{"id":"5a2caf0e7e8916be","repo":"gofiber/fiber","slug":"file-failed-to-store-file","errorCode":null,"errorMessage":"file: failed to store file","messagePattern":"file: failed to store file","errorType":"exception","errorClass":"ErrFileStore","httpStatus":null,"severity":"error","filePath":"error.go","lineNumber":99,"sourceCode":"\tSyntaxError = json.SyntaxError\n\n\t// UnmarshalTypeError describes a JSON value that was\n\t// not appropriate for a value of a specific Go type.\n\tUnmarshalTypeError = json.UnmarshalTypeError\n\n\t// UnsupportedTypeError is returned by Marshal when attempting\n\t// to encode an unsupported value type.\n\tUnsupportedTypeError = json.UnsupportedTypeError\n\n\t// UnsupportedValueError exposes json.UnsupportedValueError to describe unsupported values encountered during encoding.\n\tUnsupportedValueError = json.UnsupportedValueError\n)\n\n// File errors\nvar (\n\tErrFileHeaderNil = errors.New(\"file: file header is nil\")\n\tErrFileOpen      = errors.New(\"file: failed to open file\")\n\tErrFileRead      = errors.New(\"file: failed to read file\")\n\tErrFileStore     = errors.New(\"file: failed to store file\")\n)\n","sourceCodeStart":81,"sourceCodeEnd":102,"githubUrl":"https://github.com/gofiber/fiber/blob/9a4c7e57fe0b080a04235d28a4b0d2b4b353d58c/error.go#L81-L102","documentation":"ErrFileStore ('file: failed to store file', error.go:100) is wrapped and returned by ctx.SaveFileToStorage (ctx.go:600) when the Storage backend's SetWithContext call fails after the file was successfully read. It indicates the destination (S3, Redis, filesystem abstraction, etc.) rejected the write, not that the upload itself was malformed. The error includes the filename and target path.","triggerScenarios":"c.SaveFileToStorage(fh, \"uploads/x\", storage) where storage.SetWithContext returns an error: network/credential failure against S3, Redis connection lost, disk full for a filesystem storage, or an invalid path/key. Triggered after the body was read successfully, so the upload was valid.","commonSituations":"Expired or wrong cloud-storage credentials, transient network blips to the object store, full disk, path/key validation failures in a custom Storage implementation, or a misconfigured storage client (wrong region/endpoint).","solutions":["Inspect the wrapped error to identify the storage-specific cause (e.g. AWS S3 error codes) and fix credentials/config.","Implement retries with backoff for transient storage failures before returning to the client.","Validate the destination path/key format before calling SetWithContext, and ensure the storage client is initialized and reachable."],"exampleFix":"// before\nif err := c.SaveFileToStorage(fh, key, storage); err != nil {\n    return err // generic 500, no diagnosis\n}\n\n// after\nif err := c.SaveFileToStorage(fh, key, storage); err != nil {\n    if errors.Is(err, fiber.ErrFileStore) {\n        log.Printf(\"storage write failed for %q: %v\", key, err)\n        return fiber.NewError(fiber.StatusBadGateway, \"could not store file, please retry\")\n    }\n    return err\n}","handlingStrategy":"try-catch","validationCode":"// Verify storage connectivity before serving uploads.\nif err := storage.SetWithContext(ctx, \"__healthcheck\", []byte(\"ok\"), 0); err != nil {\n    log.Fatalf(\"storage unreachable: %v\", err)\n}","typeGuard":null,"tryCatchPattern":"if err := c.SaveFileToStorage(fh, key, storage); err != nil {\n    if errors.Is(err, fiber.ErrFileStore) {\n        log.Printf(\"store failed for %q: %v\", key, err)\n        return fiber.NewError(fiber.StatusBadGateway, \"storage unavailable, please retry\")\n    }\n    return err\n}","preventionTips":["Validate storage credentials and connectivity at startup.","Retry transient storage failures with backoff before surfacing to the client.","Sanitize/validate the destination key/path before calling SetWithContext."],"tags":["upload","storage","files","fiber"],"analyzedSha":"9a4c7e57fe0b080a04235d28a4b0d2b4b353d58c","analyzedAt":"2026-08-04T21:44:03.395Z","schemaVersion":2}