Delphi Indy 登录并下载文件

Question

问题是我无法下载文件(因为我没有登录)。我可以登录，但仅此而已。德尔福版本:XE2，Indy 版本:10.5.8.0(也在带有最新 Indy 的 Delphi XE4 上进行了测试)。有一 block cookie 的日期为 1970 年。感谢您的帮助。

验证码:(登录名和密码均为真实)

var
  IdHTTP: TIdHTTP;
  Request: TStringList;
  Response: TMemoryStream;
  File: TMemoryStream;
begin
  try
    Response := TMemoryStream.Create;
    try
      Request := TStringList.Create;
      try
        Request.Add('user[login]=1212test1212');
        Request.Add('user[password]=test1212');
        IdHTTP := TIdHTTP.Create;
        File := TMemoryStream.Create;
        try
          IdHTTP.AllowCookies := True;
          IdHTTP.CookieManager:=Form1.IdCookieManager1;
          IdHTTP.HandleRedirects := True;
          IdHTTP.Request.ContentType := 'application/x-www-form-urlencoded';
          IdHTTP.Post('http://www.twitch.tv/login', Request, Response);
          IdHTTP.Get('http://www.twitch.tv/broadcast/fmle3_config',File);
          File.SaveToFile('C:\aaa.xml');
        finally
          IdHTTP.Free;
          MS.Free;
        end;
      finally
        Request.Free;
      end;
    finally
      Response.Free;
    end;
  except
    on E: Exception do
      ShowMessage(E.Message);
  end;
end;

HTTP 分析器日志:

(Status-Line):HTTP/1.1 302 Moved Temporarily
Cache-Control:no-cache, no-store, must-revalidate
Pragma:no-cache
Set-Cookie:feature_bucket=83; domain=.twitch.tv; path=/
Set-Cookie:name=1212test1212; domain=.twitch.tv; path=/; expires=Tue, 06-Aug-2013 19:20:52 GMT
Set-Cookie:_twitch_session_id=16d9fc8368fe22701324c7ce39c9f668; domain=.twitch.tv; path=/; expires=Wed, 24-Jul-2013 07:20:52 GMT; HttpOnly
Set-Cookie:unique_id=a5b16cf36861154f9dd118e673fd4aa0; domain=.twitch.tv; path=/
Set-Cookie:persistent=46516706_1212test1212_35ptd94szs8ysrpfcckrcx21t; domain=.twitch.tv; path=/; expires=Tue, 06-Aug-2013 19:20:52 GMT; HttpOnly
Set-Cookie:login=1212test1212; domain=.twitch.tv; path=/; expires=Tue, 06-Aug-2013 19:20:52 GMT
Set-Cookie:last_login=Tue+Jul+23+19%3A20%3A52+UTC+2013; domain=.twitch.tv; path=/; expires=Tue, 06-Aug-2013 19:20:52 GMT
Set-Cookie:language=en; domain=.twitch.tv; path=/; expires=Sat, 23-Jul-2033 19:20:52 GMT
Set-Cookie:api_token=daa32f51e6d015daf9c7a1949d1ef9e0; domain=.twitch.tv; path=/; expires=Tue, 06-Aug-2013 19:20:52 GMT
Content-Length:144
Content-Type:text/html
Location:http://www.twitch.tv/
Server:nginx
Front-End-Https:off
P3P:CP="CAO PSA OUR"
status:302 Found
x-geo:PL
x-rack-cache:invalidate, pass
x-request-id:a829998aa94c51788ec9b504656639f3
x-runtime:0.272887
x-ua-compatible:IE=Edge,chrome=1
Date:Tue, 23 Jul 2013 19:20:52 GMT
Connection:close

(Status-Line):HTTP/1.1 200 OK
Cache-Control:no-cache, no-store, must-revalidate
Pragma:no-cache
Set-Cookie:_twitch_session_id=860dc07ccd1dd937f1cb6adfc84a7f14; domain=.twitch.tv; path=/; expires=Wed, 24-Jul-2013 07:20:53 GMT; HttpOnly
Set-Cookie:persistent=; domain=.twitch.tv; path=/; expires=Thu, 01-Jan-1970 00:00:00 GMT
Content-Length:59850
Content-Type:text/html; charset=utf-8
Server:nginx
Front-End-Https:off
status:200 OK
x-geo:PL
x-rack-cache:invalidate, pass
x-request-id:2557352c302a3eddfe9080882aaa3028
x-runtime:0.301446
x-ua-compatible:IE=Edge,chrome=1
Date:Tue, 23 Jul 2013 19:20:53 GMT
Connection:close

