Microsoft Graph API - Administrator Consent to update User Calendar - api

Question

I am working on a App to integrate Microsoft Graph API, is it possible for the administrator of each tenant to give consent for permissions so that the user does not need to have any interaction with our app to give permission so that we can update the user calendar?
Or does the user have to provide authorization at least once in order to get the authorization token?
I have been looking at this guide:
https://learn.microsoft.com/en-gb/graph/auth-v2-service

Answer 1

You can update users' calendar by calling ms graph api without users sign in. But it depends on the api you used if support Application api permission. For example, this api is used to create event for calendar. It support application permission.
I also want to inform you that using application permission is not the best practice because it will give your application such a big permission to manage all users' calendars. But this seems to be your goal.
Let's come back to your requirement. And using the api I mentioned as an example. You firstly need to have an azure ad application and give it the correct api permission and let the tenant admin to consent the permission by clicking "grant admin consent for xx_tenant".
Then you also need to create a client secret for your azure ad application. Going to Azure ad -> Certificates & secrets -> New cient secret. Pls copy the secret. Then assuming you have an asp.net core app used to call the graph api. Then refer to this section or my code below to use graph sdk to call the api. Pls note, graphClient.Users["user_principle"] means who creates the event, the Attendees defines whose calendars will be added events.
using Azure.Identity;
using Microsoft.Graph;
var scopes = new[] { "https://graph.microsoft.com/.default" };
var tenantId = "your_tenant_name.onmicrosoft.com";
var clientId = "azure_ad_app_id";
var clientSecret = "client_secret";
var clientSecretCredential = new ClientSecretCredential(
tenantId, clientId, clientSecret);
var graphClient = new GraphServiceClient(clientSecretCredential, scopes);
var #event = new Event
{
Subject = "Let's go for lunch",
Body = new ItemBody
{
ContentType = BodyType.Html,
Content = "Does noon work for you?"
},
Start = new DateTimeTimeZone
{
DateTime = "2022-07-15T12:00:00",
TimeZone = "Pacific Standard Time"
},
End = new DateTimeTimeZone
{
DateTime = "2017-07-15T14:00:00",
TimeZone = "Pacific Standard Time"
},
Location = new Location
{
DisplayName = "Harry's Bar"
},
Attendees = new List<Attendee>()
{
new Attendee
{
EmailAddress = new EmailAddress
{
Address = "samanthab#contoso.onmicrosoft.com",
Name = "Samantha Booth"
},
Type = AttendeeType.Required
}
},
AllowNewTimeProposals = true,
TransactionId = "7E163156-7762-4BEB-A1C6-729EA81755A7"
};
await graphClient.Users["user_principle"].Events
.Request()
.Header("Prefer","outlook.timezone=\"Pacific Standard Time\"")
.AddAsync(#event);