You can get an access token for Power BI using Azure Active Directory Authentication Libraries. The easiest way to get it is to install Microsoft.IdentityModel.Clients.ActiveDirectory NuGet package. Then to obtain an access token you need to call AcquireTokenAsync method. Here is how you can do this:
private static string redirectUri = "https://login.live.com/oauth20_desktop.srf";
private static string resourceUri = "https://analysis.windows.net/powerbi/api";
private static string authorityUri = "https://login.windows.net/common/oauth2/authorize";
// Obtain at https://dev.powerbi.com/apps
private static string clientId = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx";
private static AuthenticationContext authContext = new AuthenticationContext(authorityUri, new TokenCache());
private async void btnAuthenticate_ClickAsync(object sender, EventArgs e)
{
var authenticationResult = await authContext.AcquireTokenAsync(resourceUri, clientId, new Uri(redirectUri), new PlatformParameters(PromptBehavior.Auto));
if (authenticationResult == null)
MessageBox.Show("Call failed.");
else
MessageBox.Show(authenticationResult.AccessToken);
}
The last parameter is PromptBehavior.Auto. This means that you will be prompted for credentials, unless your identity is saved on this computer. Also, when there is no consent for access is given this app, the user will be prompted too. The authentication is performed in an interactive way - it expect that there will be a human, who will enter credentials in case they are needed. If you want to obtain an access token in non-interactive way, you can use user name and password in your code. In this case the method for obtaining the access token should look like this:
private void btnAuthenticate_Click(object sender, EventArgs e)
{
AuthenticationResult authenticationResult = null;
// First check is there token in the cache
try
{
authenticationResult = authContext.AcquireTokenSilentAsync(resourceUri, clientId).Result;
}
catch (AggregateException ex)
{
AdalException ex2 = ex.InnerException as AdalException;
if ((ex2 == null) || (ex2 != null && ex2.ErrorCode != "failed_to_acquire_token_silently"))
{
MessageBox.Show(ex.Message);
return;
}
}
if (authenticationResult == null)
{
var uc = new UserPasswordCredential("[email protected]", "<EnterStrongPasswordHere>"); // Or parameterless if you want to use Windows integrated auth
try
{
authenticationResult = authContext.AcquireTokenAsync(resourceUri, clientId, uc).Result;
}
catch (Exception ex)
{
MessageBox.Show(ex.Message + ex.InnerException == null ? "" : Environment.NewLine + ex.InnerException.Message);
return;
}
}
if (authenticationResult == null)
MessageBox.Show("Call failed.");
else
MessageBox.Show(authenticationResult.AccessToken);
}
Please note, that this call may fail, if no consent is given to your app. To do this, go to Azure Portal -> Azure Active Directory -> App registrations and locate your app. Then open your app's settings and in Required permissions select Power BI Service and click Grant permissions:
At this point you can use this access token to perform REST API calls or to embed elements in your app. This token gives access to everything which the user can access and it has been allowed to be accessed when you registered your app in the portal. If you want however to generate a token for one particular report (or tile, or dashboard), then you can call some of the Embed Token methods, e.g. GenerateTokenInGroup (using the ADAL access token to authenticate yourself in the headers of the request for generating the embedded token).
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