I make shiny app with websocket connection, and want close connection, when i exiting (stop) my shiny app. I have a suggestion that function on.exit() can solve my problem, but I do not know where to use it in shiny app. Are there any other ways to close the connection when the application stops?
You can use session$onSessionEnded for this purpose. Once the session ended the code inside will run. For example:
library(shiny)
# Define UI for application that draws a histogram
ui <- fluidPage(
# Application title
titlePanel("Old Faithful Geyser Data"),
# Sidebar with a slider input for number of bins
sidebarLayout(
sidebarPanel(
sliderInput("bins",
"Number of bins:",
min = 1,
max = 50,
value = 30)
),
# Show a plot of the generated distribution
mainPanel(
plotOutput("distPlot")
)
)
)
# Define server logic required to draw a histogram
server <- function(input, output) {
output$distPlot <- renderPlot({
# generate bins based on input$bins from ui.R
x <- faithful[, 2]
bins <- seq(min(x), max(x), length.out = input$bins + 1)
# draw the histogram with the specified number of bins
hist(x, breaks = bins, col = 'darkgray', border = 'white')
})
session$onSessionEnded(function() {
# you can put your code here to close the connection
})
}
# Run the application
shinyApp(ui = ui, server = server)
Related
When I run a shiny application on RStudio, my app runs and the URL looks like this:
Listening on http://127.0.0.1:4991
But each time I run again the app, the port changes, I wonder if there is a way to obtain the url as a variable or something like that. I mean, each time that I run the app, I want to obtain the URL and save it in a variable.
Thank you
You can get the url with session$clientData:
library(shiny)
ui <- basicPage()
server <- function(input, output, session){
observe({
print(reactiveValuesToList(session$clientData))
})
}
shinyApp(ui, server)
You can specify the port using options:
#example: https://shiny.rstudio.com/articles/basics.html
options(shiny.host = '0.0.0.0')
options(shiny.port = 8888)
ui <- fluidPage(
# App title ----
titlePanel("Hello Shiny!"),
# Sidebar layout with input and output definitions ----
sidebarLayout(
# Sidebar panel for inputs ----
sidebarPanel(
# Input: Slider for the number of bins ----
sliderInput(inputId = "bins",
label = "Number of bins:",
min = 1,
max = 50,
value = 30)
),
# Main panel for displaying outputs ----
mainPanel(
# Output: Histogram ----
plotOutput(outputId = "distPlot")
)
)
)
# Define server logic required to draw a histogram ----
server <- function(input, output) {
# Histogram of the Old Faithful Geyser Data ----
# with requested number of bins
# This expression that generates a histogram is wrapped in a call
# to renderPlot to indicate that:
#
# 1. It is "reactive" and therefore should be automatically
# re-executed when inputs (input$bins) change
# 2. Its output type is a plot
output$distPlot <- renderPlot({
x <- faithful$waiting
bins <- seq(min(x), max(x), length.out = input$bins + 1)
hist(x, breaks = bins, col = "#75AADB", border = "white",
xlab = "Waiting time to next eruption (in mins)",
main = "Histogram of waiting times")
})
}
shinyApp(ui, server)
In the following code,
is it possible to put bins in movable panel like the color change panel.
The follwoing image shows one panel is movable but the other is not movable.
library(shiny)
# Define UI for application that draws a histogram
ui <- fluidPage(
shiny::tags$head(
shinythemes::themeSelector()
),#taghead
# Application title
titlePanel("Old Faithful Geyser Data"),
# Sidebar with a slider input for number of bins
sidebarLayout(
sidebarPanel(
sliderInput("bins",
"Number of bins:",
min = 1,
max = 50,
value = 30)
),
# Show a plot of the generated distribution
mainPanel(
plotOutput("distPlot")
)
)
)
# Define server logic required to draw a histogram
server <- function(input, output) {
output$distPlot <- renderPlot({
# generate bins based on input$bins from ui.R
x <- faithful[, 2]
bins <- seq(min(x), max(x), length.out = input$bins + 1)
# draw the histogram with the specified number of bins
hist(x, breaks = bins, col = 'darkgray', border = 'white')
})
}
# Run the application
shinyApp(ui = ui, server = server)
How to make movable panel?
Please let me know.
**Answer: The following code makes a draggable panel**
library(shiny)
# Define UI for application that draws a histogram
ui <- fluidPage(
shiny::tags$head(
shinythemes::themeSelector()
),#taghead
# Application title
titlePanel("Old Faithful Geyser Data"),
# Sidebar with a slider input for number of bins
# Show a plot of the generated distribution
mainPanel(
absolutePanel(
sliderInput("bins",
"Number of bins:",
min = 1,
max = 50,
value = 30),
draggable = T
),
plotOutput("distPlot")
)
)
# Define server logic required to draw a histogram
server <- function(input, output) {
output$distPlot <- renderPlot({
# generate bins based on input$bins from ui.R
x <- faithful[, 2]
bins <- seq(min(x), max(x), length.out = input$bins + 1)
# draw the histogram with the specified number of bins
hist(x, breaks = bins, col = 'darkgray', border = 'white')
})
}
# Run the application
shinyApp(ui = ui, server = server)
Movable panels can be achieved with absolutePanel.
