public static async Task <SharePointClient> EnsureClientCreated()
{
if (_discoveryContext == null)
{
_discoveryContext = await DiscoveryContext.CreateAsync();
}
ResourceDiscoveryResult dcr = null;
try
{
dcr = await _discoveryContext.DiscoverResourceAsync(ServiceResourceId);
}
catch (AuthenticationFailedException)
{
// If the user go back in the login page an Authentication exception is launched.
return(null);
}
_lastLoggedInUser = dcr.UserId;
return(new SharePointClient(ServiceEndpointUri, async() =>
{
return (await _discoveryContext.AuthenticationContext
.AcquireTokenSilentAsync(ServiceResourceId, _discoveryContext.AppIdentity.ClientId, new Microsoft.IdentityModel.Clients.ActiveDirectory.UserIdentifier(dcr.UserId, Microsoft.IdentityModel.Clients.ActiveDirectory.UserIdentifierType.UniqueId))).AccessToken;
}));
}
private async Task <string> GetAccessToken()
{
string ServiceResourceId = "https://outlook.office365.com";
Uri ServiceEndpointUri = new Uri("https://outlook.office365.com/ews/odata");
DiscoveryContext disco = await DiscoveryContext.CreateAsync();
// this triggers user login prompt for Office 365
ResourceDiscoveryResult rdr = await disco.DiscoverResourceAsync(ServiceResourceId);
string clientId = disco.AppIdentity.ClientId;
string clientSecret = disco.AppIdentity.ClientSecret;
string refreshToken = new SessionCache().Read("RefreshToken");
ClientCredential creds = new ClientCredential(clientId, clientSecret);
AuthenticationResult authResult =
await disco.AuthenticationContext.AcquireTokenByRefreshTokenAsync(refreshToken,
creds,
ServiceResourceId);
return(authResult.AccessToken);
}
private async Task <ExchangeClient> EnsureClientCreated()
{
// get or create DiscoveryContext
DiscoveryContext disco = GetFromCache("DiscoveryContext") as DiscoveryContext;
if (disco == null)
{
disco = await DiscoveryContext.CreateAsync();
SaveInCache("DiscoveryContext", disco);
}
// obtain ResourceDiscoveryResult for Exchange
string ServiceResourceId = "https://outlook.office365.com";
ResourceDiscoveryResult dcr = await disco.DiscoverResourceAsync(ServiceResourceId);
SaveInCache("LastLoggedInUser", dcr.UserId);
string clientId = disco.AppIdentity.ClientId;
string clientSecret = disco.AppIdentity.ClientSecret;
Uri ServiceEndpointUri = new Uri("https://outlook.office365.com/ews/odata");
// create ExchangeClient object with callback function for obtaining access token
ExchangeClient exchangeClient = new ExchangeClient(ServiceEndpointUri, async() => {
AuthenticationContext authContext = disco.AuthenticationContext;
ClientCredential creds = new ClientCredential(clientId, clientSecret);
UserIdentifier userId = new UserIdentifier(dcr.UserId, UserIdentifierType.UniqueId);
// execute call across network to acquire access token
AuthenticationResult authResult =
await authContext.AcquireTokenSilentAsync(ServiceResourceId, creds, userId);
// return access token to caller as string value
return(authResult.AccessToken);
});
// return new ExchangeClient to caller
return(exchangeClient);
}
