powerdns_ddns_server.go

package main

import (
	"bytes"
	"flag"
	"fmt"
	"io"
	"log"
	"net/http"
	"net/url"
	"path"
	"strings"
)

func main() {
	var httpBind string
	var httpToken string
	var apiServer string
	var apiKey string
	var ttl int

	flag.StringVar(&httpBind, "bind", ":3741", "address and port http server bind at")
	flag.StringVar(&httpToken, "token", "", "http auth token")

	flag.StringVar(&apiServer, "pdns_api", "", "pdns api server")
	flag.StringVar(&apiKey, "pdns_key", "", "pdns key")

	flag.IntVar(&ttl, "ttl", 300, "record ttl")

	flag.Parse()

	if tmp, err := url.Parse(apiServer); err != nil {
		log.Fatal("invalid pdsn_api", apiServer, err)
		return
	} else {
		tmp.Path = ""
		apiServer = tmp.String()
	}

	http.HandleFunc("/ddns.update", func(w http.ResponseWriter, r *http.Request) {
		token := r.URL.Query().Get("token")
		domain := r.URL.Query().Get("domain")
		record := r.URL.Query().Get("record")
		ipv4 := r.URL.Query().Get("ipv4")
		ipv6 := r.URL.Query().Get("ipv6")

		if token != httpToken {
			w.WriteHeader(401)
			fmt.Fprintf(w, "invalid http auth token")
			return
		}

		if !strings.HasSuffix(domain, ".") {
			domain = domain + "."
		}

		if !strings.HasSuffix(record, ".") {
			record = record + "."
		}

		apiURL := apiServer + path.Join("/api/v1/servers/localhost/zones", domain)

		log.Print("req: ", apiURL)

		client := &http.Client{}

		postData := `{"rrsets": [`
		if ipv4 != "" {
			postData += fmt.Sprintf(`
				    {"name": "%s",
					   "type": "A",
					    "ttl": %d,
						"changetype": "REPLACE",
						"records": [ {"content": "%s", "disabled": false} ]
					}`, record, ttl, ipv4)

			if ipv6 != "" {
				postData += ","
			}
		}

		if ipv6 != "" {
			postData += fmt.Sprintf(`
				    {"name": "%s",
					   "type": "AAAA",
					    "ttl": %d,
						"changetype": "REPLACE",
						"records": [ {"content": "%s", "disabled": false} ]
					}`, record, ttl, ipv6)

		}

		postData += `]}`

		log.Print(postData, "\n")

		req, err := http.NewRequest("PATCH", apiURL, bytes.NewBufferString(postData))
		if err != nil {
			fmt.Fprintf(w, "%v", err)
			return
		}

		req.Header.Add("X-API-Key", apiKey)
		resp, err := client.Do(req)
		if err != nil {
			fmt.Fprintf(w, "%v", err)
			return
		}

		defer resp.Body.Close()

		w.WriteHeader(resp.StatusCode)
		io.Copy(w, resp.Body)
	})

	fmt.Printf("Start http server at %s\n", httpBind)
	log.Fatal(http.ListenAndServe(httpBind, nil))
}