CODEWITHSUNDEEP
rshiny
linuxiaobai
linuxiaobai

Reputation: 67

how to connect to R Shiny website using programming

We have a R shiny based website where we input some parameters and get some results. We can do it manually, but considering many actions are repeat, we want write some R code to automatically pull out the results. Look looks we cannot use some simple REST request, because the HTTP request used some information like "nonce" and "session". Also I am not familiar with the JavaScript. Could someone help me to understand how to do it?enter image description here

Upvotes: 2

Views: 378

Answers (1)

Gregor de Cillia
Gregor de Cillia

Reputation: 7635

There is a functionality session$registerDataObj which allows you to add an API endpoint for a specific shiny session. This will make the provided data available at http://{host}/session/{session_id}/dataobj/{name}.

The minimal app below invokes the produced endpoint via browseURL(). See ?shiny::session for more details.

shinyApp(
  ui = fluidPage(),
  server = function(input, output, session) {
    name <- "iris"
    session$registerDataObj(
      name = name, 
      data = iris, 
      filterFunc = function(data, req) { 
        httpResponse(content = paste('nrow: ', nrow(data))) 
      }
    )
    uri <- paste0("http://", session$request$HTTP_HOST, "/session/", 
                  session$token, "/dataobj/", name)
    browseURL(print(uri))
  }
)
#> Listening on http://127.0.0.1:5130
#> [1] "http://127.0.0.1:5130/session/fd47ff29025bbe4d9dbf922b935186b3/dataobj/iris"

This should open up a new browser tab that shows: "nrow: 150". The return value of session$registerDataObj() can also be used to create the uri with additional query parameters.

But I personally think it is better to use a database in 99% of all usecases. This would mean that there is an export button in your ui which causes the app server to write all relevant results into the database and the database is then accessed by another process that needs the app data.

Upvotes: 2

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