get download dir from browser - r

Question

I have this shinyapp where I want to download a file via a button. So I can do this by calling a downloadHandler like:
output$downloadData <- downloadHandler(
filename = "plot1.png",
content = function(file) {
plotPNG(func = function(){
plot(some.Data)
},
filename = file,
width = 3000,
height = 2000,
res = 300
)
}
)
Here the file is downloaded into the default download directory. What now if I want to download into another dir? In other words: Is there a way to determine the default download dir and to manipulate that?

Answer 1

The downloadHandler() should be able to handle this problem. The filename argument is, "A string of the filename, including extension, that the user's web browser should default to when downloading the file.." Therefore we can manipulate the default directory by defining the path in the filename.
server<-function(input,output){
output$downloadData <- downloadHandler(
# Sets filename the browser should default too
filename = function() {
paste(PATH_TO_DIR,"plot1",".png/xls/etc.",sep="")
}, # Closes Filename Function
# Creates Download file
content = function(file) {
plotPNG(func = function(){
plot(some.Data)
},
file = filename(),
width = 3000,
height = 2000,
res = 300
)
}
ui<-
downloadButton("downloadData", 'Download File')
)
This can be used in co-op with a download button, and the name of the file and path can be dynamically generated when the button is pushed by defining the path with variables. I think this may open a file browser, and I do not know if this is avoidable.
Also note that the file name, path, and content type will not appear to work in a local session (RStudio), they only work once deployed in the browser.