Error sourcing while creating Shiny app

I am trying to create a shiny dashboard to summarize customer feedback, but get error as below

Warning: Error in inherits: Operation not allowed without an active reactive context. (You tried to do something that can only be done from inside a reactive expression or observer.)
  56: <Anonymous>
Error in inherits(x, "Source") : 
  Operation not allowed without an active reactive context. (You tried to do something that can only be done from inside a reactive expression or observer.)

Below is the coding part, I have used.

library(shiny)

#Define UI
shinyUI(fluidPage(
  #Title Panel
  titlePanel(title=h4("Initial Feedback Survey",align="center")),
  sidebarLayout(
  #Sidebar panel
    sidebarPanel(
      selectInput("var","Select the variable",choices=names(data),selected=names(data)[11]),
      br(),
      radioButtons("color","Select the color",choices=c("Green","Red","Yellow"),selected="Green")
    ),
    #Main Panel
    mainPanel(
      tabsetPanel(type="tab",
                  tabPanel("Data",tableOutput("data")),
                  tabPanel("Summary",tableOutput("counts")),
                  tabPanel("Plot",plotOutput("bar")))
      
    )
    )
)
)

library(shiny)
library(shinydashboard)
library(dplyr)
library(ggplot2)
library(tm)
data=read.csv("C:\\Users\\Kafeel Basha\\Desktop\\R Files\\RShiny\\Jigsaw Data Science with R.csv",header=TRUE,stringsAsFactors = FALSE,na.strings=c("  "," ","NA",NULL,""))
data=na.omit(data)
names(data) <- gsub("[..]", " ", names(data))
names(data) <- gsub("[.]", " ", names(data))

shinyServer(function(input,output){
  demo=Corpus(VectorSource(input$var))
  demo=tm_map(demo,content_transformer(tolower))
  demo=tm_map(demo,removePunctuation)
  df<- data.frame(text=unlist(sapply(demo,`[`)),stringsAsFactors=F)
  df$text=ifelse(df$text=="poor"|df$text=="fair","BAD","GOOD")
  df%>%group_by(text)%>%summarise(count=n(),percentage=count/nrow(df))%>%as.data.frame()->stats
  rownames(stats)<-stats$text
  
  output$data<-renderTable({head(data)})
  output$counts<-renderTable({table(stats$text)})
  output$bar <- renderPlot({
    ggplot(stats,aes(x=stats$text,y=stats$percentage,fill=text))+geom_bar(stat="identity")+geom_text(label=stats$percentage,vjust=-0.5)+ggtitle("Bar Chart of Proportion")
  })})

Hi, yes, the value frominput$var can only be called inside a Shiny reactive function. You probably want to use the observeEvent() function to execute all of your data transformation. So it would be something like: `observeEvent(intput$var, [data transformation goes here])

Hi! Welcome to RStudio Community!

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Yes, Thanks. I am trying to build the dashboard using dashboardPage() instead of fluidPage().

Let me complete and get back if required.