downloadHandler not working with observeEvent - r

Question

I am trying to download a file using downloadHandler with observeEvent shiny but I am not able to download the file,
library(shiny)
load(url("http://s3.amazonaws.com/assets.datacamp.com/production/course_4850/datasets/movies.Rdata"))
ui <- fluidPage(
sidebarLayout(
# Input
sidebarPanel(
# Numeric input for number of rows to show
numericInput(inputId = "n_rows",
label = "How many rows do you want to see?",
value = 10),
# Action button to show
actionButton(inputId = "button",
label = "Show")
),
# Output:
mainPanel(
tableOutput(outputId = "datatable")
)
)
)
server <- function(input, output, session) {
# creating a reactive expression
df <- eventReactive(input$button, {
movies %>% head(input$n_rows)
})
# download a csv everytime when user click on show button
observeEvent(input$button, {
output$button <- downloadHandler(
filename = function() {
paste("data-", Sys.Date(), ".csv", sep="")
},
content = function(file) {
write.csv(df(), file)
}
)
cat("done downloading file \n")
})
# displays the data on the web in tabular format, data comes from reactive event
output$datatable <- renderTable({
df()
})
}
# Create a Shiny app object
shinyApp(ui = ui, server = server)
I was able to execute above code without any errors, but csv file is not downloading, i want to display the data table and download the displayed data on same button click event , how can i achieve this, Am I missing something, any help would be appreciated

Answer 1

Try this:
library(shiny)
library(dplyr)
load(url("http://s3.amazonaws.com/assets.datacamp.com/production/course_4850/datasets/movies.Rdata"))
ui <- fluidPage(
sidebarLayout(
# Input
sidebarPanel(
# Numeric input for number of rows to show
numericInput(inputId = "n_rows",
label = "How many rows do you want to see?",
value = 10),
# Action button to show
downloadButton('downloadData', 'Download data')
),
# Output:
mainPanel(
tableOutput(outputId = "datatable")
)
)
)
server <- function(input, output, session) {
# Reactive value for selected dataset ----
df <- reactive({
movies %>% head(input$n_rows)
})
output$datatable <- renderTable({
df()
})
output$downloadData <- downloadHandler(
filename = function() {
paste("dataset-", ".csv", sep = "")
},
content = function(file) {
write.csv(df(), file, row.names = FALSE)
})
}
# Create a Shiny app object
shinyApp(ui = ui, server = server)