Shiny modules inside other modules

Question

I am trying to put some graph modules inside another module. Not working at the moment though. I imagine that this isn't the way to do it. Any ideas on how it should be done?

library(shiny)
library(tidyverse)
library(palmerpenguins)

# modules -----------------------------------------------------------------

# module that creates graphs
graph_ui <- function(id) {
  ns <- NS(id)
  plotOutput(ns("graph"))
}

# ui that brings in graphs from other module
outer_ui <- function(id) {
  ns <- NS(id)
  tagList(
    "some text - would contain other objects too, not just graphs",
    uiOutput(ns("graph1")), # output from renderUI from graph server
    uiOutput(ns("graph2")) # output from renderUI from graph server
  )
}

# creates graphs
graph_server <- function(id, xcat, ycat) {
  moduleServer(id, function(input, output, session) {
    
      output$graph <- renderPlot({
        
        ggplot(penguins, aes(.data[[xcat]], .data[[ycat]], col = sex)) +
          geom_point()
      })
    }
  )
}

# brings in graphs
outer_server <- function(id, plot1, plot2) {
  moduleServer(
    id, function(input, output, session) {
      output$graph1 <- renderUI(graph_server("inner1")) # from graph server
      output$graph2 <- renderUI(graph_server("inner2")) # from graph server
      
    }
  )
}

# app ---------------------------------------------------------------------
ui <- fluidPage(
  outer_ui("mod1")
)

server <- function(input, output, session) {
  
  # graphs
  graph_server("inner1", xcat = "bill_length_mm", ycat = "bill_depth_mm")
  graph_server("inner2", xcat = "flipper_length_mm", ycat = "bill_depth_mm")
  
  # brings graphs in to display
  outer_server("mod1",
               graph_server$inner1, # from graph server
               graph_server$inner2) # from graph server
}
shinyApp(ui, server)

Note: also posted here: https://community.rstudio.com/t/modules-within-modules-graph-in-other-modules/115160

Answer 1

Your issue right now is in:

  # brings graphs in to display
  outer_server("mod1",
               graph_server$inner1, # from graph server
               graph_server$inner2) # from graph server

graph_server is a function, so you can't subset it with $.

The other issue is that you call graph_server at the wrong module level.

Your currently doing (in terms of nesting) :

L app_ui
  L outer_ui
    L graph_ui
L app_server
  L outer_server
  L graph_server

As you can see, the graph module parts are not at the same depth.

You should aim at:

L app_ui
  L outer_ui
    L graph_ui
L app_server
  L outer_server
    L graph_server

Here's the working structure :

library(shiny)
library(tidyverse)
library(palmerpenguins)

# Start with the lower level, just plotOutput & renderPlot
graph_ui <- function(id) {
  ns <- NS(id)
  plotOutput(ns("graph"))
}

graph_server <- function(id, xcat, ycat) {
  moduleServer(id, function(input, output, session) {
    output$graph <- renderPlot({
      ggplot(
        penguins, 
        aes(
          .data[[xcat]], 
          .data[[ycat]], 
          col = sex
        )
      ) +
        geom_point()
    })
  }
  )
}

# Here is a container for the graph module
outer_ui <- function(id) {
  ns <- NS(id)
  tagList(
    "some text - would contain other objects too, not just graphs",
    graph_ui(ns("graph1")),  # First use of the graph module
    graph_ui(ns("graph2")) # Second use of the graph module
  )
}


# Server counterpart
outer_server <- function(id) {
  moduleServer(id, function(input, output, session) {
      # Making the graphs happen
      graph_server("graph1", xcat = "bill_length_mm", ycat = "bill_depth_mm")
      graph_server("graph2", xcat = "flipper_length_mm", ycat = "bill_depth_mm")
      
    }
  )
}

# app ---------------------------------------------------------------------
ui <- fluidPage(
  outer_ui("mod1")
)

server <- function(input, output, session) {
  outer_server("mod1")
}
shinyApp(ui, server)

Cheers, Colin