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- Appendix C: Useful Scripts

- Get Internet Explorer version
- Is .NET Framework installed?
- Is Macromedia Flash Player installed?
- Connect to the Internet
- Get Installer Filename
- Prevent Multiple Instances
- More

# Appendix C: Useful Scripts

## C.1 Get Internet Explorer version

     ; GetIEVersion
     ;
     ; Based on Yazno's function, http://yazno.tripod.com/powerpimpit/
     ; Returns on top of stack
     ; 1-6 (Installed IE Version)
     ; or
     ; '' (IE is not installed)
     ;
     ; Usage:
     ;   Call GetIEVersion
     ;   Pop $R0
     ;   ; at this point $R0 is "5" or whatnot

     Function GetIEVersion
     Push $R0
       ClearErrors
       ReadRegStr $R0 HKLM "Software\Microsoft\Internet Explorer" "Version"
       IfErrors lbl_123 lbl_456

       lbl_456: ; ie 4+
         Strcpy $R0 $R0 1
       Goto lbl_done

       lbl_123: ; older ie version
         ClearErrors
         ReadRegStr $R0 HKLM "Software\Microsoft\Internet Explorer" "IVer"
         IfErrors lbl_error

           StrCpy $R0 $R0 3
           StrCmp $R0 '100' lbl_ie1
           StrCmp $R0 '101' lbl_ie2
           StrCmp $R0 '102' lbl_ie2

           StrCpy $R0 '3' ; default to ie3 if not 100, 101, or 102.
           Goto lbl_done
             lbl_ie1:
               StrCpy $R0 '1'
             Goto lbl_done
             lbl_ie2:
               StrCpy $R0 '2'
             Goto lbl_done
         lbl_error:
           StrCpy $R0 ''
       lbl_done:
       Exch $R0
     FunctionEnd

## C.2 Is .NET Framework installed?

     ; IsDotNETInstalled
     ;
     ; Based on GetDotNETVersion
     ;   http://nsis.sourceforge.net/Get_.NET_Version
     ;
     ; Usage:
     ;   Call IsDotNETInstalled
     ;   Pop $0
     ;   StrCmp $0 1 found.NETFramework no.NETFramework

     Function IsDotNETInstalled
       Push $0
       Push $1

       StrCpy $0 1
       System::Call "mscoree::GetCORVersion(w, i ${NSIS_MAX_STRLEN}, *i) i .r1"
       StrCmp $1 0 +2
         StrCpy $0 0

       Pop $1
       Exch $0
     FunctionEnd

## C.3 Is Macromedia Flash Player installed?

     ; IsFlashInstalled
     ;
     ; By Yazno, http://yazno.tripod.com/powerpimpit/
     ; Returns on top of stack
     ; 0 (Flash is not installed)
     ; or
     ; 1 (Flash is installed)
     ;
     ; Usage:
     ;   Call IsFlashInstalled
     ;   Pop $R0
     ;   ; $R0 at this point is "1" or "0"

     Function IsFlashInstalled
      Push $R0
      ClearErrors
      ReadRegStr $R0 HKCR "CLSID\{D27CDB6E-AE6D-11cf-96B8-444553540000}" ""
      IfErrors lbl_na
        StrCpy $R0 1
      Goto lbl_end
      lbl_na:
        StrCpy $R0 0
      lbl_end:
      Exch $R0
     FunctionEnd

## C.4 Connect to the Internet

     ; ConnectInternet (uses Dialer plug-in)
     ; Written by Joost Verburg
     ;
     ; This function attempts to make a connection to the internet if there is no
     ; connection available. If you are not sure that a system using the installer
     ; has an active internet connection, call this function before downloading
     ; files with NSISdl.
     ;
     ; The function requires Internet Explorer 3, but asks to connect manually if
     ; IE3 is not installed.

     Function ConnectInternet

       Push $R0

         ClearErrors
         Dialer::AttemptConnect
         IfErrors noie3

         Pop $R0
         StrCmp $R0 "online" connected
           MessageBox MB_OK|MB_ICONSTOP "Cannot connect to the internet."
           Quit ;This will quit the installer. You might want to add your own error handling.

         noie3:

         ; IE3 not installed
         MessageBox MB_OK|MB_ICONINFORMATION "Please connect to the internet now."

         connected:

       Pop $R0

     FunctionEnd

## C.5 Get Installer Filename

     System::Call 'kernel32::GetModuleFileNameA(i 0, t .R0, i 1024) i r1'
     ;$R0 will contain the installer filename

## C.6 Prevent Multiple Instances

Put the following code in your .onInit function:

     System::Call 'kernel32::CreateMutexA(i 0, i 0, t "myMutex") i .r1 ?e'
     Pop $R0

     StrCmp $R0 0 +3
       MessageBox MB_OK|MB_ICONEXCLAMATION "The installer is already running."
       Abort

'myMutex' should be replaced by a unique value.

## C.7 More

You can find more useful scripts at the NSIS Wiki, the NSIS forum and NSIS development page.

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