Downloading files in Custom NSIS Page - nsis

Question

I want to create an installer that downloads a file without freezing the UI using the inetc plugin. My question is that possible without using the ExecDos::Exec with the /ASYNC flag and then ExecDos::Wait.
In addition , i do not want installation page in my installer.
Here is my code:
!macro DOWNLOAD_PAGE
Function myTimer
${If} $0 == "OK"
${NSD_KillTimer} myTimer
SendMessage $hPBar ${PBM_SETRANGE32} 0 100
SendMessage $hPBar ${PBM_SETPOS} 100 0
Return
${EndIf}
SendMessage $hPBar ${PBM_SETRANGE32} 0 100
SendMessage $hPBar ${PBM_SETPOS} 50 0
FunctionEnd
function Page1
nsDialogs::Create 1018
Pop $Dialog
${NSD_CreateLabel} 0 0 100% 50% "Starting download..."
Pop $hInfo
${NSD_CreateProgressBar} 0 55% 100% 10u ""
Pop $hPBar
${NSD_CreateTimer} myTimer 1000
inetc::get /silent "$URL\skype.exe" "$EXEDIR\skype.exe" /end
Pop $0
nsDialogs::Show
functionEnd
function Page2
functionEnd
Page Custom Page1 Page2
!macroend
!insertmacro MUI_PAGE_WELCOME
!insertmacro MUI_PAGE_LICENSE "${NSISDIR}\Docs\Modern UI\License.txt"
!insertmacro DOWNLOAD_PAGE
!insertmacro MUI_PAGE_FINISH
Or the only option i have is using the ExecDos::Exec with the /ASYNC flag?
Perhaps, a solution it is to create another nsis installer that does the download?

Answer 1

Performing a long operation between nsDialogs::Create and nsDialogs::Show will hang the UI.
The easy solution is to download in a Section because those are executed in a different thread. You are supposed to perform most of your tasks in a Section.
If you insist on downloading something on a custom page then you can use the InetBgDL plug-in:
!include nsDialogs.nsh
!include LogicLib.nsh
Page Custom Page1
Var hInfo
Function Page1
nsDialogs::Create 1018
Pop $0
${NSD_CreateLabel} 0 0 100% 50% "Starting download..."
Pop $hInfo
InitPluginsDir
INetBgDl::Get "https://example.com/file.exe" "$PluginsDir\file.exe" /end
${NSD_CreateTimer} myTimer 1000
nsDialogs::Show
${NSD_KillTimer} myTimer
FunctionEnd
Function myTimer
InetBgDL::GetStats
${NSD_SetText} $hInfo "Status=$0$\nCompleted files=$1$\nDownloaded $3 of $4 bytes"
${If} $0 = 0 ; HTTP status code or 0 if completed without errors
${NSD_KillTimer} myTimer
MessageBox mb_ok Done
${EndIf}
FunctionEnd