policy to suit your needs.
Conclusion
Using IAM Roles helps to enhance security and eliminate risks associated with managing and transmitting Access Keys and Secret Keys. Hopefully the above guide will help you easily deploy and secure your system when uploading data from EC2 to S3 bucket.
References:
November 18, 2024
The Repository Pattern is a design pattern used to abstract data access logic, providing a clean separation between the business logic and data access layers in an application. By implementing this pattern, you encapsulate data access logic in a repository class that acts as an intermediary between the business logic and the data source (like a database, web service, or API).
In C#, the Repository Pattern helps to centralize data access logic and makes it easier to swap out different data sources (e.g., switching from an SQL database to a NoSQL database) without affecting the rest of the application. It also simplifies testing by allowing mock repositories to be used instead of actual data sources.
Entity: A class that represents the model of the data being stored in the database (e.g., Company, Customer..).
Repository Interface: Defines the contract for how data access operations are handled.
Repository Implementation: Implements the data access logic, such as querying the database.
Business Logic: The service layer or business rules of the application.
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
}
public interface ICustomerRepository
{
IEnumerable GetAll();
Product GetById(int id);
void Add(Customer customer);
void Update(Customer customer );
void Delete(int id);
}
public class CustomerRepository : ICustomerRepository
{
private readonly EntitiesDbContest _context;
public CustomerRepository(EntitiesDbContest context)
{
_context = context;
}
public IEnumerable GetAll()
{
return _context.Customers.ToList();
}
public Customer GetById(int id)
{
return _context.Customers.Find(id);
}
public void Add(Customer customer)
{
_context.Customers.Add(customer);
_context.SaveChanges();
}
public void Update(Customer customer)
{
_context.Customers.Update(customer);
_context.SaveChanges();
}
public void Delete(int id)
{
var Customer = _context.Customers.Find(id);
if (Customer != null)
{
_context.Customers.Remove(Customer);
_context.SaveChanges();
}
}
}
public class ProductService
{
private readonly IProductRepository _productRepository;
public ProductService(IProductRepository productRepository)
{
_productRepository = productRepository;
}
public IEnumerable GetProducts()
{
return _productRepository.GetAll();
}
public void AddProduct(Product product)
{
_productRepository.Add(product);
}
// Additional service methods can be added as needed
}
November 18, 2024
Besides SSR, we also have a newer concept, which is CSR. And today I will share about CSR (Client-Side Rendering).
This is also an important area of knowledge in web development.
The article will provide insights into how CSR works, its strengths, and its limitations.
Let's get started...