我如何能使一个HTTP POST请求和发送数据的主体?
当前回答
简单的GET请求
using System.Net;
...
using (var wb = new WebClient())
{
var response = wb.DownloadString(url);
}
简单的POST请求
using System.Net;
using System.Collections.Specialized;
...
using (var wb = new WebClient())
{
var data = new NameValueCollection();
data["username"] = "myUser";
data["password"] = "myPassword";
var response = wb.UploadValues(url, "POST", data);
string responseInString = Encoding.UTF8.GetString(response);
}
其他回答
为什么这不是完全无关紧要的?执行请求并不是处理结果。而且似乎还涉及到一些。net Bug——参见HttpClient中的Bug。GetAsync应该抛出WebException，而不是TaskCanceledException
我最终得到了这样的代码:
static async Task<(bool Success, WebExceptionStatus WebExceptionStatus, HttpStatusCode? HttpStatusCode, string ResponseAsString)> HttpRequestAsync(HttpClient httpClient, string url, string postBuffer = null, CancellationTokenSource cts = null) {
try {
HttpResponseMessage resp = null;
if (postBuffer is null) {
resp = cts is null ? await httpClient.GetAsync(url) : await httpClient.GetAsync(url, cts.Token);
} else {
using (var httpContent = new StringContent(postBuffer)) {
resp = cts is null ? await httpClient.PostAsync(url, httpContent) : await httpClient.PostAsync(url, httpContent, cts.Token);
}
}
var respString = await resp.Content.ReadAsStringAsync();
return (resp.IsSuccessStatusCode, WebExceptionStatus.Success, resp.StatusCode, respString);
} catch (WebException ex) {
WebExceptionStatus status = ex.Status;
if (status == WebExceptionStatus.ProtocolError) {
// Get HttpWebResponse so that you can check the HTTP status code.
using (HttpWebResponse httpResponse = (HttpWebResponse)ex.Response) {
return (false, status, httpResponse.StatusCode, httpResponse.StatusDescription);
}
} else {
return (false, status, null, ex.ToString());
}
// https://devblogs.microsoft.com/dotnet/net-5-new-networking-improvements/
} catch (TaskCanceledException ex) when (ex.InnerException is TimeoutException) {
return (false, ex.ToString(), null, WebExceptionStatus.Timeout);
} catch (TaskCanceledException ex) {
return (false, ex.ToString(), null, WebExceptionStatus.RequestCanceled);
} catch (Exception ex) {
return (false, WebExceptionStatus.UnknownError, null, ex.ToString());
}
}
这将根据postBuffer是否为空来执行GET或POST操作。
如果Success为true，响应将在ResponseAsString中。
如果Success为false，你可以检查WebExceptionStatus, HttpStatusCode和ResponseAsString，看看哪里出了问题。
执行HTTP GET和POST请求有几种方法:
方法A: HttpClient(首选)
支持。net Framework 4.5+， . net Standard 1.1+， . net Core 1.0+。
它是目前首选的方法，并且是异步的和高性能的。在大多数情况下使用内置版本，但对于非常老的平台，有一个NuGet包。
using System.Net.Http;
设置
建议为应用程序的生命周期实例化一个HttpClient并共享它，除非您有特定的理由不这样做。
private static readonly HttpClient client = new HttpClient();
请参阅HttpClientFactory以获得依赖注入解决方案。
帖子 var values = new Dictionary<string, string> ｛ {"thing1"， "hello"}， {"thing2"， "world"} }; var content = new FormUrlEncodedContent(values); var response = await client.PostAsync("http://www.example.com/recepticle.aspx"， content); var responseString =等待response.Content.ReadAsStringAsync(); 得到 var responseString = await client.GetStringAsync("http://www.example.com/recepticle.aspx");
方法B:第三方库
休息夏普
帖子 var client = new RestClient("http://example.com"); / /客户端。Authenticator =新的HttpBasicAuthenticator(用户名，密码); var request = new RestRequest("resource/{id}"); 请求。AddParameter(“thing1”、“你好”); 请求。AddParameter(“事件”、“世界”); 请求。AddHeader(“标题”、“价值”); 请求。AddFile(“文件”,路径); var response = client.Post(请求); var content = response.Content;//原始内容为字符串 var response2 = client.Post<Person>(request); var name = response2.Data.Name;
Flurl。Http
它是一个更新的库，拥有一个流畅的API，测试助手，在底层使用HttpClient，并且是可移植的。它可以通过NuGet获得。
using Flurl.Http;
帖子 var responseString = await“http://www.example.com/recepticle.aspx” .PostUrlEncodedAsync(new {thing1 = "hello"， thing2 = "world"}) .ReceiveString (); 得到 var responseString = await“http://www.example.com/recepticle.aspx” .GetStringAsync ();
方法C: HttpWebRequest(不推荐用于新工作)
支持。net Framework 1.1+， . net Standard 2.0+， . net Core 1.0+。在。net Core中，它主要是为了兼容性——它包装了HttpClient，性能较差，并且不会获得新的特性。
using System.Net;
using System.Text; // For class Encoding
using System.IO; // For StreamReader
发布 var request = （HttpWebRequest）WebRequest.Create（“http://www.example.com/recepticle.aspx”）; var postData = “thing1=” + Uri.EscapeDataString（“hello”）; postData += “&thing2=” + Uri.EscapeDataString（“world”）; var data = Encoding.ASCII.GetBytes（postData）; 请求。方法 =“开机自检”; 请求。ContentType = “application/x-www-form-urlencoded”; 请求。内容长度 = 数据。长度; 使用 （var 流 = 请求。GetRequestStream（）） { 流。写入（数据， 0， 数据.长度）; } var response = （HttpWebResponse）request.获取响应（）; var responseString = new StreamReader（response.GetResponseStream（））。ReadToEnd（）; 获取 var request = （HttpWebRequest）WebRequest.Create（“http://www.example.com/recepticle.aspx”）; var response = （HttpWebResponse）request.获取响应（）; var responseString = new StreamReader（response.GetResponseStream（））。ReadToEnd（）;
方法D: WebClient(不推荐新作品)
这是一个HttpWebRequest的包装器。与HttpClient比较。
支持。NET Framework 1.1+， NET Standard 2.0+和。NET Core 2.0+。
在某些情况下…NET Framework 4.5-4.8)，如果你需要同步地做一个HTTP请求，WebClient仍然可以使用。
using System.Net;
using System.Collections.Specialized;
帖子 使用(var client = new WebClient()) ｛ var values = new NameValueCollection(); 值["thing1"] = "hello"; Values ["thing2"] = "world"; var response = client.UploadValues("http://www.example.com/recepticle.aspx"， values); var responseString = Encoding.Default.GetString(response); } 得到 使用(var client = new WebClient()) ｛ var responseString = client.DownloadString("http://www.example.com/recepticle.aspx"); }
MSDN有一个样本。
using System;
using System.IO;
using System.Net;
using System.Text;
namespace Examples.System.Net
{
public class WebRequestPostExample
{
public static void Main()
{
// Create a request using a URL that can receive a post.
