skeleton of a shiny app to setwd and source R scripts

app.R

library(shiny)
options(shiny.reactlog=TRUE) 
# define home dir for shiny app
homed <- getwd()

# set up choices to be retrievable in server.R
progchoices <- c("This is a TEST APP" = "testapp/",
    "Yet Another Program"     = "anotherprog/")

ui <- fluidPage(
    titlePanel("CODA Bioinformatics App Launcher"),
    sidebarLayout(
        sidebarPanel(
            radioButtons(inputId = "app",
                label   = "Select an application to run:",
                choices = progchoices),
            actionButton("goButton", "Run")
    ),
        mainPanel(
        h3(textOutput("message"))
            )
    )
)


server <- function(input, output) {
    
    runandmessage <- eventReactive(input$goButton, ({
        
        # set working dir
        setwd(input$app)
        # browser()
        # find file to run
        filelist <- list.files()
        filetorun <- grep(pattern = "RUN", filelist, value = T)
        # run it
        source(filetorun)
        # return to shiny app home dir defined above
        setwd(homed)
        
        # construct message
        # get the name of the program that was selected to run
        progname <- names(progchoices[progchoices==input$app])
        # output message
        paste0(progname, " successfully ran!")
        })
    )

    output$message <- renderText ({
        
        # execute reactive expression defined above
        runandmessage()
        
    })
    
}

shinyApp(ui = ui, server = server)