{"id":"f60281be58ee122f","repo":"gofiber/fiber","slug":"file-failed-to-open-file-q-w","errorCode":null,"errorMessage":"file: failed to open file: %q: %w","messagePattern":"file: failed to open file: %q: %w","errorType":"exception","errorClass":"ErrFileOpen","httpStatus":null,"severity":"error","filePath":"ctx.go","lineNumber":572,"sourceCode":"}\n\n// SaveFile saves any multipart file to disk.\nfunc (*DefaultCtx) SaveFile(fileheader *multipart.FileHeader, path string) error {\n\tif fileheader == nil {\n\t\treturn ErrFileHeaderNil\n\t}\n\treturn fasthttp.SaveMultipartFile(fileheader, path)\n}\n\n// SaveFileToStorage saves any multipart file to an external storage system.\nfunc (c *DefaultCtx) SaveFileToStorage(fileheader *multipart.FileHeader, path string, storage Storage) error {\n\tif fileheader == nil {\n\t\treturn ErrFileHeaderNil\n\t}\n\n\tfile, err := fileheader.Open()\n\tif err != nil {\n\t\treturn fmt.Errorf(\"%w: %q: %w\", ErrFileOpen, fileheader.Filename, err)\n\t}\n\tdefer file.Close() //nolint:errcheck // not needed\n\n\tmaxUploadSize := c.app.config.BodyLimit\n\tif maxUploadSize <= 0 {\n\t\tmaxUploadSize = DefaultBodyLimit\n\t}\n\n\tif fileheader.Size > 0 && fileheader.Size > int64(maxUploadSize) {\n\t\treturn fmt.Errorf(\"%w: %q: %w\", ErrFileRead, fileheader.Filename, fasthttp.ErrBodyTooLarge)\n\t}\n\n\tbuf := bytebufferpool.Get()\n\tdefer bytebufferpool.Put(buf)\n\n\tlimitedReader := io.LimitReader(file, int64(maxUploadSize)+1)\n\tif _, err = buf.ReadFrom(limitedReader); err != nil {\n\t\treturn fmt.Errorf(\"%w: %q: %w\", ErrFileRead, fileheader.Filename, err)","sourceCodeStart":554,"sourceCodeEnd":590,"githubUrl":"https://github.com/gofiber/fiber/blob/9a4c7e57fe0b080a04235d28a4b0d2b4b353d58c/ctx.go#L554-L590","documentation":"Returned by Ctx.SaveFileToStorage when multipart.FileHeader.Open() fails while trying to read an uploaded file. It wraps the sentinel ErrFileOpen along with the offending filename and the underlying error. This happens before any bytes are read, indicating the multipart part's file descriptor could not be opened.","triggerScenarios":"Calling c.SaveFileToStorage(fileHeader, path, storage) where fileHeader.Open() returns an error. Common when the multipart form is malformed, the temporary file backing the upload was already cleaned up, or the OS denies access to the spool file.","commonSituations":"Exceeding the OS temp disk quota, a reverse proxy truncating the multipart body mid-upload, client disconnect after the body is parsed but before storage, or a corrupted multipart boundary.","solutions":["Check the wrapped underlying error to distinguish OS-level (permission/disk) from protocol-level causes.","Ensure the OS temp directory (TMPDIR) is writable and has adequate free space.","Increase or verify Server.BodyLimit so the full multipart body is buffered before SaveFileToStorage runs.","Handle the error and respond to the client with a 4xx rather than crashing the handler."],"exampleFix":"// before\nerr := c.SaveFileToStorage(fh, \"/uploads/\"+fh.Filename, storage)\nif err != nil {\n    panic(err)\n}\n\n// after\nerr := c.SaveFileToStorage(fh, \"/uploads/\"+fh.Filename, storage)\nif err != nil {\n    if errors.Is(err, fiber.ErrFileOpen) {\n        return c.Status(fiber.StatusBadRequest).SendString(\"could not open upload\")\n    }\n    return err\n}","handlingStrategy":"try-catch","validationCode":"// Validate the file header before storing\nif fileHeader == nil {\n    return fiber.ErrFileHeaderNil\n}\nif fileHeader.Size <= 0 {\n    return fmt.Errorf(\"empty upload: %q\", fileHeader.Filename)\n}","typeGuard":null,"tryCatchPattern":"if err := c.SaveFileToStorage(fh, path, storage); err != nil {\n    if errors.Is(err, fiber.ErrFileOpen) {\n        return c.Status(fiber.StatusBadRequest).SendString(\"cannot open upload\")\n    }\n    return err\n}","preventionTips":["Check fileHeader for nil and reasonable size before calling SaveFileToStorage.","Ensure the OS temp directory is writable with enough space.","Don't mutate the multipart form after parsing."],"tags":["upload","multipart","storage","filesystem","go"],"analyzedSha":"9a4c7e57fe0b080a04235d28a4b0d2b4b353d58c","analyzedAt":"2026-08-04T21:44:03.395Z","schemaVersion":2}