whois.go

package main

import (
	"context"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"net/url"
	"os"

	"golang.org/x/oauth2"
	"golang.org/x/oauth2/google"
	"google.golang.org/api/option"
	"google.golang.org/api/people/v1"
)

// Retrieve a token, saves the token, then returns the generated client.
func getClient(config *oauth2.Config) *http.Client {
	// The file token.json stores the user's access and refresh tokens, and is
	// created automatically when the authorization flow completes for the first
	// time.
	tokFile := "token.json"
	tok, err := tokenFromFile(tokFile)
	if err != nil {
		tok = getTokenFromWeb(config)
		saveToken(tokFile, tok)
	}
	return config.Client(context.Background(), tok)
}

// Request a token from the web, then returns the retrieved token.
func getTokenFromWeb(config *oauth2.Config) *oauth2.Token {
	codes := make(chan string)
	var addr string
	if up, err := url.Parse(config.RedirectURL); err != nil {
		addr = "localhost:1234"
	} else {
		addr = up.Host
	}
	server := http.Server{
		Addr: addr,
	}
	state := "state-token"
	server.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if token := r.FormValue("state"); token != state {
			log.Fatalf("invalid state token: %q", token)
		}
		codes <- r.FormValue("code")
	})

	go func() {
		//log.Printf("starting server on http://%s", server.Addr)
		if err := server.ListenAndServe(); err != nil {
			//log.Printf("while shutting down server: %v", err)
		}
	}()

	authURL := config.AuthCodeURL(state, oauth2.AccessTypeOffline)
	fmt.Printf("Go to: %v\n", authURL)

	code := <-codes
	server.Shutdown(context.Background())

	tok, err := config.Exchange(context.TODO(), code)
	if err != nil {
		log.Fatalf("Unable to retrieve token from web: %v", err)
	}
	return tok
}

// Retrieves a token from a local file.
func tokenFromFile(file string) (*oauth2.Token, error) {
	f, err := os.Open(file)
	if err != nil {
		return nil, err
	}
	defer f.Close()
	tok := &oauth2.Token{}
	err = json.NewDecoder(f).Decode(tok)
	return tok, err
}

// Saves a token to a file path.
func saveToken(path string, token *oauth2.Token) {
	//log.Printf("Saving credential file to: %s\n", path)
	f, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
	if err != nil {
		log.Fatalf("Unable to cache oauth token: %v", err)
	}
	defer f.Close()
	json.NewEncoder(f).Encode(token)
}

func main() {
	var userIDs []string
	if len(os.Args) == 1 {
		userIDs = []string{"people/me"}
	} else {
		for _, a := range os.Args[1:] {
			userIDs = append(userIDs, "people/"+a)
		}
	}
	ctx := context.Background()
	b, err := ioutil.ReadFile("credentials.json")
	if err != nil {
		log.Fatalf("Unable to read client secret file: %v", err)
	}

	// If modifying these scopes, delete your previously saved token.json.
	config, err := google.ConfigFromJSON(b, people.UserinfoProfileScope, people.UserinfoEmailScope, people.DirectoryReadonlyScope)
	if err != nil {
		log.Fatalf("Unable to parse client secret file to config: %v", err)
	}
	client := getClient(config)

	srv, err := people.NewService(ctx, option.WithHTTPClient(client))
	if err != nil {
		log.Fatalf("Unable to create people Client %v", err)
	}

	rs, err := srv.People.GetBatchGet().ResourceNames(userIDs...).
		PersonFields("names,emailAddresses").Do()
	if err != nil {
		log.Fatalf("Unable to retrieve people. %v", err)
	}

	for _, r := range rs.Responses {
		fmt.Println(r.Person.ResourceName, ":")
		for _, e := range r.Person.EmailAddresses {
			fmt.Println("\t", e.Value)
		}
	}
}