Problems with graph when I choose the delimiter after uploading the file

Hello everyone! my shiny app allows you to upload a file and get plots. My problem is that you only get the graphs if you select the right separator before loading the file. I would rather that it was possible to select the separator after loading the file and that the plots appear immediately after choosing the right separator, as is already the case for the table.
Thank you

This is my code:


library(shiny)                                                
library(DT)
library(ggplot2)
library(tidyverse)
library(purrr)
library(dplyr)
library(shinythemes)
library(wesanderson)
library(reshape2)
library(colourpicker)
library(RColorBrewer)
library(shinyLP)
library(shinyjs)



# Define UI for data upload app ----
ui <- fluidPage(
  theme = shinytheme("cerulean"), 

  
 
    
             
             sidebarLayout( 
               
               
               sidebarPanel(width=3, 
                            
                            
                            
                            conditionalPanel(
                              'input.dataset01=="Dataset"',
                              fileInput("file1", HTML('<h5><b>Choose File:</b></h5>'), 
                                        multiple = TRUE,
                                        accept = c("text/csv",
                                                   "text/comma-separated-values,text/plain",
                                                   ".csv")),
                              # Input: Checkbox if file has header 
                              checkboxInput("header", "Header", TRUE),
                              
                              # Input: Select separator 
                              radioButtons("sep", HTML('<h5><b>Separator</b></h5>'),
                                           choices = c(Semicolon = ";",
                                                       Comma = ",",
                                                       Tab = "\t"),
                                           selected = "\t"),
                              
                              
                              # Input: Select number of rows to display 
                              radioButtons("disp", HTML('<h5><b>Display</b></h5>'),
                                           choices = c(All = "all",
                                                       Head = "head"),
                                           selected = "all"),
                              
                              # Select variables to display 
                              uiOutput("checkbox1")),
                            
                          
                            conditionalPanel(   
                              'input.dataset01 === "Statistical Distribution"',
                              
                              
                              # Input: Select what to display
                              selectInput("dataset1",HTML('<h5><b>Data:</b></h5>'),
                                          choices =list( 
                                            uploaded_file = "inFile"), 
                                          selected=NULL),     
                              uiOutput("plot.params2"),
                              
                              
                              
                              radioButtons("plot.type", HTML('<h5><b>Plot Type:</b></h5>'),                                                   
                                           list("Box Plot" = "boxplot", Histogram = "histogram")),
                              
                              
                              uiOutput("conditionalInput")
                              
                            )),
               
               
               # mainPanel 
               mainPanel(
                 
                 tabsetPanel(
                   id = 'dataset01',
                   tabPanel("Dataset", h3(textOutput("caption1"), align="center"), DT::dataTableOutput("rendered_file1")),
                   tabPanel(("Statistical Distribution"),  h3(textOutput("caption3"), align="center"),
                            
                            plotOutput("p")))) 
               
             )) 
    
    
   




# Define server logic to read selected file ----
server <- function(input, output, session) {
  
  
  
  
  # Read file 1 in Dataset 
  df1 <- reactive({ 
    req(input$file1)
    read.table(input$file1$datapath,
               header = input$header,
               sep = input$sep)  
    
  })
  
  # Dynamically generate UI input when data  is uploaded 
  output$checkbox1 <- renderUI({
    checkboxGroupInput(inputId = "select_var1", 
                       label = HTML('<h5><b>Select Variables</b></h5>'), 
                       choices = names(df1()),
                       selected = names(df1()))
  })
  
  # Select columns to print 
  df1_sel <- reactive({
    req(input$select_var1)
    df1_sel <- df1() %>% select(input$select_var1)
  })
  
  # Print data table   
  output$rendered_file1 <- DT::renderDataTable({
    
    if(input$disp == "head") {
      head(df1_sel())
    }
    else {
      df1_sel()
    }
    
  })                      
  
  
  
 
  
  #plotting theme for ggplot2 global
  .theme<- theme(
    axis.line = element_line(colour = 'gray', size = .75),
    panel.background = element_blank(),
    plot.background = element_blank()
  )
  
