PowerBI Connector: AzureB2C -The field 'AccessToken' of the record wasn't found

[djuan-apex]

After a solid week of troubleshooting to build a custom connector for PowerBI, I am finally at the point where my test Azure B2C credentials are showing signed in using the custom connector. However, when I go to connect to the data, I get an error - Unable to connect. We encountered an error while trying to connect. Details: "The field 'AccessToken' of the record wasn't found."

The account is configured to allow access to a database via MS Graph, but I am not sure if the error is because there is an additional token not being passed or because the dataset doesn't have the requested record.

Very novice so getting this far was an achievement, but I am out of my depth now. Any help would be appreciated and I can supply information if someone has more familiarity.

[geologyrocks]

Welcome to the world of custom connectors! Can you share a minimum reproducible example of your code please?

[djuan-apex]

Haha! Thank youf and of course!

For the post, I used GENCON instead of the actual name of the connector and used "Database Secure Data" as a generic label. I also zapped the client ID. I maintained the URL formats as much as I could so you could get an idea of what I am connecting to and how without exposing the real details. The Uri.Parts URL is part of the original script though as it seems to help parsing during the login and allowed it to succeed although I am not sure on the why it is working. This is mostly for POC and then I will want to harden for security afterwords esp. because this seems to pass the token in the URL.

I am using Viz Studio Code with Power Query SDK to generate the .mez so that has also proven to limit some of the commands I can use. Open to suggestions on that as well. I do have Viz Studio Pro 2022 installed if that helps open up the resolution options.

[Version = "1.0.0"]
section GENCON;

// Custom URL decode function for Power Query M
UrlDecode = (input as text) as text =>
let
replacedPlus = Text.Replace(input, "+", " "),
decodePercent = (text as text) =>
List.Accumulate(
{0..Text.Length(text)-3},
text,
(state, i) =>
let
segment = Text.Range(state, i, 3),
isPercent = Text.StartsWith(segment, "%"),
hex = if isPercent then Text.Middle(segment, 1, 2) else null,
decodedChar = if isPercent then Character.FromNumber(Number.FromText("0x" & hex)) else null,
replaced = if isPercent then Text.ReplaceRange(state, i, 3, decodedChar) else state
in
replaced
)
in
decodePercent(replacedPlus);

[DataSource.Kind="GENCON", Publish="GENCON.Publish"]
shared GENCON.Contents = () =>
let
apiUrl = "https://genconcustomapiurl.eastus-01.azurewebsites.net/secret/",
response = Web.Contents(apiUrl,
[
Headers = [
Authorization = "Bearer " & Extension.CurrentCredential()[AccessToken]
]
]),
json = Json.Document(response)
in
json;

GENCON = [
TestConnection = (dataSourcePath) => { "GENCON.Contents" },
Authentication = [
OAuth = [
StartLogin = (resourceUrl, state, display) =>
let
client_id = "",
redirect_uri = "https://oauth.powerbi.com/views/oauthredirect.html",
authority = "https://genconb2c.b2clogin.com/genconb2c.onmicrosoft.com/oauth2/v2.0/authorize?p=B2C_1_repsignin",
scope = "https://genconb2c.onmicrosoft.com/CustomSecret/access_as_user openid",
response_type = "id_token token",
loginUri = authority &
"&client_id=" & client_id &
"&redirect_uri=" & Uri.EscapeDataString(redirect_uri) &
"&response_type=" & response_type &
"&scope=" & Uri.EscapeDataString(scope) &
"&state=" & state
in
[
LoginUri = loginUri,
CallbackUri = redirect_uri,
WindowHeight = 720,
WindowWidth = 1024,
Context = null
],

        FinishLogin = (context, callbackUri, state) =>
            let
                parts = Uri.Parts(callbackUri),
                fragment = Record.FieldOrDefault(parts, "Fragment", null),
                fragmentValues = if (fragment <> null) then Uri.Parts("https://dummy.com/?" & fragment)[Query] else error "Missing fragment",
                access_token = Record.Field(fragmentValues, "access_token"),
                token_type = Record.FieldOrDefault(fragmentValues, "token_type", "Bearer")
            in
                [
                    access_token = access_token,
                    token_type = token_type,
                    Label = "Database Secure Data"
                ]
    ]
]

];

GENCON.Publish = [
Beta = true,
Category = "Other",
ButtonText = { "Database Secure Data", "Connect to your assigned data" },
LearnMoreUrl = "https://learn.microsoft.com/power-bi/connect-data/desktop-data-sources",
SourceImage = GENCON.Icons,
SourceTypeImage = GENCON.Icons
];

GENCON.Icons = [
Icon16 = { Extension.Contents("GENCON16.png"), "image/png" },
Icon32 = { Extension.Contents("GENCON32.png"), "image/png" }
];

[djuan-apex]

Any thoughts here?

[EdHPOS]

Hey sorry for the lack of response, I was on holiday.

So, have you tried using camelCase accessToken? Casing matters when trying to access record values. Are you sure the payload of the CurrentCredential is PascalCase?

I spent 10 minutes trying to find a way to do case insensitive record access using the Comparer.OrdinalIgnoreCase function but couldn't find a way. That might work for you if necessary.