Document a shiny application

Question

Is there any way to generate documentation for a R shiny application?

It becomes very hard to maintain a shiny application without documentation.

It seems that all the eco-system of tests/documentation is created for an R package structure. Maybe we can emulate/extend this behavior for a shiny application?

An example :

A reactive expression is typically an R shiny element taht can contain complex data structure.

   filtered_dat <- reactive({ 
      dx[ NAME == input$crr & TOU == input$tou & 
            PlotYear == input$year. & PlotMonth == input$season]
    })

To give more context, I am here in the context of building a complete web application using R shiny. All the business-logic is wrapped in a separated package(s).

For testing Ui I think it is complicated ( one can use Rselenium for example) , but generating doc from roxygen2 comments is just parsing. It should be easy to have such tool.

Viscera

What exactly are you documenting? Much of the actual R code called in a Shiny application could live it it's own package with its own docs. – Herbage

@Herbage good point. But For me Shiny application is just a we application. Even in real web application you call external librarians but you still have the possibility to document it. What about tests? – Viscera

If you separate the the logic and UI layers rigorously, and put the logic in testable libraries, then you have a nice division that should be easy to explain and document. Not sure you could do unit tests on the UI layer in anyway, but that is always a problem anyway. Similar to joran's suggestion. – Altazimuth

@Viscera Did you ever find a solution to this that you were looking for ? – Reeding

@Reeding create a package and put all functions within it. function can have input , output as parameters. – Viscera

@Viscera Thanks for your quick reply. Do you pretty much mean, do minimal coding in the shiny ui and server code, and put in external package functions ? Some ui/server code does grow with more complex use cases so documenting would be nice – Reeding

@Reeding exactly I mean that you put all the code in the package. after all this what is done by shiny packages. So you can have a server/ui/controls file sin your packages that contain all the logic. In the shiny side , use the repo structure views/servers that contain the ui/server call of each page/view. – Viscera

@Viscera I think I understand. You create a package and put the server.R and ui.R files in the .../R/ and / or inst directories. – Reeding

@Viscera I think the answer in the following SO post essentially says what you are suggesting. – Reeding

@Reeding I think my answer is steps beyond that. – Viscera

@Viscera I am a bit new to R packages so I may not completely understand. Do you know of a simple example that captures what you are saying (i.e. a link)? if this is a lot of work than no worries, I will work on figuring it out. I was thinking the ui/server/global would go into the instr directory of the package. – Reeding

Let us continue this discussion in chat. – Viscera

Answer 1

update

Add an example of shiny application

---

There is not an ideal solution but this is basically what I am doing to deal with my shiny applications to create a robust and well "documented" shiny application:

• Create a package where you put all your logic within it. Don't worry to call input/output structure from the package as an argument. Also try to create some controls within your package. For example you can have an inline version of some basic shiny controls.

A typical package will have this structure:

 R
     ui-view1.R
     ui-view2.R
     server-server1.R
     server-server2.R
     controls.R

• Create a shiny application that is structured in a way that reflects your different applications elements. Basically create a view/server files for each app page. You can of course put the shiny application under inst/ui or put it in a separate project.

Here an example:

 app 
     ui.R
     server.R
     global.R
     views
        view1.R
        view2.R
     servers
        server1.R
        server2.R
     init 
        global1.R
        gloabl2.R

Viscera

Answer 2

It is a great question. How do you create a complex clear web application with Shiny?I believe that organize a huge project is the weakness of Shiny architecture.

First, Shiny creates a web in only one html document. This document is divided in layers, to develop a huge application you need to manage correctly the layers. However, this thing presents a significant problem, how do you organize the code?

Well, here, there are different ways to do that. Indeed you can apply different methods like Joe Cheng:

• https://github.com/jcheng5/shiny-partials

In my case, in a huge project I implemented the MVC pattern but adapting it to the Shiny architecture.

Daughtry