Lua: Support inline scripts; Add ./xray base64 encode/decode [-gzip] command (#7132)

https://github.com/XTLS/Xray-core/pull/7124#issuecomment-6110557806
https://github.com/XTLS/Xray-core/pull/7132#issuecomment-6118169645
https://github.com/XTLS/Xray-core/pull/7132#issuecomment-6126428359

main/commands/all/base64/decode.go

@@ -0,0 +1,66 @@
+package base64
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	xbase64 "github.com/xtls/xray-core/common/base64"
+	"github.com/xtls/xray-core/main/commands/base"
+)
+
+var cmdDecode = &base.Command{
+	UsageLine: "{{.Exec}} base64 decode [-gzip] <value | - | stdin:> [output-file]",
+	Short:     "Decode Base64",
+	Long: fmt.Sprintf(`
+Decode a Base64 value, or pass "-" or "stdin:" to read stdin.
+Write to output-file, or stdout if omitted.
+Accepts %s, %s, or no prefix; gzip is enabled by %s or -gzip.
+
+Examples:
+
+	{{.Exec}} base64 decode eA== out.bin
+	{{.Exec}} base64 decode -gzip H4sIAAAAAAAC/6sAAIMW3IwBAAAA out.bin
+`, xbase64.Prefix, xbase64.GzipPrefix, xbase64.GzipPrefix),
+}
+
+var decodeGzipEnabled = cmdDecode.Flag.Bool("gzip", false, "Decompress the decoded bytes with gzip.")
+
+func init() {
+	cmdDecode.Run = executeDecode
+}
+
+func executeDecode(cmd *base.Command, args []string) {
+	if len(args) == 0 || len(args) > 2 {
+		cmd.Usage()
+	}
+
+	value := args[0]
+	if value == "-" || value == "stdin:" {
+		input, err := io.ReadAll(os.Stdin)
+		if err != nil {
+			base.Fatalf("failed to read input: %s", err)
+		}
+		value = string(input)
+	}
+
+	value = strings.TrimSpace(value)
+	if *decodeGzipEnabled && !strings.HasPrefix(value, xbase64.GzipPrefix) {
+		value = xbase64.GzipPrefix + strings.TrimPrefix(value, xbase64.Prefix)
+	}
+
+	data, err := xbase64.Decode(value)
+	if err != nil {
+		base.Fatalf("failed to decode input: %s", err)
+	}
+
+	if len(args) == 2 && args[1] != "-" {
+		err = os.WriteFile(args[1], data, 0o666)
+	} else {
+		_, err = os.Stdout.Write(data)
+	}
+	if err != nil {
+		base.Fatalf("failed to write decoded output: %s", err)
+	}
+}