How to know if the app is running at local or on server? (R Shiny)

The standard way to do this in Shiny is with: Sys.getenv('SHINY_PORT'). You could write something like:

is_local <- Sys.getenv('SHINY_PORT') == ""

EDIT 2020: There still is no official way to do this, but I would opt for Yihui's method of is_local <- Sys.getenv('SHINY_PORT') == ""

---

I don't know if this is the proper way or not, but you could look at the host using session$clientData$url_hostname. When you run it locally, unless you specifically change the host, it will be 127.0.0.1 and I'm guessing on shinyapps it'll be something like shinyapps.io. Sample code

runApp(shinyApp(
  ui = fluidPage(
  ),
  server = function(input, output, session) {
    observe({
      if (session$clientData$url_hostname == "127.0.0.1") {
        setwd(...)
      }
    })
  }
))

Something of that sort should work, though I can't vouch for whether or not it's the best solution