cv-site/doc/00-GO-DOCUMENTATION-INDEX.md

CV Site Go Documentation

Comprehensive documentation for the Go implementation of the CV site.

Documentation Overview

This documentation covers the core Go systems that power the CV site, with a focus on architecture, implementation details, and practical usage examples.

📚 Documentation Files

1. Go Validation System (739 lines)

   • Tag-based validation with reflection caching
   • Built-in validation rules (required, email, pattern, etc.)
   • Security validation (injection prevention, honeypot, timing)
   • Custom rule extension guide
   • Complete ContactFormRequest example

2. Go Template System (894 lines)

   • Thread-safe template manager
   • Hot reload mechanism for development
   • Custom template functions (iterate, eq, safeHTML, dict)
   • Template organization and patterns
   • Performance optimizations

3. Go Routes and API (1,203 lines)

   • Complete route table with descriptions
   • Middleware chain architecture
   • Security features (CSP, HSTS, rate limiting)
   • Protected endpoints and authentication
   • API request/response formats

Quick Navigation

By Feature

Validation:

• Tag Syntax
• Available Rules
• ContactFormRequest Example
• Error Handling
• Security Rules

Templates:

• Custom Functions
• Hot Reload
• Thread Safety
• Template Patterns
• Security Best Practices

Routes:

• Route Table
• Middleware Stack
• Contact Form API
• PDF Export
• Security Features

By Use Case

Setting Up Validation:

1. Define struct with tags
2. Call validator
3. Handle errors

Creating Templates:

1. Initialize manager
2. Use custom functions
3. Render in handlers

Adding Routes:

1. Configure middleware
2. Register handlers
3. Apply security

System Architecture

Overall Flow

┌──────────────────────────────────────────────────────────────┐
│                        HTTP Request                          │
└──────────────────────┬───────────────────────────────────────┘
                       │
                       v
┌──────────────────────────────────────────────────────────────┐
│                    Middleware Chain                          │
│  Recovery → Logger → SecurityHeaders → DynamicCache →        │
│  Preferences → Router                                        │
└──────────────────────┬───────────────────────────────────────┘
                       │
                       v
┌──────────────────────────────────────────────────────────────┐
│                      Route Handler                           │
│  1. Parse request                                            │
│  2. Get preferences from context                             │
│  3. Load data (CV, config)                                   │
│  4. Validate input (if needed)                               │
│  5. Render template                                          │
└──────────────────────┬───────────────────────────────────────┘
                       │
                       v
┌──────────────────────────────────────────────────────────────┐
│                   Template Rendering                         │
│  1. Load template (hot reload in dev)                        │
│  2. Execute with data                                        │
│  3. Apply custom functions                                   │
│  4. Output HTML                                              │
└──────────────────────┬───────────────────────────────────────┘
                       │
                       v
┌──────────────────────────────────────────────────────────────┐
│                     HTTP Response                            │
│  - Security headers                                          │
│  - Cache headers                                             │
│  - Content-Type                                              │
│  - HTML/JSON/PDF body                                        │
└──────────────────────────────────────────────────────────────┘

Contact Form Flow

POST /api/contact
      │
      v
┌─────────────────────┐
│  BrowserOnly        │  Check User-Agent, Referer, Headers
│  Middleware         │  → 403 if not browser
└─────────┬───────────┘
          │
          v
┌─────────────────────┐
│  RateLimiter        │  5 requests/hour per IP
│  (5/hour)           │  → 429 if exceeded
└─────────┬───────────┘
          │
          v
┌─────────────────────┐
│  Parse JSON         │  Decode ContactFormRequest
│  Request Body       │
└─────────┬───────────┘
          │
          v
┌─────────────────────┐
│  Validate with      │  Tag-based validation:
│  ValidateV2()       │  - required, trim, max
│                     │  - email, pattern
│                     │  - no_injection, honeypot
│                     │  - timing (2s-24h)
└─────────┬───────────┘
          │
          ├─> Validation Failed → 400 + errors
          │
          v
┌─────────────────────┐
│  Send Email         │  SMTP or email service
└─────────┬───────────┘
          │
          v
┌─────────────────────┐
│  200 OK             │  Success response
│  {success: true}    │
└─────────────────────┘

