我如何能使一个HTTP POST请求和发送数据的主体?
当前回答
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!
其他回答
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);
}
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!
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。
这里有一些非常好的答案。让我发布一种不同的方法来设置你的头部与WebClient()。我还将向您展示如何设置API键。
var client = new WebClient();
string credentials = Convert.ToBase64String(Encoding.ASCII.GetBytes(userName + ":" + passWord));
client.Headers[HttpRequestHeader.Authorization] = $"Basic {credentials}";
//If you have your data stored in an object serialize it into json to pass to the webclient with Newtonsoft's JsonConvert
var encodedJson = JsonConvert.SerializeObject(newAccount);
client.Headers.Add($"x-api-key:{ApiKey}");
client.Headers.Add("Content-Type:application/json");
try
{
var response = client.UploadString($"{apiurl}", encodedJson);
//if you have a model to deserialize the json into Newtonsoft will help bind the data to the model, this is an extremely useful trick for GET calls when you have a lot of data, you can strongly type a model and dump it into an instance of that class.
Response response1 = JsonConvert.DeserializeObject<Response>(response);
这是一个HTTPS web请求的例子。可以在PHP脚本中回显任何结果。最后,PHP回显字符串将在c#客户端显示为警报。
string url = "https://mydomain.ir/test1.php";
StringBuilder postData = new StringBuilder();
postData.Append(String.Format("{0}={1}&", HttpUtility.HtmlEncode("username"), HttpUtility.HtmlEncode("ali")));
postData.Append(String.Format("{0}={1}", HttpUtility.HtmlEncode("password"), HttpUtility.HtmlEncode("123456789")));
StringContent myStringContent = new StringContent(postData.ToString(), Encoding.UTF8, "application/x-www-form-urlencoded");
HttpClient client = new HttpClient();
HttpResponseMessage message = client.PostAsync(url, myStringContent).GetAwaiter().GetResult();
string responseContent = message.Content.ReadAsStringAsync().GetAwaiter().GetResult();
DisplayAlert("Your Feedback", responseContent, "OK");
PHP服务器端:
<?php
if (isset($_POST["username"]) && $_POST["username"] == "ali") {
echo "Yes, hi Ali";
}
else {
echo "No, where is Ali?";
}
?>
结果将是“Yes, hi Ali”。
这是为Xamarin形式。对于一个c# .NET应用程序,将DisplayAlert替换为:
MessageBox.show(responseContent);
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