flipped-aurora/gin-vue-admin · error

function file.Open() failed, err:

Error message

function file.Open() failed, err:

What it means

Wraps the error from multipart.FileHeader.Open() in TencentCOS.UploadFile(). Open() opens the uploaded multipart file for reading; failure means the in-memory/temp file backing the upload cannot be opened.

Source

Thrown at server/utils/upload/tencent_cos.go:26

	"net/http"
	"net/url"
	"time"

	"github.com/flipped-aurora/gin-vue-admin/server/global"
	"github.com/flipped-aurora/gin-vue-admin/server/utils/logger"

	"github.com/tencentyun/cos-go-sdk-v5"
)

type TencentCOS struct{}

// UploadFile upload file to COS
func (*TencentCOS) UploadFile(ctx context.Context, file *multipart.FileHeader) (string, string, error) {
	client := NewClient()
	f, openError := file.Open()
	if openError != nil {
		logger.WithCtx(ctx).Mod("upload").Err(openError).Error("function file.Open() failed")
		return "", "", errors.New("function file.Open() failed, err:" + openError.Error())
	}
	defer f.Close() // 创建文件 defer 关闭
	fileKey := fmt.Sprintf("%d%s", time.Now().Unix(), file.Filename)

	_, err := client.Object.Put(context.Background(), global.GVA_CONFIG.TencentCOS.PathPrefix+"/"+fileKey, f, nil)
	if err != nil {
		logger.WithCtx(ctx).Mod("upload").Err(err).Error("function client.Object.Put() failed")
		return "", "", errors.New("function client.Object.Put() failed, err:" + err.Error())
	}
	return global.GVA_CONFIG.TencentCOS.BaseURL + "/" + global.GVA_CONFIG.TencentCOS.PathPrefix + "/" + fileKey, fileKey, nil
}

// DeleteFile delete file form COS
func (*TencentCOS) DeleteFile(ctx context.Context, key string) error {
	client := NewClient()
	name := global.GVA_CONFIG.TencentCOS.PathPrefix + "/" + key
	_, err := client.Object.Delete(context.Background(), name)
	if err != nil {

View on GitHub (pinned to 3136500ef3)

Solutions

1. Ensure UploadFile is called before anything else consumes the multipart form
2. Pass the original *multipart.FileHeader from c.File/FormFile directly
3. Check OS temp directory (TMPDIR) exists and is writable by the server process
4. Inspect the wrapped openError suffix for the underlying OS error (e.g. no such file, permission denied)

Example fix

// before
fh, _ := c.FormFile("file")
filePath, _ := saveLocal(fh) // consumes temp file
return cos.UploadFile(ctx, fh) // Open() fails
// after
fh, _ := c.FormFile("file")
url, key, err := cos.UploadFile(ctx, fh) // upload first
if err == nil {
    saveLocal(fh)
}

if file == nil || file.Size == 0 {
    return errors.New("invalid multipart file")
}

url, key, err := cos.UploadFile(ctx, fh)
if err != nil && strings.Contains(err.Error(), "file.Open() failed") {
    // multipart temp file gone: re-parse form or reject the request
    return fmt.Errorf("upload source unavailable: %w", err)
}

When it happens

Trigger: Calling UploadFile(ctx, file) when file.Open() fails — usually the multipart temp file was moved/cleaned before upload, or the request memory limit discarded the file.

Common situations: Handler consumed/saved the multipart form before the upload service ran (temp file already consumed), server temp dir permissions changed, or the *multipart.FileHeader was constructed manually and invalid.

Related errors

• 构造 FileHeader 失败
• function file.Open() failed, err:
• function file.Open() failed, err:
• function file.Open() failed, err:
• function client.Object.Put() failed, err:

AI-assisted analysis of flipped-aurora/gin-vue-admin@3136500ef3 (2026-08-31). Data as JSON: /api/errors/f2463dffdaf5904e. Report an issue: GitHub.