Create cascading/dynamic selectInput() in many steps with dplyr::filter() doesn't work

[Alexandre Santos]

In my shiny example below I have 3 variables (PEST, DATE_S2 and PROJECT). I would like that when I select Project, the variables  DATE_S2  and PEST would only be those contained in the selection made in Project in the input using cascading/dynamic selectInput() with filters. Here is my detaild example:

```

# Packages

library(rgdal)

library(shiny)

library(leaflet)

library(leaflet.providers)

library(ggplot2)

library(shinythemes)

library(sf)

library(lubridate)

library(dplyr)

# get AOI

download.file(

  "https://github.com/Leprechault/trash/raw/main/stands_example.zip",

  zip_path <- tempfile(fileext = ".zip")

)

unzip(zip_path, exdir = tempdir())

# Open the files

setwd(tempdir())

stands_extent <- readOGR(".", "stands_target") # Border

stands_ds <- read.csv("pred_target_stands.csv", sep=";") # Data set

stands_ds <- stands_ds %>%

  mutate(DATA_S2 = ymd(DATA_S2))

# Create the shiny dash

ui <- fluidPage(

  theme = shinytheme("cosmo"),

  titlePanel(title="My Map Dashboard"),  

  sidebarLayout(

    sidebarPanel(

      uiOutput("selectedvariable0"),

      uiOutput("selectedvariable1"),

      uiOutput("selectedvariable2"),

    ),

    mainPanel(

      textOutput("idSaida"),

      fluidRow(

        splitLayout(plotOutput("myplot"))),

      dateInput(inputId = "Dates selection", label = "Time"),

      leafletOutput("map") 

    )

  )

)

server <- function(input, output, session){

  

  

  # Importing data and save it temporary in data variable

  data <- reactive({stands_ds})

  

  currentvariable0 <- reactive({input$selectedvariable0})

  currentvariable1 <- reactive({input$selectedvariable1})

  currentvariable2 <- reactive({input$selectedvariable2})

  currentvariable3 <- reactive({input$selectedvariable3})

  currentvariable4 <- reactive({input$selectedvariable4})

  

  # Creating filters

  output$selectedvariable0 <- renderUI({

    selectInput(inputId = "selectedvariable0", "Type A",choices = var_pest(), selected = TRUE)

  })

  output$selectedvariable1 <- renderUI({

    selectInput(inputId = "selectedvariable1", "Type B",choices = var_moni(), selected = TRUE)

  })

  output$selectedvariable2 <- renderUI({

    selectInput(inputId = "selectedvariable2", "Type C",choices = var_proj(), selected = TRUE)

  })

  

  # Creating reactive function to subset data

  pest_function <- reactive({

    file1 <- data()

    pest <- req(input$selectedvariable0)

    file2 <- file1 %>% dplyr::filter(PEST==pest)

    return (file2)  

  })

  

  var_moni <- reactive({

    file1 <- pest_function()

    if(is.null(file1)){return()}

    as.list(unique(file1$DATA_S2))

  })

  

  moni_function <- reactive({

    file1 <- pest_function()

    moni <- req(input$selectedvariable1)

    file2 <- file1 %>% dplyr::filter(DATA_S2==as.Date(moni))

    return (file2)  

  })

  

  var_proj <- reactive({

    file1 <- moni_function()

    if(is.null(file1)){return()}

    as.list(unique(file1$PROJETO))

  })

  

  proj_function <- reactive({

    file1 <- moni_function()

    proj <- req(input$selectedvariable2)

    file2 <- file1 %>% dplyr::filter(PROJETO==proj)

    return (file2) 

  })

  

  var_tal <- reactive({

    file1 <- proj_function()

    if(is.null(file1)){return()}

    as.list(unique(file1$CD_TALHAO))

  })

  

  

  output$myplot <- renderPlot({

    

    #Subset stand

    stands_sel <- subset(stands_extent, stands_extent@data$ID_UNIQUE==currentvariable4())

    

    #Subset for input$var and assign this subset to new object, "fbar"

    ds_sel<- stands_ds[stands_ds$ID_UNIQUE==currentvariable4(),]

    

    #Create a map

    polys <- st_as_sf(stands_sel)

    ggplot() +

      geom_sf(data=polys) +

      geom_point(data=ds_sel,

                 aes(x=X, y=Y), color="red") +

      xlab("Longitude") + ylab("Latitude") +

      coord_sf() +

      theme_bw() +

      theme(text = element_text(size=10)) 

  })

  

  output$map <- renderLeaflet({

    

    stands_actual<-stands_ds[stands_ds$ID_UNIQUE==currentvariable4(),]

    lng <- mean(stands_actual$X)

    lat <- mean(stands_actual$Y)

    

    leaflet() %>%

      setView(lng = lng, lat = lat, zoom=17) %>%

      addProviderTiles(providers$Esri.WorldImagery) %>%                   

      addMarkers(lng=stands_actual$X, lat=stands_actual$Y, popup="Location")

    

  })   

}

shinyApp(ui, server)

##

```

But not a way to make this work. Please any help for me fix it?

Thanks in advance!!!