Refreshing jwt?

[FrederikB]

I am building a custom connector.

All requests require a jwt, which expires after 15 minutes.

I get a jwt by calling a /login endpoint. I am able to get the token, and make the requests, but can't enable automatic refreshes. Tried following a tutorial, but it does not work. 

I am pretty sure it is because I don't tell PBI how to get the new token on refresh.

query.pq

let
    result = Youandx_v2.Contents()
in
    result

.pq file, where I declare the "TestConnection", where I think something is wrong. Should I instead do something with my getJwt function?

Youandx_v2 = [
    TestConnection = (dataSourcePath) => { "Youandx.Contents" },
    Authentication = [
        UsernamePassword = [
            UsernameLabel = "Username",
            PasswordLabel = "Password"
        ]
    ],
    Label = Extension.LoadString("DataSourceLabel")
];

Another place in same file:

[DataSource.Kind="Youandx_v2", Publish="Youandx_v2.Publish"]
shared Youandx_v2.Contents = () =>
    let
        jwt = getJwt(),
        navTable = navTable(jwt)
    in
        navTable;

navTable function

navTable = (jwt as text) as table => 
    let 
        bookingTable = getBookings(jwt),
        source = #table({"Name", "Data", "ItemKind", "ItemName", "IsLeaf"}, {
            {"Bookings", bookingTable, "Table", "Table", true},
            {"Speakers", getSpeakers(jwt), "Table", "Table", true} ,
            {"Products", getProducts(jwt), "Table", "Table", true},
            {"Invoices", getInvoices(bookingTable), "Table", "Table", true}, 
            {"Line Items", getLineItems(bookingTable), "Table", "Table", true}, 
            {"Plans", getPlans(jwt), "Table", "Table", true},
            {"Speaker Account", getSpeakerAccounts(jwt), "Table", "Table", true}
        }),
        navTable = Table.ToNavigationTable(source, {"Name"}, "Name", "Data", "ItemKind", "ItemName", "IsLeaf")
    in
        navTable;

getJwt

getJwt = () => 
    let 
        username = Extension.CurrentCredential()[Username],
        password = Extension.CurrentCredential()[Password],
        URL = "https://www.youandx.com/api/v1/login",
        headers = [
            #"Content-Type"="application/json"
        ],
        bodyData = Json.FromValue([tmode = 2, hold = 0, email = username, password = password]),
        web = Web.Contents(URL, [ Content = bodyData, Headers = headers, ManualStatusHandling = {404, 400}]),
        result = Json.Document(web),
        first = Record.ToTable(result),
        Value = first{1}[Value],
        jwt = Value[jwt]
    in
        jwt;

As you can see, I get a jwt, and pass it on to navTable and then each of the functions, for example getBookings. But how do I make sure, that the getJwt function is called upon refresh?

Thanks.

EDIT: This is the message I get in the Power BI Web interface when trying to refresh the data: "Unable to refresh the model (id=3228545) because it references an unsupported data source."

[Anonymous · Accepted solution]

Hi @FrederikB ,

Please try below code to decode JWT token in custom connector.

let
    Token = "<snip>",
    Base64Url.Decode = (s) => Binary.FromText(Text.Replace(Text.Replace(s, "-", "+"), "_", "/") & {"", "", "==", "="}{Number.Mod(Text.Length(s), 4)}, BinaryEncoding.Base64),
    Parts = Json.Document(Base64Url.Decode(Text.Split(Token, "."){1}))
in
    Parts

Best Regards,
Rico Zhou

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.