R Shiny, showModal, and rmarkdown-report

Question

I've written an app which renders an r-markdown -report as html inside bsmodal, when user presses button.

It works, but it only works once. If the modal is closed and the button is entered again, the rmarkdown is not rendered anymore. If I place a renderText inside the modal instead of renderUI-part, it works OK. Does someone know why the rmarkdown gets rendered only the first time the button is pressed?

Thanks for any help,

-Kari

Minimized example code provided below.

Shiny code:

setwd("") #Set working directory here

ui <- function(id) {
  
  fluidPage(
    fluidRow(
      column(3, 
        actionButton("button", "Go!")
      )
    )
  )
}

server <- function(input, output) {

  observeEvent(input$button, {
    
   showModal(modalDialog(
     title = "Fancy report",
      tagList(
            renderUI(
              HTML(
                readLines(
                  rmarkdown::render("report.rmd",
                    encoding = "UTF-8",
                    envir = new.env()
                  ), encoding = "UTF-8"
                )
              )
            )
      ),
     easyClose = TRUE
   )
   )    
  })
}
shinyApp(ui = ui, server = server)

rmarkdown (please notice, stack interprets those 3 markdown ticks as code block start and end as well):

---
mainfont: Arial
output: html_document
---
  
```{r echo = FALSE, comment=NA, results='asis', warning=FALSE, message=FALSE}
library(knitr)
library(kableExtra)
library(tidyverse)
library(dplyr)

ds <- head(mtcars)

ds %>% kable("html", escape = F, col.names = NULL, table.attr = "style='width:90%;'")

question from:https://stackoverflow.com/questions/66047472/r-shiny-showmodal-and-rmarkdown-report

Answer 1

I was able to fix this by using bsModal instead of showModal. In case someone needs this, here's the working Shiny-code (The original r-markdown code is not touched):

setwd("C:/set-rmarkdown-file-location-here")

ui <- function(id) {
  
  fluidPage(
    fluidRow(
      column(3, 
        actionButton("button", "Go!")
      )
    ),
    fluidRow(
      column(10,
        bsModal("modalExample", "fancy report", "button", size = "large",
          uiOutput("report_ui")
        )
      )
    )
  )
}

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

  output$report_ui <- renderUI({
    
      HTML(
        readLines(
          rmarkdown::render("report.rmd",
                            encoding = "UTF-8",
                            envir = new.env()
          ), encoding = "UTF-8"
        )
      )
  })
  
}
shinyApp(ui = ui, server = server)