在 C# 代码中从客户端调用 HttpPost 方法

Question

我是 MVC 和 C# 的新手，如果这个问题看起来太简单了，很抱歉。

对于像下面这样的 HttpPost 控制器，如何在没有浏览器的情况下直接从用 C# 编写的客户端程序调用此方法（NOT 从带有提交按钮的浏览器中的 UI 表单)?我正在使用 .NET 4 和 MVC 4。

我确信答案在网络上，但到目前为止还没有找到。任何帮助表示赞赏！

[HttpPost]
public Boolean PostDataToDB(int n, string s)
{
    //validate and write to database
    return false;
}

Answer 1

例如在服务器端使用此代码：

[HttpPost]
public Boolean PostDataToDB(int n, string s)
{
    //validate and write to database
    return false;
}

您可以使用不同的方法：

与WebClient：

using (var wb = new WebClient())
{
    var data = new NameValueCollection();
    data["n"] = "42";
    data["s"] = "string value";
    
    var response = wb.UploadValues("http://www.example.org/receiver.aspx", "POST", data);
}

与HttpRequest：

var request = (HttpWebRequest)WebRequest.Create("http://www.example.org/receiver.aspx");

var postData = "n=42&s=string value";
var data = Encoding.ASCII.GetBytes(postData);

request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = data.Length;

using (var stream = request.GetRequestStream())
{
    stream.Write(data, 0, data.Length);
}

var response = (HttpWebResponse)request.GetResponse();
var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();

与HttpClient：

using (var client = new HttpClient())
{
    var values = new List<KeyValuePair<string, string>>();
    values.Add(new KeyValuePair<string, string>("n", "42"));
    values.Add(new KeyValuePair<string, string>("s", "string value"));

    var content = new FormUrlEncodedContent(values);

    var response = await client.PostAsync("http://www.example.org/receiver.aspx", content);

    var responseString = await response.Content.ReadAsStringAsync();
}

与WebRequest

WebRequest request = WebRequest.Create ("http://www.example.org/receiver.aspx");
request.Method = "POST";
string postData = "n=42&s=string value";
byte[] byteArray = Encoding.UTF8.GetBytes (postData);
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = byteArray.Length;
Stream dataStream = request.GetRequestStream ();
dataStream.Write (byteArray, 0, byteArray.Length);
dataStream.Close ();
            
//Response
WebResponse response = request.GetResponse ();
Console.WriteLine (((HttpWebResponse)response).StatusDescription);
dataStream = response.GetResponseStream ();
StreamReader reader = new StreamReader (dataStream);
string responseFromServer = reader.ReadToEnd ();
Console.WriteLine (responseFromServer);
reader.Close ();
dataStream.Close ();
response.Close ();

见msdn

Answer 2

你可以使用 首先你应该返回有效的结果：

[HttpPost]
public ActionResult PostDataToDB(int n, string s)
{
    //validate and write to database
    return Json(false);
}

之后，您可以使用 Web Api 客户端库 NuGet 包中的 HttpClient 类：

public async bool CallMethod()
{
    var rootUrl = "http:...";
    bool result;
    using (var client = new HttpClient())
    {
        client.BaseAddress = new Uri(_rootUrl);
        var response= await client.PostAsJsonAsync(methodUrl, new {n = 10, s = "some string"}); 
        result = await response.Content.ReadAsAsync<bool>();
    }

    return result;
}

你也可以使用 WebClient 类：

[HttpPost]
public Boolean PostDataToDB(int n, string s)
{
    //validate and write to database
    return false;
}

public async bool CallMethod()
    {
        var rootUrl = "http:...";
        bool result;
        using (var client = new WebClient())
        {
            var col = new NameValueCollection();
            col.Add("n", "1");
            col.Add("s", "2");
            var res = await client.UploadValuesAsync(address, col);
            string res = Encoding.UTF8.GetString(res);

            result = bool.Parse(res);
        }

    return result;
}

Answer 3

如果你决定使用 HttpClient 实现。不要为每次调用 API 创建和处置 HttpClient。相反，重用 HttpClient 的单个实例。您可以通过将实例声明为静态或实现单例模式来实现。

参考：https://aspnetmonsters.com/2016/08/2016-08-27-httpclientwrong/

如何实现单例（很好的起点，阅读该帖子中的 cmets）：https://codereview.stackexchange.com/questions/149805/implementation-of-a-singleton-httpclient-with-generic-methods

Answer 4

希望下面的代码对你有所帮助

[ActionName("Check")]
public async System.Threading.Tasks.Task<bool> CheckPost(HttpRequestMessage request)
{
    string body = await request.Content.ReadAsStringAsync();
    return true;
}