initial commit

README.md

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+# Punycoder
+
+Converts punycode domains to unicode and vice-versa.
+
+## Installation
+
+```
+go get github.com/jakewarren/punycoder
+```
+
+## Usage
+
+Simply provide either a punycode (IDN) or Unicode domain and it will be converted automagically.
+
+```
+$ punycoder bücher.example.com
+xn--bcher-kva.example.com
+$ punycoder xn--bcher-kva.example.com
+bücher.example.com
+```

main.go

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+package main
+
+import (
+	"fmt"
+	"os"
+	"regexp"
+
+	"golang.org/x/net/idna"
+)
+
+var usage = `
+██████╗ ██╗   ██╗███╗   ██╗██╗   ██╗ ██████╗ ██████╗ ██████╗ ███████╗██████╗ 
+██╔══██╗██║   ██║████╗  ██║╚██╗ ██╔╝██╔════╝██╔═══██╗██╔══██╗██╔════╝██╔══██╗
+██████╔╝██║   ██║██╔██╗ ██║ ╚████╔╝ ██║     ██║   ██║██║  ██║█████╗  ██████╔╝
+██╔═══╝ ██║   ██║██║╚██╗██║  ╚██╔╝  ██║     ██║   ██║██║  ██║██╔══╝  ██╔══██╗
+██║     ╚██████╔╝██║ ╚████║   ██║   ╚██████╗╚██████╔╝██████╔╝███████╗██║  ██║
+╚═╝      ╚═════╝ ╚═╝  ╚═══╝   ╚═╝    ╚═════╝ ╚═════╝ ╚═════╝ ╚══════╝╚═╝  ╚═╝
+
+Converts punycode to unicode and vice-versa.
+
+Usage:
+	punycoder <domain>
+`
+
+func main() {
+
+	if len(os.Args) != 2 {
+		fmt.Println(usage)
+		os.Exit(1)
+	}
+
+	domain := os.Args[1]
+	var re = regexp.MustCompile(`^xn--`)
+
+	switch {
+	case domain == "-h", domain == "--help":
+		fmt.Println(usage)
+	case re.Match([]byte(domain)):
+		//punycode was provided, convert to Unicode
+		unidomain, _ := idna.ToUnicode(domain)
+		fmt.Printf("%s\n", unidomain)
+	default:
+		//convert to ASCII punycode
+		asciidomain, _ := idna.ToASCII(domain)
+		fmt.Printf("%s\n", asciidomain)
+	}
+
+}