Why does my app work locally, but not on shinyapps.io? - r

Question

I'm trying to deploye my shiny app on shinyapps.io and I get this message :
"An error has occurred
The application failed to start (exited with code 1)."
I tried to commit setwd line and other stuff but yet I didn't find solution.
The issue might be a wrong file path ? Should I put the "read.csv" line into my server or ui function ?
Here is my code :
#setwd(dir = "/media/miles/MILES/Projets & Cours/Master_1/Semestre 2/lardjane/Shiny_app/Projet Shiny")
matches <- read.csv('./matches.csv', stringsAsFactors=FALSE, sep=",", header=TRUE)
matches <- matches[,c(3,6)]
#summary(matches)
matches$platformid <- as.factor(matches$platformid)
#levels(matches$platformid)
#install.packages('shiny')
library(shiny)
#install.packages('rsconnect')
library(rsconnect)
ui <- shinyUI(fluidPage(
# Give the page a title
titlePanel("Game time by server"),
# Generate a row with a sidebar
sidebarLayout(
# Define the sidebar with one input
sidebarPanel(
selectInput("region", "Server:",
choices=levels(matches$platformid)),
hr(),
selectInput(inputId = "n_breaks",
label = "Number of bins in histogram (approximate):",
choices = c(10, 20, 35, 50),
selected = 20),
hr(),
checkboxInput(inputId = "individual_obs",
label = strong("Show individual observations"),
value = FALSE),
checkboxInput(inputId = "density",
label = strong("Show density estimate"),
value = FALSE),
conditionalPanel(condition = "input.density == true",
sliderInput(inputId = "bw_adjust",
label = "Bandwidth adjustment:",
min = 0.2, max = 2, value = 1, step = 0.2)),
hr(),
helpText("Data from Kaggle (2014-2018) League of Legends Ranked Matches.")
),
# Create a spot for the barplot
mainPanel(
plotOutput("timePlot")
)
)
)
)
server <- function(input, output) {
# Fill in the spot we created for a plot
output$timePlot <- renderPlot({
# Render a histogramme
hist(matches[matches$platformid==input$region,2],
probability = TRUE,
breaks = as.numeric(input$n_breaks),
main = "Game Time",
ylab="",
xlab="Duration (seconds)")
if (input$individual_obs) {
rug(matches[matches$platformid==input$region,2])
}
if (input$density) {
dens <- density(matches[matches$platformid==input$region,2],
adjust = input$bw_adjust)
lines(dens, col = "blue")
}
})
}
shinyApp(ui = ui, server = server)
I would like to add one last request. I would like to display R code just below the plot. That can anyone can get access to both (app result and R code). Is that possible ?
Thank you in advance.

Answer 1

swd is not the way to solve this because of how the environments in Shiny (and R in general) work. When you launch Shiny you actually don't know what physical server your Shiny server is running on. So you need to use a generic solution.
Try this:
matches <- read.csv('./matches.csv',
stringsAsFactors=FALSE, sep=",", header=TRUE)

Answer 2

Per https://docs.rstudio.com/shinyapps.io/Storage.html, if the csv file is in the same location as the app, try :
matches <- read.csv('matches.csv', stringsAsFactors=FALSE, sep=",", header=TRUE)
However, I don't think this is your issue; I think the issue is in your rendering of the plot. You use the input$region to generate your histogram, but you don't provide a default value, so it starts as NULL, which causes an issue when you try to construct your histogram. You have 2 options to solve this.
Option 1 is to set a default value for input$region with:
selectInput("region", "Server:",
choices=levels(matches$platformid),
selected = levels(matches$platformid)[1]),
Option 2 is to use req() so that the histogram will not run if any of its required values are not truthy:
server <- function(input, output) {
# Fill in the spot we created for a plot
output$timePlot <- renderPlot({
req(input$region, input$n_breaks)
# Render a histogramme
hist(matches[matches$platformid==input$region,2],
probability = TRUE,
breaks = as.numeric(input$n_breaks),
main = "Game Time",
ylab="",
xlab="Duration (seconds)")
if (input$individual_obs) {
rug(matches[matches$platformid==input$region,2])
}
if (input$density) {
dens <- density(matches[matches$platformid==input$region,2],
adjust = input$bw_adjust)
lines(dens, col = "blue")
}
})
}