Add a pcap-split tool

internal/web/filename.go

@@ -0,0 +1,28 @@
+package web
+
+import (
+	"path"
+	"strings"
+)
+
+// safeName reduces a user supplied file name to a safe base name: directory
+// components are dropped and unusual characters replaced by '_'. fallback is
+// returned if nothing usable is left.
+func safeName(name, fallback string) string {
+	name = path.Base(strings.ReplaceAll(strings.TrimSpace(name), `\`, "/"))
+	name = strings.Map(func(r rune) rune {
+		if r >= 'a' && r <= 'z' || r >= 'A' && r <= 'Z' || r >= '0' && r <= '9' || r == '-' || r == '_' || r == '.' {
+			return r
+		}
+		return '_'
+	}, name)
+	if strings.Trim(name, "._") == "" {
+		return fallback
+	}
+	return name
+}
+
+// pcapFilename sanitizes a user supplied download name and gives it a .pcap extension.
+func pcapFilename(name string) string {
+	return strings.TrimSuffix(safeName(name, "packet.pcap"), ".pcap") + ".pcap"
+}