How to display R Shiny output in R Markdown? - r

Question

I'm new to R markdown here and I am trying to create an R Shiny app which I can enter a list of names, and then download the output (like a name list) as HTML file. I am using R markdown to create the HTML file. Here are my sample codes:
R Shiny:
library(shiny)
ui <- list(
textInput("name", "Type new text input name", value = ""),
actionButton("btn", "click me to create text input"),
uiOutput("newInputs"),
downloadButton("download_report", "Download")
)
server <- function(input, output)
{
family_member <- reactiveValues(
add_family_info = list()
)
observeEvent(input$btn, {
newid <- paste(length(family_member$add_family_info))
family_member$add_family_info <- c(family_member$add_family_info, list(c(newid, input$name)))
family_member
})
output$newInputs <- renderUI({
lapply(family_member$add_family_info, function(a)
c(paste(a[2])))
})
output$download_report <- downloadHandler(
filename = "name.html",
content = function(file) {
tempReport <- file.path(tempdir(), "name.Rmd")
file.copy("name.Rmd", tempReport, overwrite = TRUE)
params <- list(report = uiOutput("newInputs"))
rmarkdown::render(tempReport, output_file = file,
params = params,
envir = new.env(parent = globalenv()))
}
)
}
runApp(list(ui = ui, server = server))
R Markdown:
---
runtime: shiny
output: html_document
params:
report: NA
---
\
\
# Member names
`r params$report`
Appreciate any help! Thanks in advance!!!!

Answer 1

If you are just using a Shiny to render an Rmarkdown document, you don't need the runtime of the document to be Shiny. This is only needed if the document itself will ultimately be a shiny app.
Looking at the download handler
params <- list(report = uiOutput("newInputs"))
The uiOutput function generates the html for the element. It doesn't retrieve the values (you can see this if you run execute it in the console by itself). Additionally newInputs just refers to the container for the text (it's not actually inputs). Instead, you would want to use the reactive value storing the list
params <- list(report = family_member$add_family_info)
However, since this will be printed it can't be an arbitrary R object. It has to be something that cat can handle. In this case family_member$add_family_info is a list of list. Try flattening it with something like
params <- list(report = unlist(family_member$add_family_info))