search_selection_api {shiny.semantic}

Add Semantic UI search selection dropdown based on REST API

Description

Define the (multiple) search selection dropdown input for retrieving remote selection menu content from an API endpoint. API response is expected to be a JSON with property fields 'name' and 'value'. Using a search selection dropdown allows to search more easily through large lists.

Usage

search_selection_api(
  input_id,
  search_api_url,
  multiple = FALSE,
  default_text = "Select"
)

Arguments

input_id

Input name. Reactive value is available under input[[input_id]].

search_api_url

Register API url with server JSON Response containing fields 'name' and 'value'.

multiple

TRUE if the dropdown should allow multiple selections, FALSE otherwise (default FALSE).

default_text

Text to be visible on dropdown when nothing is selected.

Examples

## Only run examples in interactive R sessions
if (interactive()) {
   library(shiny)
   library(shiny.semantic)
   library(gapminder)
   library(dplyr)

   ui <- function() {
    shinyUI(
      semanticPage(
        title = "Dropdown example",
        uiOutput("search_letters"),
        p("Selected letter:"),
        textOutput("selected_letters")
      )
    )
  }

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

   search_api <- function(gapminder, q) {
     has_matching <- function(field) {
        startsWith(field, q)
      }
      gapminder %>%
        mutate(country = as.character(country)) %>%
        select(country) %>%
        unique %>%
        filter(has_matching(country)) %>%
        head(5) %>%
          transmute(name = country,
                  value = country)
    }

    search_api_url <- shiny.semantic::register_search(session,
                                                      gapminder,
                                                      search_api)
    output$search_letters <- shiny::renderUI(
      search_selection_api("search_result", search_api_url, multiple = TRUE)
    )
    output$selected_letters <- renderText(input[["search_result"]])
  })

  shinyApp(ui = ui(), server = server)
}