Issue connecting to Custom Connector with Gateway via OAuth 2.0

[SparkByte_202]

Hello everyone!

I created a custom connector to interface with Facebook's API for PowerBI Desktop, and it functions perfectly, handling logins without issue. However, when I try to use it with PowerBI Service via the 'On-premises data gateway,' I encounter a login problem. Other custom connectors work fine, but the Facebook one does not.

Here's what happens:

1. The Facebook login window opens.
2. I enter my login details.
3. I grant the necessary app permissions.
4. The window closes.

At this point, it behaves just like it does on the desktop version. But instead of a successful login, after clicking the "create" button, I receive the following error:
PBI Test Gateway: [Expression.Error] The "code" field of the record was not found.

These are the (pretty standard) OAuth methods my connector is using:

OAuthLoginStart = (resourceUrl, state, display) =>  

    let
        AuthorizeUrl = authorize_Url & Uri.BuildQueryString([
            client_id = app_id,
            redirect_uri = redirectUrl,
            scope=scopes,
            state = state
            ])
    in
        [
            LoginUri = AuthorizeUrl,
            CallbackUri = redirectUrl,
            WindowHeight = windowHeight,
            WindowWidth = windowWidth,
            Context = null
        ]; 

OAuthLoginFinish = (context, callbackUri, state) =>
    let
        parts = Uri.Parts(callbackUri)[Query],
        result = if (Record.HasFields(parts, {"error", "error_description"})) then 
                    error Error.Record(parts[error], parts[error_description], parts)
                 else
                    TokenMethod(parts[code])
    in
        result;

TokenMethod = (code) =>
    let
        response = Web.Contents(token_Url & "?" & Uri.BuildQueryString([
                client_id = app_id,
                redirect_uri = redirectUrl,
                client_secret = app_secret,
                code = code]),
            [ManualStatusHandling = {400}]),
        body = Json.Document(response),
        result = if (Record.HasFields(body, {"error", "error_description"})) then 
                    error Error.Record(body[error], body[error_description], body)
                 else
                    body
    in
        result;

Can anyone help resolve this issue?

[ReportRanger]

Hi @SparkByte_202As a workaround, maybe you can use a 3rd party connector, it can save you a lot of time compared to the other options. I've tried windsor.ai, supermetrics and funnel.io. I stayed with windsor because it is much cheaper so just to let you know other options. In case you wonder, to make the connection first search for the Facebook Ads connector in the data sources list:

After that, just grant access to your Facebook Ads account using your credentials, then on preview and destination page you will see a preview of your FB fields:

There just select the fields you need. Finally, just select PBI as your data destination and finally just copy and paste the url on PBI --> Get Data --> Web --> Paste the url. 

[Anonymous]

Hi, @SparkByte_202 

Here are a few steps you can take to troubleshoot the issue and potentially resolve the issue. Verify the redirect URI to ensure that the URI specified in the OAuth method exactly matches the URI registered in the Facebook app settings. A mismatch in the redirect URI can cause issues during the OAuth flow.
Check the OAuth response and temporarily modify the connector code to record or output the full response received in the step. This can help you verify that the expected "tag" field is present in the response of the Facebook API.
Review the custom connector implementation: Make sure that the custom connector implements this section correctly, as this is required for the custom connector to work with the on-premises data gateway. You can check the following link:

Use custom data connectors with the on-premises data gateway - Power BI | Microsoft Learn

Another potential issue could be that the PowerBI service doesn't support custom functions. If you use any custom functions in Power Query, it can cause problems.

How to Get Your Question Answered Quickly 

Best Regards

Yongkang Hua

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