shiny: display graph in new browser tab

Question

I have a shiny app for plotting graph. I've added an action button that, when clicked, opens the graph in a new browser tab. The problem is, the graph only appears in the new tab if I exit the app.

I've created an html file for the graph and saved it to the temporary directory (tempdir()). I can't and don't have permission to save the html in any directory. Can anyone help me solve this problem?

Code Below - 1) r script 2) rmarkdown

R script

ui <- fluidPage(
     #graph
     plotOutput("plot"),
     #button to show in the new tab
     actionButton(inputId = "action", label = "new tab")
     )


server <- function(input, output) {

    output$plot <- renderPlot({
      ggplot(PlantGrowth, aes(x = group, y = weight)) + geom_boxplot()
    })
 
    observeEvent(req(input$action),{
  
      plt <- ggplot(PlantGrowth, aes(x = group, y = weight)) + geom_boxplot()

      #path
      tempPreview <- file.path(tempdir(), "show.Rmd")
      #copy
      file.copy("www/show.Rmd", tempPreview, overwrite = TRUE)
  
      #height and width
      hgt <- 7
      wd <- 7
  
     #parameters for markdown
      param <- list(view = plt, height = hgt, width = wd)
      rmarkdown::render(tempPreview, output_file = "show.html",
                    params = param, envir = new.env(parent = globalenv()))
      #display the html
      browseURL(paste0(tempdir(),"/show.html"))
    })

}

Rmarkdown

---

title: ""
author: ""
date: ""
output: html_document
params:
    view: NA
    height: NA
    width: NA
-

```{r setup, include=FALSE}
   knitr::opts_chunk$set(echo = FALSE)
```

```{r echo=FALSE, fig.width=params$width, fig.height=params$height}
  params$view
```