Key Features

1. Validation System

Highlights:

• Reflection-based with sync.Map caching for performance
• Declarative tag syntax: validate:"required,email,max=254"
• 11+ built-in rules including security rules
• Extensible with custom rules
• Thread-safe concurrent validation

Performance:

• First validation: ~2000 ns/op
• Cached validations: ~1500 ns/op
• Pre-compiled regex patterns

Security:

• Email header injection prevention
• Honeypot bot detection
• Timing-based bot detection
• HTML sanitization
• UTF-8 aware length validation

2. Template System

Highlights:

• Thread-safe with sync.RWMutex
• Hot reload in development (edit without restart)
• 4 custom template functions
• Recursive partial loading
• Production caching

Custom Functions:

• iterate(count) - Generate integer ranges
• eq(a, b) - String equality
• safeHTML(s) - Safe HTML (trusted content only)
• dict(k1, v1, ...) - Create maps for sub-templates

Thread Safety:

• Development: Full lock during reload
• Production: Read-only lock (concurrent)

3. Routes and Middleware

Highlights:

• 15+ routes (public, HTMX, API, protected)
• 8 middleware layers
• Comprehensive security headers
• Rate limiting (contact: 5/hour, PDF: 3/min)
• Origin checking for PDF exports

Security Features:

• Content Security Policy (CSP)
• HTTP Strict Transport Security (HSTS)
• BrowserOnly middleware (blocks curl/Postman)
• Email header injection prevention
• Rate limiting per IP
• Origin/Referer validation

Code Examples

Validation Example

// Define struct with validation tags
type ContactFormRequest struct {
    Name    string `json:"name"    validate:"required,trim,max=100,pattern=name"`
    Email   string `json:"email"   validate:"required,email,no_injection"`
    Message string `json:"message" validate:"required,trim,max=5000,sanitize"`
}

// Validate
if err := validation.ValidateContactFormV2(req); err != nil {
    // Handle validation errors
    validationErrors := err.(validation.ValidationErrors)
    return c.JSON(400, map[string]interface{}{
        "errors": validationErrors,
    })
}

Template Example

// Initialize template manager
cfg := &config.TemplateConfig{
    Dir:         "templates",
    PartialsDir: "templates/partials",
    HotReload:   true, // Development
}
manager, _ := templates.NewManager(cfg)

// Render in handler
tmpl, _ := manager.Render("home.html")
tmpl.Execute(w, map[string]interface{}{
    "Title": "CV",
    "CV":    cvData,
})

Route Example

// Protected contact endpoint
contactRateLimiter := middleware.NewRateLimiter(5, 1*time.Hour)
protectedHandler := middleware.BrowserOnly(
    contactRateLimiter.Middleware(
        http.HandlerFunc(cvHandler.HandleContact),
    ),
)
mux.Handle("/api/contact", protectedHandler)

Testing

Run All Tests

# Run all tests
go test ./...

# Run with coverage
go test -cover ./...

# Run specific package
go test ./internal/validation/...

# Run with verbose output
go test -v ./internal/routes/...

Test Examples

# Validation tests
go test ./internal/validation/ -v

# Template tests
go test ./internal/templates/ -v

# Middleware tests
go test ./internal/middleware/ -v

# Handler tests
go test ./internal/handlers/ -v

Performance

Benchmarks

# Run benchmarks
go test -bench=. ./...

# Validation benchmarks
go test -bench=Validate ./internal/validation/

# Template benchmarks
go test -bench=Render ./internal/templates/

Typical Performance

Validation:

