Google Drive Go

• drive.DriveScope - Full access to Drive
• drive.DriveFileScope - Access to files created by the app
• drive.DriveMetadataReadonlyScope - Read-only metadata access
• drive.DriveReadonlyScope - Read-only access

3. Authentication Helper Functions

See references/auth.md for complete OAuth2 implementation including token storage and retrieval.

Common Operations

List Files

r, err := srv.Files.List().
    PageSize(10).
    Fields("nextPageToken, files(id, name, mimeType, size)").
    Do()
if err != nil {
    log.Fatalf("Unable to retrieve files: %v", err)
}

for _, file := range r.Files {
    fmt.Printf("%s (%s)\n", file.Name, file.Id)
}

Upload File

file := &drive.File{
    Name: "myfile.txt",
    MimeType: "text/plain",
}

content, err := os.Open("local-file.txt")
if err != nil {
    log.Fatalf("Unable to read file: %v", err)
}
defer content.Close()

createdFile, err := srv.Files.Create(file).Media(content).Do()
if err != nil {
    log.Fatalf("Unable to create file: %v", err)
}
fmt.Printf("File ID: %s\n", createdFile.Id)

Download File

// Get file metadata
file, err := srv.Files.Get(fileId).Do()

// Download content
resp, err := srv.Files.Get(fileId).Download()
if err != nil {
    log.Fatalf("Unable to download file: %v", err)
}
defer resp.Body.Close()

// Save to local file
out, err := os.Create(file.Name)
if err != nil {
    log.Fatalf("Unable to create local file: %v", err)
}
defer out.Close()

io.Copy(out, resp.Body)

Search Files

query := "name contains 'report' and mimeType='application/pdf'"
r, err := srv.Files.List().
    Q(query).
    Fields("files(id, name, createdTime)").
    Do()

Common query patterns:

• name = 'filename.txt' - Exact name match
• name contains 'keyword' - Partial match
• mimeType = 'application/pdf' - Filter by type
• 'parent-folder-id' in parents - Files in folder
• trashed = false - Exclude trashed files

Create Folder

folder := &drive.File{
    Name:     "My Folder",
    MimeType: "application/vnd.google-apps.folder",
}

createdFolder, err := srv.Files.Create(folder).Do()
if err != nil {
    log.Fatalf("Unable to create folder: %v", err)
}

Manage Permissions

permission := &drive.Permission{
    Type: "user",
    Role: "writer",
    EmailAddress: "[email protected]",
}

_, err := srv.Permissions.Create(fileId, permission).Do()
if err != nil {
    log.Fatalf("Unable to share file: %v", err)
}

Permission roles: owner, organizer, fileOrganizer, writer, commenter, reader

Advanced Topics

Pagination

Handle large result sets with pagination:

pageToken := ""
for {
    r, err := srv.Files.List().
        PageSize(100).
        PageToken(pageToken).
        Fields("nextPageToken, files(id, name)").
        Do()
    if err != nil {
        log.Fatalf("Error: %v", err)
    }
    
    for _, file := range r.Files {
        // Process file
    }
    
    pageToken = r.NextPageToken
    if pageToken == "" {
        break
    }
}

File Metadata Fields

Use the Fields parameter to specify which fields to return:

Fields("files(id, name, mimeType, size, createdTime, modifiedTime, webViewLink)")

Common fields: id, name, mimeType, size, createdTime, modifiedTime, parents, webViewLink, iconLink, thumbnailLink

Export Google Docs

Export Google Workspace files to different formats:

// Export Google Doc as PDF
resp, err := srv.Files.Export(fileId, "application/pdf").Download()

// Export Google Sheet as Excel
resp, err := srv.Files.Export(fileId, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet").Download()

Best Practices

1. Use appropriate scopes - Request minimum necessary permissions
2. Handle rate limits - Implement exponential backoff for retries
3. Batch operations - Use batch requests for multiple operations
4. Cache tokens - Store OAuth2 tokens to avoid repeated authorization
5. Use fields parameter - Only request needed fields to reduce bandwidth
6. Handle pagination - Always implement pagination for list operations
7. Check mime types - Validate file types before operations
8. Error handling - Properly handle API errors and network issues

Common MIME Types

• Plain text: text/plain
• PDF: application/pdf
• JPEG: image/jpeg
• PNG: image/png
• Google Docs: application/vnd.google-apps.document
• Google Sheets: application/vnd.google-apps.spreadsheet
• Google Slides: application/vnd.google-apps.presentation
• Folder: application/vnd.google-apps.folder

Resources

• Authentication details: See references/auth.md for complete OAuth2 implementation
• API documentation: https://developers.google.com/drive/api/v3/reference
• Go client library: https://pkg.go.dev/google.golang.org/api/drive/v3

Installation

go get google.golang.org/api/drive/v3
go get golang.org/x/oauth2/google