Upload data file and run source.R in Shiny app

I am trying to run my shinyapp.R (includes ui and server) using source("model.R"). I want to let a user upload a data file and run model.R in my shinyapp.R.

How should I let model.R run using user uploaded data set. It does not read the dataset I uploaded from the shiny app.

My code:

source("model.R") server <- function(input, output){ dataset <- reactive({ infile <- input$datafile if( is.null(infile) ) { return(NULL) } else { as.data.frame(read.csv(infile$datapath, header=TRUE)) } }) output$plot <- renderPlot({pred_plot}) }) ui <- fluidPage(fileInput("datafile", "Choose data file", accept = c('text/csv','.csv','.xlsx') ), mainPanel(plotOutput("plot") ) runApp(list(ui = ui, server = server)) 

I get the following error message:

Error in eval(ei, envir) : object 'dataset' not found