如何得到一个身体的整体响应？

在 WebException 中我看不到 GetResponse 的主体，这是我在 C # 中的代码:

try {
return GetResponse(url + "." + ext.ToString(), method, headers, bodyParams);
} catch (WebException ex) {
switch (ex.Status) {
case WebExceptionStatus.ConnectFailure:
throw new ConnectionException();
case WebExceptionStatus.Timeout:
throw new RequestTimeRanOutException();
case WebExceptionStatus.NameResolutionFailure:
throw new ConnectionException();
case WebExceptionStatus.ProtocolError:
if (ex.Message == "The remote server returned an error: (401) unauthorized.") {
throw new CredentialsOrPortalException();
}
throw new ProtocolErrorExecption();
default:
throw;
}

这是 Wireshark 输出的请求:

POST /api/1.0/authentication.json HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Accept: application/json
Host: nbm21tm1.teamlab.com
Content-Length: 49
Connection: Keep-Alive


userName=XXX&password=YYYHTTP/1.1 500 Server error
Cache-Control: private, max-age=0
Content-Length: 106
Content-Type: application/json; charset=UTF-8
Server: Microsoft-IIS/7.5
X-AspNet-Version: 2.0.50727
X-Powered-By: ASP.NET
X-Powered-By: ARR/2.5


Date: Mon, 06 Aug 2012 12:49:41 GMT
Connection: close


{"count":0,"startIndex":0,"status":1,"statusCode":500,"error":{"message":"Invalid username or password."}}

是否有可能以某种方式在 WebException 中看到消息文本？ 谢谢你。

93457 次浏览
小开
最佳答案 
var resp = new StreamReader(ex.Response.GetResponseStream()).ReadToEnd();


dynamic obj = JsonConvert.DeserializeObject(resp);
var messageFromServer = obj.error.message;
小开 
try {
WebClient client = new WebClient();
client.Encoding = Encoding.UTF8;
string content = client.DownloadString("https://sandiegodata.atlassian.net/wiki/pages/doaddcomment.action?pageId=524365");
Console.WriteLine(content);
Console.ReadKey();
} catch (WebException ex) {
var resp = new StreamReader(ex.Response.GetResponseStream()).ReadToEnd();
Console.WriteLine(resp);
Console.ReadKey();
}
小开

这只是改进了现有的答案。我已经编写了一个方法，通过增强消息处理抛出/重新抛出的细节，其中包括响应主体:

以下是我的代码(在 Client.cs 中) :

/// <summary>
///     Tries to rethrow the WebException with the data from the body included, if possible.
///     Otherwise just rethrows the original message.
/// </summary>
/// <param name="wex">The web exception.</param>
/// <exception cref="WebException"></exception>
/// <remarks>
///     By default, on protocol errors, the body is not included in web exceptions.
///     This solutions includes potentially relevant information for resolving the
///     issue.
/// </remarks>
private void ThrowWithBody(WebException wex) {
if (wex.Status == WebExceptionStatus.ProtocolError) {
string responseBody;
try {
//Get the message body for rethrow with body included
responseBody = new StreamReader(wex.Response.GetResponseStream()).ReadToEnd();


} catch (Exception) {
//In case of failure to get the body just rethrow the original web exception.
throw wex;
}


//include the body in the message
throw new WebException(wex.Message + $" Response body: '{responseBody}'", wex, wex.Status, wex.Response);
}


//In case of non-protocol errors no body is available anyway, so just rethrow the original web exception.
throw wex;
}

您可以在 catch 子句中使用它，就像 OP 显示的那样:

//Execute Request, catch the exception to eventually get the body
try {
//GetResponse....
}
} catch (WebException wex) {
if (wex.Status == WebExceptionStatus.ProtocolError) {
ThrowWithBody(wex);
}


//otherwise rethrow anyway
throw;
}
小开

我没有看到使用 using语句的任何答案，也没有看到使用 async的任何用法。

public static class WebExceptionExtensions
{
public static string GetResponseBody(this WebException webException)
{
if (webException.Status == WebExceptionStatus.ProtocolError)
{
try
{
using (var stream = webException.Response.GetResponseStream())
{
if (stream is null)
return string.Empty; // or webException.Message
using (var reader = new StreamReader(stream))
{
string msg = reader.ReadToEnd();
if (string.IsNullOrEmpty(msg) && webException.Response is HttpWebResponse response)
msg = $"{response.StatusDescription} ({(int)response.StatusCode})"; // provide some error message if not found


return msg;
}
}
}
catch (WebException) // we tried
{
return string.Empty; // or webException.Message
}
}
else
{
return string.Empty; // or webException.Message
}
}


public static async Task<string> GetResponseBodyAsync(this WebException webException)
{
if (webException.Status == WebExceptionStatus.ProtocolError)
{
try
{
using (var stream = webException.Response.GetResponseStream())
{
if (stream is null)
return string.Empty; // or webException.Message
using (var reader = new StreamReader(stream))
{
string msg = await reader.ReadToEndAsync();
if (string.IsNullOrEmpty(msg) && webException.Response is HttpWebResponse response)
msg = $"{response.StatusDescription} ((int){response.StatusCode})"; // provide some error message if not found


return msg;
}
}
}
catch (WebException) //  we tried
{
return string.Empty; // or webException.Message
}
}
else
{
return string.Empty; // or webException.Message
}
}
}

现在，无论何时我们捕获 WebException，都很容易获得响应主体。

try
{
// Do work here...
}
catch (WebException we)
{
Console.WriteLine(we.GetResponseBody()); // synchronous
Console.WriteLine(await we.GetResponseBodyAsync()); // or asynchronous
}
catch (Exception e)
{
throw new Exception("Unexpected error occured", e);
}

警告 ，如果尝试调用此方法两次，将得到流已被处理的异常。这种扩展方法只适用于快速显示错误并继续前进。如果需要扩展逻辑，可能需要创建自己的方法。


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