2
demonstrates how to authenticate with Google's Books API using OAuth 2.0 and retrieve a list of bookshelves from a user's library. Let's break it down step by step:
1. Authentication
- The code uses
GoogleWebAuthorizationBroker.AuthorizeAsync
to obtain user credentials for accessing the Google Books API.
- It reads the client secrets from a file named
client_secrets.json
, which contains the OAuth 2.0 credentials (e.g., client ID, client secret).
- The
GoogleClientSecrets.Load(stream).Secrets
loads the client secrets from the file.
- The
new[] { BooksService.Scope.Books }
specifies the scope of access required (Books
scope in this case).
- The
"user"
parameter indicates that the authentication is for a specific user.
- The
FileDataStore("Books.ListMyLibrary")
stores the authorization tokens securely on the local file system.
2. Creating the Service
- After obtaining the credentials, the code creates an instance of the
BooksService
class, which is used to interact with the Google Books API.
- The
BaseClientService.Initializer
is configured with:
HttpClientInitializer = credential
: Sets the authentication credentials for the service.
ApplicationName = "Books API Sample"
: Specifies the name of the application for identification purposes.
3. Retrieving Bookshelves
- The
service.Mylibrary.Bookshelves.List().ExecuteAsync()
method call retrieves a list of bookshelves from the user's library asynchronously.
Sequence of Operations
- Open the
client_secrets.json
file.
- Load the client secrets and use them to authorize the user.
- Create a
BooksService
instance with the authenticated credentials.
- Call the
List()
method on the Bookshelves
resource to retrieve the bookshelves.
- Execute the asynchronous operation to get the result.

1
This code snippet seems to use to authenticate a user with connect to the Google Books API, and fetch the list of bookshelves in their personal Google Books library.
It is reading some credentials from a file client_secrets.json and using those credentials authenticating with Google. Then it initialize a book service and call service.Mylibrary.Bookshelves.List().ExecuteAsync()
to get bookshelves of the user. Since the code is using network calls to Google the method is asynchronous