Tech Journey With Gagan

Thursday, June 26, 2025

🧩 Implementing a Lightweight Query Handler in .NET using GMediator fully free for commerical use

In modern .NET applications, maintaining clean architecture is critical — and that’s where the Mediator pattern shines. It decouples the request/response flow and promotes separation of concerns.

While libraries like MediatR are popular, sometimes you want something even lighter — with zero dependencies.

Enter: GMediator, a custom lightweight mediator implementation.

🚀 What We’ll Build
In this blog, we’ll create a simple GET API using GMediator that returns a list of products stored in an in-memory store — no database, no ORM — just the core pattern in action.
🧱 Step 1: Define the Product Model

Code Snippet

public class Product

{

    public Guid Id { get; set; } = Guid.NewGuid();

    public string Name { get; set; }

    public decimal Price { get; set; }

}

💾 Step 2: Create an In-Memory Store

Code Snippet


public static class ProductStore

{

    public static List<Product> Products { get; set; } = new()

    {

        new Product { Name = "Laptop", Price = 1200 },

        new Product { Name = "Mouse", Price = 20 },

        new Product { Name = "Keyboard", Price = 45 }

    };

}

📬 Step 3: Create the Query Request

Code Snippet

using GMediator.Interfaces;

public class GetAllProducts : IRequest<List<Pro>> { }

public class Pro
{
    public Guid Id { get; set; } = Guid.NewGuid();
    public string Name { get; set; }
    public decimal Price { get; set; }
}
🧠 Step 4: Implement the Query Handler
using GMediator.Interfaces;

public class GetAllProductsHandler : IRequestHandler<GetAllProducts, List<Pro>>
{
    public Task<List<Pro>> Handle(GetAllProducts request, CancellationToken cancellationToken)
    {
        var products = ProductStore.Products
            .Select(x => new Pro { Id = x.Id, Name = x.Name, Price = x.Price })
            .ToList(); // Important: convert to List<Pro>

        return Task.FromResult(products);
    }
}

🎯 Step 5: Create the Controller

Code Snippet

[ApiController]
[Route("api/[controller]")]
public class ProductsController : ControllerBase
{
    private readonly IMediator _mediator;

    public ProductsController(IMediator mediator)
    {
        _mediator = mediator;
    }

    [HttpGet]
    public async Task<IActionResult> Get()
    {
        var products = await _mediator.Send(new GetAllProducts());
        return Ok(products);
    }
}

🧪 Step 6: Register GMediator in Program.cs

Code Snippet

builder.Services.AddGMediator(); // Register your custom GMediator

💡 Final Thoughts
GMediator is a great option for internal projects, low-dependency APIs, or learning the Mediator pattern hands-on.
You can extend this by adding Create, Update, Delete, or integrating with a real database like SQLite or SQL Server.

Wednesday, June 11, 2025

Building a Scalable .NET Backend Using Clean Architecture (With Optional Layers) in just an second

If you're building a new .NET backend, Clean Architecture is the best way to keep your code organized, scalable, and future-proof.
🧱 What is Clean Architecture?
It's a way to structure your project into layers:
Domain – core business models
Application – commands, queries, interfaces
Infrastructure – external services (API, logging, etc.)
Persistence – database (EF Core, SQL)
API – controllers
Tests – optional unit/integration tests
⚙️ Script-Based Setup
You can auto-generate this structure using a simple CMD script.
✅ You choose what to include:
Want Infrastructure? Type y
Need Tests? Type n
Want to skip Persistence? Type n

Steps To use:

1. use notepad save below code as setup-architecture.cmd

Code Snippet

@echo off
SETLOCAL ENABLEEXTENSIONS

:: Prompt for solution name
set /p SOLUTION_NAME=Enter your solution name (e.g., ResumeAI.Optimizer): 

:: Prompt for optional layers
set /p ADD_TESTS=Do you want to add a Tests project? (y/n): 
set /p ADD_PERSISTENCE=Do you want to add a Persistence layer? (y/n): 
set /p ADD_INFRASTRUCTURE=Do you want to add an Infrastructure layer? (y/n): 

:: Create Solution
echo Creating solution...
dotnet new sln -n %SOLUTION_NAME%

:: Create Base Projects
dotnet new webapi -n %SOLUTION_NAME%.API
dotnet new classlib -n %SOLUTION_NAME%.Application
dotnet new classlib -n %SOLUTION_NAME%.Domain

:: Optional Projects
if /i "%ADD_INFRASTRUCTURE%"=="y" (
    dotnet new classlib -n %SOLUTION_NAME%.Infrastructure
)

if /i "%ADD_PERSISTENCE%"=="y" (
    dotnet new classlib -n %SOLUTION_NAME%.Persistence
)

if /i "%ADD_TESTS%"=="y" (
    dotnet new xunit -n %SOLUTION_NAME%.Tests
)

