我有一个像这样简单的http://issamsoft.com/app2/page1.aspx的Asp .net页面
我想向其中发布一些数据并从响应中提取数据，
通过使用TIdHttp。我试图像这样在Delphi2009中做到这一点:
Procedure TForm1.Button1Click(Sender: TObject);
Const
VIEWSTATE = '/wEPDwUKMjA3NjE4MDczNmRkSxPt/LdmgqMd+hN+hkbiqIZuGUk=';
EVENTVALIDATION = '/wEWAwL40NXEDALs0bLrBgKM54rGBtmtdOYy+U7IFq8B25bYT1d4o1iK';
FORMPARAMS = 'TextBox1=Issam&Button1=Button';
URL = 'http://issamsoft.com/app2/page1.aspx';
var
http: TIdHttp;
lstParams: TStringList;
begin
http := TIdHTTP.Create(self);
lstParams := TStringList.Create;
try
lstParams.Add('__VIEWSTATE='+VIEWSTATE);
lstParams.Add('__EVENTVALIDATION='+EVENTVALIDATION);
lstParams.Add(FORMPARAMS);
http.Request.ContentType := 'application/x-www-form-urlencoded';
Memo1.Lines.Text := http.Post(url,lstParams);
finally
http.Free;
lstParams.Free;
end;
end;
但是TIdhttp始终会给出错误(HTTP/1.1 500 Internal Server Error。)
我在idHttp单元中阅读了一些评论，讨论了HTTP协议(protocol)v 1.1这样的问题:
我的代码有问题吗？还是TidHttp Bug？如果问题出在
TIdHttp，有什么解决方法吗？还是有其他使用Indy组件的解决方案？
除了。我已经使用WebClient在C#中提出了一个解决方案，并且效果很好。
private void button1_Click(object sender, EventArgs e)
{
WebClient myClient = new WebClient();
string viewstate = HttpUtility.UrlEncodeUnicode(@"/wEPDwUKMjA3NjE4MDczNmRkSxPt/LdmgqMd+hN+hkbiqIZuGUk=");
string eventvaildation = HttpUtility.UrlEncodeUnicode(@"/wEWAwL40NXEDALs0bLrBgKM54rGBtmtdOYy+U7IFq8B25bYT1d4o1iK");
string postdata = "__VIEWSTATE=" + viewstate + "&" +
"__EVENTVALIDATION=" + eventvaildation + "&TextBox1=Issam&Button1=Button";
myClient.Headers.Add("Content-Type", "application/x-www-form-urlencoded");
byte[] responce = myClient.UploadData("http://issamsoft.com/app2/page1.aspx", Encoding.ASCII.GetBytes(postdata));
txtResponse.Text = Encoding.ASCII.GetString(responce);
}
在哪里可以在Delphi中找到像WebClient这样的(好/可信赖)类？免费首选:)
编辑:
我希望VIEWSTATE，EVENTVALIDATION的机制对您足够清楚，它们是服务器生成的哈希值，并且它们可能会更改(已经更改)，我的原始项目中有一段代码只是用于提取当前的VIEWSTATE，EVENTVALIDATION值，但是我省略该部分只是为了使我的示例简单明了，因此，当您尝试上面的代码时，必须从当前页面源中获取VIEWSTATE，EVENTVALIDATION值。
最佳答案
这很可能是由于以下事实造成的:在C#中，您使用＆符号(和)字符来连接VIEWSTATE，EVENTVALIDATION和FORMPARAMS。
但是在Delphi中，您使用了TStringList和Add。
Add不会在与号之间添加(＆)(和)，而是在两个之间添加CR + LF。
因此，您在Delphi中发送的数据与在C#中发送的数据不同。
如果您在Delphi中更改字符串连接逻辑以匹配C#中的逻辑，则无论您在Delphi端使用哪种WebClient，它都应该起作用。
--jeroen
编辑:20090830
此代码有效；使用Fiddler2检查C#和IE7输出，我发现您还需要转义'/'和'='字符。
编辑2:20090831
自昨天以来，网站上的VIEWSTATE和EVENTVALIDATION有所改变(尽管我不确定为什么)。我已经更改了代码，并且在将我的更改发布到此答案时有效。
这是从Internet Explorer 7中发布页面时每个Fiddler捕获的新请求内容:
__VIEWSTATE=%2FwEPDwUKMjA3NjE4MDczNmRk5%2FC2iWwvlAB3L1wYzRpm3KZhRC0%3D&__EVENTVALIDATION=%2FwEWAwLXzuATAuzRsusGAoznisYGSYOqDGy4vMunY6A8xi6ahQEPI5Q%3D&TextBox1=Issam&Button1=Button
这是从Delphi示例发布时的新请求:
__VIEWSTATE=%2FwEPDwUKMjA3NjE4MDczNmRk5%2FC2iWwvlAB3L1wYzRpm3KZhRC0%3D&__EVENTVALIDATION=%2FwEWAwLXzuATAuzRsusGAoznisYGSYOqDGy4vMunY6A8xi6ahQEPI5Q%3D&TextBox1=Issam&Button1=Button
现在，以下示例给出了此结果(请注意结果中的“ Issam ”):
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head><title>
</title></head>
<body>
<form name="form1" method="post" action="page1.aspx" id="form1">
