SharePoint Online获取自定义审核报告

Question

我正在尝试使用OAuth令牌身份验证方法获取SharePoint在线自定义审核报告的表单“ /_layout/15/CustomizeReport.aspx?Category=Auditing”HTML响应。我尝试在请求标头中传递身份验证访问令牌，但引发了未经授权的异常。而如果我使用用户凭据，它将在HttpResponse中返回HTML，而我不再想要使用它。

string reportUrl = spsite.Url + "/_layouts/15/CustomizeReport.aspx?ReportId=f43c916f-4450-4737-b889-8078c9826841&Category=Auditing";
HttpClient httpClient = new HttpClient() { DefaultRequestHeaders = { Authorization = new AuthenticationHeaderValue("Bearer", ManageAPIAccessToken) } };
HttpRequestMessage req = new HttpRequestMessage(new HttpMethod("GET"), reportUrl);
HttpResponseMessage resp = httpClient.SendAsync(req, HttpCompletionOption.ResponseHeadersRead).Result;

由于没有REST端点或CSOM支持，有人可以指出我如何获得此页面响应吗？