go-webring/main.go

// SPDX-FileCopyrightText: 2021 Amolith <amolith@secluded.site>
//
// SPDX-License-Identifier: BSD-2-Clause

package main

import (
	"fmt"
	"html/template"
	"log"
	"net"
	"net/http"
	"strings"

	flag "github.com/spf13/pflag"
)

type RingMember struct {
	id  string
	url string
}

type Ring struct {
	ring         []RingMember
	index        *template.Template
	ringModTime  int64
	indexModTime int64
}

// Pre-define all of our flags
var (
	flagListen  *string = flag.StringP("listen", "l", "127.0.0.1:2857", "host:port or /unix/socket/path go-webring will listen on")
	flagMembers *string = flag.StringP("members", "m", "list.txt", "Path to list of webring members")
	flagIndex   *string = flag.StringP("index", "i", "index.html", "Path to home page template")
	// These are not (and might never be) implemented, we'll see
	// flagCert  *string = flag.StringP("cert", "c", "cert.crt", "Path to certificate")
	// flagKey   *string = flag.StringP("key", "k", "cert.key", "Path to private certificate key")
)

func ListenAndServeUnix(srv *http.Server) error {
	addr := srv.Addr
	if strings.Index(addr, "/") != 0 {
		return fmt.Errorf("unix address wrong: %v", addr)
	}
	ln, err := net.Listen("unix", addr)
	if err != nil {
		return err
	}
	return srv.Serve(ln)
}

func main() {
	if *flagListen == "" {
		panic("socket addr is empty; please specify -l")
	}

	m := Ring{}
	m.init()

	mux := http.NewServeMux()

	httpServer := &http.Server{
		Addr:    *flagListen,
		Handler: mux,
	}

	mux.HandleFunc("/", m.root)
	mux.HandleFunc("/next", m.next)
	mux.HandleFunc("/previous", m.previous)
	mux.HandleFunc("/random", m.random)

	var err error
	if strings.Contains(httpServer.Addr, ":") {
		err = httpServer.ListenAndServe()
	} else {
		err = ListenAndServeUnix(httpServer)
	}
	if err == http.ErrServerClosed {
		log.Println("Web server closed")
	} else {
		log.Fatalln(err)
	}
}

func (m *Ring) init() {
	flag.Parse()
	log.Println("Listening on", *flagListen)
	log.Println("Looking for members in", *flagMembers)
	m.parseList()
	log.Println("Found", len(m.ring), "members")
	log.Println("Building homepage with", *flagIndex)
	m.parseIndex()
}