R/spsServerCollections.R

In systemPipeR/systemPipeShiny: systemPipeShiny: An Interactive Framework for Workflow Management and Visualization

################## A Collections of server utilities############################
# Can be used in other shiny projects, no need to use under SPS framework
## use on top of shiny

# spsDebounce <- function(value, millis=1500){
#     shiny::debounce(function(){value}, millis)
# }


waitInput <- function(expr, session = getDefaultReactiveDomain()) {
    observeEvent(once = TRUE, reactiveValuesToList(session$input), {
        # print("loaded")
        force(expr)
    }, ignoreInit = TRUE)
}



#' Load tabular files as tibbles to server
#' @description load a file to server end. It's designed to be used with a
#' input file source switch button.
#' It uses [vroom::vroom] to load the file. In SPS, this
#' function is usually combined as downstream of  [dynamicFileServer()]
#' function on on the server side to
#' read the file into R. This loading function only works for parsing
#' tabular data, use [vroom::vroom()] internally.
#'
#' If no user data is uploaded, it will return the example dataset that is prepared
#' by the developer. If the developer does not provide the dataset either,
#' it will return a 8-row empty tibble.
#' @param choice where this file comes from, one of 'upload' or example 'eg'?
#' @param data_init a tibble to return if `upload_path` or `eg_path` is not
#' provided. Return a 8x8 empty tibble if not provided
#' @param upload_path when `choice` is "upload", where to load the file, will
#' return `data_init` if this param is not provided
#' @param eg_path when `choice` is "eg", where to load the file, will
#' return `data_init` if this param is not provided
#' @param comment comment characters to parse the datafile,
#' see help file of [vroom::vroom]
#' @param delim delimiter characters to parse the data file,
#' see help file of [vroom::vroom]
#' @param col_types columns specifications, see help file of [vroom::vroom]
#' @param ... other params for vroom, see help file of [vroom::vroom]
#' @details This is function is wrapped by the [shinyCatch()] function, so it
#' will show loading information both on console and on UI. This function
#' prevents loading file errors to crash the Shiny app, so any kind of file upload will not
#' crash the app. To show message on UI, `spsDepend("toastr")` must be used in Shiny UI
#' function, see examples.
#' @return returns a tibble and `NULL` if parsing fails
#' @export
#' @importFrom shinyAce is.empty
#' @importFrom dplyr as_tibble
#' @importFrom vroom vroom
#' @examples
#' if(interactive()){
#'   # change value to 'local' to see the difference
#'   spsOption("mode", value = "server")
#'   ui <- fluidPage(
#'     spsDepend("toastr"),
#'     radioButtons(
#'       "data_source", "Choose your data file source:",
#'       c("Upload" = "upload", "Example" = "eg"),
#'       selected = "eg"
#'     ),
#'     dynamicFile("data_path", label = "input file"),
#'     dataTableOutput("df")
#'   )
#'
#'   server <- function(input, output, session) {
#'     tmp_file <- tempfile(fileext = ".csv")
#'     write.csv(iris, file = tmp_file)
#'     upload_path <- dynamicFileServer(input, session, "data_path")
#'     data_df <- reactive({
#'       loadDF(choice = input$data_source,
#'              upload_path = upload_path()$datapath,
#'              delim = ",", eg_path = tmp_file)
#'     })
#'     output$df <- renderDataTable(data_df())
#'   }
#'   shinyApp(ui, server)
#' }
loadDF <- function(choice, data_init=NULL, upload_path=NULL, eg_path=NULL,
                   comment = "#", delim = "\t",
                   col_types = vroom::cols(), ...){
    df <- shinyCatch({
        choice <- match.arg(choice, c("upload", "eg"))
        if(!inherits(data_init, "data.frame")){
            data_init <- data.frame(matrix("", 8,8), stringsAsFactors = FALSE) %>%
                dplyr::as_tibble()
        }
        else {data_init}
        if(!any(class(data_init) %in% c("tbl_df", "tbl", "data.frame"))) {
            stop("data_init need to be dataframe or tibble")
        }
        data_init <- dplyr::as_tibble(data_init)
        if (choice == "upload" & shinyAce::is.empty(upload_path))
            return(data_init)
        if (choice == "eg" & shinyAce::is.empty(eg_path))
            return(data_init)
        upload_path <- switch(choice,
                              "upload" = upload_path,
                              "eg" = eg_path,
        )
        df <- shinyCatch(vroom::vroom(
            upload_path,  delim = delim, comment = comment,
            col_types = col_types, ...
        ))
        if(is.null(df)){msg("Can't read file, return empty", "error")}
        if(!names(df) %>% validUTF8() %>% all()){
            msg("non UTF-8 coding detected, return empty", "error")}
        df
    })
    return(df)
}


