Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/internal/server/middleware/cors.go

@@ -0,0 +1,116 @@
+package middleware
+
+import (
+	"log"
+	"net/http"
+	"strings"
+	"sync"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/gin-gonic/gin"
+)
+
+var corsWarningOnce sync.Once
+
+// CORS 跨域中间件
+func CORS(cfg config.CORSConfig) gin.HandlerFunc {
+	allowedOrigins := normalizeOrigins(cfg.AllowedOrigins)
+	allowAll := false
+	for _, origin := range allowedOrigins {
+		if origin == "*" {
+			allowAll = true
+			break
+		}
+	}
+	wildcardWithSpecific := allowAll && len(allowedOrigins) > 1
+	if wildcardWithSpecific {
+		allowedOrigins = []string{"*"}
+	}
+	allowCredentials := cfg.AllowCredentials
+
+	corsWarningOnce.Do(func() {
+		if len(allowedOrigins) == 0 {
+			log.Println("Warning: CORS allowed_origins not configured; cross-origin requests will be rejected.")
+		}
+		if wildcardWithSpecific {
+			log.Println("Warning: CORS allowed_origins includes '*'; wildcard will take precedence over explicit origins.")
+		}
+		if allowAll && allowCredentials {
+			log.Println("Warning: CORS allowed_origins set to '*', disabling allow_credentials.")
+		}
+	})
+	if allowAll && allowCredentials {
+		allowCredentials = false
+	}
+
+	allowedSet := make(map[string]struct{}, len(allowedOrigins))
+	for _, origin := range allowedOrigins {
+		if origin == "" || origin == "*" {
+			continue
+		}
+		allowedSet[origin] = struct{}{}
+	}
+	allowHeaders := []string{
+		"Content-Type", "Content-Length", "Accept-Encoding", "X-CSRF-Token", "Authorization",
+		"accept", "origin", "Cache-Control", "X-Requested-With", "X-API-Key", "X-Admin-UI-Request", "X-User-UI-Request",
+	}
+	// OpenAI Node SDK 会发送 x-stainless-* 请求头，需在 CORS 中显式放行。
+	openAIProperties := []string{
+		"lang", "package-version", "os", "arch", "retry-count", "runtime",
+		"runtime-version", "async", "helper-method", "poll-helper", "custom-poll-interval", "timeout",
+	}
+	for _, prop := range openAIProperties {
+		allowHeaders = append(allowHeaders, "x-stainless-"+prop)
+	}
+	allowHeadersValue := strings.Join(allowHeaders, ", ")
+
+	return func(c *gin.Context) {
+		origin := strings.TrimSpace(c.GetHeader("Origin"))
+		originAllowed := allowAll
+		if origin != "" && !allowAll {
+			_, originAllowed = allowedSet[origin]
+		}
+
+		if originAllowed {
+			if allowAll {
+				c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
+			} else if origin != "" {
+				c.Writer.Header().Set("Access-Control-Allow-Origin", origin)
+				c.Writer.Header().Add("Vary", "Origin")
+			}
+			if allowCredentials {
+				c.Writer.Header().Set("Access-Control-Allow-Credentials", "true")
+			}
+			c.Writer.Header().Set("Access-Control-Allow-Headers", allowHeadersValue)
+			c.Writer.Header().Set("Access-Control-Allow-Methods", "POST, OPTIONS, GET, PUT, DELETE, PATCH")
+			c.Writer.Header().Set("Access-Control-Expose-Headers", "ETag, Server-Timing")
+			c.Writer.Header().Set("Access-Control-Max-Age", "86400")
+		}
+		// 处理预检请求
+		if c.Request.Method == http.MethodOptions {
+			if originAllowed {
+				c.AbortWithStatus(http.StatusNoContent)
+			} else {
+				c.AbortWithStatus(http.StatusForbidden)
+			}
+			return
+		}
+
+		c.Next()
+	}
+}
+
+func normalizeOrigins(values []string) []string {
+	if len(values) == 0 {
+		return nil
+	}
+	normalized := make([]string, 0, len(values))
+	for _, value := range values {
+		trimmed := strings.TrimSpace(value)
+		if trimmed == "" {
+			continue
+		}
+		normalized = append(normalized, trimmed)
+	}
+	return normalized
+}