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Getting Started

Installation

go get github.com/grokify/gogoogle

Authentication

GoGoogle uses OAuth2 for authentication. You'll need:

  1. A Google Cloud project with APIs enabled
  2. OAuth2 credentials (client_secret.json)
  3. User authorization (generates token.json)

Enable Google APIs

  1. Go to Google Cloud Console
  2. Create or select a project
  3. Enable the APIs you need:
  4. Gmail API
  5. Google Sheets API
  6. Google Slides API
  7. etc.

Create OAuth Credentials

  1. Go to APIs & Services > Credentials
  2. Click Create Credentials > OAuth client ID
  3. Select Desktop app as application type
  4. Download the JSON file as client_secret.json

Authorize Your Application

Use goauth for OAuth2 flow:

import (
    "context"
    "github.com/grokify/goauth/google"
)

client, err := google.NewClientOAuthCLITokenStore(google.ClientOAuthCLITokenStoreConfig{
    Context:   ctx,
    AppConfig: clientSecretJSON,  // Contents of client_secret.json
    Scopes:    []string{
        "https://www.googleapis.com/auth/gmail.send",
        "https://www.googleapis.com/auth/spreadsheets.readonly",
    },
    TokenFile: "token.json",      // Will be created after authorization
    State:     "my-app",
})
if err != nil {
    log.Fatal(err)
}

On first run, this opens a browser for user authorization. The token is saved to token.json for subsequent runs.

Common OAuth Scopes

Gmail

Scope Description
gmail.send Send emails only
gmail.readonly Read emails only
gmail.modify Read, send, delete emails
gmail.labels Manage labels 
import "github.com/grokify/gogoogle/gmailutil/v1"

scopes := []string{gmailutil.GmailSendScope}

Sheets

Scope Description
spreadsheets.readonly Read spreadsheets
spreadsheets Read and write spreadsheets

Slides

Scope Description
presentations.readonly Read presentations
presentations Read and write presentations

Create Service Clients

After authentication, create service clients:

Gmail

import "github.com/grokify/gogoogle/gmailutil/v1"

service, err := gmailutil.NewGmailService(ctx, httpClient)
if err != nil {
    log.Fatal(err)
}

Sheets

import "google.golang.org/api/sheets/v4"

service, err := sheets.NewService(ctx, option.WithHTTPClient(httpClient))
if err != nil {
    log.Fatal(err)
}

Slides

import "google.golang.org/api/slides/v1"

service, err := slides.NewService(ctx, option.WithHTTPClient(httpClient))
if err != nil {
    log.Fatal(err)
}

Environment Variables

For production, store credentials securely:

export GOOGLE_CLIENT_SECRET=$(cat client_secret.json)
export GOOGLE_TOKEN=$(cat token.json)

clientSecret := []byte(os.Getenv("GOOGLE_CLIENT_SECRET"))

Next Steps