feat: 使用 viper 绑定配置，open ai api 添加认证配置

internal/http/middleware/auth.go

@@ -0,0 +1,40 @@
+package middleware
+
+import (
+	"net/http"
+	"strings"
+)
+
+// OpenAIAuth 中间件验证 OpenAI API 请求的令牌
+func OpenAIAuth(apiToken string, next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// 如果没有配置令牌，跳过验证
+		if apiToken == "" {
+			next.ServeHTTP(w, r)
+			return
+		}
+
+		// 获取请求头中的 Authorization
+		authHeader := r.Header.Get("Authorization")
+		if authHeader == "" {
+			http.Error(w, "未提供授权令牌", http.StatusUnauthorized)
+			return
+		}
+
+		// 验证格式是否为 "Bearer {token}"
+		parts := strings.SplitN(authHeader, " ", 2)
+		if len(parts) != 2 || parts[0] != "Bearer" {
+			http.Error(w, "授权格式无效", http.StatusUnauthorized)
+			return
+		}
+
+		// 验证令牌是否正确
+		if parts[1] != apiToken {
+			http.Error(w, "令牌无效", http.StatusUnauthorized)
+			return
+		}
+
+		// 令牌验证通过，继续处理请求
+		next.ServeHTTP(w, r)
+	})
+}