  
 
  
  #Read in the uploaded data file and create a reactive variable called data_set
  dataset1 <- reactive({if(is.null(input$file1)) return(NULL)
    read.table(input$file1$datapath, header = TRUE, sep=input$sep)     
  })
  
  output$plot.params2<- renderUI({
    req(input$file1)
    
    req(input$sep)
    list(
      fluidRow(selectInput(inputId = "variable", label = HTML('<h5><b>Variable:</b></h5>'), choices = names(dataset1()), selected = " ")), 
      fluidRow(selectInput(inputId = "group", label = HTML('<h5><b>Group:</b></h5>'), choices = names(dataset1()), selected = " ")) 
    )})
  
  
 
  
  output$caption3<-renderText({
    req(input$file1)
    
    
    switch(input$plot.type,
           
           "boxplot" 	= 	"   Box Plot",
           
           "histogram" =	"Histogram"
           
    )
  })
  
  
  
  #get data object
  get_data<-reactive({
    
    req(input$file1) 
    
    
    if(!exists(input$dataset1)) return() 
    
    check<-function(x){is.null(x) || x==""}
    if(check(input$dataset1)) return()
    
    obj<-list(data=get(input$dataset1),
              variable=input$variable,
              group=input$group
    )
    
    #require all to be set to proceed
    if(any(sapply(obj,check))) return()
    #make sure choices had a chance to update
    check<-function(obj){
      !all(c(obj$variable,obj$group) %in% colnames(obj$data))
    }
    
    if(check(obj)) return()
    
    
    obj
    
  })
  
  #plotting function using ggplot2
  output$p <- renderPlot({
    
    req(input$file1) 
    req(input$variable)
    req(input$group)
    
    plot.obj<-get_data()
    
    #conditions for plotting
    if(is.null(plot.obj)) return()
    
    #make sure variable and group have loaded
    if(plot.obj$variable == "" | plot.obj$group =="") return()
    
    
    
    #plot types
    plot.type<-switch(input$plot.type,
                      "boxplot" 	= list(geom_boxplot(), 
                                        scale_fill_manual(values=wes_palette(n=3, name="Moonrise3"))),
                      
                      
                      "histogram" =	list(geom_histogram(alpha=0.8,position="identity"),
                                         scale_fill_manual(values=wes_palette(n=3, name="Moonrise3")))  
                     
    )
    
   
    
    if(input$plot.type=="boxplot")	{		#control for 1D or 2D graphs
      p<-ggplot(plot.obj$data,
                aes_string(
                  x 		= plot.obj$group,
                  y 		= plot.obj$variable,
                  fill 	= plot.obj$group # let type determine plotting
                )
      ) + plot.type
      
      if(input$show.points==TRUE)
      {
        p<-p+ geom_point(color='black',alpha=0.5, position = 'jitter')
      }
      
    } else {
      
      p<-ggplot(plot.obj$data,
                aes_string(
                  x 		= plot.obj$variable,
                  fill 	= plot.obj$group,
                  group 	= plot.obj$group
                  
                )
      ) + plot.type
    }
    
    
   
   
    
    p<-p+labs(
      fill 	= input$group,
      x 		= "",
      y 		= input$variable
    )  
    .theme
    print(p)
  }, bg="transparent")
  
  #show points only for boxplot 
  output$conditionalInput <- renderUI({
    if(input$plot.type=="boxplot"){
      checkboxInput("show.points", "show points", NULL)
    }})
  
  # set uploaded file
  upload_data<-reactive({
    
    req(input$file1)
    req(input$sep)
    
    
    inFile <- input$file1
    
    if (is.null(inFile)) 
      return(NULL)
    
    #could also store in a reactiveValues
    read.table(inFile$datapath,   
               header = TRUE,
               sep = input$sep)                 
  })                                      
  

  
  observeEvent(input$file1,{
    inFile<<-upload_data()
  })
  
 
  
  
}

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