Get current authenticated Username via Azure Function on Node.js

Question

What would be the best approach to retrieve O365/AzureAD user's details such as username who consumes an Azure Function on Node?

Only Online authenticated users are allowed to consume the Azure Function

All the examples I see are related to Azure Functions on C#.

Answer 1

If you're using Azure AD and node.js, the easiest way is to look at the X-MS-CLIENT-PRINCIPAL-NAME HTTP request header. Here is my test code for your reference.

module.exports = async function (context, req) {
    context.log('JavaScript HTTP trigger function processed a request.');

    if (req.query.name || (req.body && req.body.name)) {
        context.res = {
            // status: 200, /* Defaults to 200 */
            body: "Hello " + (req.query.name || req.body.name)+". CurrentUser:"+req.headers['x-ms-client-principal-name']
        };
    }
    else {
        context.res = {
            status: 400,
            body: "Please pass a name on the query string or in the request body"
        };
    }
};

Reference:

Advanced usage of authentication and authorization in Azure App Service