public bool Authorize(GoogleAccount account)
{
DictionaryDataStore dataStore = new DictionaryDataStore();
if (account != null)
{
account.LoadDataStore(dataStore: ref dataStore);
}
try {
UserCredential credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
clientSecrets: GoogleSecrets.ToClientSecrets(Secrets),
scopes: GoogleScopes.ToStrings(Scopes),
user: "******",
taskCancellationToken: CancellationToken.None,
dataStore: dataStore
).Result;
Accounts.Add(GoogleAccount.SaveAccount(broker: this, credential: credential, dataStore: dataStore));
return(true);
} catch (TokenResponseException ex) {
if (ex.Message.Contains("invalid_grant"))
{
return(account.Reauthenticate());
}
else
{
Log.Error(ex);
}
return(false);
}
}
public UserCredential Authorize(string googleUser)
{
return(GoogleWebAuthorizationBroker.AuthorizeAsync(
GoogleSecrets.ToClientSecrets(Secrets),
GoogleScopes.ToStrings(Scopes),
googleUser, System.Threading.CancellationToken.None,
new FileDataStore(AppName)
).Result);
}
public static async Task <string> GetRefreshToken(string clientId, string clientSecret, string appName, GoogleScopes googleScope)
{
// Generates state and PKCE values.
var state = RandomDataBase64Url(32);
var codeVerifier = RandomDataBase64Url(32);
var codeChallenge = Base64UrlencodeNoPadding(Sha256(codeVerifier));
const string CodeChallengeMethod = "S256";
// Creates a redirect URI using an available port on the loopback address.
var redirectUri = $"http://{IPAddress.Loopback}:{GetRandomUnusedPort()}/";
// Creates an HttpListener to listen for requests on that redirect URI.
var http = new HttpListener();
http.Prefixes.Add(redirectUri);
http.Start();
var scope = GoogleScopes[googleScope];
// Creates the OAuth 2.0 authorization request.
var authorizationRequest =
$"{AuthorizationEndpoint}?response_type=code" +
$"&scope=openid%20{scope}" +
$"&redirect_uri={System.Uri.EscapeDataString(redirectUri)}" +
$"&client_id={clientId}" +
$"&state={state}" +
$"&code_challenge={codeChallenge}" +
$"&code_challenge_method={CodeChallengeMethod}";
// Opens request in the browser.
System.Diagnostics.Process.Start(authorizationRequest);
// Waits for the OAuth authorization response.
var context = await http.GetContextAsync();
// Sends an HTTP response to the browser.
var response = context.Response;
var responseString = $"<html><head><meta http-equiv=\'refresh\' content=\'10;url=https://google.com\'></head><body>Please return to the {appName}.</body></html>";
var buffer = System.Text.Encoding.UTF8.GetBytes(responseString);
response.ContentLength64 = buffer.Length;
var responseOutput = response.OutputStream;
await responseOutput.WriteAsync(buffer, 0, buffer.Length).ContinueWith((task) =>
{
responseOutput.Close();
http.Stop();
});
// Checks for errors.
if (context.Request.QueryString.Get("error") != null)
{
throw new GoogleException($"OAuth authorization error: {context.Request.QueryString.Get("error")}.");
}
if (context.Request.QueryString.Get("code") == null ||
context.Request.QueryString.Get("state") == null)
{
throw new GoogleException("Malformed authorization response. " + context.Request.QueryString);
}
// extracts the code
var code = context.Request.QueryString.Get("code");
var incomingState = context.Request.QueryString.Get("state");
// Compares the receieved state to the expected value, to ensure that
// this app made the request which resulted in authorization.
if (incomingState != state)
{
throw new GoogleException($"Received request with invalid state ({incomingState})");
}
// Starts the code exchange at the Token Endpoint.
return(await PerformCodeExchange(clientId, clientSecret, code, codeVerifier, redirectUri));
}
