如何将Microsoft Teams传入Webhook消息转发至指定聊天？

可行性说明 #

完全可行，但Teams传入Webhook是单向的（仅支持向Teams发送消息，无法监听接收Teams内的消息），因此需要借助Microsoft Graph API完成转发需求，核心是获取目标聊天的Chat ID，并通过Graph API发送消息。

步骤1：获取目标聊天的Chat ID #

两种便捷获取方式：

• Teams客户端提取：打开目标聊天窗口，点击右上角「更多选项」→「获取链接」，链接中的threadId参数值即为Chat ID（格式类似19:xxxxxx@thread.tacv2）。
• Graph API查询：调用GET /me/chats（委派权限）或GET /users/{user-id}/chats（应用权限）接口，返回结果中每个聊天对象的id字段就是Chat ID。

步骤2：注册Azure AD应用并配置权限 #

要使用Graph API发送消息，需先在Azure AD中注册应用：

1. 注册应用后，添加Microsoft Graph权限：
   • 后台运行场景（无用户交互）：添加ChatMessage.Send应用权限，并完成管理员同意。
   • 用户交互场景：添加ChatMessage.Send委派权限。
2. 记录应用的Client ID、Client Secret（应用权限），或配置授权码流（委派权限），用于获取Graph API访问令牌。

步骤3：C#实现代码示例 #

场景1：发送原消息时同步转发（适用于你的代码推送消息到Webhook时，同时转发到目标Chat）

using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;

// 配置参数
var teamsWebhookUrl = "你的传入Webhook地址";
var targetChatId = "目标聊天的Chat ID";
var azureAdClientId = "你的Azure AD应用Client ID";
var azureAdClientSecret = "你的Azure AD应用Client Secret";
var tenantId = "你的租户ID";

// 1. 发送消息到原Teams Webhook
var messageContent = new { text = $"Application started by {Environment.UserName}" };
using (var httpClient = new HttpClient())
{
    var webhookContent = new StringContent(
        JsonSerializer.Serialize(messageContent), 
        Encoding.UTF8, 
        "application/json");
    await httpClient.PostAsync(teamsWebhookUrl, webhookContent);
}

// 2. 获取Graph API访问令牌（应用权限流）
using (var tokenClient = new HttpClient())
{
    var tokenRequest = new FormUrlEncodedContent(new[]
    {
        new KeyValuePair<string, string>("grant_type", "client_credentials"),
        new KeyValuePair<string, string>("client_id", azureAdClientId),
        new KeyValuePair<string, string>("client_secret", azureAdClientSecret),
        new KeyValuePair<string, string>("scope", "https://graph.microsoft.com/.default")
    });

    var tokenResponse = await tokenClient.PostAsync(
        $"https://login.microsoftonline.com/{tenantId}/oauth2/v2.0/token", 
        tokenRequest);
    var tokenData = JsonSerializer.Deserialize<JsonElement>(await tokenResponse.Content.ReadAsStringAsync());
    var accessToken = tokenData.GetProperty("access_token").GetString();

    // 3. 转发消息到目标Chat
    using (var graphClient = new HttpClient())
    {
        graphClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
        var chatMessage = new { body = new { content = messageContent.text } };
        var chatContent = new StringContent(
            JsonSerializer.Serialize(chatMessage), 
            Encoding.UTF8, 
            "application/json");
        await graphClient.PostAsync(
            $"https://graph.microsoft.com/v1.0/chats/{targetChatId}/messages", 
            chatContent);
    }
}

场景2：监听Teams聊天消息自动转发（适用于Teams内收到消息后自动转发到目标Chat）

需使用Graph API订阅功能监听消息创建事件，再触发转发：

1. 创建消息订阅：

// 配置参数
var sourceChatId = "需要监听的源聊天ID";
var notificationUrl = "你的公网通知端点（接收Graph事件通知）";
var accessToken = "已获取的Graph API访问令牌";

var subscription = new
{
    changeType = "created",
    notificationUrl = notificationUrl,
    resource = $"chats/{sourceChatId}/messages",
    expirationDateTime = DateTime.UtcNow.AddDays(3),
    clientState = "随机验证字符串"
};

using (var graphClient = new HttpClient())
{
    graphClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
    var subscriptionContent = new StringContent(
        JsonSerializer.Serialize(subscription), 
        Encoding.UTF8, 
        "application/json");
    await graphClient.PostAsync("https://graph.microsoft.com/v1.0/subscriptions", subscriptionContent);
}

2. 通知端点处理转发逻辑（以ASP.NET Core为例）：

using System.Net.Http.Headers;
using System.Text.Json;

[HttpPost("teams-message-notification")]
public async Task<IActionResult> HandleMessageNotification([FromBody] JsonElement notification)
{
    // 解析通知中的消息ID
    var resourceData = notification.GetProperty("resourceData");
    var messageId = resourceData.GetProperty("id").GetString();
    var sourceChatId = "源聊天ID";
    var targetChatId = "目标聊天ID";
    var accessToken = "Graph API访问令牌";

    // 获取完整消息内容
    using (var graphClient = new HttpClient())
    {
        graphClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
        var messageResponse = await graphClient.GetAsync(
            $"https://graph.microsoft.com/v1.0/chats/{sourceChatId}/messages/{messageId}");
        var message = JsonSerializer.Deserialize<JsonElement>(await messageResponse.Content.ReadAsStringAsync());
        var messageContent = message.GetProperty("body").GetProperty("content").GetString();

        // 转发到目标Chat
        var chatMessage = new { body = new { content = messageContent } };
        var chatContent = new StringContent(
            JsonSerializer.Serialize(chatMessage), 
            Encoding.UTF8, 
            "application/json");
        await graphClient.PostAsync(
            $"https://graph.microsoft.com/v1.0/chats/{targetChatId}/messages", 
            chatContent);
    }

    return Ok();
}

内容的提问来源于stack exchange，提问作者A. Drews