c# - Microsoft Graph API : HttpStatusCode 200, 内容长度-1？

Question

我正在尝试使用 Ms Graph API 连接到 Outlook 并下载附件。到目前为止我写的是

 private static async Task<HttpWebRequest> createHttpRequestWithToken(Uri uri)
 {
        HttpWebRequest newRequest = (HttpWebRequest)HttpWebRequest.Create(uri);

        string clientId = "myClientId";
        string clientSecret = "myClientSecret";
        ClientCredential creds = new ClientCredential(clientId, clientSecret);

        AuthenticationContext authContext = new AuthenticationContext("https://login.windows.net/myAzureAD/oauth2/token");
        AuthenticationResult authResult = await authContext.AcquireTokenAsync("https://graph.microsoft.com/", creds);
        newRequest.Headers.Add(HttpRequestHeader.Authorization, "Bearer " + authResult.AccessToken);
        newRequest.ContentType = "application/json";

        return newRequest;
  } 

我用它来调用我需要的图形 API。首先，我尝试调用此 URL:

Uri uri = new Uri(("https://graph.microsoft.com/v1.0/users/myEmailId/messages"));
HttpWebRequest request = createHttpRequestWithToken(uri).Result;
HttpWebResponse response = (HttpWebResponse)request.GetResponse();

运行代码后，我收到 HttpStatusCode 200 的响应，但内容长度为 -1。我目前被困在这里。有人可以帮助我解决哪里出错/如何进一步调试这段代码吗？

提前致谢。

Answer 1

API 使用“Transfer-Encoding: chunked”，因此不会返回 Content-Length header 。这就是为什么您会看到response.ContentLength 属性的默认值为-1。要读取响应正文，只需读取通过response.GetResponseStream()方法获取的响应流即可。