<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUKMjA3NjE4MDczNg9kFgICAw9kFgICBQ8PFgIeBFRleHQFDVdlbGNvbWUgSXNzYW1kZGSCDMOkTMjkZJgqLkhpK99twpD5+A==" />
<input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="/wEWAwKr+O/BBQLs0bLrBgKM54rGBlueO5BU/6BAJMZfHNwh5fsQFuAm" />
<div>
<input name="TextBox1" type="text" value="Issam" id="TextBox1" />
<input type="submit" name="Button1" value="Button" id="Button1" />
<br />
<span id="Label1">Welcome Issam</span>
<br />
</div>
</form>
</body>
</html>
编辑3:20090831
确实，VIEWSTATE和EVENTVALIDATION再次发生了变化:它们以某种方式不断变化:似乎涉及时间因素。
所以我修改了代码，现在它可以从GET请求中提取VIEWSTATE和EVENTVALIDATION，然后将其放入POST请求中。
此外，似乎也需要转义“+”和“:”。
因此，我深入研究了ASP.NET页面生成逻辑，发现它们使用HttpUtility.UrlEncode进行转义，最终转义 HttpUtility。
因此，我将Reflector反向工程的Delphi代码改编为THttpUtility类。
这是最终的代码:
{$DEFINE FIDDLER}
unit HttpPostExampleFormUnit;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, IdBaseComponent, IdComponent, IdTCPConnection, IdTCPClient, IdHTTP;
type
THttpPostExampleForm = class(TForm)
Button1: TButton;
Memo1: TMemo;
procedure Button1Click(Sender: TObject);
private
procedure Log(const What: string; const Content: string);
procedure LogClear;
end;
var
HttpPostExampleForm: THttpPostExampleForm;
implementation
uses
HttpUtilityUnit;
{$R *.dfm}
procedure AddFormParameter(const StringStream: TStringStream; const ParameterName: string; const ParameterValue: string);
var
EncodedParameterValue: string;
begin
StringStream.WriteString(ParameterName);
StringStream.WriteString('=');
EncodedParameterValue := THttpUtility.UrlEncode(ParameterValue);
StringStream.WriteString(EncodedParameterValue);
end;
procedure AddFormParameterSeparator(const StringStream: TStringStream);
begin
StringStream.WriteString('&');
end;
function ExtractHiddenParameter(const ParameterName: string; const Request: string): string;
//<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUKMjA3NjE4MDczNg9kFgICAw9kFgICBQ8PFgIeBFRleHQFDVdlbGNvbWUgSXNzYW1kZGSCDMOkTMjkZJgqLkhpK99twpD5+A==" />
const
PrefixMask = 'input type="hidden" name="%s" id="%s" value="';
Suffix = '" />';
var
Prefix: string;
PrefixLength: Integer;
PrefixPosition: Integer;
SuffixPosition: Integer;
begin
Prefix := Format(PrefixMask, [ParameterName, ParameterName]);
PrefixPosition := Pos(Prefix, Request);
if PrefixPosition = 0 then
Result := ''
else
begin
PrefixLength := Length(Prefix);
Result := Copy(Request,
PrefixPosition + PrefixLength,
1 + Length(Request) - PrefixPosition - PrefixLength);
SuffixPosition := Pos(Suffix, Result);
if SuffixPosition = 0 then
Result := ''
else
Delete(Result, SuffixPosition, 1 + Length(Result) - SuffixPosition);
end;
end;
procedure THttpPostExampleForm.Button1Click(Sender: TObject);
const
DefaultVIEWSTATE = '/wEPDwUKMjA3NjE4MDczNmRk5%2FC2iWwvlAB3L1wYzRpm3KZhRC0=';
DefaultEVENTVALIDATION = '/wEWAwLXzuATAuzRsusGAoznisYGSYOqDGy4vMunY6A8xi6ahQEPI5Q=';
FORMPARAMS = 'TextBox1=Issam&Button1=Button';
URL = 'http://issamsoft.com/app2/page1.aspx';
