I wonder if I can create a shiny app (something similar to excel spreadsheet) that I can authorize multiple users to log in (like using shinyapp.io) to edit/input simultaneously? The reason I want to use shiny rather than only excel spreadsheet is because I might add more features (such as statistical estimation, visualization, etc.) based on the data uploaded by multiple users using R.
Look forward to any suggestions/advice Thanks!
I found the following pattern working for me: Create a reactiveVal object outside the server and then access/update it in the app. Here, I wrote a wrapper for getting and appending massages to a chat. (code below)
However, I think this pattern only works if all users share the same R session and the data will be lost if the current R session ends (all users disconnect). Therefore, you might want to look into this article to get a hang of persistent storage methods. Also, look at the documentation of reactiveFileReader for a more conveniet way of accessing files.
library(shiny)
ui <- fluidPage(
sidebarLayout(
sidebarPanel(
textInput("msg", "Message", placeholder = "type a message in the chat"),
actionButton("submit", "submit")
),
mainPanel(
verbatimTextOutput("text")
)
)
)
createChat <- function(initVal) {
chat_text <- reactiveVal(initVal)
list(
get = function(){ chat_text() },
append = function(val) {
chat_text(paste0(isolate(chat_text()), "\n", val))
}
)
}
myChat <- createChat("## This is a chat ##\n")
server <- function(input, output) {
observeEvent(input$submit, {
myChat$append(input$msg)
})
output$text <- renderText(myChat$get())
}
shinyApp(ui = ui, server = server)
