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// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// The hello binary runs hello.ipn.dev.
package main // import "tailscale.com/cmd/hello"
import (
"context"
_ "embed"
"encoding/json"
"flag"
"html/template"
"io/ioutil"
"log"
"net/http"
"os"
"strings"
"tailscale.com/client/tailscale"
"tailscale.com/client/tailscale/apitype"
)
var (
httpAddr = flag.String("http", ":80", "address to run an HTTP server on, or empty for none")
httpsAddr = flag.String("https", ":443", "address to run an HTTPS server on, or empty for none")
testIP = flag.String("test-ip", "", "if non-empty, look up IP and exit before running a server")
)
//go:embed hello.tmpl.html
var embeddedTemplate string
func main() {
flag.Parse()
if *testIP != "" {
res, err := tailscale.WhoIs(context.Background(), *testIP)
if err != nil {
log.Fatal(err)
}
e := json.NewEncoder(os.Stdout)
e.SetIndent("", "\t")
e.Encode(res)
return
}
if devMode() {
// Parse it optimistically
var err error
tmpl, err = template.New("home").Parse(embeddedTemplate)
if err != nil {
log.Printf("ignoring template error in dev mode: %v", err)
}
} else {
if embeddedTemplate == "" {
log.Fatalf("embeddedTemplate is empty; must be build with Go 1.16+")
}
tmpl = template.Must(template.New("home").Parse(embeddedTemplate))
}
http.HandleFunc("/", root)
log.Printf("Starting hello server.")
errc := make(chan error, 1)
if *httpAddr != "" {
log.Printf("running HTTP server on %s", *httpAddr)
go func() {
errc <- http.ListenAndServe(*httpAddr, nil)
}()
}
if *httpsAddr != "" {
log.Printf("running HTTPS server on %s", *httpsAddr)
go func() {
errc <- http.ListenAndServeTLS(*httpsAddr,
"/etc/hello/hello.ipn.dev.crt",
"/etc/hello/hello.ipn.dev.key",
nil,
)
}()
}
log.Fatal(<-errc)
}
func devMode() bool { return *httpsAddr == "" && *httpAddr != "" }
func getTmpl() (*template.Template, error) {
if devMode() {
tmplData, err := ioutil.ReadFile("hello.tmpl.html")
if os.IsNotExist(err) {
log.Printf("using baked-in template in dev mode; can't find hello.tmpl.html in current directory")
return tmpl, nil
}
return template.New("home").Parse(string(tmplData))
}
return tmpl, nil
}
// tmpl is the template used in prod mode.
// In dev mode it's only used if the template file doesn't exist on disk.
// It's initialized by main after flag parsing.
var tmpl *template.Template
type tmplData struct {
DisplayName string // "Foo Barberson"
LoginName string // "foo@bar.com"
ProfilePicURL string // "https://..."
MachineName string // "imac5k"
MachineOS string // "Linux"
IP string // "100.2.3.4"
}
func tailscaleIP(who *apitype.WhoIsResponse) string {
if who == nil {
return ""
}
for _, nodeIP := range who.Node.Addresses {
if nodeIP.IP().Is4() && nodeIP.IsSingleIP() {
return nodeIP.IP().String()
}
}
for _, nodeIP := range who.Node.Addresses {
if nodeIP.IsSingleIP() {
return nodeIP.IP().String()
}
}
return ""
}
func root(w http.ResponseWriter, r *http.Request) {
if r.TLS == nil && *httpsAddr != "" {
host := r.Host
if strings.Contains(r.Host, "100.101.102.103") {
host = "hello.ipn.dev"
}
http.Redirect(w, r, "https://"+host, http.StatusFound)
return
}
if r.RequestURI != "/" {
http.Redirect(w, r, "/", http.StatusFound)
return
}
tmpl, err := getTmpl()
if err != nil {
w.Header().Set("Content-Type", "text/plain")
http.Error(w, "template error: "+err.Error(), 500)
return
}
who, err := tailscale.WhoIs(r.Context(), r.RemoteAddr)
var data tmplData
if err != nil {
if devMode() {
log.Printf("warning: using fake data in dev mode due to whois lookup error: %v", err)
data = tmplData{
DisplayName: "Taily Scalerson",
LoginName: "taily@scaler.son",
ProfilePicURL: "https://placekitten.com/200/200",
MachineName: "scaled",
MachineOS: "Linux",
IP: "100.1.2.3",
}
} else {
log.Printf("whois(%q) error: %v", r.RemoteAddr, err)
http.Error(w, "Your Tailscale works, but we failed to look you up.", 500)
return
}
} else {
data = tmplData{
DisplayName: who.UserProfile.DisplayName,
LoginName: who.UserProfile.LoginName,
ProfilePicURL: who.UserProfile.ProfilePicURL,
MachineName: firstLabel(who.Node.ComputedName),
MachineOS: who.Node.Hostinfo.OS,
IP: tailscaleIP(who),
}
}
w.Header().Set("Content-Type", "text/html; charset=utf-8")
tmpl.Execute(w, data)
}
// firstLabel s up until the first period, if any.
func firstLabel(s string) string {
if i := strings.Index(s, "."); i != -1 {
return s[:i]
}
return s
}
|
