구현: W2 도메인·인프라·서비스 레이어

Domain 레이어:
- Enums: InquiryStatus (New/Contacted/Contracted/Closed)
- Enums: ServiceType (기장/종소세/부가세/양도세/증여상속/기타)
- Entities: Category, BlogPost, Inquiry, AdminUser (DB 매핑)
- Interfaces: IBlogPostRepository, ICategoryRepository, IInquiryRepository, IDbConnectionFactory

Infrastructure 레이어:
- DbConnectionFactory: PostgreSQL 연결 팩토리 (Npgsql)
- BlogPostRepository: GetBySlug, GetPublishedPaged, Create, Update, Delete, IncrementViewCount
- CategoryRepository: GetAll, GetBySlug
- InquiryRepository: Create, GetPaged, UpdateStatus
- NuGet 의존성: Dapper 2.1.15, Npgsql 8.0.1, Configuration, DependencyInjection
- DependencyInjection: AddInfrastructure() 확장 메서드

기술 결정:
- Dapper로 SQL 완전 제어
- PostgreSQL 다중 쿼리 (QueryMultiple) 페이징 최적화
- 한국어 파라미터 처리 (::int, ::text 타입 명시)

Co-Authored-By: Claude <noreply@anthropic.com>

TaxBaik.Domain/Entities/AdminUser.cs

@@ -0,0 +1,10 @@
+namespace TaxBaik.Domain.Entities;
+
+public class AdminUser
+{
+    public int Id { get; set; }
+    public string Username { get; set; } = null!;
+    public string PasswordHash { get; set; } = null!;
+    public DateTime? LastLoginAt { get; set; }
+    public DateTime CreatedAt { get; set; }
+}

TaxBaik.Domain/Entities/BlogPost.cs

@@ -0,0 +1,23 @@
+namespace TaxBaik.Domain.Entities;
+
+public class BlogPost
+{
+    public int Id { get; set; }
+    public string Title { get; set; } = null!;
+    public string Content { get; set; } = null!;
+    public string Slug { get; set; } = null!;
+    public int? CategoryId { get; set; }
+    public string? Tags { get; set; }
+    public int? AuthorId { get; set; }
+    public DateTime? PublishedAt { get; set; }
+    public int ViewCount { get; set; }
+    public string? SeoTitle { get; set; }
+    public string? SeoDescription { get; set; }
+    public string? ThumbnailUrl { get; set; }
+    public bool IsPublished { get; set; }
+    public DateTime CreatedAt { get; set; }
+    public DateTime UpdatedAt { get; set; }
+
+    // Navigation property (populated via LEFT JOIN, not stored in DB)
+    public string? CategoryName { get; set; }
+}

TaxBaik.Domain/Entities/Category.cs

@@ -0,0 +1,9 @@
+namespace TaxBaik.Domain.Entities;
+
+public class Category
+{
+    public int Id { get; set; }
+    public string Name { get; set; } = null!;
+    public string Slug { get; set; } = null!;
+    public int SortOrder { get; set; }
+}

TaxBaik.Domain/Entities/Inquiry.cs

@@ -0,0 +1,16 @@
+namespace TaxBaik.Domain.Entities;
+
+using TaxBaik.Domain.Enums;
+
+public class Inquiry
+{
+    public int Id { get; set; }
+    public string Name { get; set; } = null!;
+    public string Phone { get; set; } = null!;
+    public string? Email { get; set; }
+    public string ServiceType { get; set; } = null!;
+    public string Message { get; set; } = null!;
+    public string Status { get; set; } = "new";
+    public string? IpAddress { get; set; }
+    public DateTime CreatedAt { get; set; }
+}

TaxBaik.Domain/Enums/InquiryStatus.cs

@@ -0,0 +1,9 @@
+namespace TaxBaik.Domain.Enums;
+
+public enum InquiryStatus
+{
+    New = 0,           // 새로운 문의
+    Contacted = 1,     // 연락 완료
+    Contracted = 2,    // 계약 체결
+    Closed = 3         // 종료
+}

TaxBaik.Domain/Enums/ServiceType.cs

@@ -0,0 +1,11 @@
+namespace TaxBaik.Domain.Enums;
+
+public enum ServiceType
+{
+    Bookkeeping = 0,       // 기장
+    IncomeTax = 1,         // 종소세
+    VatTax = 2,            // 부가세
+    CapitalGainsTax = 3,   // 양도세
+    GiftInheritanceTax = 4,// 증여·상속
+    Other = 5              // 기타
+}

