account.go

package googlewrapper

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

	"golang.org/x/oauth2"
	"golang.org/x/oauth2/google"
	calendar "google.golang.org/api/calendar/v3"
)

func ForceNewCreds(config *oauth2.Config) (err error) {

	GetClient(config, "")

	return err
}

// Retrieve a token, saves the token, then returns the generated client.
func GetClient(config *oauth2.Config, token string) *http.Client {
	tok := &oauth2.Token{}
	err := json.Unmarshal([]byte(token), tok)
	if err != nil {
		tok = GetTokenFromWeb(config)
		SaveToken("token.json", 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 {
	authURL := config.AuthCodeURL("state-token", oauth2.AccessTypeOffline)
	fmt.Printf("Go to the following link in your browser then type the "+
		"authorization code: \n%v\n", authURL)

	var authCode string
	if _, err := fmt.Scan(&authCode); err != nil {
		log.Fatalf("Unable to read authorization code: %v", err)
	}

	tok, err := config.Exchange(oauth2.NoContext, authCode)
	if err != nil {
		log.Fatalf("Unable to retrieve token from web: %v", err)
	}
	return tok
}

func TokenFromFile(file string) (*oauth2.Token, error) {
	f, err := os.Open(file)
	defer f.Close()
	if err != nil {
		return nil, err
	}
	tok := &oauth2.Token{}
	err = json.NewDecoder(f).Decode(tok)
	return tok, err
}

func ConfigFromString(configString string) (config *oauth2.Config, err error) {
	config, err = google.ConfigFromJSON([]byte(configString), calendar.CalendarScope)
	if err != nil {
		log.Fatalf("Unable to parse client secret file to config: %v", err)
	}

	return config, err
}

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