Build the call tree of a running Shiny app

call_tree_app() inspects a shiny::shinyApp() object at runtime, rather than parsing source files on disk. It extracts the server function, collects every function visible in the server's enclosing environment chain, and builds the call graph among them, in the same shape call_stack() returns.

call_tree_app() never calls into the shiny package itself; it only inspects the structure of the shiny.appobj you pass in, so stackcallr does not need shiny installed unless you're building one.

This only works on a shiny.appobj. It can't inspect the ShinyAppHandle returned by shiny::startApp(): that handle is a runtime control object (stop()/status()/url()/result()) for an app that may be running in a separate process, and it exposes no reference back to the app's UI, server, or environment. Pass the shiny.appobj itself, before calling startApp() on it.

Usage

call_tree_app(
  app,
  app_fun = "app",
  ui_fun = NULL,
  server_fun = NULL,
  modules_only = FALSE
)

Arguments

app

A shiny.appobj, as returned by shiny::shinyApp() or shiny::shinyAppDir(). Not the ShinyAppHandle returned by shiny::startApp().

app_fun

Character scalar; label used for the root node. The app object doesn't store the name of its own launch function, so this is display text only. Default "app".

ui_fun

Character scalar or NULL; name of the UI function. When NULL (the default), call_tree_app() tries to recover it automatically, which only works when ui was passed to shiny::shinyApp() as an unevaluated function (shinyApp(ui = app_ui, ...)). If ui was pre-evaluated (shinyApp(ui = app_ui(), ...)), supply the name explicitly so the UI branch is included.

server_fun

Character scalar or NULL; name of the server function. When NULL (the default), the name is inferred by comparing function bodies against those visible in the server's environment.

modules_only

Logical; see call_tree_dir(). Default FALSE.

Value

An object of class call_stack (see call_stack()).

See also

call_tree_dir() for the file-based equivalent.

Examples

if (FALSE) { # \dontrun{
app <- shiny::shinyApp(ui = app_ui, server = app_server)
call_tree_app(app)
call_tree_app(app, modules_only = TRUE)
} # }