Merge pull request #1 from FullstackCodingGuy/graphql-implementation

Graphql implementation

Author: codeandwhisky

README.md

@@ -8,27 +8,38 @@ This project is a boilerplate for building .NET API applications with various fe
 
 ## Features
 
-- [ ] [Vertical Slicing Architecture](https://github.com/FullstackCodingGuy/Developer-Fundamentals/wiki/Architecture-%E2%80%90-Vertical-Slicing-Architecture)
+- [x] [Vertical Slicing Architecture](https://github.com/FullstackCodingGuy/Developer-Fundamentals/wiki/Architecture-%E2%80%90-Vertical-Slicing-Architecture)
 - [x] Swagger
 - [x] Minimal API
+- [x] **GraphQL API with HotChocolate**
+  - [x] Professional architecture with clean separation
+  - [x] Complete blog management domain (Blogs, Posts, Comments)
+  - [x] DataLoaders for N+1 query prevention
+  - [x] Real-time subscriptions with Redis
+  - [x] Built-in GraphQL Playground and Schema explorer
+  - [x] Query complexity analysis and rate limiting
+  - [x] Field-level authorization support
+  - [x] Comprehensive error handling
+  - [x] Performance monitoring and observability
 - [x] Authentication using JWT Bearer tokens
-- [ ] Authorization
+- [x] Authorization with role-based access control
 - [x] Rate limiting to prevent API abuse
 - [x] CORS policies for secure cross-origin requests
 - [x] Response caching and compression
 - [x] Logging with Serilog
 - [x] Health check endpoint
 - [x] [Middlewares](https://github.com/FullstackCodingGuy/dotnetapi-boilerplate/tree/main/src/Middlewares)
-- [ ] Entity Framework
-- [ ] Serilog
-- [ ] FluentValidation
+- [x] Entity Framework Core with SQLite
+- [x] Serilog with structured logging
+ - [x] FluentValidation
 - [ ] Vault Integration
 - [ ] MQ Integration
-- [ ] Application Resiliency
-- [ ] Performance
-  - [ ] Response Compression
-  - [ ] Response Caching 
-  - [ ] Metrics
+- [x] Application Resiliency (GraphQL level)
+- [x] Performance
+  - [x] Response Compression
+  - [x] Response Caching 
+  - [x] GraphQL query optimization
+  - [x] DataLoaders for efficient data fetching
 - [ ] Deployment
   - [ ] Docker
   - [ ] Podman
@@ -98,13 +109,251 @@ docker-compose down
 
 The application includes a health check endpoint to verify that the API is running. You can access it at:
 
-
 ```
 GET /health
 
 This will return a simple "Healthy" message.
 ```
 