:: Add Projects to Solution
echo Adding projects to solution...
dotnet sln add .\%SOLUTION_NAME%.API\%SOLUTION_NAME%.API.csproj
dotnet sln add .\%SOLUTION_NAME%.Application\%SOLUTION_NAME%.Application.csproj
dotnet sln add .\%SOLUTION_NAME%.Domain\%SOLUTION_NAME%.Domain.csproj

if /i "%ADD_INFRASTRUCTURE%"=="y" (
    dotnet sln add .\%SOLUTION_NAME%.Infrastructure\%SOLUTION_NAME%.Infrastructure.csproj
)

if /i "%ADD_PERSISTENCE%"=="y" (
    dotnet sln add .\%SOLUTION_NAME%.Persistence\%SOLUTION_NAME%.Persistence.csproj
)

if /i "%ADD_TESTS%"=="y" (
    dotnet sln add .\%SOLUTION_NAME%.Tests\%SOLUTION_NAME%.Tests.csproj
)

:: Add Project References
echo Adding project references...

:: API references
dotnet add .\%SOLUTION_NAME%.API\%SOLUTION_NAME%.API.csproj reference ^
    .\%SOLUTION_NAME%.Application\%SOLUTION_NAME%.Application.csproj ^
    .\%SOLUTION_NAME%.Domain\%SOLUTION_NAME%.Domain.csproj

if /i "%ADD_INFRASTRUCTURE%"=="y" (
    dotnet add .\%SOLUTION_NAME%.API\%SOLUTION_NAME%.API.csproj reference .\%SOLUTION_NAME%.Infrastructure\%SOLUTION_NAME%.Infrastructure.csproj
)

if /i "%ADD_PERSISTENCE%"=="y" (
    dotnet add .\%SOLUTION_NAME%.API\%SOLUTION_NAME%.API.csproj reference .\%SOLUTION_NAME%.Persistence\%SOLUTION_NAME%.Persistence.csproj
)

:: Application references Domain
dotnet add .\%SOLUTION_NAME%.Application\%SOLUTION_NAME%.Application.csproj reference .\%SOLUTION_NAME%.Domain\%SOLUTION_NAME%.Domain.csproj

:: Infrastructure and Persistence references
if /i "%ADD_INFRASTRUCTURE%"=="y" (
    dotnet add .\%SOLUTION_NAME%.Infrastructure\%SOLUTION_NAME%.Infrastructure.csproj reference ^
        .\%SOLUTION_NAME%.Application\%SOLUTION_NAME%.Application.csproj ^
        .\%SOLUTION_NAME%.Domain\%SOLUTION_NAME%.Domain.csproj
)

if /i "%ADD_PERSISTENCE%"=="y" (
    dotnet add .\%SOLUTION_NAME%.Persistence\%SOLUTION_NAME%.Persistence.csproj reference ^
        .\%SOLUTION_NAME%.Application\%SOLUTION_NAME%.Application.csproj ^
        .\%SOLUTION_NAME%.Domain\%SOLUTION_NAME%.Domain.csproj
)

:: Test references
if /i "%ADD_TESTS%"=="y" (
    dotnet add .\%SOLUTION_NAME%.Tests\%SOLUTION_NAME%.Tests.csproj reference ^
        .\%SOLUTION_NAME%.Application\%SOLUTION_NAME%.Application.csproj
)

echo.
echo ✅ Clean Architecture setup completed for %SOLUTION_NAME%!
echo.

ENDLOCAL
pause

2. save this file in respective folder where u want your project files
3. open cmd at this location and run this script by just type its name only that is setup-architecture.cmd

Wednesday, May 28, 2025

🔄 How to Extend Component Logic and Template in Angular (Simple Guide) => use of extends and ngTemplateOutlet

When building Angular apps, you might have common logic or reusable layouts across components. Instead of duplicating code, you can use extends in TypeScript and ng-template + ngTemplateOutlet in HTML.

Let’s walk through a simple example with 2 components where one extends logic and also injects custom HTML.

✅ Step 1: Create a Child Component (as base layout)

This is the reusable component that contains a common layout and logic.

child.component.ts

import { Component, Input, TemplateRef } from '@angular/core';

@Component({
  selector: 'app-child',
  templateUrl: './child.component.html',
})
export class ChildComponent {
  @Input() title: string = 'Base Title';
  @Input() contentTemplate?: TemplateRef<any>;

  getTitle(): string {
    return this.title;
  }
}

child.component.html

<div class="card">
  <h2>{{ getTitle() }}</h2>

  <ng-container *ngIf="contentTemplate; else defaultContent">
    <ng-container *ngTemplateOutlet="contentTemplate"></ng-container>
  </ng-container>

  <ng-template #defaultContent>
    <p>This is default content from ChildComponent.</p>
  </ng-template>
</div>

✅ Layout and logic are defined here.
✅ Accepts external HTML through contentTemplate.

