Refresh Tokenを取得する処理を追加 refs #1

.gitignore

@@ -13,3 +13,5 @@
 
 # Dependency directories (remove the comment below to include it)
 # vendor/
+
+token.json

gmail_service.go

@@ -0,0 +1,119 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+
+	"cloud.google.com/go/storage"
+	"golang.org/x/oauth2"
+	"google.golang.org/api/gmail/v1"
+)
+
+type GmailService struct {
+	gus *gmail.UsersService
+}
+
+func NewGmailService(ctx context.Context, gmailService *gmail.Service) (*GmailService, error) {
+	gmailUserService := gmail.NewUsersService(gmailService)
+	return &GmailService{
+		gus: gmailUserService,
+	}, nil
+}
+
+type WatchResponse struct {
+	HistoryID  int64
+	Expiration int64
+}
+
+func (s *GmailService) Watch(ctx context.Context, userID string, req *gmail.WatchRequest) (*WatchResponse, error) {
+	res, err := s.gus.Watch(userID, req).Context(ctx).Do()
+	if err != nil {
+		return nil, fmt.Errorf("failed GmailUserService.Watch.userID=%s,req=%#v : %w", userID, req, err)
+	}
+	return &WatchResponse{
+		HistoryID:  int64(res.HistoryId),
+		Expiration: res.Expiration,
+	}, nil
+}
+
+func getCredentialFile(ctx context.Context) ([]byte, error) {
+	gcs, err := storage.NewClient(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		if err := gcs.Close(); err != nil {
+			fmt.Printf("failed gcs.Close() err=%v", err)
+		}
+	}()
+
+	r, err := gcs.Bucket("sinmetal-ironhead-config").Object("client_secret.json").NewReader(ctx)
+	if err != nil {
+		return nil, err
+	}
+	return ioutil.ReadAll(r)
+}
+
+// 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)
+}
+
+// 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) {
+	fmt.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 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)
+	}
+	unescapeAuthCode, err := url.QueryUnescape(authCode)
+	if err != nil {
+		log.Fatalf("url.QueryUnescape: %v", err)
+	}
+
+	tok, err := config.Exchange(context.Background(), unescapeAuthCode)
+	if err != nil {
+		log.Fatalf("Unable to retrieve token from web: %v", err)
+	}
+	return tok
+}

gmail_service_test.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"context"
+	"testing"
+
+	"golang.org/x/oauth2/google"
+	"google.golang.org/api/gmail/v1"
+	"google.golang.org/api/option"
+)
+
+func TestGmailService_Watch(t *testing.T) {
+	ctx := context.Background()
+
+	clientSecret, err := getCredentialFile(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	config, err := google.ConfigFromJSON(clientSecret, gmail.GmailMetadataScope)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	token := getTokenFromWeb(config)
+	client := config.Client(ctx, token)
+	gmailService, err := gmail.NewService(ctx, option.WithHTTPClient(client))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	s, err := NewGmailService(ctx, gmailService)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	resp, err := s.Watch(ctx, "[email protected]", &gmail.WatchRequest{
+		TopicName: "projects/sinmetal-ironhead/topics/gmail",
+		LabelIds:  []string{"tbf-stackdriver-notifications"},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("%#v", resp)
+}

go.mod

@@ -1,3 +1,9 @@
 module github.com/sinmetalcraft/ironhead
 
 go 1.11
+
+require (
+	cloud.google.com/go/storage v1.10.0
+	golang.org/x/oauth2 v0.0.0-20201208152858-08078c50e5b5
+	google.golang.org/api v0.36.0
+)