Power BI - how to authenticate to app powerbi com silently

Question

I have tried the method outlined in the Microsoft docs

which involves creating an app in Active Directory and then having code something very similar to:

var authContextUrl = "https://login.windows.net/common/oauth2/authorize";
var authenticationContext = new AuthenticationContext(authContextUrl);
var redirectUri = "https://dev.powerbi.com/Apps/SignInRedirect";
var pp = new PlatformParameters(PromptBehavior.Auto);
var result = authenticationContext.AcquireTokenAsync(PowerBiApiResource, clientId, new Uri(redirectUri), pp).GetAwaiter().GetResult();

if (result == null)
{
    throw new InvalidOperationException("Failed to obtain the PowerBI API token");
}

var token = result.AccessToken;
return token;

I got this code working but it always insisted on prompting for a username and password, which is a problem for a function app.

I have also tried the approach in the silent function specified here

https://community.powerbi.com/t5/Developer/Data-Refresh-by-using-API-Need-Steps/m-p/209371#M6614

   static string getAccessTokenSilently()
    {

        HttpWebRequest request = System.Net.HttpWebRequest.CreateHttp("https://login.windows.net/common/oauth2/token");
        //POST web request to create a datasource.
        request.KeepAlive = true;
        request.Method = "POST";
        request.ContentLength = 0;
        request.ContentType = "application/x-www-form-urlencoded";

        //Add token to the request header
        request.Headers.Add("Authorization", String.Format("Bearer {0}", token));

        NameValueCollection parsedQueryString = HttpUtility.ParseQueryString(String.Empty);
        parsedQueryString.Add("client_id", clientID);
        parsedQueryString.Add("grant_type", "password");
        parsedQueryString.Add("resource", resourceUri);
        parsedQueryString.Add("username", username);
        parsedQueryString.Add("password", password);
        string postdata = parsedQueryString.ToString();


        //POST web request
        byte[] dataByteArray = System.Text.Encoding.ASCII.GetBytes(postdata); ;
        request.ContentLength = dataByteArray.Length;

        //Write JSON byte[] into a Stream
        using (Stream writer = request.GetRequestStream())
        {
            writer.Write(dataByteArray, 0, dataByteArray.Length);
            var response = (HttpWebResponse)request.GetResponse();
            var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
            dynamic responseJson = JsonConvert.DeserializeObject<dynamic>(responseString);
            return responseJson["access_token"];
        }


    }

This code doesn't work.

Also this has issues, although I haven't tried it:

https://docs.microsoft.com/en-us/power-bi/developer/get-azuread-access-token

There doesn't appear to be anything up to date available that works that explains how to do this. Does anyone know how?

Answer 1

 I have to create the application in AD using https://dev.powerbi.com/apps and then login using a powerbi pro userid and password, using the following code:

public static string GetPowerBiAccessToken(string tenantId, string clientId, string userId, string password)
{
    var url = $"https://login.windows.net/{tenantId}/oauth2/token";

    var request = (HttpWebRequest)WebRequest.Create(url);
    request.KeepAlive = true;
    request.Method = "POST";
    request.ContentType = "application/x-www-form-urlencoded";
    var dataToPost = new Dictionary<string,string>
    {
        {"client_id", clientId},
        {"grant_type", "password"},
        {"resource", PowerBiApiResource},
        {"username", userId},
        {"password", password},
        {"redirect_uri", "https://dev.powerbi.com/Apps/SignInRedirect" }
    };

    var postData = string.Empty;
    foreach (var item in dataToPost)
    {
        if (!string.IsNullOrEmpty(postData))
            postData += "&";
        postData += $"{item.Key}={item.Value}";
    }

    var dataByteArray = System.Text.Encoding.ASCII.GetBytes(postData);
    request.ContentLength = dataByteArray.Length;

    using (var writer = request.GetRequestStream())
    {
        writer.Write(dataByteArray, 0, dataByteArray.Length);
    }

    var response = (HttpWebResponse)request.GetResponse();
    var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
    var responseJson = JsonConvert.DeserializeObject<dynamic>(responseString);
    return responseJson["access_token"];
}

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