JoinInfo.cs

// <copyright file="JoinInfo.cs" company="Microsoft Corporation">
// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT license.
// </copyright>

namespace Sample.Common.Meetings
{
    using System;
    using System.IO;
    using System.Net;
    using System.Runtime.Serialization;
    using System.Runtime.Serialization.Json;
    using System.Text;
    using System.Text.RegularExpressions;
    using Microsoft.Graph;

    /// <summary>
    /// Gets the join information.
    /// </summary>
    public class JoinInfo
    {
        /// <summary>
        /// Parse Join URL into its components.
        /// NOTE: This method only works with the OLD Teams meeting URL format that includes a context parameter.
        /// For NEW shorter Teams meeting URLs (introduced with MCnumber rollout), you should:
        /// 1. Use the Graph API to query the OnlineMeeting by JoinWebUrl to get meeting details.
        /// 2. Use JoinMeetingIdMeetingInfo with the meeting ID and passcode from the API response.
        /// Example: var meeting = await graphClient.Communications.OnlineMeetings.Request().Filter($"JoinWebUrl eq '{encodedUrl}'").GetAsync().
        /// </summary>
        /// <param name="joinURL">Join URL from Team's meeting body.</param>
        /// <returns>Parsed data.</returns>
        public static (ChatInfo, MeetingInfo) ParseJoinURL(string joinURL)
        {
            if (string.IsNullOrWhiteSpace(joinURL))
            {
                throw new ArgumentException($"Join URL cannot be null, empty, or whitespace: {joinURL}", nameof(joinURL));
            }

            var decodedURL = WebUtility.UrlDecode(joinURL);

            //// Old URL format with context parameter:
            //// https://teams.microsoft.com/l/meetup-join/19:cd9ce3da56624fe69c9d7cd026f9126d@thread.skype/1509579179399?context={"Tid":"72f988bf-86f1-41af-91ab-2d7cd011db47","Oid":"550fae72-d251-43ec-868c-373732c2704f","MessageId":"1536978844957"}
            //// New shorter URL format (not supported by this parser):
            //// https://teams.microsoft.com/l/meetup-join/...

            var regex = new Regex("https://teams\\.microsoft\\.com.*/(?<thread>[^/]+)/(?<message>[^/]+)\\?context=(?<context>{.*})");
            var match = regex.Match(decodedURL);
            if (!match.Success)
            {
                // Check if this is a new shorter URL format
                if (decodedURL.Contains("teams.microsoft.com") && decodedURL.Contains("/meetup-join/") && !decodedURL.Contains("?context="))
                {
                    throw new NotSupportedException(
                        $"This appears to be a new shorter Teams meeting URL format which is not supported by this parser. " +
                        $"To join meetings with this URL format, please use the Graph API to resolve the meeting details:\n" +
                        $"1. Query: GET /communications/onlineMeetings?$filter=JoinWebUrl eq '{Uri.EscapeDataString(joinURL)}'\n" +
                        $"2. Use JoinMeetingIdMeetingInfo with the meeting.JoinMeetingIdSettings from the response.\n" +
                        $"See: https://learn.microsoft.com/graph/api/resources/joinmeetingidmeetinginfo");
                }

                throw new ArgumentException($"Join URL cannot be parsed: {joinURL}.", nameof(joinURL));
            }

            using (var stream = new MemoryStream(Encoding.UTF8.GetBytes(match.Groups["context"].Value)))
            {
                var ctxt = (Context)new DataContractJsonSerializer(typeof(Context)).ReadObject(stream);
                var chatInfo = new ChatInfo
                {
                    ThreadId = match.Groups["thread"].Value,
                    MessageId = match.Groups["message"].Value,
                    ReplyChainMessageId = ctxt.MessageId,
                };

                var meetingInfo = new OrganizerMeetingInfo
                {
                    Organizer = new IdentitySet
                    {
                        User = new Identity { Id = ctxt.Oid },
                    },
                };
                meetingInfo.Organizer.User.SetTenantId(ctxt.Tid);

                return (chatInfo, meetingInfo);
            }
        }

        /// <summary>
        /// Join URL context.
        /// </summary>
        [DataContract]
        private class Context
        {
            /// <summary>
            /// Gets or sets the Tenant Id.
            /// </summary>
            [DataMember]
            public string Tid { get; set; }

            /// <summary>
            /// Gets or sets the AAD object id of the user.
            /// </summary>
            [DataMember]
            public string Oid { get; set; }

            /// <summary>
            /// Gets or sets the chat message id.
            /// </summary>
            [DataMember]
            public string MessageId { get; set; }
        }
    }
}