How to use user uploaded xlsx on shiny app which would use that data to generate choices for filter input?

I have a shiny app that takes a dataframe from which some filter options are generated so that users can pick one, and a table is generated as the output. That dataframe originates from an .xlsx file which is read at the beginig of the app. But i would like the user to upload the file. The data has the following structure:

ID    <- c(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19)
Provincia <- c("Santa Fe",  "Santa Fe", "Cordoba"   ,"Santa Fe" ,"Santa Fe",    "Cordoba",  "Cordoba"   ,"Santa Fe",    "Cordoba"   ,"Cordoba"  ,"Santa Fe",    "Santa Fe", "Santa Fe"  ,"Santa Fe",    "Santa Fe", "Cordoba",  "Cordoba"   ,"Cordoba","Santa Fe")
Ciudad <- c("Carlos Paz",   "Esperanza" ,"Rafaela"  ,"Carlos Paz",  "Carlos Paz"    ,"Rafaela"  ,"Villa General" ,"Belgrano"    ,"Villa General Belgrano",  "Rafaela","Esperanza",  "Rafaela",  "Esperanza" ,"Esperanza",   "Villa General" ,"Belgrano",    "Carlos Paz",   "Carlos Paz",   "Esperanza")
Valor1 <- rpois(n = 19, lambda = 10) 
Valor2 <- runif(n = 19, min = 1, max = 10)
Color <- c("Rojo",  "Azul", "Rojo", "Azul","Rojo",  "Azul","Rojo",  "Azul","Rojo",  "Azul","Rojo",  "Azul","Rojo",  "Azul","Rojo",  "Azul","Rojo",  "Azul","Rojo")
df <- data.frame(ID,Provincia,Ciudad,Valor1,Valor2,Color)

This is the working shiny app:

library(shiny)
library(tidyverse)
library(readxl)
library(arsenal)

base <- read_excel("Libro1.xlsx")

prov_list <- base %>% distinct(Provincia)%>%arrange(Provincia)
todos <- " ALL"
prov_list <- rbind(todos, prov_list)
prov_list <- split(prov_list,prov_list$Provincia)

ui <- fluidPage(
  
  titlePanel("Título"),
  
  sidebarLayout(
    sidebarPanel(
      selectInput(
        inputId = "var1",
        label = "Select province",
        choices = ls(prov_list),
        selected = " ALL",
        multiple = FALSE
      ),
      selectInput(
        inputId = "var2",
        label = "Select city",
        choices = NULL
      )
    ),
    
    mainPanel(
      tabsetPanel(
        type = "tabs",
        tabPanel(
          "Tabla 1",
          htmlOutput("table")
        )
      )
    )
  )
)

server <- function(input, output, session) {
  
  observeEvent(input$var1,{
    updateSelectInput(session,'var2',
                      choices=c(" ALL",unique(base$Ciudad[base$Provincia==input$var1])))
  })
  
  My_Uploaded_Data <- reactive({
    My_Uploaded_Data<-base
    My_Uploaded_Data
  })
  
  filtered_data_0 <- reactive({
    filtered_data_0<-My_Uploaded_Data()
    filtered_data_0 %>%filter(if(input$var1!= ' ALL')  (Provincia == input$var1) else TRUE)
  })
  
  filtered_data <- reactive({
    filtered_data<-filtered_data_0()
    filtered_data %>%filter(if(input$var2!= ' ALL')  (Ciudad == input$var2) else TRUE)
  })
  
  
  controles <- reactive({
    tableby.control(
      test = T,
      total = T,
      numeric.test = "anova", cat.test = "chisq",
      numeric.stats = c("meanCI"),
      cat.stats = c("countpct"),
      stats.labels = list(
        meanCI = "Media (95%CI)",
        countpct = "n (%)")
    )
  })
  
  output$table <- function(){
    
    x <- filtered_data()
    
    my_controls <- controles()
    
    tab1 <- tableby(Color ~ Valor1+Valor2,
                    data=x,
                    control=my_controls)
    
    aver <- as.data.frame(summary(tab1,digits=1,
                                  text = "html"))
    
    kable(aver,align = "lccc", escape = FALSE)%>%
      kable_styling(bootstrap_options = c("striped", "hover","condensed","responsive"), full_width = TRUE)
    
  }
}

shinyApp(ui = ui, server = server)

And here i tried to get the user to upload the file:

library(shiny)
library(tidyverse)
library(readxl)
library(arsenal)

ui <- fluidPage(
  
  titlePanel("Título"),
  
  sidebarLayout(
    sidebarPanel(
      fileInput("upload", "Please select file", accept = c(".xlsx")),
      selectInput(
        inputId = "var1",
        label = "Select province",
        choices = ls(prov_list),
        selected = " ALL",
        multiple = FALSE
      ),
      selectInput(
        inputId = "var2",
        label = "Select city",
        choices = NULL
      )
    ),
    
    mainPanel(
      tabsetPanel(
        type = "tabs",
        tabPanel(
          "Tabla 1",
          htmlOutput("table")
        )
      )
    )
  )
)

server <- function(input, output, session) {
  
  base <- reactive({
    upload <- input$upload
    base <- read_excel(upload$datapath)
  })
  
  prov_list <- base() %>% distinct(Provincia)%>%arrange(Provincia)
  todos <- " ALL"
  prov_list <- rbind(todos, prov_list)
  prov_list <- split(prov_list,prov_list$Provincia)
  
  
  observeEvent(input$var1,{
    updateSelectInput(session,'var2',
                      choices=c(" ALL",unique(base()$Ciudad[base()$Provincia==input$var1])))
  })
  
  My_Uploaded_Data <- reactive({
    My_Uploaded_Data<-base()
    My_Uploaded_Data
  })
  
  filtered_data_0 <- reactive({
    filtered_data_0<-My_Uploaded_Data()
    filtered_data_0 %>%filter(if(input$var1!= ' ALL')  (Provincia == input$var1) else TRUE)
  })
  
  filtered_data <- reactive({
    filtered_data<-filtered_data_0()
    filtered_data %>%filter(if(input$var2!= ' ALL')  (Ciudad == input$var2) else TRUE)
  })
  
  
  controles <- reactive({
    tableby.control(
      test = T,
      total = T,
      numeric.test = "anova", cat.test = "chisq",
      numeric.stats = c("meanCI"),
      cat.stats = c("countpct"),
      stats.labels = list(
        meanCI = "Media (95%CI)",
        countpct = "n (%)")
    )
  })
  
  output$table <- function(){
    
    x <- filtered_data()
    
    my_controls <- controles()
    
    tab1 <- tableby(Color ~ Valor1+Valor2,
                    data=x,
                    control=my_controls)
    
    aver <- as.data.frame(summary(tab1,digits=1,
                                  #labelTranslations = my_labels,
                                  text = "html"))
    
    kable(aver,align = "lccc", escape = FALSE)%>%
      kable_styling(bootstrap_options = c("striped", "hover","condensed","responsive"), full_width = TRUE)
    
  }
}

shinyApp(ui = ui, server = server)

But i get the error : 'Operation not allowed without an active reactive context. You tried to do something that can only be done from inside a reactive consumer', which i'm not sure how to go about fixing. Any help would be much apreciated!