使用 c# http 客户端时，请求标头必须仅包含 ASCII 字符吗？

Question

我正在使用HttpClient通过传递标头进行 POST 调用，但在某些时候我收到如下错误：

Request headers must contain only ASCII characters.

使用堆栈跟踪：

at System.Net.Http.HttpConnection.WriteStringAsync(String s)
   at System.Net.Http.HttpConnection.WriteHeadersAsync(HttpHeaders headers, String cookiesFromContainer)
   at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.SendWithNtConnectionAuthAsync(HttpConnection connection, HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.DiagnosticsHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)

这是我的代码：

public HttpWrapper(string endpoint, Func<IDictionary<string, string>> NewHeader)
{
    _httpClient = new HttpClient();
    _httpClient.BaseAddress = new Uri(endpoint);

    if (NewHeader != null)
    {
        var headers = NewHeader();
        foreach (var header in headers)
        {
            _httpClient.DefaultRequestHeaders.TryAddWithoutValidation(header.Key, header.Value);
        }
    }
}

我需要做些什么header.Value来解决这个问题吗？我在网上阅读，所以看起来我需要在这里使用 Utf-8，但不确定如何正确使用？

更新

我今天得到了这样的标头值，它抛出了同样的异常，因为HttpUtility.HtmlEncode它没有做任何事情。另外我不确定这个角色是<0x94>什么？任何想法为什么会发生？

我也不确定

Answer 1

您可以尝试将标头值编码为 HTML：

\n

_httpClient.DefaultRequestHeaders.TryAddWithoutValidation(header.Key, HttpUtility.HtmlEncode(header.Value));\n

\n

您的字符串 Erg\xc3\xa4nzendes 将是“ Ergänzendes”。

\n