Windows shell integration command is not working, possible syntax error

Question

I want to create a shell extension to run shiny apps in a local process on a Windows 7 Professional 64 bit. I need a command like R -e "shiny::runApp('~/shinyapp')" as defined in the shiny tutorial webpage. I usually create a directory called shiny in every data folder I have. So the supposed command should be always sth like: R -e "shiny::runApp('%1'/shiny) for me."

So I created a key named "Shine!" and a subkey named "command" in HKEY_CLASSES_ROOT\Directory\shell with a value C:\Program Files\R\R-2.15.1\bin\x64\R.exe -e "shiny::runApp('%1/shiny')" The dir structure in regedit is as below:

Now, whenever I right-click the data folder (containing the shiny folder) and click "Shine!", an R console (a cmd console) opens and closes, but the app is not working (the apps are thoroughly checked and working, I also checked the regedit command in cmd).

To be honest, I don't know C, windows shell or any MSDN stuff. I checked several questions, links and documents, but preferred to come up with a simple solution with no error checking (missing folder, etc).

I think I'm missing a syntax error here, so I tried several versions such as only '%1' and right-clicking the shiny folder, also versions like '/'%1/'/shiny' etc. What is wrong and more importantly, how can I debug a right-click with the %1 thing, while the cmd window is closing as quick as hell?

Answer 1

%1 is expanded by the Windows shell to the name of the folder you right-clicked.

So, if the command you want to execute is:

"C:\Program Files\R\R-2.15.1\bin\x64\R.exe" -e "shiny::runApp('%1/shiny')"

you can replace it with a call to cmd.exe that remains open after execution and preserves the double-quotes (by doubling them inside an extra pair of double quotes), so you can check the r.exe's command output:

cmd /k " ""C:\Program Files\R\R-2.15.1\bin\x64\R.exe"" -e ""shiny::runApp('%1/shiny')"" "

I have no experience with R, but my guess is that the runApp command deals badly with the backslashes in the Windows path, or that it contains a space, and I also guess that "~" works with the current directory, as Windows doesn't have a real $HOME directory.

The solution for that is to chain a CD command and the R.exe call via cmd.exe:

cmd /c " cd /d ""%~1"" & ""C:\Program Files\R\R-2.15.1\bin\x64\R.exe"" -e ""shiny::runApp('~/shiny')"" "

(cmd /c closes the new window, cmd /k keeps it open after exectution, so the last example closes the window after launching R.exe).

Answer 2

Use ProcessMonitor to determine exact arguments and working directory of R started. When you get these values - you can setup your debugger with same settings.