maildownloader/main.go

97 lines
2.3 KiB
Go

package main
import (
"context"
"encoding/json"
"fmt"
"log"
"net/http"
"os"
"golang.org/x/oauth2"
"golang.org/x/oauth2/google"
"google.golang.org/api/gmail/v1"
"google.golang.org/api/option"
)
func getClient(config *oauth2.Config) *http.Client {
token_file := "token.json"
token, err := tokenFromFile(token_file)
if err != nil {
token = getTokenFromWeb(config)
saveToken(token_file, token)
}
return config.Client(context.Background(), token)
}
func getTokenFromWeb(config *oauth2.Config) *oauth2.Token {
auth_url := config.AuthCodeURL("state-token", oauth2.AccessTypeOffline)
fmt.Printf("Go to the following link in your browser, then type the " +
"authorization code: \n%v\n", auth_url)
var auth_code string
if _, err := fmt.Scan(&auth_code) ; err != nil {
log.Fatalf("Unable to read authorization code: %v", err)
}
token, err := config.Exchange(context.TODO(), auth_code)
if err != nil {
log.Fatalf("Unable to retrieve token from web: %v", err)
}
return token
}
func tokenFromFile(file string) (*oauth2.Token, error) {
f, err := os.Open(file)
if err != nil {
return nil, err
}
defer f.Close()
token := &oauth2.Token{}
err = json.NewDecoder(f).Decode(token)
return token, err
}
func saveToken(path string, token *oauth2.Token) {
fmt.Printf("Saving credential file to: %s\n", path)
file, 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 file.Close()
json.NewEncoder(file).Encode(token)
}
func main() {
ctx := context.Background()
creds_b, err := os.ReadFile("credentials.json")
if err != nil {
log.Fatalf("Unable to read client secret file: %v", err)
}
config, err := google.ConfigFromJSON(creds_b, gmail.GmailReadonlyScope)
if err != nil {
log.Fatalf("Unable to parse client secret file to config: %v", err)
}
client := getClient(config)
service, err := gmail.NewService(ctx, option.WithHTTPClient(client))
if err != nil {
log.Fatalf("Unable to retrieve Gmail client: %v", err)
}
user := "me"
r, err := service.Users.Labels.List(user).Do()
if err != nil {
log.Fatalf("Unable to retrieve labels: %v", err)
}
if len(r.Labels) == 0 {
fmt.Println("No labels found")
return
}
fmt.Println("Labels:")
for _, label := range r.Labels {
fmt.Printf("- %s\n", label.Name)
}
}