{"record":{"id":"f0ba1483c9e65179","repo":"lionsoul2014/ip2region","slug":"loading-header-w","errorCode":null,"errorMessage":"loading header: %w","messagePattern":"loading header: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"binding/golang/xdb/util.go","lineNumber":147,"sourceCode":"func IPMiddle(sip, eip []byte) ([]byte, error) {\n\tbuf, err := IPAdd(sip, eip)\n\tif err != nil {\n\t\treturn []byte{}, fmt.Errorf(\"IPSub(%s, %s): %w\", IP2String(sip), IP2String(eip), err)\n\t}\n\n\treturn IPHalf(buf), nil\n}\n\n// Verify if the current Searcher could be used to search the specified xdb file.\n// Why do we need this check ?\n// The future features of the xdb impl may cause the current searcher not able to work properly.\n//\n// @Note: You Just need to check this ONCE when the service starts\n// Or use another process (eg, A command) to check once Just to confirm the suitability.\nfunc Verify(handle *os.File) error {\n\theader, err := LoadHeader(handle)\n\tif err != nil {\n\t\treturn fmt.Errorf(\"loading header: %w\", err)\n\t}\n\n\t// get the runtime ptr bytes\n\truntimePtrBytes := 0\n\tswitch header.Version {\n\tcase Structure20:\n\t\truntimePtrBytes = 4\n\tcase Structure30:\n\t\truntimePtrBytes = header.RuntimePtrBytes\n\tdefault:\n\t\treturn fmt.Errorf(\"invalid version: %d\", header.Version)\n\t}\n\n\t// 1, confirm the xdb file size.\n\t// to sure that the MaxFilePointer does no overflow\n\tstat, err := handle.Stat()\n\tif err != nil {\n\t\treturn fmt.Errorf(\"file stat: %w\", err)","sourceCodeStart":129,"sourceCodeEnd":165,"githubUrl":"https://github.com/lionsoul2014/ip2region/blob/c1a1fc7d5941760db3f8431dc05c48cf7f0e30a1/binding/golang/xdb/util.go#L129-L165","documentation":"Verify validates an xdb file handle and starts by loading the file's header via LoadHeader; if that read/parse fails, the underlying error is wrapped as \"loading header\". This typically indicates the file is too small, unreadable, or not an xdb file at all.","triggerScenarios":"Calling xdb.Verify(handle) or VerifyFromFile on a file smaller than the header, with wrong permissions, an empty file, or a random/corrupted file; passing a closed *os.File.","commonSituations":"Pointing the tool at a wrong path that resolved to a directory or empty placeholder; partially downloaded xdb; file corrupted in transit; running the check as a user lacking read permission.","solutions":["Check the file exists, is a regular file, and is readable by the current user","Re-download the xdb file and confirm its size/checksum","Ensure the handle is opened successfully and not closed before Verify","Confirm the file is actually an xdb v2/v3 data file, not HTML from a failed download"],"exampleFix":"// before\nf, _ := os.Open(\"bad.xdb\")\nerr := xdb.Verify(f) // loading header: ...\n// after\nstat, err := os.Stat(\"bad.xdb\")\nif err != nil || stat.Size() < 256 { log.Fatal(\"xdb missing or truncated\") }\nerr = xdb.VerifyFromFile(\"bad.xdb\")","handlingStrategy":"validation","validationCode":"func xdbReadable(path string) error {\n    info, err := os.Stat(path)\n    if err != nil { return err }\n    if !info.Mode().IsRegular() { return fmt.Errorf(\"%s is not a regular file\", path) }\n    if info.Size() < 256 { return fmt.Errorf(\"%s too small (%d bytes) to be an xdb file\", path, info.Size()) }\n    f, err := os.Open(path)\n    if err != nil { return err }\n    defer f.Close()\n    return nil\n}","typeGuard":null,"tryCatchPattern":"if err := xdb.VerifyFromFile(dbPath); err != nil {\n    return fmt.Errorf(\"xdb %s failed verification: %w\", dbPath, err)\n}","preventionTips":["Verify the xdb file once at service startup","Check file size and readability before opening","Validate download integrity (checksum) before deploying the data file","Ensure the handle passed to Verify is open and not yet closed"],"tags":["go","file-validation","corrupt-file"],"backgroundTag":"xdb-file-invalid","analyzedSha":"c1a1fc7d5941760db3f8431dc05c48cf7f0e30a1","analyzedAt":"2026-09-02T16:58:39.988Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-09T21:17:11.164Z"}