How to send an HTTP request to Delphi 2010 using WinInet

Question

I want to send an HTTP request to Delphi 2010 using WinInet, but my script does not work; /

This is my Delphi script:

uses WinInet; procedure TForm1.Button1Click(Sender: TObject); var hNet,hURL,hRequest: HINTERNET; begin hNet := InternetOpen(PChar('User Agent'),INTERNET_OPEN_TYPE_PRECONFIG or INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0); if Assigned(hNet) then begin try hURL := InternetConnect(hNet,PChar('http://localhost/delphitest.php'),INTERNET_DEFAULT_HTTP_PORT,nil,nil,INTERNET_SERVICE_HTTP,0,DWORD(0)); if(hURL<>nil) then hRequest := HttpOpenRequest(hURL, 'POST', PChar('test=test'),'HTTP/1.0',PChar(''), nil, INTERNET_FLAG_RELOAD or INTERNET_FLAG_PRAGMA_NOCACHE,0); if(hRequest<>nil) then HttpSendRequest(hRequest, nil, 0, nil, 0); InternetCloseHandle(hNet); except ShowMessage('error'); end end; end; 

and my php script:

 $data = $_POST['test']; $file = "test.txt"; $fp = fopen($file, "a"); flock($fp, 2); fwrite($fp, $data); flock($fp, 3); fclose($fp); 

Answer 1

Main problems:

• The second InternetConnect parameter should contain only the server name, and not the entire server side URL of the script.

• The third parameter of HttpOpenRequest should be the name of the script file, and not the POST data!

• The actual POST data should be the fourth parameter of the HttpSendRequest .

Minor issues

• INTERNET_OPEN_TYPE_PRECONFIG or INTERNET_OPEN_TYPE_PRECONFIG : Enough with INTERNET_OPEN_TYPE_PRECONFIG .

• DWORD(0) is redundant. 0 enough.

Code example

I use the following code for POST data:

 procedure WebPostData(const UserAgent: string; const Server: string; const Resource: string; const Data: AnsiString); overload; var hInet: HINTERNET; hHTTP: HINTERNET; hReq: HINTERNET; const accept: packed array[0..1] of LPWSTR = (PChar('*/*'), nil); header: string = 'Content-Type: application/x-www-form-urlencoded'; begin hInet := InternetOpen(PChar(UserAgent), INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0); try hHTTP := InternetConnect(hInet, PChar(Server), INTERNET_DEFAULT_HTTP_PORT, nil, nil, INTERNET_SERVICE_HTTP, 0, 1); try hReq := HttpOpenRequest(hHTTP, PChar('POST'), PChar(Resource), nil, nil, @accept, 0, 1); try if not HttpSendRequest(hReq, PChar(header), length(header), PChar(Data), length(Data)) then raise Exception.Create('HttpOpenRequest failed. ' + SysErrorMessage(GetLastError)); finally InternetCloseHandle(hReq); end; finally InternetCloseHandle(hHTTP); end; finally InternetCloseHandle(hInet); end; end; 

For instance:

 WebPostData('My UserAgent', 'www.rejbrand.se', 'mydir/myscript.asp', 'value=5'); 

Update in response to OP response

To read data from the Internet, use the InternetReadFile function. I use the following code to read a small (single line) text file from the Internet:

 function WebGetData(const UserAgent: string; const Server: string; const Resource: string): string; var hInet: HINTERNET; hURL: HINTERNET; Buffer: array[0..1023] of AnsiChar; i, BufferLen: cardinal; begin result := ''; hInet := InternetOpen(PChar(UserAgent), INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0); try hURL := InternetOpenUrl(hInet, PChar('http://' + Server + Resource), nil, 0, 0, 0); try repeat InternetReadFile(hURL, @Buffer, SizeOf(Buffer), BufferLen); if BufferLen = SizeOf(Buffer) then result := result + AnsiString(Buffer) else if BufferLen > 0 then for i := 0 to BufferLen - 1 do result := result + Buffer[i]; until BufferLen = 0; finally InternetCloseHandle(hURL); end; finally InternetCloseHandle(hInet); end; end; 

Sample Usage:

 WebGetData('My UserAgent', 'www.rejbrand.se', '/MyDir/update/ver.txt') 

This function, therefore, only reads data without a preliminary POST. However, the InternetReadFile function can also be used with a descriptor created by HttpOpenRequest , so it will work in your case HttpOpenRequest . You know that the WinInet link is MSDN, right? All functions of the Windows API are described in detail there, for example InternetReadFile .

Answer 2

 var BufferIn : INTERNET_BUFFERS; Buffer: array[0..1024] of Byte; FTmp: TSomeStream: FURL: string; ... begin ... // Create FTmp, set FUrl, ... NetHandle := InternetOpen( 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3', INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0); UrlHandle := HttpOpenRequest(NetHandle, 'POST', PChar(FURL), nil, nil, nil, INTERNET_FLAG_NO_CACHE_WRITE, 0); ... // Check handles, etc try BufferIn.dwBufferTotal := FTmp.Size; if not HttpSendRequestEx(UrlHandle, @BufferIn, nil, 0, 0) then raise Exception.CreateFmt('Error on HttpSendRequestEx %d\n', [GetLastError()]); size := FTmp.Read(Buffer, 1024); InternetWriteFile(UrlHandle, @Buffer, size, BytesWritten); while (BytesWritten = size) and (BytesWritten > 0) do begin size := FTmp.Read(Buffer, 1024); InternetWriteFile(UrlHandle, @Buffer, size, BytesWritten); end; finally FTmp.Free; InternetCloseHandle(UrlHandle); InternetCloseHandle(NetHandle); end; 

Answer 3

Http://www.utilmind.com has a library (called the HTTPGet component for Delphi 32). It sets visual controls in your component palette. He does exactly what you want, so you can take a look.