Afero Google Drive Driver

About

It provides an afero filesystem implementation of a Google Drive backend.

This was created to provide a backend to the ftpserver but can definitely be used in any other code.

I'm very opened to any improvement through issues or pull-request that might lead to a better implementation or even better testing.

Key points

• Download & upload file streaming
• 60% coverage: This isn't great, I intend to improve it to reach 80%. As it's a third-party API more would take way too much time.
• Very carefully linted

Known limitations

• File appending / seeking for write is not supported because Google Drive doesn't support it, it could be simulated by rewriting entire files.
• Chmod is saved as a property and not used at this time.
• No files listing cache. This means that every directory of a path results in a request that happens every single time a path is analyzed. In other word opening /a/b/c/file.txt for writing will create at least 4 request, and the same will happen for reading.

How to use

Note: Errors handling is skipped for brevity but you definitely have to handle it.

import (
	"github.com/fclairamb/afero-gdrive/oauthhelper"
)

func main() {
  // We declare the OAuh2 app
  helper := oauthhelper.Auth{
    ClientID:     os.Getenv("GOOGLE_CLIENT_ID"),
    ClientSecret: os.Getenv("GOOGLE_CLIENT_SECRET"),
    Authenticate: func(url string) (string, error) {
     return "", ErrNotSupported
    },
  }

  // Pass a token 
  token, _ := base64.StdEncoding.DecodeString(os.Getenv("GOOGLE_TOKEN"))
  helper.Token = new(oauth2.Token)
  json.Unmarshal(token, helper.Token)
	
  // Initialize the authenticated client
  client, _ := helper.NewHTTPClient(context.Background())
  
  // Initialize the FS from the athenticated http client
  fs, _ := New(client)

  // And use it
  file, _ := fs.OpenFile("my_file.txt", os.O_WRONLY, 0777)
  file.WriteString("Hello world !")
  file.Close()
}

Credits

This is a fork from T4cC0re/gdriver which is itself a fork of eun/gdriver.

The code was massively modified. Most of the changes are improvements. The file listing API from the original implemented based on callbacks is much better though, but this was needed to respect the afero API.