How to pass tables and plots from different modules in Shiny app as parameters to R Markdown?

[YonghuiDong]

Dear golem development team,

In this Shiny app, the user can upload a file, and get the results as tables and plots. I want to download the results as HTML document.

I tried to either pass a reactive plot object or a global variable plot object to the 'params', and none of them worked.

1. Could you please help me check what the problem is?
2. What is the best way in golem to pass plots as parameters in R markdown file? I feel like using global variable is a bit too work for me.

Thanks a lot.

Dong

Below is my minimal example:

# Module 1, 
plot_ui <- function(id) {
  ns <- NS(id)
  tagList(
    plotOutput(ns("plot1")),
    plotOutput(ns("plot2"))
  )
}

plot_server <- function(id, r) {
  moduleServer(id, function(input, output, session) {
    plot1 <- reactive({plot(x = mtcars$wt, y = mtcars$mpg)})
    output$plot1 <-renderPlot({
      plot1()
    })
    output$plot2 <- renderPlot({
      r$scatterPlot <- plot(x = mtcars$wt, y = mtcars$mpg)
      r$scatterPlot
    })
  }
  )
}

# Module 2
choice_ui <- function(id) {
  ns <- NS(id)
  tagList(
    sliderInput(inputId = ns("slider"),
                label = "Slider",
                min = 1,
                max = 100,
                value = 50),
    downloadButton(outputId = ns("report_button"),
                   label = "Generate report"
    )
  )
}

choice_server <- function(id, r) {
  moduleServer(id, function(input, output, session){
    output$report_button<- downloadHandler(
      filename = "report.html",
      content = function(file) {
        tempReport <- file.path(tempdir(), "myRport.Rmd")
        file.copy("inst/app/www/myReport.Rmd", tempReport, overwrite = TRUE)
        params <- list(n = input$slider,
                       plot1 = plot1(),
                       plot2 = r$scatterPlot
                       )
        rmarkdown::render(tempReport, 
                          output_file = file,
                          params = params,
                          envir = new.env(parent = globalenv())
        )
      }
    )
  }
  )
}


# Application
library(shiny)
app_ui <- function() {
  fluidPage(
    plot_ui("plot_ui_1"),
    choice_ui("choice_ui_2")
  )
}

app_server <- function(input, output, session) {
  r <- reactiveValues()
  plot_server("plot_ui_1", r = r)
  choice_server("choice_ui_2", r = r)
}

shinyApp(app_ui, app_server)

[YonghuiDong]

I figured out the solution:

1. Export the output in the module
2. Pass them in the download module server file
3. Include in the download module server file in the general server file

Here is a mini example.

library(shiny)
library(ggplot2)
library(rmarkdown)
# Module 1,
plot_ui <- function(id) {
  ns <- NS(id)
  tagList(
    plotOutput(ns("plot1")),
    plotOutput(ns("plot2"))
  )
}

plot_server <- function(id) {
  moduleServer(id, function(input, output, session) {
    myplot1 <- reactive({
      ggplot(mtcars, aes(wt, mpg)) +
        geom_point()
    })
    myplot2 <- reactive({
      ggplot(mtcars, aes(wt, drat)) +
        geom_point()
    })
    output$plot1 <-renderPlot({
      myplot1()
    })
    output$plot2 <-renderPlot({
      myplot2()
    })

    plotList <- list(myplot1 = myplot1, myplot2 = myplot2)
    return(plotList)
  })
}

# Module 2
download_ui <- function(id) {
  ns <- NS(id)
  tagList(
    downloadButton(outputId = ns("report_button"),
                   label = "Generate report"
    )
  )
}

download_server <- function(id, plotList) {
  moduleServer(id, function(input, output, session){
    output$report_button<- downloadHandler(
      filename = "report.html",
      content = function(file) {
        tempReport <- file.path(tempdir(), "myRport.Rmd")
        file.copy("myReport.Rmd", tempReport, overwrite = TRUE)
        params <- list(plot1 = plotList$myplot1(),
                       plot2 = plotList$myplot2()
                       )
        rmarkdown::render(tempReport,
                          output_file = file,
                          params = params,
                          envir = new.env(parent = globalenv())
        )
      }
    )
  }
  )
}

# Application
library(shiny)
library(ggplot2)

app_ui <- function() {
  fluidPage(
    plot_ui("plot_ui_1"),
    download_ui("download_ui_2")
  )
}

app_server <- function(input, output, session) {
  getPlot <- plot_server("plot_ui_1")
  download_server("download_ui_2", plotList = getPlot)
}

shinyApp(app_ui, app_server)