#' Dynamically generate Shiny file selection component based on option
#' @description  Depending on the "mode" in SPS options, this function renders
#' a similar UI components but behaves differently on server.
#'
#' 1. `local` mode will not copy file, directly
#' use a path pointer.
#' 2. `server` mode upload file and store in temp. Expect
#' similar behavior as [shiny::fileInput].
#' @details To setup the option:
#'
#' The `local` mode uses functions from [shinyFiles] so it will reach file system
#' on the **server end**. Although the latest [shinyFiles] limits users to only
#' specified server end location (folder), there is still some **risk**. That's why
#' it is named "local", you are encouraged to run the app on your local computer.
#' The advantage of "local" is: for some very large files, it does not upload and
#' store in the temp. Rather, it directly parses the path on the local file system
#' and return the path immediately. It means the file has to exist on the file
#' system that serves the Shiny app. If you deploy the app on places like shinyapps.io,
#' users can only choose files from server.
#'
#' On the other hand, `server` mode uses original but enhanced shiny default upload component.
#' Users can upload files from local to server. So users do not have access to
#' server end file system if you deploy it online. However, the limitations are:
#'
#' 1. not ideal for large files, default limit is 30MB, and there is no break-point
#' upload.
#' 2. If you are running the app on your own computer, local end and server end is
#' the same, which is your computer. Using `server` mode will make a copy of your
#' existing file to temp location and this is a waste of time and storage.
#'
#' To set up options:
#'
#' 1. Under SPS framework, edit options in `global.R`.
#' 2. Outside SPS framework with your own Shiny app, use [spsUtil::spsOption()] function,
#' like `spsUtil::spsOption("mode", "server")` or `spsUtil::spsOption("mode", "local")` to
#' set up mode.
#'
#' If you are not sure what mode you are on, use `spsUtil::spsOption('mode')` to check.
#'
#' @param id element ID, Use `ns()` to wrap the id if you are using within a shiny
#' module, but DO NOT use `ns()` to wrap the id on server side
#' @param title element title
#' @param label upload button label
#' @param icon button icon, an object create by [shiny::icon]
#' @param style additional button style, only works for `local` mode
#' @param multiple bool, are multiple files allowed?
#' @param buttonType string, Bootstrap button markup (color).
#' Default in SPS is 'primary', other valid values include 'info', 'success', 'default',
#' 'warning', 'danger'.
#' @param mode string, one of "local" or "server"
#' @param placeholder string, text to display before the file is uploaded
#'
#' @importFrom shinyAce is.empty
#' @importFrom shinyFiles shinyFilesButton
#' @return a Shiny upload component on UI
#'
#' For the server end it returns a
#' **reactive** object which is a dataframe, need to extract the value inside reactive
#' expression, observe, or inside `isolate`. See examples
#' @export
#'
#' @examples
#' # Simple example
#' if(interactive()){
#'     spsOption("mode", value = "server") # Change the value to 'local' to see difference
#'     ui <- fluidPage(
#'         dynamicFile(id = "server_file", label = "server"),
#'         verbatimTextOutput("server_out")
#'     )
#'
#'     server <- function(input,output,session){
#'         file_server <- dynamicFileServer(input,session, id = "server_file")
#'         output$server_out <- renderPrint({
#'             file_server()  # remember to use `()` for reactive value
#'         })
#'     }
#'     shinyApp(ui = ui, server = server)
#' }
#' # To demostrate different modes in the same app, we can set options before the function.
#' # This is NOT recommended, you should stick with only one mode for the entire app.
#' if(interactive()){
#'     spsOption("mode", "local")
#'     local_ui <- dynamicFile("local_file", "local")
#'     spsOption("mode", "server")
#'     server_ui <- dynamicFile("server_file", "server")
#'     ui <- fluidPage(
#'         column(
#'             6,
#'             local_ui,
#'             verbatimTextOutput("local_out")
#'         ),
#'         column(
#'             6,
#'             server_ui,
#'             verbatimTextOutput("server_out")
#'         )
#'     )
#'
#'     server <- function(input,output,session){
#'         spsOption("mode", "local")
#'         file_local <- dynamicFileServer(input,session, id = "local_file")
#'         output$local_out <- renderPrint({
#'             file_local() # remember to use `()` for reactive value
#'         })
#'         spsOption("mode", "server")
#'         file_server <- dynamicFileServer(input,session, id = "server_file")
#'         output$server_out <- renderPrint({
#'             file_server()
#'         })
#'     }
#'     shinyApp(ui = ui, server = server)
#' }
dynamicFile <- function(
    id, title = "Select your file:",
    label = "Browse", icon = NULL,
    style = "", multiple = FALSE,
    buttonType = "primary",
    placeholder = "No file selected",
    mode = spsOption('mode')
    ){
    # assertions
    stopifnot(is.character(id) && length(id) == 1)
    stopifnot(is.character(title) && length(title) == 1)
    stopifnot(is.character(label) && length(label) == 1)
    stopifnot(is.character(style) && length(style) == 1)
    stopifnot(is.character(buttonType) && length(buttonType) == 1)
    stopifnot(is.character(placeholder) && length(placeholder) == 1)
    stopifnot(is.logical(multiple) && length(multiple) == 1)
    mode <- match.arg(mode, c("local", "server"))
    icon <- if(shinyAce::is.empty(icon)) icon("upload") else icon
    validateIcon(icon)