• Contact form validation: ~1.5 µs
• Email validation: ~500 ns
• Pattern matching: ~300 ns (pre-compiled)

Templates:

• Template render (cached): ~50-100 µs
• Hot reload: ~1-2 ms (development only)

Routes:

• Middleware overhead: ~10-20 µs per request
• Rate limiter check: ~100-200 ns
• Total request latency: <5 ms (p50), <20 ms (p99)

Environment Configuration

Development

export GO_ENV=development
export TEMPLATE_HOT_RELOAD=true
export PORT=8080

Production

export GO_ENV=production
export TEMPLATE_HOT_RELOAD=false
export ALLOWED_ORIGINS="juan.andres.morenorub.io"
export PORT=8080

File Organization

cv/
├── doc/
│   ├── 24-GO-VALIDATION-SYSTEM.md   # Validation docs
│   ├── 25-GO-TEMPLATE-SYSTEM.md     # Template docs
│   ├── 26-GO-ROUTES-API.md          # Routes/API docs
│   └── 00-GO-DOCUMENTATION-INDEX.md # This file
│
├── internal/
│   ├── validation/
│   │   ├── validator.go             # Core validator
│   │   ├── rules.go                 # Validation rules
│   │   ├── errors.go                # Error types
│   │   └── contact.go               # ContactFormRequest
│   │
│   ├── templates/
│   │   └── template.go              # Template manager
│   │
│   ├── routes/
│   │   └── routes.go                # Route setup
│   │
│   ├── middleware/
│   │   ├── security.go              # Security middleware
│   │   ├── browser_only.go          # BrowserOnly middleware
│   │   ├── contact_rate_limit.go    # Rate limiting
│   │   ├── logger.go                # Request logging
│   │   ├── recovery.go              # Panic recovery
│   │   └── preferences.go           # User preferences
│   │
│   └── handlers/
│       ├── cv.go                    # CV handlers
│       ├── cv_contact.go            # Contact handler
│       ├── cv_pdf.go                # PDF handler
│       └── health.go                # Health check
│
└── templates/
    ├── *.html                       # Main templates
    └── partials/                    # Partial templates

Best Practices

Validation

1. Use tag-based validation for all struct validation
2. Order rules correctly: transformations first (trim, sanitize), then validations
3. Use global validator instance to benefit from caching
4. Combine security rules for defense in depth
5. UTF-8 aware: Use max/min for character count, not byte count

Templates

1. Disable hot reload in production for performance
2. Use safeHTML only with trusted content (YAML/config)
3. Organize templates logically (main, partials, HTMX)
4. Leverage custom functions for reusable logic
5. Test template execution to catch errors early

Routes

1. Register specific routes first to avoid conflicts
2. Apply security middleware to sensitive endpoints
3. Use rate limiting for resource-intensive operations
4. Log all requests for monitoring
5. Implement health checks for load balancers

Troubleshooting

Common Issues

Validation not working:

• Check tag syntax: validate:"rule1,rule2=param"
• Ensure field is exported (capitalized)
• Verify validator instance is created

Template not found:

• Check file exists in templates directory
• Verify filename matches Render("name")
• Check template loading logs

Rate limit too strict:

• Adjust limit in middleware initialization
• Clear rate limiter state (restart or implement clear endpoint)

CORS errors:

• Add domain to ALLOWED_ORIGINS environment variable
• Check OriginChecker middleware configuration

Contributing

When adding new features:

1. Update documentation in relevant .md file
2. Add tests for new functionality
3. Update route table if adding endpoints
4. Document security implications if applicable
5. Add examples for complex features

Version History

• v1.0 (2025-12-06) - Initial comprehensive documentation
  • Validation system with tag-based approach
  • Template system with hot reload
  • Complete route and middleware documentation

License

This documentation is part of the CV site project.

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Last Updated: December 6, 2025 Total Documentation: 2,836+ lines across 3 files Coverage: Validation, Templates, Routes, Middleware, Security