feat: jwt token example

Program.cs

@@ -1,6 +1,9 @@
+using Microsoft.AspNetCore.Authentication.JwtBearer;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.IdentityModel.Tokens;
 using QuotifyBE.Data;
 using QuotifyBE.Entities;
+using System.Text;
 
 var builder = WebApplication.CreateBuilder(args);
 
@@ -9,7 +12,34 @@ var connectionString = builder.Configuration.GetConnectionString("DefaultConnect
 builder.Services.AddDbContext<ApplicationDbContext>(options =>
     options.UseNpgsql(connectionString));
 
+var JwtSecret = builder.Configuration["JwtSecret"]
+    ?? throw new InvalidOperationException("JWT token secret is not configured!!! Please configure JwtSecret in appsettings.json!");
+
+var DomainName = builder.Configuration["DomainName"]
+    ?? throw new InvalidOperationException("Domain name is not configured!!! Please configure DomainName in appsettings.json!");
+
+// Configure JWT authentication
+// https://medium.com/@solomongetachew112/jwt-authentication-in-net-8-a-complete-guide-for-secure-and-scalable-applications-6281e5e8667c
+builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
+    .AddJwtBearer(options =>
+    {
+        options.TokenValidationParameters = new TokenValidationParameters
+        {
+            ValidateIssuer = true,
+            ValidateAudience = true,
+            ValidateLifetime = true,
+            ValidateIssuerSigningKey = true,
+            ValidIssuer = DomainName,
+            ValidAudience = DomainName,
+            IssuerSigningKey = new SymmetricSecurityKey(
+                Encoding.UTF8.GetBytes(JwtSecret)
+            )
+        };
+    });
+
 // Add services to the container.
+builder.Services.AddAuthorization();
+builder.Services.AddSingleton(builder.Configuration);
 
 builder.Services.AddControllers();
 // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
@@ -28,6 +58,7 @@ if (app.Environment.IsDevelopment())
 
 app.UseHttpsRedirection();
 
+app.UseAuthentication();
 app.UseAuthorization();
 
 app.MapControllers();