download - Archive button in R shiny, activate only once -

i have following code runs perfectly!. however, want restrict archiving of data pushing "export all" button once per day. tried use if statements , not successful. fact code running on shiny-server pro , different browser sessions created. suggestions?.

 library(shiny) library(shinybs) library(xlconnect) library(lubridate)     cdata <- ' candidate,party,province,age,gender "l, l",ndp,quebec,22,female "m, m",bloc quebecois,quebec,43,female "m, s",bloc quebecois,quebec,34,female "s, d",ndp,quebec,,female "s, l",ndp,quebec,72,female "f, h",liberal,british columbia,71,female "t, n",ndp,quebec,70,female "s, j",liberal,ontario,68,female "r, francine",ndp,quebec,67,female "d, patricia",conservative,ontario,66,female "s, joy",conservative,manitoba,65,female "w, alice",conservative,british columbia,64,female "o, tilly",conservative,new brunswick,63,female "a, diane",conservative,alberta,63,female "d, linda",ndp,alberta,63,female "b, carolyn",liberal,ontario,62,female "n, peggy",ndp,ontario,61,female "m, irene",ndp,ontario,61,female "s, jinny",ndp,british columbia,60,female "f, judy",liberal,newfoundland,60,female "c, jean",ndp,british columbia,60,female "d, libby",ndp,british columbia,59,female "y, lynne",conservative,saskatchewan,59,female "d, anne",ndp,quebec,58,female "m, elizabeth",green,british columbia,58,female "m, joyce",liberal,british columbia,58,female "f, kerry",conservative,british columbia,57,female "b, lois",conservative,ontario,57,female "b, marj",ndp,quebec,57,female "c, joan",conservative,alberta,56,female "c, olivia",ndp,ontario,55,female "m, cathy",conservative,british columbia,55,female "f, diane",conservative,ontario,55,female "l, helene",ndp,quebec,54,female "g, nina",conservative,british columbia,54,female "h, carol",ndp,ontario,54,female "p, gail",conservative,prince edward island,53,female "t, susan",conservative,ontario,53,female "y, wai",conservative,british columbia,52,female' con <- textconnection(cdata) cel <- read.csv(con, header=true, stringsasfactors = false) cel$votes <- round(runif(nrow(cel), min=500, max=15000)) thedatadf <- cel   ui <- fluidpage(     titlepanel("archive data post on stack overflow"),    #  button , alert, use alert control onetime archive    sidebarlayout(       sidebarpanel(         bsalert("alert"),         downloadbutton("archivebtn", "archive all")       ),        # show table       mainpanel(         dt::datatableoutput('thedata')       )    ) )   server <- function(input, output,session) {   output$thedata <- dt::renderdatatable(dt::datatable(thedatadf,options = list(pagelength = 25,scrollx = true),                                                               rownames = false,class = 'cell-border stripe')                                                             %>% formatstyle(c(2:ncol(thedatadf)),                                                               color = styleinterval(55, c('red', 'black'))))    output$archivebtn <- downloadhandler(       filename = function() {        paste("archivedata-", ymd(sys.date()), ".xlsx", sep="")     },     content = function(file) {             fname <- paste(file,"xlsx",sep=".")             wb <- loadworkbook(fname, create = true)             #creating sheets within excel workbook             createsheet(wb, name = "the arc data")             #writing sheet within excel workbook :              writeworksheet(wb, thedatadf, sheet = "the arc data", startrow = 1, startcol = 1)             saveworkbook(wb)             file.rename(fname,file)       # create message complition of archive       createalert(session, "alert", "examplealert", style="success",title = "archive complete!",                         content = "data archived", append = false)      }    )    }  # run application  shinyapp(ui = ui, server = server)