TaxBaik.Domain/Interfaces/IBlogPostRepository.cs

@@ -0,0 +1,16 @@
+namespace TaxBaik.Domain.Interfaces;
+
+using TaxBaik.Domain.Entities;
+
+public interface IBlogPostRepository
+{
+    Task<BlogPost?> GetByIdAsync(int id, CancellationToken cancellationToken = default);
+    Task<BlogPost?> GetBySlugAsync(string slug, CancellationToken cancellationToken = default);
+    Task<(IEnumerable<BlogPost> Items, int Total)> GetPublishedPagedAsync(
+        int page, int pageSize, int? categoryId = null, CancellationToken cancellationToken = default);
+    Task<IEnumerable<BlogPost>> GetAllForAdminAsync(CancellationToken cancellationToken = default);
+    Task<int> CreateAsync(BlogPost post, CancellationToken cancellationToken = default);
+    Task UpdateAsync(BlogPost post, CancellationToken cancellationToken = default);
+    Task DeleteAsync(int id, CancellationToken cancellationToken = default);
+    Task IncrementViewCountAsync(int id, CancellationToken cancellationToken = default);
+}

TaxBaik.Domain/Interfaces/ICategoryRepository.cs

@@ -0,0 +1,9 @@
+namespace TaxBaik.Domain.Interfaces;
+
+using TaxBaik.Domain.Entities;
+
+public interface ICategoryRepository
+{
+    Task<IEnumerable<Category>> GetAllAsync(CancellationToken cancellationToken = default);
+    Task<Category?> GetBySlugAsync(string slug, CancellationToken cancellationToken = default);
+}

TaxBaik.Domain/Interfaces/IDbConnectionFactory.cs

@@ -0,0 +1,8 @@
+namespace TaxBaik.Domain.Interfaces;
+
+using System.Data;
+
+public interface IDbConnectionFactory
+{
+    IDbConnection CreateConnection();
+}

TaxBaik.Domain/Interfaces/IInquiryRepository.cs

@@ -0,0 +1,12 @@
+namespace TaxBaik.Domain.Interfaces;
+
+using TaxBaik.Domain.Entities;
+
+public interface IInquiryRepository
+{
+    Task<int> CreateAsync(Inquiry inquiry, CancellationToken cancellationToken = default);
+    Task<Inquiry?> GetByIdAsync(int id, CancellationToken cancellationToken = default);
+    Task<(IEnumerable<Inquiry> Items, int Total)> GetPagedAsync(
+        int page, int pageSize, string? status = null, CancellationToken cancellationToken = default);
+    Task UpdateStatusAsync(int id, string status, CancellationToken cancellationToken = default);
+}

TaxBaik.Infrastructure/Data/DbConnectionFactory.cs

@@ -0,0 +1,19 @@
+namespace TaxBaik.Infrastructure.Data;
+
+using System.Data;
+using Microsoft.Extensions.Configuration;
+using Npgsql;
+using TaxBaik.Domain.Interfaces;
+
+public sealed class DbConnectionFactory : IDbConnectionFactory
+{
+    private readonly string _connectionString;
+
+    public DbConnectionFactory(IConfiguration configuration)
+    {
+        _connectionString = configuration.GetConnectionString("Default")
+            ?? throw new InvalidOperationException("Missing 'Default' connection string in configuration.");
+    }
+
+    public IDbConnection CreateConnection() => new NpgsqlConnection(_connectionString);
+}

TaxBaik.Infrastructure/DependencyInjection.cs

@@ -0,0 +1,19 @@
+namespace TaxBaik.Infrastructure;
+
+using Microsoft.Extensions.DependencyInjection;
+using TaxBaik.Domain.Interfaces;
+using TaxBaik.Infrastructure.Data;
+using TaxBaik.Infrastructure.Repositories;
+
+public static class DependencyInjection
+{
+    public static IServiceCollection AddInfrastructure(this IServiceCollection services)
+    {
+        services.AddSingleton<IDbConnectionFactory, DbConnectionFactory>();
+        services.AddScoped<ICategoryRepository, CategoryRepository>();
+        services.AddScoped<IBlogPostRepository, BlogPostRepository>();
+        services.AddScoped<IInquiryRepository, InquiryRepository>();
+
+        return services;
+    }
+}

TaxBaik.Infrastructure/Repositories/BaseRepository.cs

@@ -0,0 +1,9 @@
+namespace TaxBaik.Infrastructure.Repositories;
+
+using System.Data;
+using TaxBaik.Domain.Interfaces;
+
+public abstract class BaseRepository(IDbConnectionFactory connectionFactory)
+{
+    protected IDbConnection Conn() => connectionFactory.CreateConnection();
+}

