Having Trouble Getting Download Handler in Shiny to Work - r

Question

I am trying to build a shiny platform that can take in an input file, paste the output into a table on display, and then have a download button to download the results of the file back to your computer. I've tried numerous different ways, and it hasn't worked.
UI Code:
tabItem(tabName = "home",
h2("Cancer Publications Compiler"),
sidebarLayout(position = "left",
# File Upload
sidebarPanel(
radioButtons("data_t", "Select the Data Type Here",
c(Excel = ",", "Text = "\t")),
fileInput("data_f", "Upload Your Data Here")),
# Download Input
mainPanel(width = 8,align = "center",
div(style = "border:1px black solid;width:90%;font-size:10px;",tableOutput("out_chart")),
downloadButton("downloadData", "Download")))
),
Server:
fileext = reactive({
switch(input$data_t,
"Excel" = "csv", "Text" = "txt")
})
## Create Output for file selector ##
data_file <- reactive({
if(is.null(input$data_f)){return()}
else{
file_spec <- input$data_f
aa <- read.table(file_spec$datapath, header = TRUE, sep = input$data_t)
return(aa)
}
})
# Connects the input and output to launch the data table
## Create Output for table from tool ##
output$out_chart <- renderTable({
if(is.null(input$data_f)){return()}
else {
data_file()
}
})
output$donwloadData <- downloadHandler(
filename = function(){
paste("data-", fileext(), sep = ".")
},
content = function(file){
sep <- switch(input$data_t, "Excel" = ",", "Text" = "\t")
write.table(data_file(), file, sep = sep,
row.names = FALSE)
})
Can anyone help me with a fix for this problem so that the download handler will work how I want it to?
UPDATE: I have edited the code and have updated it on here. My problem now is that when I click download to download the outputted table, I am getting a .htm download of a very low rendered and weird looking version of my webpage.

Answer 1

You had some typos, and other issues. Try this
ui <- fluidPage(
tabItem(tabName = "home",
h2("Cancer Publications Compiler"),
sidebarLayout(position = "left",
# File Upload
sidebarPanel(
radioButtons("data_t", "Select the Data Type Here", c("Excel" = "csv", "Text" = "txt")) ,
fileInput("data_f", "Upload Your Data Here")
),
# Download Input
mainPanel(width = 8,align = "center",
div(style = "border:1px black solid;width:90%;font-size:10px;",tableOutput("out_chart")),
downloadButton("downloadData", "Download"))
)
)
)
server<- function (input, output, session) {
sep <- reactive({
req(input$data_t)
switch(input$data_t,
"csv" = ",", "txt" = "\t")
})
## Create Output for file selector ##
data_file <- reactive({
if(is.null(input$data_f)){return()}
else{
file_spec <- input$data_f
aa <- read.table(file_spec$datapath, header = TRUE, sep = sep())
return(aa)
}
})
# Connects the input and output to launch the data table
## Create Output for table from tool ##
output$out_chart <- renderTable({
print(input$data_t)
if(is.null(input$data_f)){return()}
else {
data_file()
}
})
output$downloadData <- downloadHandler(
filename = function(){
paste("data-", input$data_t, sep = ".")
},
content = function(file){
write.table(data_file(), file, sep = sep(), row.names = FALSE)
}
)
}
shinyApp(ui = ui, server = server)