__VIEWSATE = '__VIEWSTATE';
__EVENTVALIDATION = '__EVENTVALIDATION';
var
VIEWSTATE: string;
EVENTVALIDATION: string;
getHttp: TIdHttp;
getRequest: string;
postHttp: TIdHttp;
ParametersStringStream: TStringStream;
postRequest: string;
begin
LogClear();
getHttp := TIdHTTP.Create(self);
try
getRequest := getHttp.Get(URL);
Log('GET Request', getRequest);
VIEWSTATE := ExtractHiddenParameter(__VIEWSATE, getRequest);
EVENTVALIDATION := ExtractHiddenParameter(__EVENTVALIDATION, getRequest);
Log('Extracted VIEWSTATE', VIEWSTATE);
Log('Extracted EVENTVALIDATION', EVENTVALIDATION);
finally
getHttp.Free();
end;
postHttp := TIdHTTP.Create(self);
{$IFDEF FIDDLER}
postHttp.ProxyParams.ProxyServer := '127.0.0.1';
postHttp.ProxyParams.ProxyPort := 8888;
{$ENDIF FIDDLER}
postHttp.HTTPOptions := postHttp.HTTPOptions + [hoKeepOrigProtocol];
ParametersStringStream := TStringStream.Create('');
try
AddFormParameter(ParametersStringStream, __VIEWSATE, VIEWSTATE);
AddFormParameterSeparator(ParametersStringStream);
AddFormParameter(ParametersStringStream, __EVENTVALIDATION, EVENTVALIDATION);
AddFormParameterSeparator(ParametersStringStream);
ParametersStringStream.WriteString(FORMPARAMS);
postHttp.Request.ContentType := 'application/x-www-form-urlencoded';
ParametersStringStream.Seek(0, soFromBeginning);
Log('POST Parameters', ParametersStringStream.DataString);
postRequest := postHttp.Post(url, ParametersStringStream);
Log('POST Request', postRequest);
finally
postHttp.Free;
ParametersStringStream.Free;
end;
end;
procedure THttpPostExampleForm.Log(const What, Content: string);
begin
Memo1.Lines.Add(What + '=');
Memo1.Lines.Add(Content);
end;
procedure THttpPostExampleForm.LogClear;
begin
Memo1.Lines.Clear;
end;
end.
和THttpUtlity类:
unit HttpUtilityUnit;
interface
type
THttpUtility = class
private
class function IsSafe(const ch: Char): boolean;
public
class function UrlEncode(s: string): string;
end;
implementation
uses
Classes, SysUtils;
class function THttpUtility.IsSafe(const ch: Char): boolean;
begin
if ((((ch >= 'a') and (ch <= 'z')) or ((ch >= 'A') and (ch <= 'Z'))) or ((ch >= '0') and (ch <= '9'))) then
Result := True
else
case ch of
'''',
'(',
')',
'*',
'-',
'.',
'_',
'!':
Result := True;
else
Result := False;
end;
end;
class function THttpUtility.UrlEncode(s: string): string;
var
ch: Char;
HexCh: string;
StringStream: TStringStream;
Index: Integer;
Ordinal: Integer;
begin
StringStream := TStringStream.Create('');
try
//Note: this is not yet UTF-16 compatible; check before porting to Delphi 2009
for Index := 1 to Length(s) do
begin
ch := s[Index];
if IsSafe(ch) then
StringStream.WriteString(Ch)
else
begin
Ordinal := Ord(Ch);
HexCh := IntToHex(Ordinal, 2);
StringStream.WriteString('%'+HexCh);
end;
end;
Result := StringStream.DataString;
finally
StringStream.Free;
end;
end;
end.
这应该可以帮助您。
--jeroen
关于asp.net - 使用Delphi和TIdHttp将数据发布到ASP .NET页面，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/1351181/