How to download data of bar chart from shiny dashboard? - r

Question

I am getting error file, while downloading data of bar chart rendered in shiny UI.
There is a download button just below the chart. While click on the 'Download data' button, data should be downloaded into csv format.
Code:
library(shiny)
library(ECharts2Shiny)
dat <- data.frame(c(1, 2, 3), c(2, 4, 6))
names(dat) <- c("Type-A", "Type-B")
row.names(dat) <- c("Time-1", "Time-2", "Time-3")
ui <- fluidpage( loadEChartsLibrary(),
tags$div(id="test", style="width:50%;height:400px;"),
deliverChart(div_id = "test"), downloadButton("test", "Download Data"))
server <- function(input, output) {
renderBarChart(div_id = "test", grid_left = '1%', direction = "vertical",
data = dat)
}
shinyApp(ui = ui, server = server)
I want to download the data of that bar chart in ".csv" format.
Can anyone help me out to correct the code?
Thank you.

Answer 1

I think you cannot use the same "renderTable" server output for all of your UI inputs. AKA, you need to make a separate input and output for your image in the form of a downloadable file. Here is an example of what I did to download a .csv file:
output$downloadData <- reactive({
output$downloadData <- downloadHandler(
filename = function() {
paste("ProcessedData-", Sys.Date(), ".csv", sep="")
},
content = function(file) {
write.csv(DataTable, file)
}
)
Therefore in your download button you would replace "test" with "downloadData" so that it connects to a new server output. Notice that I am creating the file here with write.csv, but not actually writing to any disk just generating the file and passing it into the downloadData output for users to trigger and then save to their own disk when they hit the downloadData input button. You are trying to save a picture so I suggest trying something along the lines of generating an image file inside of the content call. Recall that you can save images as objects:
#up in the UI somewhere
ui <- fluidpage(loadEChartsLibrary(),
tags$div(id="test", style="width:50%;height:400px;"),
deliverChart(div_id = "test"), downloadButton("downloadData", "Download Data"))
server <- function(input, output) {
output$test <- renderBarChart(div_id = "test", grid_left = '1%', direction = "vertical",
data = dat)
output$downloadData <- reactive({
output$downloadData <- downloadHandler(
filename = function() {
paste("Image.png", sep="") #just the file name you want to have as default
},
content = function(file) {
write.csv(DataTable, file)
)
}
I don't have your actual code so this may not work as a plug and play solution, but I believe this is the right direction.