refactor(model): 重构模型实体和数据访问层

common/util/files.go

@@ -0,0 +1,69 @@
+package util
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// DetectFileType 根据返回的二进制内容推断 contentType + 扩展名（尽量稳定）
+func DetectFileType(data []byte) (contentType string, ext string) {
+	if len(data) == 0 {
+		return "application/octet-stream", ""
+	}
+	ct := http.DetectContentType(data)
+	// gateway.DetectContentType 可能带 charset 等参数：text/plain; charset=utf-8
+	if idx := strings.Index(ct, ";"); idx > 0 {
+		ct = strings.TrimSpace(ct[:idx])
+	}
+	switch ct {
+	case "audio/mpeg":
+		return ct, ".mp3"
+	case "audio/wave", "audio/wav", "audio/x-wav":
+		return ct, ".wav"
+	case "video/mp4":
+		return ct, ".mp4"
+	case "image/png":
+		return ct, ".png"
+	case "image/jpeg":
+		return ct, ".jpg"
+	case "application/pdf":
+		return ct, ".pdf"
+	case "text/plain":
+		return ct, ".txt"
+	case "application/json":
+		return ct, ".json"
+	default:
+		// 兜底：尝试从 ct 截取 subtype 作为后缀（例如 application/json）
+		if parts := strings.Split(ct, "/"); len(parts) == 2 {
+			sub := parts[1]
+			// 避免出现 "plain; charset=utf-8" 之类的后缀
+			if idx := strings.Index(sub, ";"); idx > 0 {
+				sub = strings.TrimSpace(sub[:idx])
+			}
+			return ct, "." + sub
+		}
+		return ct, ""
+	}
+}
+
+// SaveTmpResult 将模型输出写入临时文件，用于 OSS 上传失败后的“仅重试 OSS”。
+func SaveTmpResult(taskID string, data []byte, ext string) (string, error) {
+	dir := filepath.Join(os.TempDir(), "model-asynch")
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		return "", err
+	}
+	if ext == "" {
+		ext = ".bin"
+	}
+	if ext[0] != '.' {
+		ext = "." + ext
+	}
+	path := filepath.Join(dir, fmt.Sprintf("%s%s", taskID, ext))
+	if err := os.WriteFile(path, data, 0o644); err != nil {
+		return "", err
+	}
+	return path, nil
+}