0

我正在使用 OAuth2 在 Windows Phone 7 中使用 Google API 做一些工作。

在调用 API 之前，我需要更新访问令牌（如果需要）。

我遇到的问题是等待更新令牌的异步请求完成，然后再继续调用 API。

我已经让它与下面的代码一起工作，但我对它不满意。我正在寻找一种更好的替代方法，而不是在 while 循环中简单地轮询变量。

    /// <summary>
    /// Calls the API.
    /// </summary>
    /// <param name="callback">The callback.</param>
    /// <param name="api">The API.</param>
    /// <param name="queryStrings">The query strings.</param>
    public static void CallApi(AsyncCallback callback, string api, Dictionary<string, string> queryStrings = null)
    {
        var uri = new Uri(string.Format("{0}{1}{2}", ApiBaseUrl, api, queryStrings.ToQueryString()));

        if (accessTokenExpires < DateTime.Now.AddSeconds(300))
        {
            RefreshAccessToken();
        }

        // Start new thread so we don't lock up the UI thread while waiting
        var thread = new Thread(
            () =>
                {
                    // Wait for the access token to be updated
                    while (accessTokenExpires < DateTime.Now.AddSeconds(300)) ;

                    var request = WebRequest.CreateHttp(uri);
                    request.Headers["Authorization"] = string.Format("OAuth {0}", accessToken);
                    request.BeginGetResponse(callback, request);
                });

        thread.Start();
    }

    /// <summary>
    /// Refresh the access token.
    /// </summary>
    private static void RefreshAccessToken()
    {
        if (Config.GoogleOAuthRefreshToken == string.Empty)
        {
            // TODO - Present the OAuth popup to the user
            return;
        }

        var uri = new Uri(GetTokenUrl);

        var request = WebRequest.CreateHttp(uri);
        request.Method = "POST";
        request.ContentType = "application/x-www-form-urlencoded";

        request.BeginGetRequestStream(RefreshToken_GetRequest, request);
    }
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2 回答 2

2

我认为你已经开始了你需要的东西，但只需要充分利用 WebRequest 的异步特性。这是如何做到这一点的示例

public static void CallApi(AsyncCallback callback, string api, Dictionary<string, string> queryStrings = null)
{
    var uri = new Uri(string.Format("{0}{1}{2}", ApiBaseUrl, api, queryStrings.ToQueryString()));

    RefreshAccessToken(() =>
        {
            var request = WebRequest.CreateHttp(uri);
            request.Headers["Authorization"] = string.Format("OAuth {0}", accessToken);
            request.BeginGetResponse(callback, request);
        });
}

private static void RefreshAccessToken(Action callback)
{
    if(IsTokenExpired() == false)
    {
        if(callback != null) callback();
        return;
    }
    if (Config.GoogleOAuthRefreshToken == string.Empty)
    {
        // TODO - Present the OAuth popup to the user
        return;
    }

    var uri = new Uri(GetTokenUrl);

    var request = WebRequest.CreateHttp(uri);
    request.Method = "POST";
    request.ContentType = "application/x-www-form-urlencoded";

    request.BeginGetRequestStream(asyncResult =>
    {
        // Do anything for POST
        request.BeginGetResponse(asyncResult2 =>
        {
            // Read stream, and process
            if(callback != null) callback();
        }, null);
    }, request);
}

private bool IsTokenExpired()
{
    return accessTokenExpires < DateTime.Now.AddSeconds(300);
}
于 2012-08-23T18:02:14.947 回答
0

您是否考虑过使用Async-CTP或 VS 2012 将此逻辑转换为 Task.Delay 调用？它甚至可能对您的网络请求代码有所帮助。

于 2012-08-23T16:52:18.373 回答