Initial working version, with example.

cmd/example/example.go

@@ -0,0 +1,63 @@
+/*
+example is a short example program showing the detailed result from a lookup.
+*/
+package main
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"os"
+
+	"src.lwithers.me.uk/go/dnsxl"
+)
+
+var (
+	xlist *dnsxl.XList
+)
+
+func main() {
+	if len(os.Args) < 2 {
+		fmt.Fprintln(os.Stderr, "Expecting one or more names/IPs to look up")
+		os.Exit(1)
+	}
+
+	xlist = dnsxl.New(nil)
+	xlist.AddServers("sbl.spamhaus.org", "xbl.spamhaus.org", "pbl.spamhaus.org")
+
+	for i := 1; i < len(os.Args); i++ {
+		lookup(os.Args[i])
+	}
+}
+
+func lookup(name string) {
+	fmt.Printf("==== %s ====\n", name)
+	ips, err := net.DefaultResolver.LookupIP(context.Background(), "ip", name)
+	switch {
+	case err != nil:
+		fmt.Printf("Failed to look up name: %v\n", err)
+		return
+	case len(ips) == 0:
+		fmt.Println("No addresses found for name")
+		return
+	}
+
+	for _, ip := range ips {
+		fmt.Printf("--- %s\n", ip)
+		res, err := xlist.LookupIP(ip)
+		if err != nil {
+			fmt.Printf("Failed to look up IP: %v\n", err)
+			continue
+		}
+		for _, r := range res {
+			switch {
+			case r.Error != nil:
+				fmt.Printf("%s\tError: %v\n", r.Server, r.Error)
+			case r.InList:
+				fmt.Printf("%s\tEntry in list (reason: %q)\n", r.Server, r.Reason)
+			default:
+				fmt.Printf("%s\tEntry not in list\n", r.Server)
+			}
+		}
+	}
+}