NET Core中的WebRequest重定向 [英] Redirect of WebRequest in .NET Core

问题描述

我使用.NET 4.7.1用C#编写了以下程序:

I wrote the following program in C# using .NET 4.7.1:

var req = (HttpWebRequest) WebRequest.Create(myUrl);
req.MediaType = "GET";
req.AllowAutoRedirect = false;
var rsp = req.GetResponse();
Console.WriteLine(rsp.Headers["Location"]);

我所请求的网站返回了301响应，"Location"(位置)标头包含要重定向到的URL.

The site I am requesting from is returning a 301 response, and the "Location" header contains the URL to redirect to.

如果我使用.NET Core 2.1进行完全相同的操作，则会从对 GetResponse 的调用中引发 WebException .如何避免这种情况?

If I do the exact same thing using .NET Core 2.1, I will instead get a WebException thrown from the call to GetResponse. How can I avoid this?

推荐答案

基于此，您需要将其捕获在 try/catch 块中，并检查 WebException :

Based on this, you need to trap it in try/catch block and inspect the WebException:

如果您设置 AllowAutoRedirect ，那么您最终将不遵循重定向.这意味着以301响应结束. HttpWebRequest (与 HttpClient 不同)会为非成功(非200)引发异常状态代码.因此，获取异常(很可能是 WebException )是预期的.S o，如果您需要处理该重定向(即HTTPS->HTTP)，您需要将其捕获在try/catch块中并进行检查WebException等..这是 HttpWebRequest 的标准用法.

If you set AllowAutoRedirect, then you will end up not following the redirect. That means ending up with the 301 response. HttpWebRequest (unlike HttpClient) throws exceptions for non-successful (non-200) status codes. So, getting an exception (most likely a WebException) is expected. So, if you need to handle that redirect (which is HTTPS -> HTTP by the way), you need to trap it in try/catch block and inspect the WebException etc. That is standard use of HttpWebRequest.

这就是我们建议开发人员使用 HttpClient 的原因，它使用起来更容易模式.

That is why we recommend devs use HttpClient which has an easier use pattern.

类似这样的东西:

WebResponse rsp;

try 
{
   rsp = req.GetResponse();
}

catch(WebException ex) 
{
    if(ex.Message.Contains("301"))
        rsp = ex.Result;
}

这篇关于NET Core中的WebRequest重定向的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！