{"record":{"id":"04290204fdda6854","repo":"yorukot/superfile","slug":"error-generating-ps-thumbnail-outputpath-s-w","errorCode":null,"errorMessage":"error generating ps thumbnail, outputPath: %s : %w","messagePattern":"error generating ps thumbnail, outputPath: (.+?) : %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"src/pkg/file_preview/thumbnail_generator.go","lineNumber":136,"sourceCode":"func (g *psGenerator) generateThumbnail(inputPath string, outputPathWithoutExt string) (string, error) {\n\toutputPath := outputPathWithoutExt + thumbOutputExt\n\tctx, cancel := context.WithTimeout(context.Background(), thumbGenerationTimeout)\n\tdefer cancel()\n\n\t// gs -dSAFER -dBATCH -dNOPAUSE -sPageList=1 -sDEVICE=jpeg -r150 -sOutputFile=output.jpg input.ps\n\toutputParam := \"-sOutputFile=\" + outputPath\n\tgs := exec.CommandContext(ctx, \"gs\",\n\t\t\"-dSAFER\", \"-dBATCH\", \"-dNOPAUSE\", // Standard GS operators\n\t\t\"-sPageList=1\",  // Output only the first page\n\t\t\"-sDEVICE=jpeg\", // Output format\n\t\t\"-r150\",         // Resolution (the same as for pdf)\n\t\toutputParam,     // Result (variable because of golangci-lint)\n\t\tinputPath,       // Input file\n\t)\n\n\terr := gs.Run()\n\tif err != nil {\n\t\treturn \"\", fmt.Errorf(\"error generating ps thumbnail, outputPath: %s : %w\",\n\t\t\toutputPath, err)\n\t}\n\n\treturn outputPath, nil\n}\n\ntype ThumbnailGenerator struct {\n\t// This is a cache. Key -> Video file path, Value -> Thumbnail file path\n\t// TODO: We can potentially make it persistent, preventing generation\n\t// of thumbnail on every launch or superfile\n\ttempFilesCache map[string]string\n\ttempDirectory  string\n\tmu             sync.Mutex\n\tgenerators     []thumbnailGeneratorInterface\n}\n\nfunc NewThumbnailGenerator() (*ThumbnailGenerator, error) {\n\ttmp, err := os.MkdirTemp(\"\", \"superfiles-*\")","sourceCodeStart":118,"sourceCodeEnd":154,"githubUrl":"https://github.com/yorukot/superfile/blob/b72f550bc6e75913f48eb49fdd258e1a2df2fe88/src/pkg/file_preview/thumbnail_generator.go#L118-L154","documentation":"This error is returned when the Ghostscript (gs) child process exits non-zero while converting a PostScript file to a thumbnail image. It wraps gs's stderr output so the actual interpreter error is visible. It signals the PS/EPS rasterization step failed.","triggerScenarios":"generateThumbnail invoking gs with the computed output parameter and inputPath when ghostscript is not installed, the .ps/.eps file is malformed or uses unsupported PostScript Level constructs, or the output location is unwritable.","commonSituations":"ghostscript not installed on the host; corrupt or non-PostScript content saved with a .ps extension; EPS files with broken previews; license/security policy changes in newer Ghostscript versions blocking certain operators (e.g. -dSAFER restricting file access).","solutions":["Check gs is installed: `which gs`; install ghostscript if absent.","Reproduce with the same gs flags manually to read the raw interpreter error.","Validate the file is actually PostScript (`file <input>`); skip thumbnailing if not.","If newer Ghostscript's -dSAFER blocks input/output paths, adjust the gs flags in the generator.","Fall back to a generic PS/EPS icon on failure."],"exampleFix":"// before\nthumb, err := gen.generateThumbnail(psPath)\n// after\nthumb, err := gen.generateThumbnail(psPath)\nif err != nil {\n    log.Warnf(\"ps thumbnail failed: %v\", err)\n    thumb = defaultPSIconPath\n}","handlingStrategy":"try-catch","validationCode":"if _, err := exec.LookPath(\"gs\"); err != nil { return errors.New(\"ghostscript not installed\") }\nhead := make([]byte, 4); f, _ := os.Open(psPath); n, _ := f.Read(head); f.Close()\nif !strings.HasPrefix(string(head[:n]), \"%!\") { return errors.New(\"not a PostScript file\") }","typeGuard":null,"tryCatchPattern":"thumb, err := gen.generateThumbnail(psPath)\nif err != nil {\n    log.Warnf(\"ps thumbnail failed: %v\", err)\n    thumb = \"\" // fall back to PS icon\n}","preventionTips":["Install ghostscript in deployment environments that promise PS/EPS previews.","Verify the %! PostScript header before invoking gs.","Review gs flags (e.g. -dSAFER) when upgrading Ghostscript versions.","Cache failures to avoid repeated gs invocations on the same file."],"tags":["ghostscript","thumbnail","external-command","postscript"],"backgroundTag":"ghostscript-thumbnail-failed","analyzedSha":"b72f550bc6e75913f48eb49fdd258e1a2df2fe88","analyzedAt":"2026-09-01T04:38:08.254Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}