Microsoft Graph - Accessing OnlineMeetings Transcripts - Invalid format 'application/octet-stream, application/json' specified

Question

Ok I have the following C# code used in a console app:

var deviceCodeCredential = new DeviceCodeCredential(new DeviceCodeCredentialOptions
{
    AuthorityHost = AzureAuthorityHosts.AzurePublicCloud,
    ClientId = AzureClientID,
    TenantId = AzureTenantID,
    DeviceCodeCallback = (code, cancellation) =>
    {
        Console.WriteLine(code.Message);
        return Task.FromResult(0);
    }
});

var graphClient = new GraphServiceClient(deviceCodeCredential, 
    new[] { "User.Read", "OnlineMeetingTranscript.Read.All" });  
          
var meeting = await graphClient.Me.OnlineMeetings.GetAsync((requestConfiguration) =>
{
    requestConfiguration.QueryParameters.Filter = "joinWebUrl eq '" + TeamsURL + "'";
});

var transcript = await graphClient.Me.OnlineMeetings[meeting.Value[0].Id].Transcripts.GetAsync();

var transcriptText = await graphClient.Me.OnlineMeetings[meeting.Value[0].Id].Transcripts[transcript.Value[0].Id].Content.GetAsync((requestConfiguration) =>
{
    requestConfiguration.Headers.Add("Content-Type", "text/vtt");
});    

/*
API Docuementation suggests I do this: https://learn.microsoft.com/en-us/graph/api/calltranscript-get?view=graph-rest-1.0&tabs=csharp#example-2-get-a-calltranscript-content

However the "QueryParameters" returned is of type "DefaultQueryParameters"(which appears to be empty), so the for "Format" property does exist and the code won't build

var transcriptText = await graphClient.Me.OnlineMeetings[meeting.Value[0].Id].Transcripts[transcript.Value[0].Id].Content.GetAsync((requestConfiguration) =>
{
    requestConfiguration.QueryParameters.Format = "text/vtt";
});    
*/

However when I run this instead of receiving the transcript, I receive the following error:

Invalid format 'application/octet-stream, application/json' specified.

How do I work around this, how can I instruct the graph API to expect a "application/octet-stream" output from the API.

Answer 1

Initially, I too got same error when I ran your code in my environment to get call transcript content:

To resolve the error, make use of below modified code that gives online meeting transcript content in console like this:

using System.Text;
using Azure.Identity;
using Microsoft.Graph;
using Microsoft.Graph.Models.ODataErrors;

namespace MSOnlineMeeting
{
    class Program
    {
        static async Task Main(string[] args)
        {
            var scopes = new[] { "User.Read", "OnlineMeetingTranscript.Read.All", "OnlineMeetings.Read" };
            var AzureTenantID = "tenantId";
            var AzureClientID = "appId";

            var options = new DeviceCodeCredentialOptions
            {
                AuthorityHost = AzureAuthorityHosts.AzurePublicCloud,
                ClientId = AzureClientID,
                TenantId = AzureTenantID,
                DeviceCodeCallback = (code, cancellation) =>
                {
                    Console.WriteLine(code.Message);
                    return Task.FromResult(0);
                },
            };

            var deviceCodeCredential = new DeviceCodeCredential(options);
            var graphClient = new GraphServiceClient(deviceCodeCredential, scopes);

            try
            {
                var meetings = await graphClient.Me.OnlineMeetings.GetAsync((requestConfiguration) =>
                {
                    requestConfiguration.QueryParameters.Filter = "joinWebUrl eq 'URL'";
                });

                if (meetings.Value.Count == 0)
                {
                    Console.WriteLine("No meetings found.");
                    return;
                }

                var meetingId = meetings.Value[0].Id;

                var transcripts = await graphClient.Me.OnlineMeetings[meetingId].Transcripts.GetAsync();

                if (transcripts.Value.Count == 0)
                {
                    Console.WriteLine("No transcripts found.");
                    return;
                }

                var transcriptId = transcripts.Value[0].Id;

                var transcriptContentStream = await graphClient.Me.OnlineMeetings[meetingId].Transcripts[transcriptId].Content.GetAsync((requestConfiguration) =>
                {
                    requestConfiguration.Headers.Add("Accept", "text/vtt");
                });

                using (var memoryStream = new MemoryStream())
                {
                    await transcriptContentStream.CopyToAsync(memoryStream);
                    string transcriptText = Encoding.UTF8.GetString(memoryStream.ToArray());
                    Console.WriteLine(transcriptText);
                }
            }
            catch (ODataError odataError)
            {
                Console.WriteLine($"Error Code: {odataError.Error.Code}");
                Console.WriteLine($"Error Message: {odataError.Error.Message}");
            }
        }
    }
}

Response:

Reference: Get callTranscript - Microsoft Graph v1.0