package strutil import ( "bytes" "encoding/base64" "encoding/hex" "encoding/json" "errors" "fmt" "github.com/andybalholm/brotli" "github.com/klauspost/compress/flate" "github.com/klauspost/compress/gzip" "github.com/klauspost/compress/zstd" "io" "strconv" "strings" "tinyrdm/backend/types" "unicode/utf8" ) // ConvertTo convert string to specified type // @param decodeType empty string indicates automatic detection // @param formatType empty string indicates automatic detection func ConvertTo(str, decodeType, formatType string) (value, resultDecode, resultFormat string) { if len(str) <= 0 { // empty content if len(formatType) <= 0 { resultFormat = types.VIEWAS_PLAIN_TEXT } else { resultFormat = formatType } if len(decodeType) <= 0 { resultDecode = types.DECODE_NONE } else { resultDecode = decodeType } return } // decode first value, resultDecode = decodeWith(str, decodeType) // then format content value, resultFormat = viewAs(value, formatType) return } func decodeWith(str, decodeType string) (value, resultDecode string) { if len(decodeType) > 0 { switch decodeType { case types.DECODE_NONE: value = str resultDecode = decodeType return case types.DECODE_BASE64: if base64Str, ok := decodeBase64(str); ok { value = base64Str } else { value = str } resultDecode = decodeType return case types.DECODE_GZIP: if gzipStr, ok := decodeGZip(str); ok { value = gzipStr } else { value = str } resultDecode = decodeType return case types.DECODE_DEFLATE: if falteStr, ok := decodeDeflate(str); ok { value = falteStr } else { value = str } resultDecode = decodeType return case types.DECODE_ZSTD: if zstdStr, ok := decodeZStd(str); ok { value = zstdStr } else { value = str } resultDecode = decodeType return case types.DECODE_BROTLI: if brotliStr, ok := decodeBrotli(str); ok { value = brotliStr } else { value = str } resultDecode = decodeType return } } return autoDecode(str) } // attempt try possible decode method // if no decode is possible, it will return the origin string value and "none" decode type func autoDecode(str string) (value, resultDecode string) { if len(str) > 0 { var ok bool if value, ok = decodeBase64(str); ok { resultDecode = types.DECODE_BASE64 return } if value, ok = decodeGZip(str); ok { resultDecode = types.DECODE_GZIP return } // FIXME: skip decompress with deflate due to incorrect format checking //if value, ok = decodeDeflate(str); ok { // resultDecode = types.DECODE_DEFLATE // return //} if value, ok = decodeZStd(str); ok { resultDecode = types.DECODE_ZSTD return } if value, ok = decodeBrotli(str); ok { resultDecode = types.DECODE_BROTLI return } } value = str resultDecode = types.DECODE_NONE return } func viewAs(str, formatType string) (value, resultFormat string) { if len(formatType) > 0 { switch formatType { case types.VIEWAS_PLAIN_TEXT: value = str resultFormat = formatType return case types.VIEWAS_JSON: if jsonStr, ok := decodeJson(str); ok { value = jsonStr } else { value = str } resultFormat = formatType return case types.VIEWAS_HEX: if hexStr, ok := decodeToHex(str); ok { value = hexStr } else { value = str } resultFormat = formatType return case types.VIEWAS_BINARY: if binStr, ok := decodeBinary(str); ok { value = binStr } else { value = str } resultFormat = formatType return } } return autoViewAs(str) } // attempt automatic convert to possible types // if no conversion is possible, it will return the origin string value and "plain text" type func autoViewAs(str string) (value, resultFormat string) { if len(str) > 0 { var ok bool if value, ok = decodeJson(str); ok { resultFormat = types.VIEWAS_JSON return } if containsBinary(str) { if value, ok = decodeToHex(str); ok { resultFormat = types.VIEWAS_HEX return } } } value = str resultFormat = types.VIEWAS_PLAIN_TEXT return } func decodeJson(str string) (string, bool) { str = strings.TrimSpace(str) if (strings.HasPrefix(str, "{") && strings.HasSuffix(str, "}")) || (strings.HasPrefix(str, "[") && strings.HasSuffix(str, "]")) { var out bytes.Buffer if err := json.Indent(&out, []byte(str), "", " "); err == nil { return out.String(), true } } return str, false } func decodeBase64(str string) (string, bool) { if decodedStr, err := base64.StdEncoding.DecodeString(str); err == nil { if s := string(decodedStr); utf8.ValidString(s) { return s, true } } return str, false } func decodeBinary(str string) (string, bool) { var binary strings.Builder for _, char := range str { binary.WriteString(fmt.Sprintf("%08b", int(char))) } return binary.String(), true } func decodeToHex(str string) (string, bool) { decodeStr := hex.EncodeToString([]byte(str)) var resultStr strings.Builder for i := 0; i < len(decodeStr); i += 2 { resultStr.WriteString("\\x") resultStr.WriteString(decodeStr[i : i+2]) } return resultStr.String(), true } func decodeGZip(str string) (string, bool) { if reader, err := gzip.NewReader(strings.NewReader(str)); err == nil { defer reader.Close() var decompressed []byte if decompressed, err = io.ReadAll(reader); err == nil { return string(decompressed), true } } return str, false } func decodeDeflate(str string) (string, bool) { reader := flate.NewReader(strings.NewReader(str)) defer reader.Close() if decompressed, err := io.ReadAll(reader); err == nil { return string(decompressed), true } return str, false } func decodeZStd(str string) (string, bool) { if reader, err := zstd.NewReader(strings.NewReader(str)); err == nil { defer reader.Close() if decompressed, err := io.ReadAll(reader); err == nil { return string(decompressed), true } } return str, false } func decodeBrotli(str string) (string, bool) { reader := brotli.NewReader(strings.NewReader(str)) if decompressed, err := io.ReadAll(reader); err == nil { return string(decompressed), true } return str, false } func SaveAs(str, viewType, decodeType string) (value string, err error) { value = str switch viewType { case types.VIEWAS_JSON: if jsonStr, ok := encodeJson(str); ok { value = jsonStr } else { err = errors.New("invalid json data") return } case types.VIEWAS_HEX: if hexStr, ok := encodeHex(str); ok { value = hexStr } else { err = errors.New("invalid hex data") return } case types.VIEWAS_BINARY: if binStr, ok := encodeBinary(str); ok { value = binStr } else { err = errors.New("invalid binary data") return } } switch decodeType { case types.DECODE_NONE: return case types.DECODE_BASE64: value, _ = encodeBase64(value) return case types.DECODE_GZIP: if gzipStr, ok := encodeGZip(str); ok { value = gzipStr } else { err = errors.New("fail to build gzip") } return case types.DECODE_DEFLATE: if deflateStr, ok := encodeDeflate(str); ok { value = deflateStr } else { err = errors.New("fail to build deflate") } return case types.DECODE_ZSTD: if zstdStr, ok := encodeZStd(str); ok { value = zstdStr } else { err = errors.New("fail to build zstd") } return case types.DECODE_BROTLI: if brotliStr, ok := encodeBrotli(str); ok { value = brotliStr } else { err = errors.New("fail to build brotli") } return } return str, errors.New("fail to save with unknown error") } func encodeJson(str string) (string, bool) { var data any if err := json.Unmarshal([]byte(str), &data); err == nil { var jsonByte []byte if jsonByte, err = json.Marshal(data); err == nil { return string(jsonByte), true } } return str, false } func encodeBase64(str string) (string, bool) { return base64.StdEncoding.EncodeToString([]byte(str)), true } func encodeBinary(str string) (string, bool) { var result strings.Builder total := len(str) for i := 0; i < total; i += 8 { b, _ := strconv.ParseInt(str[i:i+8], 2, 8) result.WriteByte(byte(b)) } return result.String(), true } func encodeHex(str string) (string, bool) { hexStrArr := strings.Split(str, "\\x") hexStr := strings.Join(hexStrArr, "") if decodeStr, err := hex.DecodeString(hexStr); err == nil { return string(decodeStr), true } return str, false } func encodeGZip(str string) (string, bool) { var compress = func(b []byte) (string, error) { var buf bytes.Buffer writer := gzip.NewWriter(&buf) if _, err := writer.Write([]byte(str)); err != nil { writer.Close() return "", err } writer.Close() return string(buf.Bytes()), nil } if gzipStr, err := compress([]byte(str)); err == nil { return gzipStr, true } return str, false } func encodeDeflate(str string) (string, bool) { var compress = func(b []byte) (string, error) { var buf bytes.Buffer writer, err := flate.NewWriter(&buf, flate.DefaultCompression) if err != nil { return "", err } if _, err = writer.Write([]byte(str)); err != nil { writer.Close() return "", err } writer.Close() return string(buf.Bytes()), nil } if deflateStr, err := compress([]byte(str)); err == nil { return deflateStr, true } return str, false } func encodeZStd(str string) (string, bool) { var compress = func(b []byte) (string, error) { var buf bytes.Buffer writer, err := zstd.NewWriter(&buf) if err != nil { return "", err } if _, err = writer.Write([]byte(str)); err != nil { writer.Close() return "", err } writer.Close() return string(buf.Bytes()), nil } if zstdStr, err := compress([]byte(str)); err == nil { return zstdStr, true } return str, false } func encodeBrotli(str string) (string, bool) { var compress = func(b []byte) (string, error) { var buf bytes.Buffer writer := brotli.NewWriter(&buf) if _, err := writer.Write([]byte(str)); err != nil { writer.Close() return "", err } writer.Close() return string(buf.Bytes()), nil } if brotliStr, err := compress([]byte(str)); err == nil { return brotliStr, true } return str, false }