Ubuntu Server Configuration

This document contains some information regarding how to configure an Ubuntu server to host mirtCAT applications. For more information visit https://www.rstudio.com/products/shiny/download-server/ and http://docs.rstudio.com/shiny-server/

Installation

The following commands should be executed in the terminal.

install R + shiny + mirtCAT

• sudo apt-get install r-base
• sudo su - -c "R -e \"install.packages('shiny', repos='https://cran.rstudio.com/')\""
• sudo su - -c "R -e \"install.packages('mirtCAT', repos='https://cran.rstudio.com/')\""

install gdebi

• sudo apt-get install gdebi-core
• sudo gdebi shiny-server-1.5.1.deb

edit default config file

• cd /etc/shiny-server/
• ls

applications are hosted in

• cd /srv/shiny-server/
• mkdir app_name
• cd app_name/
• touch app.R

application publicly available with

• http://your_server_ip:3838/app_name/

You may want to purchase a domain name so that your IP address is not publicly advertised.

some useful commands

• sudo systemctl start shiny-server
• sudo systemctl stop shiny-server
• sudo systemctl restart shiny-server
• sudo systemctl status shiny-server

Example application

The following is an example of how to host an application with mirtCAT on your server. Note that the last line must be createShinyGUI() in order for the application to properly execute. As well, you’ll likely want to save the results of the test directly to the server, which can be done by creating a final_fun function input.

library("mirtCAT")
options(stringsAsFactors = FALSE)

### Create simple non-adaptive interface ###

## Potential options for each item
options <- matrix(c("Strongly Disagree", "Disagree", "Neutral", "Agree", "Strongly Agree"),
                  nrow = 3, ncol = 5, byrow = TRUE)

questions <- c("Building CATs with mirtCAT is difficult.",
               "Building tests with mirtCAT requires a lot of coding.",
               "I would use mirtCAT in my research.")

df <- data.frame(Question = questions, Option = options, Type = "radio")

# save person results to a folder to /shared/ directory where objects are named based on the system time
final_fun <- function(person){
    time <- paste0('/shared/', gsub(' ', '_', as.character(Sys.time())), '.rds')
    saveRDS(person, time)
}

# setup internal objects (placed in hidden mirtCAT environment)
mirtCAT_preamble(df = df, final_fun = final_fun, shinyGUI = list(stopApp=FALSE,
                                                 forced_choice=TRUE))

# this must be the last line (implicitly wrapped in runApp() by shinyserver)
createShinyGUI()