Saving & loading settings

functions/io/data_io.R

+read_data <- function(path, header, sep, quote) {
+  tryCatch(
+    {
+      df <- read.csv(path,
+                     header,
+                     sep,
+                     quote)
+    },
+    error = function(e) {
+      ## return a safeError if a parsing error occurs
+      stop(safeError(e))
+    }
+  )
+  return(df)
+  
+}
+
+
+save_settings <- function(settings, path) {
+  json_settings = toJSON(settings)
+  print(path)
+  # if (!grepl('.*\\.json$', json_settings) ) {
+  #   path = paste0(path,'.json')
+  # }
+  
+  
+  write(json_settings, path, append = FALSE)
+  print('downloaded')
+}
+
+read_settings <- function(path){
+  json_data <- fromJSON(file = path)
+  return(json_data)
+}
+
+test_settings_io <- function()
+{
+  path = 'C:/Users/meechan/Documents/settings.json'
+  save_settings(c('a','b'), path)
+  read_settings(path)
+}

functions/io/settings.R

+getSettings <- function( s ) {
+  if ( exists("s") && !is.null(s) ) {
+    return(s)
+    
+  } else {
+    return(NULL)
+  }
+}
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server.R

+library(RJSONIO)
+library(rjson)
+source('./functions/io/data_io.R')
+source('./functions/io/settings.R')
+
+
+server <- function (input, output) {
+  data <- reactive({
+    
+    if (is.null(input$datafile)) return(NULL)
+    
+    ## After the user selects and uploads a data file,
+    ## the content of the data file will be shown.
+    
+    req(input$datafile)
+    
+    read_data(input$datafile$datapath,
+              header = input$header,
+              sep = input$sep,
+              quote = input$quote) 
+  })
+  
+  settings <- reactive({
+    if (is.null(input$settings_file)) return(NULL)
+    
+    ## After the user selects and uploads a data file,
+    ## the content of the data file will be shown.
+    
+    req(input$settings_file)
+    
+    read_settings(input$settings_file$datapath)
+    
+    
+  })
+  
+  output$content <- renderDT(data(), server = TRUE)
+  
+  output$Paths <- renderUI({
+    checkboxGroupInput(inputId = "ImagePaths", 
+                       label = "Select Image columns", 
+                       choices = names(data()),
+                       selected = getSettings(settings()) )
+  })
+  
+  output$downloadData <- downloadHandler(
+    
+    filename = function() {
+      return('Settings')
+    },
+    
+    # This function should write data to a file given to it by
+    # the argument 'file'.
+    content = function(file) {
+      print(file)
+      save_settings(input$ImagePaths, file)
+    }
+  )
+  
+  output$selected_paths = renderPrint({
+    s = input$ImagePaths
+    if (length(s)) {
+      cat('These variables were selected:\n\n')
+      cat(s, sep = ', ')
+      print(str(input$ImagePaths))
+    }
+  })
+  
+}
+

ui.R

+library('shiny')
+
+ui <- navbarPage("",
+  tabPanel("Load", 
+           fluidRow(
+               ## Input: Select a file
+               fileInput("datafile", "Select data file (in CSV format)",
+                         multiple = FALSE,
+                         accept = c("text/csv",
+                                    "text/comma-separated-values,text/plain",
+                                    ".csv")),
+               
+               ## Horizontal line
+               tags$hr(),
+               
+               ## Input: Checkbox if file has header
+               checkboxInput("header", "File has header", TRUE),
+               
+               ## Input: Select separator
+               radioButtons("sep", "Separator",
+                            choices = c(Comma = ",",
+                                        Semicolon = ";",
+                                        Tab = "\t"),
+                            selected = "\t"),
+               
+               ## Input: Select quotes
+               radioButtons("quote", "Quote",
+                            choices = c(None = "",
+                                        "Double Quote" = '"',
+                                        "Single Quote" = "'"),
+                            selected = '"'),
+               
+               tags$hr()
+             ),
+           
+           fluidRow(
+             DTOutput("content")
+           ),
+           
+           fluidRow(title = 'settings',
+                    
+                    
+                    fileInput("image", "Select an image file:",
+                              multiple = FALSE,
+                              accept = c('.png','.jpg','.tif','.jpeg')),
+                    
+                    uiOutput("Paths"),
+                    
+                    downloadButton('downloadData', 'Download'),
+                    verbatimTextOutput('selected_paths'),
+                    
+                    fileInput("settings_file", "Select settings json file:",
+                              multiple = FALSE,
+                              accept = c('.json'))
+                    
+                    
+             
+           )
+           
+           
+           
+           ),
+  tabPanel("Plot")
+)
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