Edit
Solved: Was an issue with the shiny servers which they have now fixed
I have an odd issue where I copy the user guide exactly and the sample app won't deploy properly for me. The app works as expected locally but when I deploy to shinyapps.io the app only loads the ui and even that is buggy.
The UI:
## ui.R
library(shiny)
shinyUI(fluidPage(
# Application title
titlePanel("Old Faithful Geyser Data"),
# Sidebar with a slider input for number of bins
sidebarLayout(
sidebarPanel(
sliderInput("bins",
"Number of bins:",
min = 1,
max = 50,
value = 30)
),
# Show a plot of the generated distribution
mainPanel(
plotOutput("distPlot")
)
)
))
The server
## server.R
library(shiny)
shinyServer(function(input, output) {
output$distPlot <- renderPlot({
# generate bins based on input$bins from ui.R
x <- faithful[, 2]
bins <- seq(min(x), max(x), length.out = input$bins + 1)
# draw the histogram with the specified number of bins
hist(x, breaks = bins, col = 'darkgray', border = 'white')
})
})
When I run locally I get as expected:
image
However when I deploy I get:
image (notice the input is changed to a text input)
Would appreciate any help
I have a shiny app with a longer computation depending on the input. I am wondering if it is possible to display a text in the main panel at the same time when the computation is done (and not before).
Let's make an easy example. I simulated the longer computation with Sys.sleep():
# Define UI for application that draws a histogram
ui <- shinyUI(fluidPage(
# Application title
titlePanel("Old Faithful Geyser Data"),
# Sidebar with a slider input for number of bins
sidebarLayout(
sidebarPanel(
sliderInput("bins",
"Number of bins:",
min = 1,
max = 50,
value = 30)
),
# Show a plot of the generated distribution
mainPanel(
h3('This is an example'),
plotOutput("distPlot")
)
)
))
# Define server logic required to draw a histogram
server <- shinyServer(function(input, output) {
output$distPlot <- renderPlot({
# generate bins based on input$bins from ui.R
x <- faithful[, 2]
bins <- seq(min(x), max(x), length.out = input$bins + 1)
# draw the histogram with the specified number of bins
hist(x, breaks = bins, col = 'darkgray', border = 'white')
Sys.sleep(5)
})
})
# Run the application
shinyApp(ui = ui, server = server)
The goal would be, to show the text 'This is an example' at the same time the computation is done and not before.
I think I have to make the text somehow reactive, but so far I haven't found a solution for this. Maybe a conditionalPanel could do it, but how can I bring the computation time in the condition? Any ideas?
Would this be what you search for? Your text variable as a reactive after observing the event of distPlot
library(shiny)
# Define UI for application that draws a histogram
ui <- shinyUI(fluidPage(
# Application title
titlePanel("Old Faithful Geyser Data"),
# Sidebar with a slider input for number of bins
sidebarLayout(
sidebarPanel(
sliderInput("bins",
"Number of bins:",
min = 1,
max = 50,
value = 30)
),
# Show a plot of the generated distribution
mainPanel(
textOutput('text1'),
plotOutput("distPlot")
)
)
))
# Define server logic required to draw a histogram
server <- shinyServer(function(input, output) {
output$distPlot <- renderPlot({
# generate bins based on input$bins from ui.R
x <- faithful[, 2]
bins <- seq(min(x), max(x), length.out = input$bins + 1)
# draw the histogram with the specified number of bins
hist(x, breaks = bins, col = 'darkgray', border = 'white')
Sys.sleep(2)
})
observeEvent(plotOutput("distPlot"), {
output$text1 <- renderText({ paste("Number of bins:", input$bins)})
})
})
# Run the application
shinyApp(ui = ui, server = server)
Is there a way to get italic words in my shiny titlePanel?
I tried
library(shiny)
# Define UI for application that draws a histogram
ui <- shinyUI(fluidPage(
# Application title
titlePanel("Old <em>Faithful Geyser</em> Data"),
# Sidebar with a slider input for number of bins
sidebarLayout(
sidebarPanel(
sliderInput("bins",
"Number of bins:",
min = 1,
max = 50,
value = 30)
),
# Show a plot of the generated distribution
mainPanel(
plotOutput("distPlot")
)
)
))
# Define server logic required to draw a histogram
server <- shinyServer(function(input, output) {
output$distPlot <- renderPlot({
# generate bins based on input$bins from ui.R
x <- faithful[, 2]
bins <- seq(min(x), max(x), length.out = input$bins + 1)
# draw the histogram with the specified number of bins
hist(x, breaks = bins, col = 'darkgray', border = 'white')
})
})
# Run the application
shinyApp(ui = ui, server = server)
and this print the title as Old <em>Faithful Geyser</em> Data. The em does not get interpreted. Am I doing something wrong or isn't there a way to get italic font in the title?
hello try this it should work
titlePanel( div(HTML("Old <em>Faithful Geyser</em> Data")))