CSV quick plot error - csv

Question

I would like to use the CSV quick plot application to analyze data however even with all the packages installed the app continues to show an error. The error message is:
Error in file(file, "rt") : cannot open the connection
Warning in run(timeoutMs) :
cannot open file
The code is below:
UI
library(shiny)
shinyUI(pageWithSidebar(
headerPanel("CSV Quick Plot"),
sidebarPanel(
fileInput('infile', 'Choose file to upload',
accept = c(
'text/csv',
'text/comma-separated-values',
'text/tab-separated-values',
'text/plain',
'.csv',
'.tsv'
)
),
selectInput("plotType", label = "Select Plot Type",
c("Histogram" = "hist",
"Correlation" = "corr")),
dateInput("date", "Date:"),
submitButton("Submit")
),
mainPanel(
h3('Output Information'),
h4('File entered'),
verbatimTextOutput("ofile"),
h4('You selected plot type'),
verbatimTextOutput("oplotType"),
h4('You entered'),
verbatimTextOutput("odate"),
plotOutput('newHist')
)
))
server
library(UsingR)
library(shiny)
library(Hmisc)
library(corrplot)
wd <- getwd()
setwd(wd)
shinyServer(
function(input, output) {
output$ofile <- renderPrint({input$infile})
output$oplotType <- renderPrint({input$plotType})
output$odate <- renderPrint({input$date})
plotdata <- reactive({
filestr <- input$infile
read.csv(filestr$name)
if(is.null(input$file1))
return(NULL)
})
output$newHist <- renderPlot({
hist(plotdata())
})
# Conditional plot selection is test in progress
# corrdf <- cor(plotdata)
# output$newHist <- renderPlot({
# corrplot(corrdf, method = "circle")
# })
}
)
Please help me in getting this application to run. Thank you!

Answer 1

There are three problems with your code.
you're checking for if(is.null(input$file1)) but I believe you want to use input$infile
the above check should be done BEFORE read.csv because if there is no file chosen, you don't want to read a file
when reading the file you want to use filestr$datapath instead of filestr$name. The name only gives you the name of the file on the user's local machine, while the datapath gives the actual full path to the file that's been uplodaed
Here is a simplification of your app that only deals with selecting a file and reading it into csv, demonstrating all those points
runApp(shinyApp(
ui = fluidPage(
fileInput('infile', 'Choose file to upload',
accept = c(
'text/csv',
'text/comma-separated-values',
'text/tab-separated-values',
'text/plain',
'.csv',
'.tsv'
)
)
),
server = function(input, output, session) {
plotdata <- reactive({
if (is.null(input$infile)) {
return()
}
filestr <- input$infile
read.csv(filestr$datapath)
})
observe({
cat(str(plotdata()))
})
}
))