Use the primary functions and procedures

You can only use the primay function DwinsHs_ReadRemoteURL to download the files or access the web server. The DwinsHs_GetRemoteSize function, DwinsHs_Setproxy and DwinsHs_ProcessMessages procedures can be used too. Optional progress indicator can be created by yourself.

1. Prepartory step:

   Copy the file dwinshs.iss to your installation script folder or a sub-folder in it.

2. Include the "dwinshs.iss" file:

   Please include the dwinshs.iss file at the beginning of the "[Code]" section. If the file is placed in the sub-folder of your installation scripts folder, please add path of the sub-folder in order to locate it. For exampe:

   [Code]
   #include "dwinshs.iss"
   ......

   You can specify the size of read buffer by defining the macro DwinsHs_Data_Buffer_Length before including the dwinshs.iss file. By default, it's 4096 bytes. For example:

   [Code]
   #define DwinsHs_Data_Buffer_Length 8192
   #include "dwinshs.iss"
   ......

3. Create a download progress indicator:

   Optional, you can create a download progress indicator in your Setup wizard page, and define the OnRead callback function for the DwinsHs_ReadRemoteURL function to update the indicator:

   var
     DownloadIndicator: TNewProgressBar;
   ...
   procedure InitializeWizard();
   begin
     ...
     // Create the download progress indicator
     DownloadIndicator := TNewProgressBar.Create(PageFromId(wpReady));
     DownloadIndicator.Left := ScaleX(20);
     DownloadIndicator.Top := ScaleY(200);
     DownloadIndicator.Width := ScaleX(200);
     DownloadIndicator.Height:= ScaleY(20);
     DownloadIndicator.Min := 0;
     DownloadIndicator.Parent := PageFromId(wpReady).Surface;
     ...
   end;
   ...
   // The callback function for DwinsHs_ReadRemoteURL
   function OnRead(URL, Agent: AnsiString; Method: TReadMethod; Index, TotalSize, ReadSize,
     CurrentSize: {#BIG_INT}; var ReadStr: AnsiString): Boolean;
   begin
     if Index = 0 then DownloadIndicator.Max := 100;
     DownloadIndicator.Position := (ReadSize * 100) div TotalSize; // Update the download progress indicator
     Result := True; // Continue to download
   end;

4. Specify the proxy settings:

   Optional, you can use the DwinsHs_Setproxy procedure to specify the proxy or direct configuration for downloading. The user Inetnet configuration specified in the control panel will be used if you don't specify them. For example:

   [Code]
   ...
   procedure InitializeWizard();
   begin
     ...
     // Specify the proxy or direct configuration
     DwinsHs_SetProxy(pmProxy, ppHttp, 'www.proxy_example.com', 8080, 'username', 'password');
     ...
   end;
   ...

5. Start to download or access to your web script:

   Please call the DwinsHs_ReadRemoteURL function to start the downloading operation or visit your web server script. If the OnRead callback function is used, specify it in the OnRead parameter, specify nil in it othwise:

   procedure CurPageChanged(CurPageID: Integer);
   var
     Response: AnsiString;
     Size: {#BIG_INT};
   begin
     ...
     if (CurPageId = wpReady) then
     begin
       // Initialize download progress indicator
       DownloadIndicator.Position := 0;
       // Disbale to continue before download completes
       WizardForm.NextButton.Enabled := False;
       // Enable to continue after download successfully, save the remote file automatically
       WizardForm.NextButton.Enabled := DwinsHs_ReadRemoteURL('http://www.xxx.com/yyy/abc.zip',
         '', rmGet, Response, Size, ExpandConstant('{tmp}') + '\abc.zip', @OnRead) = READ_OK;
     end;
     ...
   end;

