googleoauth2callback

A Go package that simplifies Google OAuth2 authentication flow with a local callback server.

This package is useful when you need to:

• Authenticate with Google OAuth2 in CLI applications
• Handle OAuth2 callback flow automatically
• Store and reuse OAuth2 tokens

Usage

Setup Google OAuth2 Credentials

1. Access Google Cloud Console

   • Go to Google Cloud Console
   • Select or create a new project

2. Create OAuth2 Credentials

   • Navigate to "APIs & Services" → "Credentials"
   • Click "Create Credentials" → "OAuth client ID"
   • Choose "Web application" as the application type
   • Enter a name and click "Create"

3. Download and Save Credentials

   • Click the download button (JSON) for your created credentials
   • Save the downloaded file as credentials.json in your project root directory
   • Add both credentials.json and token.json to your .gitignore file to exclude them from version control

Example

package main

import (
	"log"

	"github.com/yuya-takeyama/googleoauth2callback"
	"google.golang.org/api/drive/v3"
)

func main() {
	callback := googleoauth2callback.New(
		googleoauth2callback.WithCredentialsFile("credentials.json"),
		googleoauth2callback.WithRedirectURL("http://localhost:4567/callback"),
		googleoauth2callback.WithScopes([]string{"https://www.googleapis.com/auth/drive.readonly"}),
	)

	client, err := callback.GetClient()
	if err != nil {
		log.Fatal(err)
	}

	srv, err := drive.NewService(context.Background(), option.WithHTTPClient(client))
	if err != nil {
		log.Fatal(err)
	}

    // ...
}