Azure Functions using Cancellation Token with Http Trigger

I know this is an old question, but I found the answer to this issue.

In Azure Functions, there are 2 cancellation tokens.

The token passed in Function Method parameter is the Host Cancellation Token - cancellation is requested when the host is about to shut down.

The other token is req.HttpContext.RequestAborted property. It's being cancelled when browser cancels the request - this is what you were after.

In addition, you can use following code:

using var cancellationSource = CancellationTokenSource.CreateLinkedTokenSource(hostCancellationToken, req.HttpContext.RequestAborted);

To get a token that cancels when either host or request is being cancelled.

Without using Durable Functions, I don't think it's possible. Here's a sample using Durable:

[FunctionName("ApprovalWorkflow")]public static async Task Run(    [OrchestrationTrigger] IDurableOrchestrationContext context){    await context.CallActivityAsync("RequestApproval", null);    using (var timeoutCts = new CancellationTokenSource())    {        DateTime dueTime = context.CurrentUtcDateTime.AddHours(72);        Task durableTimeout = context.CreateTimer(dueTime, timeoutCts.Token);        Task<bool> approvalEvent = context.WaitForExternalEvent<bool>("ApprovalEvent");        if (approvalEvent == await Task.WhenAny(approvalEvent, durableTimeout))        {            timeoutCts.Cancel();            await context.CallActivityAsync("ProcessApproval", approvalEvent.Result);        }        else        {            await context.CallActivityAsync("Escalate", null);        }    }}

https://docs.microsoft.com/en-us/azure/azure-functions/durable/durable-functions-overview?tabs=csharp#human