extract_query_param: Extract parameters ID from query string
In jdtrat/shinyrandomize: What the Package Does (One Line, Title Case)

Description Usage Arguments Details Value See Also Examples

View source: R/query-helpers.R

This function is useful for parsing individual parameters from a query string. It can be used both outside of and within a Shiny application.

1	extract_query_param(param, active_session = TRUE, query_string)

`param`	The query parameter whose value should be retrieved.
`active_session`	LOGICAL: TRUE (default) for use in interactive shiny sessions. FALSE for parsing a character string supplied by `query_string` with query parameters.
`query_string`	If not run in an active session, the character string containing query parameters to parse.

For use outside of a Shiny application, extract_query_param() is most similar to shiny::parseQueryString(), and within a Shiny application, it is most similar to shiny::getQueryString(). Both shiny functions return named lists of all query parameters and their values. In contrast, extract_query_param() returns a character string representing the value of the supplied parameter.

The value from the requested query parameter.

Other Query Strings: format_query_param(), insert_query_param()

# Outside of a Shiny application

extract_query_param(param = "best_cat",
                    active_session = FALSE,
                    query_string = "?person=jdt&favorite_food=sushi&best_cat=tucker")


# Within a Shiny application

if (interactive()) {

library(shiny)
library(shinyrandomize)

ui <- fluidPage(
  textInput("extractingParam", "Which parameter do you want to extract?"),
  verbatimTextOutput("query")
)

server <- function(input, output, session) {

  # On start up, insert the following query string:
  # "?person=jdt&favorite_food=sushi&best_cat=tucker"
  observe({
    if (session$clientData$url_search == "") {
      insert_query_param(param = c("person", "favorite_food", "best_cat"),
                         value = c("jdt", "sushi", "tucker"))
    }
  })

  # When one of the query parameters, 'person', 'food',
  # or 'best_cat' is specified, extract and show it.
  # The output will only appear for a valid parameter.
  observeEvent(input$extractingParam, {
    output$query <- renderText({
      extract_query_param(param = input$extractingParam)
    })
  })

}

shinyApp(ui, server)

}