(Status-Line):HTTP/1.1 302 Moved Temporarily
Cache-Control:must-revalidate, no-cache, no-store, private
Pragma:no-cache
Set-Cookie:_twitch_session_id=860dc07ccd1dd937f1cb6adfc84a7f14; domain=.twitch.tv; path=/; expires=Wed, 24-Jul-2013 07:20:54 GMT; HttpOnly
Content-Length:150
Content-Type:text/html
Location:http://www.twitch.tv/signup
Server:nginx
Front-End-Https:off
status:302 Found
x-geo:PL
x-rack-cache:miss
x-request-id:b35e5b998a633b80cfb1f53373e5627a
x-runtime:0.029409
X-UA-Compatible:IE=Edge,chrome=1
Date:Tue, 23 Jul 2013 19:20:54 GMT
Connection:keep-alive

http://img197.imageshack.us/img197/7007/xgyf.jpg

Answer 1

您没有登录到正确的 URL。 http://www.twitch.tv/login 只是用户在网络浏览器中填写的 HTML 登录表单，然后提交到真实的登录 URL，即 https://改为 secure.twitch.tv/user/login。如果您查看该登录表单的 HTML，您会看到它，以及您需要提交但当前未提交的几个隐藏表单字段。

此外，由于实际登录 URL 使用的是 HTTPS，因此您需要将 SSL IOHandler 附加到 TIdHTTP，例如 TIdSSLIOHandlerSocketOpenSSL。

更复杂的是，当请求 http://www.twitch.tv/login 时，所需的 authenticity_token 值是动态生成的，因此您需要首先下载登录表单的HTML，手动解析出token值，然后完成登录提交。

试试这个:

var
  IdHTTP: TIdHTTP;
  IdSSL: TIdSSLIOHandlerSocketOpenSSL;
  HTML, AuthToken: string;
  Request: TStringList;
  File: TMemoryStream;
begin
  try
    IdHTTP := TIdHTTP.Create;
    try
      IdSSL := TIdSSLIOHandlerSocketOpenSSL.Create(IdHTTP);
      IdHTTP.IOHandler := IdSSL;

      IdHTTP.AllowCookies := True;
      IdHTTP.CookieManager := Form1.IdCookieManager1;
      IdHTTP.HandleRedirects := True;

      HTML := IdHTTP.Get('http://www.twitch.tv/login');
      AuthToken := ...; // parse the HTML to extract the authenticity_token value...

      Request := TStringList.Create;
      try
        Request.Add('utf8=✓');
        Request.Add('authenticity_token=' + AuthToken);
        Request.Add('redirect_on_login=http://www.twitch.tv/');
        Request.Add('embed_form=false');
        Request.Add('user[login]=1212test1212');
        Request.Add('user[password]=test1212');

        IdHTTP.Post('https://secure.twitch.tv/user/login', Request, nil, IndyTextEncoding_UTF8);
      finally
        Request.Free;
      end;

      File := TMemoryStream.Create;
      try
        IdHTTP.Get('http://www.twitch.tv/broadcast/fmle3_config', File);
        File.SaveToFile('C:\aaa.xml');
      finally
        File.Free;
      end;
    finally
      IdHTTP.Free;
    end;
  except
    on E: Exception do
      ShowMessage(E.Message);
  end;
end;

话虽如此，由于登录表单在登录成功时会重定向到指定的 URL，因此您可以尝试这种稍微短一些的方法来避免一次往返:

var
  IdHTTP: TIdHTTP;
  IdSSL: TIdSSLIOHandlerSocketOpenSSL;
  HTML, AuthToken: string;
  Request: TStringList;
  File: TMemoryStream;
begin
  try
    IdHTTP := TIdHTTP.Create;
    try
      IdSSL := TIdSSLIOHandlerSocketOpenSSL.Create(IdHTTP);
      IdHTTP.IOHandler := IdSSL;

      IdHTTP.AllowCookies := True;
      IdHTTP.CookieManager := Form1.IdCookieManager1;
      IdHTTP.HandleRedirects := True;

      HTML := IdHTTP.Get('http://www.twitch.tv/login');
      AuthToken := ...; // parse the HTML to extract the authenticity_token value...

      Request := TStringList.Create;
      try
        Request.Add('utf8=✓');
        Request.Add('authenticity_token=' + AuthToken);
        Request.Add('redirect_on_login=http://www.twitch.tv/broadcast/fmle3_config');
        Request.Add('embed_form=false');
        Request.Add('user[login]=1212test1212');
        Request.Add('user[password]=test1212');

        File := TMemoryStream.Create;
        try
          IdHTTP.Post('https://secure.twitch.tv/user/login', Request, File, IndyTextEncoding_UTF8);
          File.SaveToFile('C:\aaa.xml');
        finally
          File.Free;
        end;
      finally
        Request.Free;
      end;
    finally
      IdHTTP.Free;
    end;
  except
    on E: Exception do
      ShowMessage(E.Message);
  end;
end;