   Or

   procedure CurPageChanged(CurPageID: Integer);
   var
     Response: AnsiString;
     Size: {#BIG_INT};
   begin
     ...
     if (CurPageId = wpReady) then
     begin
       // Initialize download progress indicator
       DownloadIndicator.Position := 0;
       // Disbale to continue before download completes
       WizardForm.NextButton.Enabled := False;
       // Enable to continue after download successfully
       WizardForm.NextButton.Enabled := DwinsHs_ReadRemoteURL('http://www.xxx.com/yyy/...',
         '', rmGet, Response, Size, '', @OnRead) = READ_OK;
       // Save the remote file if download successfully
       if WizardForm.NextButton.Enabled then
         SaveStringToFile(ExpandConstant('{tmp}') + '\...', Response, False);
       // Or verify the remote response
       if Response = 'registered' then
       begin
         ...
       end;
     end;
     ...
   end;

6. Catch event when user click on "Back" button:

   Optional, you can catch the event when user click on "Back" button, then stop downloading and move to previous wizard page. For example:

   var
     BackClicked: Boolean;
   ...
   // The callback function for DwinsHs_ReadRemoteURL
   function OnRead(URL, Agent: AnsiString; Method: TReadMethod; Index, TotalSize, ReadSize,
     CurrentSize: {#BIG_INT}; var ReadStr: AnsiString): Boolean;
   begin
     ...
     Result := not BackClicked; // Determine whether download was cancelled
     ...
   end;
   ...
   procedure CurPageChanged(CurPageID: Integer);
   var
     Response: AnsiString;
     Size: {#BIG_INT};
   begin
     if (CurPageId = wpReady) then
     begin
       // Allow to download
       BackClicked := False;
       // Disbale to continue before download completes
       WizardForm.NextButton.Enabled := False;
       // Enable to continue after download successfully
       WizardForm.NextButton.Enabled := DwinsHs_ReadRemoteURL('http://www.xxx.com/yyy/abc.zip',
         '', rmGet, Response, Size, ExpandConstant('{tmp}') + '\abc.zip', @OnRead) = READ_OK;
       ...
     end;
   end;
   ...
   function BackButtonClick(CurPageID: Integer): Boolean;
   begin
     // Stop to download
     BackClicked := True;
     Result := True;
   end;

   Or

   ...
   procedure CurPageChanged(CurPageID: Integer);
   var
     Response: AnsiString;
     Size: {#BIG_INT};
   begin
     if (CurPageId = wpReady) then
     begin
       // Allow to download
       DwinsHs_CancelDownload := cdNone;
       // Disbale to continue before download completes
       WizardForm.NextButton.Enabled := False;
       // Enable to continue after download successfully
       WizardForm.NextButton.Enabled := DwinsHs_ReadRemoteURL('http://www.xxx.com/yyy/abc.zip',
         '', rmGet, Response, Size, ExpandConstant('{tmp}') + '\abc.zip', nil) = READ_OK;
     end;
   end;
   ...
   function BackButtonClick(CurPageID: Integer): Boolean;
   begin
     // Stop to download
     DwinsHs_CancelDownload := cdBack;
     Result := True;
   end;

7. Prevent re-download of already downloaded file:

   If you click on the "Back" button to move the Setup wizard to previous wizard page after the remote file was downloaded successfully, then click on the "Next" button to move it back to the wizard page which the download will be started, the download operation will be executed once again. Please use the following code to prevent the behavior:

   var
     Downloaded: Boolean;
   ...
   procedure InitializeWizard();
   begin
     ...
     Downloaded := False;
     ...
   end;
   ...
   procedure CurPageChanged(CurPageID: Integer);
   var
     Response: AnsiString;
     Size: {#BIG_INT};
   begin
     if (CurPageId = wpReady) and (not Downloaded) then
     begin
       // Disbale to continue before download completes
       WizardForm.NextButton.Enabled := False;
       // Enable to continue after download successfully
       WizardForm.NextButton.Enabled := DwinsHs_ReadRemoteURL('http://www.xxx.com/yyy/abc.zip',
         '', rmGet, Response, Size, ExpandConstant('{tmp}') + '\abc.zip', nil) = READ_OK;
       Downloaded := WizardForm.NextButton.Enabled;
     end;
   end;

8. Congratulations!

   Compile your setup script and watch the download wizard page at work! If it doesn't work, please add a link to our website in your web page, then contact us and send your link page to us.

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