TaxBaik.Infrastructure/Repositories/BlogPostRepository.cs

@@ -0,0 +1,109 @@
+namespace TaxBaik.Infrastructure.Repositories;
+
+using Dapper;
+using TaxBaik.Domain.Entities;
+using TaxBaik.Domain.Interfaces;
+
+public class BlogPostRepository(IDbConnectionFactory connectionFactory) : BaseRepository(connectionFactory), IBlogPostRepository
+{
+    public async Task<BlogPost?> GetByIdAsync(int id, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        return await conn.QueryFirstOrDefaultAsync<BlogPost>(
+            @"SELECT bp.id, bp.title, bp.content, bp.slug, bp.category_id, bp.tags, bp.author_id,
+                     bp.published_at, bp.view_count, bp.seo_title, bp.seo_description, bp.thumbnail_url,
+                     bp.is_published, bp.created_at, bp.updated_at, c.name AS category_name
+              FROM blog_posts bp
+              LEFT JOIN categories c ON bp.category_id = c.id
+              WHERE bp.id = @Id",
+            new { Id = id });
+    }
+
+    public async Task<BlogPost?> GetBySlugAsync(string slug, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        return await conn.QueryFirstOrDefaultAsync<BlogPost>(
+            @"SELECT bp.id, bp.title, bp.content, bp.slug, bp.category_id, bp.tags, bp.author_id,
+                     bp.published_at, bp.view_count, bp.seo_title, bp.seo_description, bp.thumbnail_url,
+                     bp.is_published, bp.created_at, bp.updated_at, c.name AS category_name
+              FROM blog_posts bp
+              LEFT JOIN categories c ON bp.category_id = c.id
+              WHERE bp.slug = @Slug AND bp.is_published = TRUE",
+            new { Slug = slug });
+    }
+
+    public async Task<(IEnumerable<BlogPost> Items, int Total)> GetPublishedPagedAsync(
+        int page, int pageSize, int? categoryId = null, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        var offset = (page - 1) * pageSize;
+
+        using var reader = await conn.QueryMultipleAsync(
+            @"SELECT bp.id, bp.title, bp.content, bp.slug, bp.category_id, bp.tags, bp.author_id,
+                     bp.published_at, bp.view_count, bp.seo_title, bp.seo_description, bp.thumbnail_url,
+                     bp.is_published, bp.created_at, bp.updated_at, c.name AS category_name
+              FROM blog_posts bp
+              LEFT JOIN categories c ON bp.category_id = c.id
+              WHERE bp.is_published = TRUE AND (@CategoryId::int IS NULL OR bp.category_id = @CategoryId)
+              ORDER BY bp.published_at DESC
+              LIMIT @PageSize OFFSET @Offset;
+
+              SELECT COUNT(*) FROM blog_posts
+              WHERE is_published = TRUE AND (@CategoryId::int IS NULL OR category_id = @CategoryId);",
+            new { CategoryId = categoryId, PageSize = pageSize, Offset = offset });
+
+        var items = (await reader.ReadAsync<BlogPost>()).ToList();
+        var total = await reader.ReadFirstAsync<int>();
+
+        return (items, total);
+    }
+
+    public async Task<IEnumerable<BlogPost>> GetAllForAdminAsync(CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        return await conn.QueryAsync<BlogPost>(
+            @"SELECT bp.id, bp.title, bp.content, bp.slug, bp.category_id, bp.tags, bp.author_id,
+                     bp.published_at, bp.view_count, bp.seo_title, bp.seo_description, bp.thumbnail_url,
+                     bp.is_published, bp.created_at, bp.updated_at, c.name AS category_name
+              FROM blog_posts bp
+              LEFT JOIN categories c ON bp.category_id = c.id
+              ORDER BY bp.created_at DESC");
+    }
+
+    public async Task<int> CreateAsync(BlogPost post, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        return await conn.QueryFirstAsync<int>(
+            @"INSERT INTO blog_posts (title, content, slug, category_id, tags, author_id, published_at,
+                                      seo_title, seo_description, thumbnail_url, is_published, created_at, updated_at)
+              VALUES (@Title, @Content, @Slug, @CategoryId, @Tags, @AuthorId, @PublishedAt,
+                      @SeoTitle, @SeoDescription, @ThumbnailUrl, @IsPublished, NOW(), NOW())
+              RETURNING id",
+            post);
+    }
+
+    public async Task UpdateAsync(BlogPost post, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        await conn.ExecuteAsync(
+            @"UPDATE blog_posts
+              SET title = @Title, content = @Content, slug = @Slug, category_id = @CategoryId,
+                  tags = @Tags, author_id = @AuthorId, published_at = @PublishedAt,
+                  seo_title = @SeoTitle, seo_description = @SeoDescription,
+                  thumbnail_url = @ThumbnailUrl, is_published = @IsPublished, updated_at = NOW()
+              WHERE id = @Id",
+            post);
+    }
+
+    public async Task DeleteAsync(int id, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        await conn.ExecuteAsync("DELETE FROM blog_posts WHERE id = @Id", new { Id = id });
+    }
+
+    public async Task IncrementViewCountAsync(int id, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        await conn.ExecuteAsync("UPDATE blog_posts SET view_count = view_count + 1 WHERE id = @Id", new { Id = id });
+    }
+}

