我如何能使一个HTTP POST请求和发送数据的主体?
当前回答
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.
}
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。
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.
}
当使用Windows.Web.Http命名空间时，对于POST而不是FormUrlEncodedContent，我们编写HttpFormUrlEncodedContent。同样，响应类型为HttpResponseMessage。其余的就像Evan Mulawski写的那样。
到目前为止，我找到了简单的解决方案(一行程序，没有错误检查，没有等待响应):
(new WebClient()).UploadStringAsync(new Uri(Address), dataString);
请谨慎使用!
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);
}
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