    if (mode == "local") {
        div(class = "form-group shiny-input-container sps-file",
            tags$label(class="control-label", `for`=id, title),
            div(class="input-group",
                tags$label(
                    class="input-group-btn input-group-prepend",
                    shinyFiles::shinyFilesButton(
                        id, label,
                        title = title, multiple = multiple,
                        buttonType = buttonType,
                        icon = icon,
                        style = style
                    )
                ),
                textInput(inputId = glue("{id}-text"), label = NULL, placeholder=placeholder, width = "100%") %>%
                    {
                      .[['children']][[2]][['attribs']][['readonly']] <- 'true'
                      .
                    }
            )
        )
    } else {
        tag <- fileInput(inputId = id, label = title, multiple = multiple, buttonLabel = list(icon, label), placeholder = placeholder)
        tag$children[[2]]$children[[1]]$children[[1]]$attribs$class <- paste0("btn btn-", buttonType ," btn-file")
        tag
    }
}


#' @rdname dynamicFile
#' @param input shiny server input
#' @param session shiny server session
#' @param roots a named character vector, paths where users can reach
#' on the server, so only required for "server" mode, default is
#' current directory + all system volumes. You can lock users to a specific path,
#' so they are not allowed to browse parent folders.
#' like only current directory: `c(current=getwd())`; a temp folder:
#' `c(current=tempdir())`; unlimited: `c(shinyFiles::getVolumes()())`
#' @export
#' @importFrom shinyFiles getVolumes shinyFileChoose parseFilePaths
dynamicFileServer <- function(
    input, session, id,
    mode = spsOption('mode'),
    roots = c(root = "default")){

    mode <- match.arg(mode, c("local", "server"))

    file_return <- reactiveVal(NULL)
    if(names(roots)[1] == "root" & roots[1] == "default")
        roots = c(current=getwd(), shinyFiles::getVolumes()())
    if (mode == "local") {
        shinyFiles::shinyFileChoose(input, id, roots = roots, session = session)
        observeEvent(input[[id]],
                     file_return({
                         req(is.list(input[[id]]))
                         file_selected <- shinyFiles::parseFilePaths(roots, input[[id]])
                         updateTextInput(inputId = glue("{id}-text"),
                                         session = session,
                                         placeholder = unname(file_selected$datapath))
                         as.data.frame(file_selected)
                     })
        )
        file_return
    } else {
        observe(file_return(input[[id]]))
        file_return
    }
}