Split utils out to a separate subpackage

irc/utils/args.go

@@ -0,0 +1,35 @@
+// Copyright (c) 2016-2017 Daniel Oaks <daniel@danieloaks.net>
+// released under the MIT license
+
+package utils
+
+// ArgsToStrings takes the arguments and splits them into a series of strings,
+// each argument separated by delim and each string bounded by maxLength.
+func ArgsToStrings(maxLength int, arguments []string, delim string) []string {
+	var messages []string
+
+	var buffer string
+	for {
+		if len(arguments) < 1 {
+			break
+		}
+
+		if len(buffer) > 0 && maxLength < len(buffer)+len(delim)+len(arguments[0]) {
+			messages = append(messages, buffer)
+			buffer = ""
+			continue
+		}
+
+		if len(buffer) > 1 {
+			buffer += delim
+		}
+		buffer += arguments[0]
+		arguments = arguments[1:]
+	}
+
+	if len(buffer) > 0 {
+		messages = append(messages, buffer)
+	}
+
+	return messages
+}

irc/utils/net.go

@@ -0,0 +1,70 @@
+// Copyright (c) 2012-2014 Jeremy Latt
+// Copyright (c) 2016 Daniel Oaks <daniel@danieloaks.net>
+// released under the MIT license
+
+package utils
+
+import (
+	"net"
+	"strings"
+)
+
+// IPString returns a simple IP string from the given net.Addr.
+func IPString(addr net.Addr) string {
+	addrStr := addr.String()
+	ipaddr, _, err := net.SplitHostPort(addrStr)
+	//TODO(dan): Why is this needed, does this happen?
+	if err != nil {
+		return addrStr
+	}
+	return ipaddr
+}
+
+// AddrLookupHostname returns the hostname (if possible) or address for the given `net.Addr`.
+func AddrLookupHostname(addr net.Addr) string {
+	return LookupHostname(IPString(addr))
+}
+
+// LookupHostname returns the hostname for `addr` if it has one. Otherwise, just returns `addr`.
+func LookupHostname(addr string) string {
+	names, err := net.LookupAddr(addr)
+	if err == nil && len(names) > 0 {
+		candidate := strings.TrimSuffix(names[0], ".")
+		if IsHostname(candidate) {
+			return candidate
+		}
+	}
+
+	// return original address if no hostname found
+	if len(addr) > 0 && addr[0] == ':' {
+		// fix for IPv6 hostnames (so they don't start with a colon), same as all other IRCds
+		addr = "0" + addr
+	}
+	return addr
+}
+
+var allowedHostnameChars = "abcdefghijklmnopqrstuvwxyz1234567890-."
+
+// IsHostname returns whether we consider `name` a valid hostname.
+func IsHostname(name string) bool {
+	// IRC hostnames specifically require a period
+	if !strings.Contains(name, ".") || len(name) < 1 || len(name) > 253 {
+		return false
+	}
+
+	// ensure each part of hostname is valid
+	for _, part := range strings.Split(name, ".") {
+		if len(part) < 1 || len(part) > 63 || strings.HasPrefix(part, "-") || strings.HasSuffix(part, "-") {
+			return false
+		}
+	}
+
+	// ensure all chars of hostname are valid
+	for _, char := range strings.Split(strings.ToLower(name), "") {
+		if !strings.Contains(allowedHostnameChars, char) {
+			return false
+		}
+	}
+
+	return true
+}

irc/utils/net_test.go

@@ -0,0 +1,49 @@
+// Copyright (c) 2012-2014 Jeremy Latt
+// Copyright (c) 2016 Daniel Oaks <daniel@danieloaks.net>
+// released under the MIT license
+
+package utils
+
+import "testing"
+
+// hostnames from https://github.com/DanielOaks/irc-parser-tests
+var (
+	goodHostnames = []string{
+		"irc.example.com",
+		"i.coolguy.net",
+		"irc-srv.net.uk",
+		"iRC.CooLguY.NeT",
+		"gsf.ds342.co.uk",
+		"324.net.uk",
+		"xn--bcher-kva.ch",
+	}
+
+	badHostnames = []string{
+		"-lol-.net.uk",
+		"-lol.net.uk",
+		"_irc._sctp.lol.net.uk",
+		"irc",
+		"com",
+		"",
+	}
+)
+
+func TestIsHostname(t *testing.T) {
+	for _, name := range goodHostnames {
+		if !IsHostname(name) {
+			t.Error(
+				"Expected to pass, but could not validate hostname",
+				name,
+			)
+		}
+	}
+
+	for _, name := range badHostnames {
+		if IsHostname(name) {
+			t.Error(
+				"Expected to fail, but successfully validated hostname",
+				name,
+			)
+		}
+	}
+}