WebRequest request = WebRequest.Create("http://www.contoso.com/PostAccepter.aspx");
// Set the Method property of the request to POST.
request.Method = "POST";
// Create POST data and convert it to a byte array.
string postData = "This is a test that posts this string to a Web server.";
byte[] byteArray = Encoding.UTF8.GetBytes(postData);
// Set the ContentType property of the WebRequest.
request.ContentType = "application/x-www-form-urlencoded";
// Set the ContentLength property of the WebRequest.
request.ContentLength = byteArray.Length;
// Get the request stream.
Stream dataStream = request.GetRequestStream();
// Write the data to the request stream.
dataStream.Write(byteArray, 0, byteArray.Length);
// Close the Stream object.
dataStream.Close();
// Get the response.
WebResponse response = request.GetResponse();
// Display the status.
Console.WriteLine(((HttpWebResponse)response).StatusDescription);
// Get the stream containing content returned by the server.
dataStream = response.GetResponseStream();
// Open the stream using a StreamReader for easy access.
StreamReader reader = new StreamReader(dataStream);
// Read the content.
string responseFromServer = reader.ReadToEnd();
// Display the content.
Console.WriteLine(responseFromServer);
// Clean up the streams.
reader.Close();
dataStream.Close();
response.Close();
}
}
}
简单的GET请求
using System.Net;
...
using (var wb = new WebClient())
{
var response = wb.DownloadString(url);
}
简单的POST请求
using System.Net;
using System.Collections.Specialized;
...
using (var wb = new WebClient())
{
var data = new NameValueCollection();
data["username"] = "myUser";
data["password"] = "myPassword";
var response = wb.UploadValues(url, "POST", data);
string responseInString = Encoding.UTF8.GetString(response);
}
这个解决方案只使用标准的. net调用。
测试:
在企业WPF应用程序中使用。使用async/await来避免阻塞UI。 兼容。net 4.5+。 在没有参数的情况下进行测试(在幕后需要一个“GET”)。 使用参数进行测试(需要幕后的“POST”)。 使用标准的网页(如谷歌)进行测试。 使用内部基于java的web服务进行测试。
参考:
// Add a Reference to the assembly System.Web
代码:
using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using System.Web;
private async Task<WebResponse> CallUri(string url, TimeSpan timeout)
{
var uri = new Uri(url);
NameValueCollection rawParameters = HttpUtility.ParseQueryString(uri.Query);
var parameters = new Dictionary<string, string>();
foreach (string p in rawParameters.Keys)
{
parameters[p] = rawParameters[p];
}
var client = new HttpClient { Timeout = timeout };
HttpResponseMessage response;
if (parameters.Count == 0)
{
response = await client.GetAsync(url);
}
else
{
var content = new FormUrlEncodedContent(parameters);
string urlMinusParameters = uri.OriginalString.Split('?')[0]; // Parameters always follow the '?' symbol.
response = await client.PostAsync(urlMinusParameters, content);
}
var responseString = await response.Content.ReadAsStringAsync();
return new WebResponse(response.StatusCode, responseString);
}
private class WebResponse
{
public WebResponse(HttpStatusCode httpStatusCode, string response)
{
this.HttpStatusCode = httpStatusCode;
this.Response = response;
}
public HttpStatusCode HttpStatusCode { get; }
public string Response { get; }
}
不带参数调用(在幕后使用“GET”):
var timeout = TimeSpan.FromSeconds(300);
WebResponse response = await this.CallUri("http://www.google.com/", timeout);
if (response.HttpStatusCode == HttpStatusCode.OK)
{
Console.Write(response.Response); // Print HTML.
}
使用参数调用(在幕后使用“POST”):
var timeout = TimeSpan.FromSeconds(300);
WebResponse response = await this.CallUri("http://example.com/path/to/page?name=ferret&color=purple", timeout);
if (response.HttpStatusCode == HttpStatusCode.OK)
{
Console.Write(response.Response); // Print HTML.
}
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