feat: 完成后端中间件系统完善

## 🛡️ 新增功能
- 实现完整的CORS中间件，支持开发/生产环境配置
- 实现请求日志中间件，完整的请求生命周期记录
- 实现全局错误处理中间件，统一错误响应格式
- 创建中间件管理器，支持链式中间件和配置管理

## 🔧 技术改进
- 更新配置系统支持中间件配置
- 修复go-zero日志API兼容性问题
- 创建完整的中间件测试用例
- 编译测试通过，功能完整可用

## 📊 进度提升
- 项目总进度从42.5%提升至50.0%
- 中优先级任务完成率达55%
- 3个中优先级任务同时完成

## 🎯 完成的任务
14. 实现 CORS 中间件
16. 实现请求日志中间件
17. 完善全局错误处理

Co-authored-by: Claude Code <claude@anthropic.com>

backend/internal/middleware/middleware.go

@@ -0,0 +1,203 @@
+package middleware
+
+import (
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	"photography-backend/internal/config"
+
+	"github.com/zeromicro/go-zero/core/logx"
+)
+
+// MiddlewareManager 中间件管理器
+type MiddlewareManager struct {
+	config         config.Config
+	corsMiddleware *CORSMiddleware
+	logMiddleware  *LoggerMiddleware
+	errorMiddleware *ErrorMiddleware
+	authMiddleware *AuthMiddleware
+}
+
+// NewMiddlewareManager 创建中间件管理器
+func NewMiddlewareManager(c config.Config) *MiddlewareManager {
+	return &MiddlewareManager{
+		config:          c,
+		corsMiddleware:  NewCORSMiddleware(getCORSConfig(c)),
+		logMiddleware:   NewLoggerMiddleware(getLoggerConfig(c)),
+		errorMiddleware: NewErrorMiddleware(getErrorConfig(c)),
+		authMiddleware:  NewAuthMiddleware(c.Auth.AccessSecret),
+	}
+}
+
+// getCORSConfig 获取CORS配置
+func getCORSConfig(c config.Config) CORSConfig {
+	env := getEnvironment()
+	
+	if env == "production" {
+		// 生产环境使用严格的CORS配置
+		return ProductionCORSConfig(getProductionOrigins())
+	}
+	
+	// 开发环境使用宽松的CORS配置
+	return DefaultCORSConfig()
+}
+
+// getLoggerConfig 获取日志配置
+func getLoggerConfig(c config.Config) LoggerConfig {
+	env := getEnvironment()
+	
+	config := DefaultLoggerConfig()
+	
+	if env == "development" {
+		// 开发环境启用详细日志
+		config.EnableRequestBody = true
+		config.EnableResponseBody = true
+		config.MaxBodySize = 4096
+	}
+	
+	return config
+}
+
+// getErrorConfig 获取错误配置
+func getErrorConfig(c config.Config) ErrorConfig {
+	env := getEnvironment()
+	
+	if env == "development" {
+		return DevelopmentErrorConfig()
+	}
+	
+	return DefaultErrorConfig()
+}
+
+// getEnvironment 获取环境变量
+func getEnvironment() string {
+	env := os.Getenv("GO_ENV")
+	if env == "" {
+		env = os.Getenv("ENV")
+	}
+	if env == "" {
+		// 默认为开发环境
+		env = "development"
+	}
+	return strings.ToLower(env)
+}
+
+// getProductionOrigins 获取生产环境允许的来源
+func getProductionOrigins() []string {
+	origins := os.Getenv("CORS_ALLOWED_ORIGINS")
+	if origins == "" {
+		return []string{
+			"https://photography.iriver.top",
+			"https://admin.photography.iriver.top",
+		}
+	}
+	return strings.Split(origins, ",")
+}
+
+// Chain 链式中间件
+func (m *MiddlewareManager) Chain(handler http.HandlerFunc, middlewares ...func(http.HandlerFunc) http.HandlerFunc) http.HandlerFunc {
+	// 从右到左包装中间件
+	for i := len(middlewares) - 1; i >= 0; i-- {
+		handler = middlewares[i](handler)
+	}
+	return handler
+}
+
+// GetGlobalMiddlewares 获取全局中间件
+func (m *MiddlewareManager) GetGlobalMiddlewares() []func(http.HandlerFunc) http.HandlerFunc {
+	return []func(http.HandlerFunc) http.HandlerFunc{
+		m.errorMiddleware.Handle,  // 错误处理 (最外层)
+		m.corsMiddleware.Handle,   // CORS 处理
+		m.logMiddleware.Handle,    // 日志记录
+	}
+}
+
+// GetAuthMiddleware 获取认证中间件
+func (m *MiddlewareManager) GetAuthMiddleware() func(http.HandlerFunc) http.HandlerFunc {
+	return m.authMiddleware.Handle
+}
+
+// ApplyGlobalMiddlewares 应用全局中间件
+func (m *MiddlewareManager) ApplyGlobalMiddlewares(handler http.HandlerFunc) http.HandlerFunc {
+	return m.Chain(handler, m.GetGlobalMiddlewares()...)
+}
+
+// ApplyAuthMiddlewares 应用认证中间件
+func (m *MiddlewareManager) ApplyAuthMiddlewares(handler http.HandlerFunc) http.HandlerFunc {
+	middlewares := append(m.GetGlobalMiddlewares(), m.GetAuthMiddleware())
+	return m.Chain(handler, middlewares...)
+}
+
+// HealthCheck 健康检查处理器 (不使用中间件)
+func (m *MiddlewareManager) HealthCheck(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusOK)
+	w.Write([]byte(`{"status":"ok","timestamp":"` + 
+		time.Now().Format("2006-01-02T15:04:05Z07:00") + `"}`))
+}
+
+// Middleware 中间件接口
+type Middleware interface {
+	Handle(next http.HandlerFunc) http.HandlerFunc
+}
+
+// MiddlewareFunc 中间件函数类型
+type MiddlewareFunc func(next http.HandlerFunc) http.HandlerFunc
+
+// Handle 实现Middleware接口
+func (f MiddlewareFunc) Handle(next http.HandlerFunc) http.HandlerFunc {
+	return f(next)
+}
+
+// Use 应用中间件到处理器
+func Use(handler http.HandlerFunc, middlewares ...Middleware) http.HandlerFunc {
+	for i := len(middlewares) - 1; i >= 0; i-- {
+		handler = middlewares[i].Handle(handler)
+	}
+	return handler
+}
+
+// Recovery 通用恢复中间件
+func Recovery() MiddlewareFunc {
+	return func(next http.HandlerFunc) http.HandlerFunc {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			defer func() {
+				if err := recover(); err != nil {
+					fields := map[string]interface{}{
+						"error":  err,
+						"method": r.Method,
+						"path":   r.URL.Path,
+					}
+					logx.WithContext(r.Context()).Errorf("Panic recovered in Recovery middleware: %+v", fields)
+					
+					http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+				}
+			}()
+			next(w, r)
+		})
+	}
+}
+
+// RequestID 请求ID中间件
+func RequestID() MiddlewareFunc {
+	return func(next http.HandlerFunc) http.HandlerFunc {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			requestID := r.Header.Get("X-Request-ID")
+			if requestID == "" {
+				requestID = generateRequestID()
+			}
+			
+			w.Header().Set("X-Request-ID", requestID)
+			r.Header.Set("X-Request-ID", requestID)
+			
+			next(w, r)
+		})
+	}
+}
+
+// generateRequestID 生成请求ID
+func generateRequestID() string {
+	return randomString(16)
+}