+## GraphQL API
+
+This boilerplate includes a comprehensive GraphQL implementation using HotChocolate, designed with professional architecture patterns and enterprise-grade features.
+
+### GraphQL Features
+
+#### 🏗️ **Professional Architecture**
+- **Clean Architecture**: Vertical slicing with clear separation of concerns
+- **Domain-Driven Design**: Blog management domain with Blogs, Posts, and Comments
+- **Repository Pattern**: Abstracted data access with Entity Framework Core
+- **Service Layer**: Business logic separation with comprehensive services
+
+#### 🚀 **Core GraphQL Capabilities**
+- **Complete CRUD Operations**: Full Create, Read, Update, Delete support
+- **Advanced Querying**: Complex filtering, sorting, and pagination
+- **Real-time Subscriptions**: Live updates using Redis as message broker
+- **Field-level Authorization**: Granular security control
+- **Input Validation**: Comprehensive data validation and sanitization
+
+#### ⚡ **Performance Optimization**
+- **DataLoaders**: Automatic N+1 query prevention with batch loading
+- **Query Complexity Analysis**: Protection against expensive queries
+- **Response Caching**: Intelligent caching strategies
+- **Database Optimization**: Efficient EF Core queries with projections
+
+#### 🔐 **Security & Observability**
+- **JWT Authentication**: Seamless integration with existing auth
+- **Role-based Authorization**: Fine-grained access control
+- **Rate Limiting**: GraphQL-specific rate limiting
+- **Comprehensive Logging**: Structured logging with Serilog
+- **Error Handling**: Professional error responses with detailed context
+
+#### 🛠️ **Developer Experience**
+- **Built-in GraphQL Playground**: Interactive query interface at `/graphql`
+- **Schema Explorer**: Full schema documentation and introspection
+- **Type Safety**: Strongly typed resolvers and models
+- **Extensible Design**: Easy to add new types and features
+
+### GraphQL Endpoints
+
+#### **Main GraphQL Endpoint**
+```
+POST /graphql
+```
+- Primary endpoint for all GraphQL operations
+- Supports queries, mutations, and subscriptions
+- Built-in GraphQL Playground available in development
+
+#### **GraphQL Playground** (Development)
+```
+GET /graphql
+```
+- Interactive GraphQL IDE
+- Schema exploration and documentation
+- Query testing and validation
+- Real-time subscription testing
+
+### Example Queries
+
+#### **Get All Blogs with Posts**
+```graphql
+query GetBlogsWithPosts {
+  blogs {
+    id
+    name
+    description
+    posts {
+      id
+      title
+      content
+      author {
+        name
+        email
+      }
+      comments {
+        id
+        content
+        author
+      }
+    }
+  }
+}
+```
+
+#### **Create a New Blog**
+```graphql
+mutation CreateBlog {
+  createBlog(input: {
+    name: "Tech Blog"
+    description: "A blog about technology"
+    author: "John Doe"
+    tags: ["tech", "programming"]
+  }) {
+    blog {
+      id
+      name
+      description
+      author
+      tags
+      createdAt
+    }
+    errors {
+      message
+    }
+  }
+}
+```
+
+#### **Subscribe to New Posts**
+```graphql
+subscription NewPosts {
+  onPostCreated {
+    id
+    title
+    content
+    blog {
+      name
+    }
+    author {
+      name
+    }
+  }
+}
+```
+
+#### **Complex Query with Filtering**
+```graphql
+query SearchPosts {
+  posts(
+    where: {
+      and: [
+        { title: { contains: "GraphQL" } }
+        { isPublished: { eq: true } }
+        { createdAt: { gte: "2024-01-01" } }
+      ]
+    }
+    order: [{ createdAt: DESC }]
+    take: 10
+  ) {
+    id
+    title
+    content
+    blog {
+      name
+    }
+    commentCount
+    viewCount
+  }
+}
+```
+
+### Architecture Overview
+
+```
+Features/GraphQL/
+├── Configuration/          # GraphQL server configuration
+│   └── GraphQLConfiguration.cs
+├── Models/                 # GraphQL types and DTOs
+│   ├── BlogType.cs
+│   ├── PostType.cs
+│   ├── CommentType.cs
+│   └── AuthorType.cs
+├── Services/              # Business logic services
+│   ├── IBlogService.cs
+│   ├── BlogService.cs
+│   ├── IPostService.cs
+│   └── PostService.cs
+├── Resolvers/             # GraphQL resolvers
+│   ├── Query.cs           # Query operations
+│   ├── Mutation.cs        # Mutation operations
+│   ├── Subscription.cs    # Real-time subscriptions
+│   └── FieldResolvers.cs  # Field-level resolvers
+└── DataLoaders/           # Performance optimization
+    ├── BlogDataLoaders.cs
+    └── PostDataLoaders.cs
+```
+
+### Performance Features
+
+#### **DataLoaders**
+Automatically batches and caches database queries to prevent N+1 problems:
+- `BlogByIdDataLoader`: Efficient blog loading by ID
+- `PostsByBlogIdDataLoader`: Batch loading of posts by blog
+- `CommentsByPostIdDataLoader`: Efficient comment loading
+
+#### **Query Complexity Analysis**
+Protects against expensive queries with configurable limits:
+- Maximum query depth: 10 levels
+- Maximum query complexity: 1000 points
+- Field introspection limits in production
+
+#### **Caching Strategy**
+Multi-level caching for optimal performance:
+- DataLoader-level caching (request scoped)
+- Service-level caching for expensive operations
+- Response caching for static data
+
+### Getting Started with GraphQL
+
+1. **Start the application**:
+   ```bash
+   dotnet run
+   ```
+
+2. **Open GraphQL Playground**:
+   Navigate to `http://localhost:8000/graphql`
+
+3. **Explore the Schema**:
+   Use the schema explorer to understand available types and operations
+
+4. **Try Sample Queries**:
+   Copy and paste the example queries above
+
+5. **Test Real-time Features**:
+   Open multiple browser tabs to test subscriptions
+
+### Configuration
+
+GraphQL is configured in `Features/GraphQL/Configuration/GraphQLConfiguration.cs` with:
+
+- **HotChocolate Server**: Latest version with all features enabled
+- **Entity Framework Integration**: Automatic query translation
+- **Redis Subscriptions**: Real-time capabilities
+- **Authentication Integration**: JWT token validation
+- **Error Handling**: Professional error responses
+- **Performance Monitoring**: Query execution tracking
+
+### Best Practices Implemented
+
+- **Single Responsibility**: Each resolver handles one concern
+- **Dependency Injection**: All services properly registered
+- **Async/Await**: Non-blocking operations throughout
+- **Error Boundaries**: Comprehensive error handling
+- **Type Safety**: Strong typing for all operations
+- **Documentation**: Inline documentation for all types
+- **Testing Ready**: Architecture supports unit and integration testing
+
+This GraphQL implementation provides a solid foundation for building modern, efficient APIs with excellent developer experience and enterprise-grade performance.
+
 ### Logging with Serilog
 
 Serilog is configured to log to the console and a file with daily rotation. You can customize the logging settings in the `serilog.json` file.