Question

我正在尝试使用RestSharp GitHub wiki上的文档来实现对我的REST API服务的调用，但特别是我遇到了ExecuteAsync方法的问题。

目前我的代码对于API类来说是这样的：

public class HarooApi
{
    const string BaseUrl = "https://domain.here";

    readonly string _accountSid;
    readonly string _secretKey;

    public HarooApi(string accountSid, string secretKey)
    {
        _accountSid = accountSid;
        _secretKey = secretKey;
    }

    public T Execute<T>(RestRequest request) where T : new()
    {
        var client = new RestClient();
        client.BaseUrl = BaseUrl;
        client.Authenticator = new HttpBasicAuthenticator(_accountSid, _secretKey);
        request.AddParameter("AccountSid", _accountSid, ParameterType.UrlSegment);
        client.ExecuteAsync<T>(request, (response) =>
        {
            return response.Data;
        });
    }
}

我知道这与GitHub页面上的内容略有不同，但我在WP7中使用它，并且相信该示例适用于C＃，因此使用了ExecuteAsync方法。

我的问题是ExecuteAsync命令应包含的内容。我无法使用return response.Data，因为我已收到警告：

'System.Action<RestSharp.RestResponse<T>,RestSharp.RestRequestAsyncHandle>' returns void, a return keyword must not be followed by an object expression

有没有人对如何解决此问题或可能有帮助的教程有任何见解？

Answer 1

老问题但是如果你正在使用C＃5，你可以通过创建一个任务T的TaskCompleteSource来创建一个通用的执行类。你的代码看起来像这样：

public Task<T> ExecuteAsync<T>(RestRequest request) where T : new()
    {
        var client = new RestClient();
        var taskCompletionSource = new TaskCompletionSource<T>();
        client.BaseUrl = BaseUrl;
        client.Authenticator = new HttpBasicAuthenticator(_accountSid, _secretKey);
        request.AddParameter("AccountSid", _accountSid, ParameterType.UrlSegment);
        client.ExecuteAsync<T>(request, (response) => taskCompletionSource.SetResult(response.Data));
        return taskCompletionSource.Task;
    }

并像这样使用它：

private async Task DoWork()
    {
        var api = new HarooApi("MyAcoountId", "MySecret");
        var request = new RestRequest();
        var myClass = await api.ExecuteAsync<MyClass>(request);

        // Do something with myClass
    }

Answer 2

您的代码应如下所示：

public class HarooApi
{
    const string BaseUrl = "https://domain.here";

    readonly string _accountSid;
    readonly string _secretKey;

    public HarooApi(string accountSid, string secretKey)
    {
        _accountSid = accountSid;
        _secretKey = secretKey;
    }

    public void ExecuteAndGetContent(RestRequest request, Action<string> callback)
    {
        var client = new RestClient();
        client.BaseUrl = BaseUrl;
        client.Authenticator = new HttpBasicAuthenticator(_accountSid, _secretKey);
        request.AddParameter("AccountSid", _accountSid, ParameterType.UrlSegment);
        client.ExecuteAsync(request, response =>
        {
            callback(response.Content);
        });
    }

    public void ExecuteAndGetMyClass(RestRequest request, Action<MyClass> callback)
    {
        var client = new RestClient();
        client.BaseUrl = BaseUrl;
        client.Authenticator = new HttpBasicAuthenticator(_accountSid, _secretKey);
        request.AddParameter("AccountSid", _accountSid, ParameterType.UrlSegment);
        client.ExecuteAsync<MyClass>(request, (response) =>
        {
            callback(response.Data);
        });
    }
}

我添加了两个方法，因此您可以检查您想要的内容（来自响应正文的字符串内容，或此处由MyClass表示的反序列化类）

Answer 3

作为fine answer Gusten的替代（或补充）。您可以使用ExecuteTaskAsync。这样您就不必手动处理TaskCompletionSource。请注意签名中的async关键字。

public async Task<T> ExecuteAsync<T>(RestRequest request) where T : new()
{
    var client = new RestClient();
    client.BaseUrl = BaseUrl;
    client.Authenticator = new HttpBasicAuthenticator(_accountSid, _secretKey);
    request.AddParameter("AccountSid", _accountSid, ParameterType.UrlSegment);
    IRestResponse<T> response = await client.ExecuteTaskAsync<T>(request);
    return response.Data;
}

Answer 4

或更准确地说是这样：

    public async Task<IRestResponse<T>> ExecuteAsync<T>(IRestRequest request) where T : class, new()
    {
        var client = new RestClient(_settingsViewModel.BaseUrl);

        var taskCompletionSource = new TaskCompletionSource<IRestResponse<T>>();
        client.ExecuteAsync<T>(request, restResponse =>
        {
            if (restResponse.ErrorException != null)
            {
                const string message = "Error retrieving response.";
                throw new ApplicationException(message, restResponse.ErrorException);
            }
            taskCompletionSource.SetResult(restResponse);
        });

        return await taskCompletionSource.Task;
    }

Answer 5

以下完成了工作

public async Task<IRestResponse<T>> ExecuteAsync<T>(IRestRequest request) where T : class, new()
{
    var client = new RestClient
    {
        BaseUrl = _baseUrl,
        Authenticator = new HttpBasicAuthenticator(_useraname, _password),
        Timeout = 3000,
    };

    var tcs = new TaskCompletionSource<T>();
    client.ExecuteAsync<T>(request, restResponse =>
    {
        if (restResponse.ErrorException != null)
        {
            const string message = "Error retrieving response.";
            throw new ApplicationException(message, restResponse.ErrorException);
        }
        tcs.SetResult(restResponse.Data);
    });

    return await tcs.Task as IRestResponse<T>;

}

Answer 6

自public static RestRequestAsyncHandle ExecuteAsync(this IRestClient client, IRestRequest request, Action<IRestResponse> callback)起已弃用，您应该改为使用public Task<IRestResponse> ExecuteAsync(IRestRequest request, CancellationToken token = default)。

以下代码

client.ExecuteAsync(request, response => { callback(response.Content); });

应该改为

await client.ExecuteAsync(request).ContinueWith(task => callback(task.Result.Content));

我应该如何在Windows Phone 7上使用RestSharp实现ExecuteAsync？

6 个答案: