Time triggered Azure function - Bearer token generation to call a protected API

Question

I am trying to write an Azure function which is time triggered and runs every 10 minutes.

The function needs to call an API which expects a bearer token.

How do I generate the token? Since it is time based, I can't have a user to login and give function authorization token by signing into MS Identity platform which can be used to get the access token.

Answer 1

You just need to get the token by the code below in your timer trigger function:

HttpClient client = new HttpClient();
var values = new Dictionary<string, string>
{
    { "client_id", "<your app client id>" },
    { "scope", "<scope>" },
    { "username", "<your user name>" },
    { "password", "<your password>" },
    { "grant_type", "password" },
};

var content = new FormUrlEncodedContent(values);

var response = await client.PostAsync("https://login.microsoftonline.com/<your tenant id>/oauth2/v2.0/token", content);

var responseString = await response.Content.ReadAsStringAsync();

Then you need to parse responseString(in json type) and use the access token in it to request your api.

Update:

Get token by client credential:

HttpClient client = new HttpClient();
var values = new Dictionary<string, string>
{
    { "client_id", "<your app client id>" },
    { "scope", "<scope>" },
    { "client_secret", "<your app client secret>" },
    { "grant_type", "client_credentials" },
};

var content = new FormUrlEncodedContent(values);

var response = await client.PostAsync("https://login.microsoftonline.com/<your tenant id>/oauth2/v2.0/token", content);

var responseString = await response.Content.ReadAsStringAsync();