Dynamically embed learnr tutorial within Shiny app

shiny
,
#1

I have a Shiny app running on my own Ubuntu server, it runs flawlessly.

Embedded in my app I also include a learnr tutorial. Both the Shiny app (myapp/) and the learnr tutorial (mylearnr/) are inside /srv/shiny-server.

I call the learnr tutorial from within the Shiny app like this:

# UI side:
htmlOutput("practice")

# Server side:
output$practice <- renderUI({
    tags$iframe(
      src="https://myserver.com/shiny/mylearnr/", 
      width="100%", height="100%", frameBorder=0, style="height: 100vh;", scrolling = 'yes'
    )
  })

The problem with the current set-up is that the learnr tutorial being deployed is always the same. The code above just embeds the current HTML file inside /srv/shiny-server/mylearnr in the Shiny app.

I tried to make it such that the Shiny app renders a new learnr tutorial each time it runs, like below. But this gives an error, the learnr tutorial is not rendered, and the Shiny app ends up freezing.

# Server side:
output$practice <- renderUI({
    rmarkdown::render("/../mylearnr/mylearnr.Rmd")   # this did not work
    tags$iframe(
      src="https://myserver.com/shiny/mylearnr/", 
      width="100%", height="100%", frameBorder=0, style="height: 100vh;", scrolling = 'yes'
    )
  })

How can I achieve what I want? Any help appreciated.

Thanks in advance,
bruce

#2

Can you please provide us with the error message?

What is the trigger for re-rendering the Rmd file? Or is it rendered only once on startup?

renderUI needs a updated reactive dependency to run again.

#3

Hi,
Thanks for getting back at me and apologies for the late reply.

Here's the error message:

An error has occurred. Check your logs or contact the app author for clarification.

About your question: I have no trigger, hence it should be the case that the Rmd file is only rendered once per session. That is OK for me. I only want to have different HTML across sessions (users).

The Rmd file renders if I execute the rmarkdown::render() command manually. But I get this error while running the command from the Shiny app. I was wondering whether this could be a permissions problem. The files are in /srv/shiny-server with rw permissions for user and group and r permission for others...

Any suggestions are more than welcome, thanks in advance.

#4

Are you making sure, that for each shiny session a separate HTML file is generated? Otherwise it might be the case, that the file is opened in one session while another tries to overwrite it.

What is written to the log?