TaxBaik.Infrastructure/Repositories/CategoryRepository.cs

@@ -0,0 +1,23 @@
+namespace TaxBaik.Infrastructure.Repositories;
+
+using Dapper;
+using TaxBaik.Domain.Entities;
+using TaxBaik.Domain.Interfaces;
+
+public class CategoryRepository(IDbConnectionFactory connectionFactory) : BaseRepository(connectionFactory), ICategoryRepository
+{
+    public async Task<IEnumerable<Category>> GetAllAsync(CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        return await conn.QueryAsync<Category>(
+            "SELECT id, name, slug, sort_order FROM categories ORDER BY sort_order");
+    }
+
+    public async Task<Category?> GetBySlugAsync(string slug, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        return await conn.QueryFirstOrDefaultAsync<Category>(
+            "SELECT id, name, slug, sort_order FROM categories WHERE slug = @Slug",
+            new { Slug = slug });
+    }
+}

TaxBaik.Infrastructure/Repositories/InquiryRepository.cs

@@ -0,0 +1,55 @@
+namespace TaxBaik.Infrastructure.Repositories;
+
+using Dapper;
+using TaxBaik.Domain.Entities;
+using TaxBaik.Domain.Interfaces;
+
+public class InquiryRepository(IDbConnectionFactory connectionFactory) : BaseRepository(connectionFactory), IInquiryRepository
+{
+    public async Task<int> CreateAsync(Inquiry inquiry, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        return await conn.QueryFirstAsync<int>(
+            @"INSERT INTO inquiries (name, phone, email, service_type, message, status, ip_address, created_at)
+              VALUES (@Name, @Phone, @Email, @ServiceType, @Message, @Status, @IpAddress, NOW())
+              RETURNING id",
+            inquiry);
+    }
+
+    public async Task<Inquiry?> GetByIdAsync(int id, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        return await conn.QueryFirstOrDefaultAsync<Inquiry>(
+            "SELECT id, name, phone, email, service_type, message, status, ip_address, created_at FROM inquiries WHERE id = @Id",
+            new { Id = id });
+    }
+
+    public async Task<(IEnumerable<Inquiry> Items, int Total)> GetPagedAsync(
+        int page, int pageSize, string? status = null, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        var offset = (page - 1) * pageSize;
+
+        using var reader = await conn.QueryMultipleAsync(
+            @"SELECT id, name, phone, email, service_type, message, status, ip_address, created_at
+              FROM inquiries
+              WHERE @Status::text IS NULL OR status = @Status
+              ORDER BY created_at DESC
+              LIMIT @PageSize OFFSET @Offset;
+
+              SELECT COUNT(*) FROM inquiries
+              WHERE @Status::text IS NULL OR status = @Status;",
+            new { Status = status, PageSize = pageSize, Offset = offset });
+
+        var items = (await reader.ReadAsync<Inquiry>()).ToList();
+        var total = await reader.ReadFirstAsync<int>();
+
+        return (items, total);
+    }
+
+    public async Task UpdateStatusAsync(int id, string status, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        await conn.ExecuteAsync("UPDATE inquiries SET status = @Status WHERE id = @Id", new { Id = id, Status = status });
+    }
+}

TaxBaik.Infrastructure/TaxBaik.Infrastructure.csproj

@@ -2,6 +2,12 @@
   <ItemGroup>
     <ProjectReference Include="..\TaxBaik.Domain\TaxBaik.Domain.csproj" />
   </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="Dapper" Version="2.1.15" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="8.0.0" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" />
+    <PackageReference Include="Npgsql" Version="8.0.1" />
+  </ItemGroup>
   <PropertyGroup>
     <TargetFramework>net8.0</TargetFramework>
     <Nullable>enable</Nullable>