There was a need for me to build a prediction model in R and a Shiny app to allow users to get predictions out of my model. As the building of a prediction model take quite a while, it is not feasible for my shiny app to build the prediction model on demand.
There must be a way for my Shiny app to load my prediction model only once for fulfilling prediction requests from the users. As with many other programming languages, there are mechanisms in R that allow me to save my environment objects in one session and load them back in another session. This post documents how I can save and load environment objects in R.
There is a number dial that changes rapidly and a text field for the user to enter his name. When the user clicks on the "get lucky number" button, jQuery is used to send the lucky number on the number dial and the user name to the server.
The server generates a text file based on the input from the user and sends the file back to the browser. The browser will then show a download dialog box for the user to decide whether to save a copy of the file or view the file using one of the native applications found in his/her computer.