如何在ASP.NET Core 6.0中正确注册GraphServiceClient

问题场景 #

在控制器中注入GraphServiceClient并调用_client.Me.GetAsync()获取用户部门信息时，抛出以下错误：

InvalidOperationException: Unable to resolve service for type 'Microsoft.Graph.GraphServiceClient' while attempting to activate 'ExternalApp.Areas.Budget.Controllers.Controller'

控制器代码如下：

namespace ExternalApp.Areas.Budget.Controllers
{
    public class Controller : BaseController
    {
        private readonly BudgetDbContext _db;
        private readonly GraphServiceClient _client;

        public Controller(
            ILogger<BaseController> logger,
            BudgetDbContext db,
            GraphServiceClient client) : base(logger)
        {
            _db = db;
            _client = client;
        }

        public async Task<JsonResult> GetVehicleAcquisitions()
        {
            var data = _db.VehicleAcquisitions.AsQueryable();

            var user = await _client.Me.GetAsync();

            if (User.IsInRole("Administrator"))
                data = _db.VehicleAcquisitions
                    .Where(x => x.GlSegment3.SSegment3Desc
                        .Contains(user.Department))
                    .AsQueryable();

            // Other code
        }
    }
}

当前Program.cs代码：

var builder = WebApplication.CreateBuilder(args);

builder.Host.ConfigureServices((hostContext, services) =>
{
    services.AddMicrosoftIdentityWebAppAuthentication(hostContext.Configuration);
});

builder.Services.AddControllersWithViews();

builder.Services.AddDbContext<BudgetDbContext>(options =>
    options.UseSqlServer(builder.Configuration
        .GetConnectionString("BudgetEntities"))
        .UseLazyLoadingProxies()
);

var app = builder.Build();

if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Home/Error");
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();
app.UseAuthentication();
app.UseAuthorization();
app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");

app.Run();

解决方案 #

1. 安装必要的NuGet包 #

确保已安装以下包：

• Microsoft.Graph
• Microsoft.Identity.Web.MicrosoftGraph

可通过命令行安装：

Install-Package Microsoft.Graph
Install-Package Microsoft.Identity.Web.MicrosoftGraph

2. 修改Program.cs注册GraphServiceClient #

在AddMicrosoftIdentityWebAppAuthentication之后，添加Graph服务的注册，利用Microsoft Identity Web的扩展方法简化配置：

var builder = WebApplication.CreateBuilder(args);

builder.Host.ConfigureServices((hostContext, services) =>
{
    services.AddMicrosoftIdentityWebAppAuthentication(hostContext.Configuration)
        // 启用下游API的令牌获取
        .EnableTokenAcquisitionToCallDownstreamApi()
        // 注册GraphServiceClient，读取配置文件中的Graph参数
        .AddMicrosoftGraph(hostContext.Configuration.GetSection("MicrosoftGraph"))
        // 使用内存缓存存储令牌
        .AddInMemoryTokenCaches();
});

builder.Services.AddControllersWithViews();

builder.Services.AddDbContext<BudgetDbContext>(options =>
    options.UseSqlServer(builder.Configuration
        .GetConnectionString("BudgetEntities"))
        .UseLazyLoadingProxies()
);

// 剩余代码保持不变
var app = builder.Build();

if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Home/Error");
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();
app.UseAuthentication();
app.UseAuthorization();
app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");

app.Run();

3. 配置appsettings.json中的Graph参数 #

在appsettings.json中添加Microsoft Graph的配置节点：

"MicrosoftGraph": {
  "BaseUrl": "https://graph.microsoft.com/v1.0",
  "Scopes": "User.Read"
}

Scopes需包含实际业务需要的权限，获取用户部门仅需User.Read即可。

4. 验证控制器使用 #

控制器中的注入和调用代码无需修改，现在GraphServiceClient可被正常解析，_client.Me.GetAsync()能正确获取用户信息。

内容的提问来源于stack exchange，提问作者csharpdev