R shiny to download files by selecting the checkbox - r

Question

There is this piece of code in which basically from UI page in which I want to select the file names for through checkbox and after selecting those, then clicking on download button selected files will get downloaded. I am stuck at UI i am unable to get those checkboxes on UI.
its showing the output as
[object] [Object]
the code is below -
ui <- fluidPage(
verbatimTextOutput("links_list")
)
server <- function(input, output, session) {
get.files <- reactive({
list.files("/Users/harshmeetsingh/Downloads/")
})
obsList <- list()
output$links_list <- renderUI({
lapply(as.list(1:length(get.files())), function(i)
{
btName <- get.files()[i]
print(btName)
# creates an observer only if it doesn't already exists
if (is.null(obsList[[btName]])) {
obsList[[btName]] <<- btName
}
fluidRow(checkboxInput(btName, get.files()[i]) )
})
})
output$downloadzip<-downloadHandler(
filename = function(){
paste0("Extract.zip")
},
content = function(file){
files <- NULL;
for (i in 1:length(obsList)){
if(input[[obsList[[i]]]])
files <- c(paste("output_file/",obsList[[i]],sep=""),files)
}
#create the zip file
zip(file,files)
},
contentType = "application/zip"
)
tempText <- eventReactive({input$TempTest},{
l<-c()
for (i in 1:length(obsList)){
if(input[[obsList[[i]]]])
l<-c(l,paste("output_file/",obsList[[i]],sep=""))
}
return(paste(l) )
},
ignoreInit = TRUE)
output$Temp <- renderPrint({ tempText()})
}
shinyApp(ui=ui,server=server)

Answer 1

We can use checkboxGroupInput() to select all the files. input$files_chosen will be a list with all the filenames selected.
Notice that this app is showing the files in the home directory. This can be modified changing the path supplied in setwd().
app:
library(shiny)
#to use relative paths inside zip function
setwd('~')
ui <- fluidPage(
downloadButton('downloadzip'),
uiOutput("links_list")
)
server <- function(input, output, session) {
get.files <- reactive({
list.files()
})
output$links_list <- renderUI({checkboxGroupInput(inputId = 'files_chosen',
label = 'Choose Files',
choices = get.files())
})
output$downloadzip <- downloadHandler(
filename = function(){
"Extract.zip"
},
content = function(file){
#create the paths to look for the files.
files <- input$files_chosen
#create the zip file
zip(zipfile = file, files = files)
},
contentType = "application/zip"
)
}
shinyApp(ui=ui,server=server)