inst/examples/app.R

In byandell/ewing: Ewing's Quantitative Population Ethology

library(shiny)

# Define UI for data upload app ----
ui <- fluidPage(
  
  # App title ----
  titlePanel("Uploading Files"),
  
  # Sidebar layout with input and output definitions ----
  sidebarLayout(
    
    # Sidebar panel for inputs ----
    sidebarPanel(
      
      # Input: Select a file ----
      fileInput("file1", "Choose XLSX File",
                multiple = FALSE,
                accept = c(".xls",
                           ".xlsx")),
      
      # Horizontal line ----
      tags$hr(),
      
      selectInput("sheet", "Sheet", 
                  c("organism.features", "future.host", "future.parasite", "host.parasite",
                    "substrate.host", "substrate.parasite", "substrate.substrate",
                    "TemperatureBase", "TemperaturePar"),
                  "organism.features"),
      
      # Input: Checkbox if file has header ----
      checkboxInput("header", "Header", TRUE),
      
      # Input: Select separator ----
      radioButtons("sep", "Separator",
                   choices = c(Comma = ",",
                               Semicolon = ";",
                               Tab = "\t"),
                   selected = ","),
      
      # Input: Select quotes ----
      radioButtons("quote", "Quote",
                   choices = c(None = "",
                               "Double Quote" = '"',
                               "Single Quote" = "'"),
                   selected = '"'),
      
      # Horizontal line ----
      tags$hr(),
      
      # Input: Select number of rows to display ----
      radioButtons("disp", "Display",
                   choices = c(Head = "head",
                               All = "all"),
                   selected = "head")
      
    ),
    
    # Main panel for displaying outputs ----
    mainPanel(
      
      # Output: Data file ----
      tableOutput("contents")
      
    )
    
  )
)

# Define server logic to read selected file ----
server <- function(input, output) {
  
  output$contents <- renderTable({
    
    # input$file1 will be NULL initially. After the user selects
    # and uploads a file, head of that data file by default,
    # or all rows if selected, will be shown.
    
    req(input$file1)
    
    # when reading semicolon separated files,
    # having a comma separator causes `read.csv` to error
    tryCatch(
      {
        browser()
        df <- xx(input$file1$datapath, sheet = input$sheet)
      },
      error = function(e) {
        # return a safeError if a parsing error occurs
        stop(safeError(e))
      }
    )
    
    if(input$disp == "head") {
      return(head(df))
    }
    else {
      return(df)
    }
    
  })
  
}
xx <- function(datapath, sheet) {
  readxl::read_excel(datapath, sheet = sheet)
}

# Create Shiny app ----
shinyApp(ui, server)