Getting URL parameters in a shiny dashboard app

[tmilliman]

Has anyone been successful in using URL parameters in a shiny dashboard app? I've experimented with the many posts and documentation for using the session$clientData$url_search string. I can get several simple examples to work but have not been able to access the url_search string from within the dashboard environment.

[pieterjanvc]

Hi,

Could you please provide us with a comprehensive example using the post below to let us reproduce the issue and see where you get stuck:

Shiny debugging and reprex guide

Shiny issues can be challenging to resolve relative to other problems with your code or statistical methods. Shiny apps are often large, complex projects with interacting files. When seeking help from others it is considered polite to: First, do your best to work through RStudio's debugging tools to diagnose your issue on your own. Often those shiny logs and tracebacks are useful to others trying to help out. Second, strive to minimize the effort required to replicate your issue. You can do this with a reproducible example ("reprex"). Shiny Debugging Errors in Shiny code can be difficult to track down. If you don't know where your problem is coming from, you can track it down with some o…

Thanks,
PJ

[tmilliman]

PJ,

In coming up with a simple example I managed to get this to work. Here's the example in case anyone else has the same trouble.

Tom

library(shiny)
library(shinydashboard)

ui <- dashboardPage(
  dashboardHeader(title="Query Parameters"),
  dashboardSidebar(),
  dashboardBody(
    h3("URL components"),
    verbatimTextOutput("urlText"),
    h3("Parsed query string"),
    verbatimTextOutput("queryText")
  )
)

server <- function(input, output, session) {
  
  # Return the components of the URL in a string:
  output$urlText <- renderText({
    paste(sep = "",
          "protocol: ", session$clientData$url_protocol, "\n",
          "hostname: ", session$clientData$url_hostname, "\n",
          "pathname: ", session$clientData$url_pathname, "\n",
          "port: ",     session$clientData$url_port,     "\n",
          "search: ",   session$clientData$url_search,   "\n"
    )
  })
  
  # Parse the GET query string
  output$queryText <- renderText({
    query <- parseQueryString(session$clientData$url_search)
    
    # Return a string with key-value pairs
    paste(names(query), query, sep = "=", collapse=", ")
  })
}

shinyApp(ui, server)

[andresrcs]

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