如何在Microsoft Graph v5 SDK中通过AccessToken初始化GraphServiceClient

在Microsoft Graph v5 SDK中，DelegateAuthenticationProvider已被移除，替代方案是实现IAuthenticationProvider接口，或使用BaseBearerTokenAuthenticationProvider简化开发。以下是适配.NET 8 ASP.NET Core Web API的完整实现：

步骤1：自定义身份验证提供器 #

直接继承BaseBearerTokenAuthenticationProvider，它已封装基础逻辑，只需传入请求中的accessToken即可：

using Microsoft.Graph;
using Microsoft.Graph.Authentication;

public class CustomBearerTokenAuthProvider : BaseBearerTokenAuthenticationProvider
{
    private readonly string _accessToken;

    public CustomBearerTokenAuthProvider(string accessToken)
    {
        _accessToken = accessToken;
    }

    protected override Task<string> GetAuthorizationTokenAsync(
        HttpRequestMessage requestMessage,
        CancellationToken cancellationToken)
    {
        return Task.FromResult(_accessToken);
    }
}

步骤2：初始化GraphServiceClient并调用邀请接口 #

注意v5的API调用语法已调整，不再需要.Request()方法，直接使用fluent API调用：

var authorizationHeader = HttpContext.Request.Headers["Authorization"].FirstOrDefault();
if (string.IsNullOrEmpty(authorizationHeader) || !authorizationHeader.StartsWith("Bearer "))
{
    return BadRequest("无效的授权头");
}

var accessToken = authorizationHeader.Substring("Bearer ".Length);

// 使用自定义身份验证提供器初始化GraphServiceClient
var authProvider = new CustomBearerTokenAuthProvider(accessToken);
var _graphServiceClient = new GraphServiceClient(authProvider);

var invitation = new Invitation
{
    InvitedUserEmailAddress = userEmail,
    SendInvitationMessage = true,
    InviteRedirectUrl = "https://loremipsum.app",
    InvitedUserType = "guest" // 默认值为guest，可选member
};

// v5中直接调用PostAsync提交请求
var invite = await _graphServiceClient.Invitations.PostAsync(invitation);

return Ok(invite);

关键变化说明 #

• 身份验证提供器替换：DelegateAuthenticationProvider被移除，改用实现IAuthenticationProvider或继承BaseBearerTokenAuthenticationProvider
• API调用语法：v5简化了请求构建逻辑，不再需要.Request()方法，直接对实体调用对应HTTP方法（如PostAsync）
• 错误处理增强：建议添加对Authorization头的有效性检查，避免空引用或格式错误导致的异常

内容的提问来源于stack exchange，提问作者wasi hyder