c# - 重新发送 HttpRequestMessage - 异常

Question

我想多次发送完全相同的请求，例如:

HttpClient client = new HttpClient();
HttpRequestMessage req = new HttpRequestMessage(HttpMethod.Get, "http://example.com");

await client.SendAsync(req, HttpCompletionOption.ResponseContentRead);
await client.SendAsync(req, HttpCompletionOption.ResponseContentRead);

第二次发送请求将抛出异常并显示消息:

The request message was already sent. Cannot send the same requestmessage multiple times.

有没有办法“克隆”请求以便我可以再次发送？

我的真实代码在 HttpRequestMessage 上设置的变量比上面的示例更多，例如 header 和请求方法等变量。

Answer 1

我编写了以下扩展方法来克隆请求。

public static HttpRequestMessage Clone(this HttpRequestMessage req)
{
    HttpRequestMessage clone = new HttpRequestMessage(req.Method, req.RequestUri);

    clone.Content = req.Content;
    clone.Version = req.Version;

    foreach (KeyValuePair<string, object> prop in req.Properties)
    {
        clone.Properties.Add(prop);
    }

    foreach (KeyValuePair<string, IEnumerable<string>> header in req.Headers)
    {
        clone.Headers.TryAddWithoutValidation(header.Key, header.Value);
    }

    return clone;
}