K210.ORG

uses

  Wininet;

 

{$R *.DFM}

 

function DownloadURL(AUrl, TargetFileName, ProxyName, ProxyBypass: PChar):

  Boolean;

const

  BUFFERSIZE = 4096;

var

  hSession: HINTERNET;

  hService: HINTERNET;

  lpBuffer: array[0..BufferSize + 1] of Byte;

  BufferLength: DWORD;

  dwBytesRead: DWORD;

  dwSizeOfRq, Reserved, dwByteToRead: DWORD;

  localFile: file;

  fsize: DWORD;

begin

  Result := False;

 

{ Initialize the Win32 Internet functions. }

 

  hSession := InternetOpen('MyApp', // Agent

    INTERNET_OPEN_TYPE_PRECONFIG, // dwAccessType

    nil, // lpszProxyName (optional)

    nil, // lpszProxyBypass (optional)

    0); // dwFlags

 

{

dwAccessType indicates the client machine's type of access to the

Internet,

with one of the following values:

 

INTERNET_OPEN_TYPE_DIRECT indicates client does not have to go through a

proxy server to access the Internet

INTERNET_OPEN_TYPE_PROXY indicates client must first pass through a proxy

server

to access the Internet.

INTERNET_OPEN_TYPE_PRECONFIG indicates client program should use whatever

value

is in the Registry to determine the type of

access.

 

dwFlags allows you to specify two options when the handle is created:

 

INTERNET_FLAG_OFFLINE indicates that all requests should be satisfied from

the cache.

INTERNET_FLAG_ASYNC indicates that requests should be satisfied using

asynchronous behavior.

}

 

// hSession := InternetOpen( 'MyApp', INTERNET_OPEN_TYPE_DIRECT, nil, nil,  0);

 

{ See if the session handle is valid }

 

if hSession = nil then

begin

  ShowMessage('Internet session initialization failed!');

  Exit;

end;

 

// Set options for the internet handle

// InternetSetOption(hSession, INTERNET_OPTION_CONNECT_TIMEOUT,

@timeOutMS, sizeOf(timeOutMS));

 

{

InternetOpenUrl opens a handle to the Internet file using a URL.

The flags indicate that the file will always be read from the Internet

rather

than the cache.

}

 

hService := InternetOpenUrl(hSession,

  PChar(AUrl),

  nil,

  0,

  INTERNET_FLAG_DONT_CACHE or

  INTERNET_FLAG_PRAGMA_NOCACHE or

  INTERNET_FLAG_RELOAD,

  0);

 

{

INTERNET_FLAG_RELOAD: causes the program to reload the URL even if a copy

exists in the cache.

INTERNET_FLAG_DONT_CACHE: indicates not to cache the file retrieved.

INTERNET_FLAG_RAW_DATA: returns raw data if specified.

For FTP and Gopher, this data will be placed in the appropriate

_FIND_DATA structure.

INTERNET_FLAG_SECURE: is for conducting secure HTTP transactions via

either SSL or PCT.

INTERNET_FLAG_EXISTING_CONNECT: instructs WinInet to attempt to use an

existing connection to the remote server.

}

 

 

{ See if the session handle is valid }

if hSession = nil then

begin

  ShowMessage('Internet session initialization failed!');

  InternetCloseHandle(hService);

  Exit;

end;

 

HttpQueryInfo(hService, HTTP_QUERY_STATUS_CODE or HTTP_QUERY_FLAG_NUMBER,

  @dwByteToRead,

  dwSizeOfRq, Reserved);

 

{ if dwByteToRead >= HTTP_STATUS_AMBIGUOUS then

begin

InternetCloseHandle(hService);

ShowMessage('STATUS CODE : ' + IntToStr(filesize));

Exit;

end; }

 

AssignFile(localFile, TargetFileName);

{$I-}

Rewrite(localFile, 1);

{$I+}

if IOResult <> 0 then

begin

  ShowMessage('Cannot create local file');

  InternetCloseHandle(hService);

  Exit;

end;

BufferLength := BUFFERSIZE;

 

{

These three variables will store the size of the file,

the size of the HttpQueryInfo content, and the number of bytes read in

total,

}

 

// determine the length of a file in bytes.

 

dwByteToRead := 0;

dwSizeOfRq := 4; // BufferLength

Reserved := 0;

 

{

With this call, an attempt is made to get the file's size.

If the attempt fails, the dwByteToRead variable is set to 0,

and no percentage or total size is displayed when the file is

downloaded.

}

 

if not HttpQueryInfo(hService,

  HTTP_QUERY_CONTENT_LENGTH or HTTP_QUERY_FLAG_NUMBER,

  @dwByteToRead,

  dwSizeOfRq,

  Reserved) then dwByteToRead := 0;

FSize := 0;

BufferLength := BUFFERSIZE;

 

while (BufferLength > 0) do

begin

// Read data from the hService handle

  if not InternetReadFile(hService, @lpBuffer, BUFFERSIZE, BufferLength)

    then Break;

  if (BufferLength > 0) and (BufferLength <= BUFFERSIZE) then

    BlockWrite(localFile, lpBuffer, BufferLength);

 

  fsize := fsize + BufferLength;

// Application.ProcessMessages;

// Check the size of the remaining data. If it is zero, break.

  if BufferLength > 0 then Result := True;

end; {while}

 

CloseFile(localFile);

Result := True;

// Close the Internet handle that the application has opened.

InternetCloseHandle(hService);

end;

 

// Test it

 

procedure TForm1.Button1Click(Sender: TObject);

begin

  DownloadURL('http://XYZ.html', 'c:\test.html', PChar('Proxyname'), PChar('Proxy Bypass'));

end;