How to continue download on error in Inno Setup? - download

Question

My Inno Setup script downloads some resources using built-in functionalities.
It creates Download Wizard Page:
DownloadPage := CreateDownloadPage(SetupMessage(msgWizardPreparing), SetupMessage(msgPreparingDesc), #OnDownloadProgress);
It adds several items that should be downloaded:
if WizardIsTaskSelected('taskA') then
begin
DownloadPage.Add('https://randomresource/taskA.zip', 'taskA.zip', '');
end;
if WizardIsTaskSelected('taskB') then
begin
DownloadPage.Add('https://randomresource/taskB.zip', 'taskB.zip', '');
end;
and last step is to show the Wizard Page and start downloading:
try
try
DownloadPage.Download;
Result := True;
except
SuppressibleMsgBox(AddPeriod(GetExceptionMessage), mbCriticalError, MB_OK, IDOK);
Result := False;
end;
finally
DownloadPage.Hide;
end;
All of the above is basically from examples provided by Inno Setup. There is one issue: if any of the downloads fails (throws exception or anything) it interrupts the whole download process and other items will not be downloaded. I would want it to continue downloading the rest of the files. I went through the Inno Setup documentation and didn't find any flag which would enable that. Is there a solution for that? Thanks in advance.

Answer 1

A simple solution is to download each file separately.
The below code will allow user to select what to do on each file's download error:
Retry the download
Skip the download
Abort the installation.
var
DownloadPage: TDownloadWizardPage;
function RobustDownload(
Url, BaseName, RequiredSHA256OfFile: String): Boolean;
var
Retry: Boolean;
Answer: Integer;
begin
repeat
try
DownloadPage.Clear;
DownloadPage.Add(Url, BaseName, RequiredSHA256OfFile);
DownloadPage.Download;
Retry := False;
Result := True;
except
if DownloadPage.AbortedByUser then
begin
Log('Aborted by user.')
Result := False;
Retry := False;
end
else
begin
// Make sure the page displays the URL that fails to download
DownloadPage.Msg2Label.Caption := Url;
Answer :=
SuppressibleMsgBox(
AddPeriod(GetExceptionMessage),
mbCriticalError, MB_ABORTRETRYIGNORE, IDABORT);
Retry := (Answer = IDRETRY);
Result := (Answer <> IDABORT);
end;
end;
until not Retry;
end;
function NextButtonClick(CurPageID: Integer): Boolean;
begin
if CurPageID = wpReady then
begin
try
DownloadPage :=
CreateDownloadPage(
SetupMessage(msgWizardPreparing), SetupMessage(msgPreparingDesc),
#OnDownloadProgress);
DownloadPage.Show;
Result :=
RobustDownload('https://example.com/setup1.exe', 'setup1.exe', '') and
RobustDownload('https://example.com/setup2.exe', 'setup2.exe', '') and
RobustDownload('https://example.com/setup3.exe', 'setup3.exe', '');
finally
DownloadPage.Hide;
end;
end
else Result := True;
end;