Use Custom `end`-Function to Provide Immediate Feedback using Knitr

This example shows how to use the package ShinyItemBuilder to display a feedback after an assessment.

library(ShinyItemBuilder)

For illustration purposes, three items from the demo01 included in the package ShinyItemBuilder are used. After calling getDemoPool("demo01") the object item_pool contains information about all items, but we only select item 2, 3 and 4:

item_pool <- getDemoPool("demo01")
item_pool <- item_pool[c(2,3,4),]

	Project	Task
2	SinglePageItems_01SC.zip	task0
3	SinglePageItems_02MC.zip	task0
4	SinglePageItems_03TXT.zip	task0

To implement the booklet design, we overwrite the end function.

assessment_config <- getConfig(Verbose = T) 

After calling getConfig(), the object assessment_config already contains the (default) implementation of the end-function:

assessment_config$end
#> function (session) 
#> {
#>     showModal(modalDialog(title = "You Answered all Items", "Please close the browser / tab.", 
#>         footer = tagList(actionButton("endActionButtonOK", "Restart"))))
#> }
#> <bytecode: 0x55b51462fc88>
#> <environment: 0x55b51463ce48>

This function can be overwritten by assigning a new function end = function(session) with the same signature. In this new function, we first load the data gathered for this session, stored in the variable session$userData$cbasession:

data <- runtime.data[[session$userData$cbasession]

In the following lines we create a simple data.frame representation of the scoring results:

  a <- NULL
  for (d in 1:dim(data$ResultData)[1]){
    s <- parse_ib_scoring(data$ResultData[d,"Resultdata"])
    a <- rbind(a,cbind(Project=data$ResultData[d,"Project"],
                       Task=data$ResultData[d,"Task"],
                       Scope=data$ResultData[d,"Scope"],
                       s[s$Active,c("Name","ResultText")]))
  }

This is followed by the markdown template that will be used to generate the feedback. In this example the markdown is created within the function, but it could also be stored in a separate *.Rmd file.

After writing the markdown template to file (see write(template, ...)), render it to html (see rmarkdown::render(...)), the generated content is loaded from file as base64 encoded string (see base64enc::dataURI(file = ...)). Finally, the generated html (as base64 encoded string) is displayed in a modal dialog:

  showModal(modalDialog(
    title = "Feedback",
    footer = tagList(actionButton("endActionButtonOK", "Restart")),
    renderUI({
      tags$iframe(src=b64, height=400, width=550, frameBorder=0)
    }),
  ), session)

Taking everything together, this is an custom end-function that provides immediate feedback about the scores obtained in CBA ItemBuilder items:

assessment_config$end <- function(session) {

  data <- runtime.data[[session$userData$cbasession]]
  a <- NULL
  for (d in 1:dim(data$ResultData)[1]){
    s <- parse_ib_scoring(data$ResultData[d,"Resultdata"])
    a <- rbind(a,cbind(Project=data$ResultData[d,"Project"],
                       Task=data$ResultData[d,"Task"],
                       Scope=data$ResultData[d,"Scope"],
                       s[s$Active,c("Name","ResultText")]))
  }
 
  template <- '---
    output: html_document
    ---
    ### Your Results: A Score of `r sum(a$Name == "ScoreCorrect")`

    ```{r, echo=F}
    knitr::kable(a)
    ```
'
  write(template, file=paste0(session$userData$cbasession,".rmd"), append = FALSE)
  
  tmpfile <- rmarkdown::render(paste0(session$userData$cbasession,".rmd"))
  b64 <- base64enc::dataURI(file = tmpfile, mime = "text/html")

  if (file.exists(tmpfile))
    file.remove(tmpfile)

  if (file.exists(paste0(session$userData$cbasession,".rmd")))
    file.remove(paste0(session$userData$cbasession,".rmd"))

  showModal(modalDialog(
    title = "Feedback",
    footer = tagList(actionButton("endActionButtonOK", "Restart")),
    renderUI({
      tags$iframe(src=b64, height=400, width=550, frameBorder=0)
    }),
  ), session)
}

Note that the dialog includes the actionButton with the name endActionButtonOK (see footer = tagList(actionButton("endActionButtonOK", "Restart"))), that restarts the assessment.