本文整理自网络，侵删。
前两天帮人写程序
用IdHTTP控件往一网站发包
如下：
Delphi代码
IdHTTP1.Request.Connection:='Keep-Alive';
IdHTTP1.Request.UserAgent:='Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Maxthon)';
// idhttp1.Request.UserAgent := 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Maxthon; .NET CLR 1.1.4322)';
idHTTP1.Request.ContentType:='application/x-www-form-urlencoded';
IdHTTP1.Request.Referer:='http://www.xxx.com';
IdHTTP1.Request.Accept:='image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-excel, application/msword, */*';
IdHTTP1.Request.AcceptLanguage:='zh-cn';
IdHTTP1.Request.AcceptEncoding:='gzip, deflate';
IdHTTP1.Request.CacheControl:='no-cache';
IdHTTP1.ReadTimeout:=60000;
IdHTTP1.ProtocolVersion:=pv1_1;
sHtml:=IdHTTP1.Post('http://www.xxx.com/login.asp',sPost);
但用抓包工具看，却发现是用的http1.0，而不是http1.1，明明设置了IdHTTP1.ProtocolVersion:=pv1_1
查看INDY的源码，发现在IdHTTP.pas中有如下代码和注释：
Delphi代码
OldProtocol := FProtocolVersion;
// If hoKeepOrigProtocol is SET, is possible to assume that the developer
// is sure in operations of the server
if not (hoKeepOrigProtocol in FOptions) then
FProtocolVersion := pv1_0;
原因很明显了，于是改代码：
Delphi代码
IdHTTP1.Request.Connection:='Keep-Alive';
IdHTTP1.Request.UserAgent:='Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Maxthon)';
IdHTTP1.Request.ContentType:='application/x-www-form-urlencoded';
IdHTTP1.Request.Referer:='http://www.xxx.com';
IdHTTP1.Request.Accept:='image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-excel, application/msword, */*';
IdHTTP1.Request.AcceptLanguage:='zh-cn';
IdHTTP1.Request.AcceptEncoding:='gzip, deflate';
IdHTTP1.Request.CacheControl:='no-cache';
IdHTTP1.ReadTimeout:=60000;
IdHTTP1.HTTPOptions:=IdHTTP1.HTTPOptions+[hoKeepOrigProtocol];//关键这行
IdHTTP1.ProtocolVersion:=pv1_1;
sHtml:=IdHTTP1.Post('http://www.xxx.com/login.asp',sPost);
再用抓包工具看，能看到确实是使用http1.1协议了。 相关阅读 >>
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