"如何为单个请求禁用 HttpWebRequest 中的“期望：100 继续”标头？"

Question

HttpWebRequest<\/code> automatically appends an Expect: 100-continue<\/code> header for POST requests. Various sources around the internet suggest that this can be disabled as follows:

System.Net.ServicePointManager.Expect100Continue = false;

Answer 1

The HttpWebRequest class has a property called ServicePoint which can be used to change this setting for a specific request. For example:

var req = (HttpWebRequest) WebRequest.Create(...);
req.ServicePoint.Expect100Continue = false;

Answer 2

If you also need to set a proxy, make sure to do that first. Otherwise Expect100Continue will be reverted to true again. So:

HttpWebRequest webRequest = WebRequest.CreateHttp(_url);
webRequest.Proxy = new WebProxy(_proxyHost, _proxyPort);
webRequest.ServicePoint.Expect100Continue = false;

Answer 3

This can also be overwritten in the config:

<system.net>
    <settings>
        <servicePointManager expect100Continue="false"/>
    </settings>
</system.net>