Display R Shiny Plot After Inputting File - r

Question

I would like to display a chart (for a Shiny app), based on data inputted by a user through a file. With the current setup, there is an error message claiming the data is not found, so the plot (from the rCharts package) does not get displayed.
Code attached below:
ui.R
library(rCharts)
library(shinydashboard)
library(shiny)
dashboardPage(
skin = "black",
header <- dashboardHeader(
titleWidth = 475
),
sidebar <- dashboardSidebar(
sidebarMenu(
)
),
body <- dashboardBody(
tabItems(
tabItem("setup",
box(width = 4,title = tags$b('Input Dataset'), solidHeader = T, status = 'primary', collapsible = T,
helpText("Default max. file size is 5 MB. Please upload both files for analysis in csv format."),
fileInput("file1","Upload the first file"),
fileInput("file2","Upload the second file")
),
box(height = 500, width = 12,title = tags$b('Visualize Data'), solidHeader = T, status = 'primary',
showOutput("myPlot", "Highcharts")
)
)
)
)
)
server.R
library(shiny)
library(rCharts)
# Define server logic required to draw a histogram
shinyServer(function(input, output) {
observe({
file1 = input$file1
file2 = input$file2
if (is.null(file1) || is.null(file2)) {
return(NULL)
}
data1 = read.csv(file1$datapath)
data2 = read.csv(file2$datapath)
})
output$myPlot<-renderChart2({
# Prepare data
data1[,2] <- (data1[,2])/sum(data1[,2])
# Create chart
a <- rCharts:::Highcharts$new()
a$chart(type = "column")
a$xAxis(categories = rownames(x))
a$yAxis(title = list(text = "Normalized Intensity"))
a$data(data1)
a$set(width = 600, height = 500)
return(a)
})
})

Answer 1

Try adding something like this. Make sure you check for nrow and return and empty Highcharts$new() object as renderChart2 expects one.
library(shiny)
library(rCharts)
# Define server logic required to draw a histogram
shinyServer(function(input, output) {
data1 <- reactive({read.csv(file1$datapath)})
data2 <- reactive({read.csv(file2$datapath)})
output$myPlot<-renderChart2({
data1 <- data1()
# Prepare data
if(nrow(data1==0)){return(Highcharts$new())}
data1[,2] <- (data1[,2])/sum(data1[,2])
# Create chart
a <- rCharts:::Highcharts$new()
a$chart(type = "column")
a$xAxis(categories = rownames(x))
a$yAxis(title = list(text = "Normalized Intensity"))
a$data(data1)
a$set(width = 600, height = 500)
return(a)
})
})