Reactive function to read rtf in rshiny - shiny

Question

I am new to R and RShiny. Am building an application to compare two rtf files where a user can choose the two files dynamically. Is there a reactive function that I can use to read an rtf file before I pass it on to renderDiffr? Here is one version of the code I generated but the issue I am having is for these two rtf files I pick under folder1 and folder2 should be passed to renderDiffr below. I am sure there is a simple solution that I am yet to figure out. Would appreciate your help.
library(diffr)
library(shiny)
ui <- fluidPage(
# Main title of the page
titlePanel(HTML("<center>Comparison of two files</center>")),
# Browse buttons to select files
sidebarLayout(position="left",
sidebarPanel(
#fileInput("selectfolder1","Select file from folder 1"),
#fileInput("selectfolder2","Select file from folder 2"),
# Submit button to perform the compare
actionButton("goButton", "Compare", class = "btn-success")
),
mainPanel(
verbatimTextOutput("folder1"),
verbatimTextOutput("folder2"),
diffrOutput("value")
)))
shinyServer(
server <- function(input, output, session){
re1<-reactive({
file1<-file.choose()
})
output$folder1<-renderText({
re1()
})
re2<-reactive({
file2<-file.choose()
})
output$folder2<-renderText({
re2()
})
re3<-reactive({
input$goButton
x<-diffr(folder1,folder2, before="Folder 1",after="Folder 2")
})
output$value<-renderDiffr({
re3()
})
}
)
shinyApp(ui, server)

Answer 1

According to this documentation you pass the result of diffr() to diffrOutput().
What I changed:
When you use a reactive function make sure that you return the result at the end of it. I use return() for clarity (though it's not necessary).
In diffr(folder1,folder2, ...) I used diffr(re1(), re2(), ...) for obvious reasons.
I also skipped the re3 reactive In this sample and used diffr() directly in renderDiffr. But that is merely to reduce complexity.
library(diffr)
library(shiny)
ui <- fluidPage(
# Main title of the page
titlePanel(HTML("<center>Comparison of two files</center>")),
# Browse buttons to select files
sidebarLayout(position="left",
sidebarPanel(
#fileInput("selectfolder1","Select file from folder 1"),
#fileInput("selectfolder2","Select file from folder 2"),
# Submit button to perform the compare
actionButton("goButton", "Compare", class = "btn-success")
),
mainPanel(
verbatimTextOutput("folder1"),
verbatimTextOutput("folder2"),
diffrOutput("FileDiff", width="600px", height="auto")
)))
shinyServer(
server <- function(input, output, session){
re1<-reactive({
file1<-file.choose()
file1
})
output$folder1<-renderText({
re1()
})
re2<-reactive({
file2<-file.choose()
file2
})
output$folder2<-renderText({
re2()
})
# re3<-reactive({
# input$goButton
# x<-diffr(folder1,folder2, before="Folder 1",after="Folder 2")
# return(x)
# })
output$FileDiff <- renderDiffr({
input$goButton
diffr(re1(), re2(), before="Folder 1", after="Folder 2")
})
}
)
shinyApp(ui, server)