✅ Step 2: Create a Parent Component That Extends Child

This component inherits logic from ChildComponent and injects its own template content.

parent.component.ts

import { Component, TemplateRef, ViewChild } from '@angular/core';
import { ChildComponent } from './child.component';

@Component({
  selector: 'app-parent',
  templateUrl: './parent.component.html',
})
export class ParentComponent extends ChildComponent {
  @ViewChild('customHtml', { static: true }) customHtml!: TemplateRef<any>;

  override title = 'Title from ParentComponent';

  ngOnInit() {
    this.contentTemplate = this.customHtml;
  }
}

parent.component.html

<ng-template #customHtml>
  <p>This is custom HTML from <strong>ParentComponent</strong>.</p>
</ng-template>

<app-child [title]="title" [contentTemplate]="contentTemplate"></app-child>

✅ Inherits logic like title and getTitle() from ChildComponent.
✅ Injects its own content via ng-template.

✅ Final Output

ChildComponent provides the reusable layout.
ParentComponent injects dynamic HTML and extends the logic.
This keeps your code DRY, clean, and scalable.

Use Cases: shared card layouts, reusable modal structures, dashboards, etc.

Friday, May 2, 2025

🧹 How to Remove SSR (Server Side Rendering) from an Angular 19 Project

Sometimes you add Angular SSR using @angular/ssr, but later want to return to a clean client-side app. Here's how to fully remove SSR (Server-Side Rendering) from your Angular project. 🔥 Step 1: Delete SSR Files Remove these files from the src/ folder: main.server.ts app.server.module.ts server.ts Any .server.ts files like: app.routes.server.ts app.config.server.ts 🛠️ Step 2: Update angular.json Inside "architect > build > options", remove the following:

 "server": "src/main.server.ts", "outputMode": "server", "ssr": { "entry": "src/server.ts" }

Also remove the entire "server" block from angular.json if it exists. 🧾 Step 3: Clean Up TypeScript Config ❌ Delete: tsconfig.server.json ✅ Edit tsconfig.app.json like this:

 { "extends": "./tsconfig.json", "compilerOptions": { "outDir": "./out-tsc/app", "types": [] }, "files": [], "include": ["src/**/*.ts"] }

🧹 Step 4: Uninstall SSR Dependencies 🖥️ Run in Terminal / PowerShell / CMD:

 npm uninstall @angular/platform-server @nguniversal/express-engine express

🚀 Step 5: Clean & Serve PowerShell (Windows):

 Remove-Item -Recurse -Force node_modules, dist, .angular npm install ng serve

Mac/Linux terminal:

 rm -rf node_modules dist .angular npm install ng serve

✅ Done! Your Angular app is now SSR-free and runs entirely with Client-Side Rendering (CSR) — faster dev, fewer headaches!

Saturday, March 29, 2025

🚀 How to Copy a SQL Server Database Using a .bacpac File (Schema + Data) || Clone DB

#Clone Database
Need to duplicate a full SQL Server database — including tables, views, stored procedures and data — without writing complex scripts?

Let me show you a simple, reliable method: Exporting and Importing a Data-tier Application (.bacpac). It’s perfect for backups, migrations, and creating dev/test clones.

Step 1: Export the Source Database

Open SQL Server Management Studio (SSMS).
Right-click your source database → Tasks → Export Data-tier Application.
Choose "Save to local disk", then pick a file path and name (YourDatabase.bacpac).
Click Next through the wizard and generate the .bacpac file.

Step 2: Import into Target Server

In SSMS, right-click Databases → Import Data-tier Application.
Select the .bacpac file you exported.
Give the new database a name.
Complete the wizard. 🎉 Done!

🧩 Diagram

[ Source DB ]
     |
     |  Export as .bacpac
     ↓
[ YourFile.bacpac ]
     |
     |  Import on Target Server
     ↓
[ New DB Clone ]
 Why Use This?
🔄 Migrate databases between environments (dev, staging, prod).
🛠️ Create dev/test clones without risking production.
📦 Archive snapshots with both schema and data.

Friday, March 14, 2025

Run ai model in python code with ollama

First download and install ollama By this blog:
Tech Journey With Gagan: Run Any AI Model with ollama in windows

For Use AI model in python:
1. run this script
Note: this example for mistral ai model please change acording to your model

Declare function

import requests
def ai_generate(prompt):
    response = requests.post('http://localhost:11434/api/generate', json={
        'model': 'mistral',
        'prompt': prompt,
        'stream': False
    })
    return response.json().get('response', 'Error: No response from AI.')