Store a value in the survey data — sd_store

This function allows storing additional values to be included in the survey data, such as respondent IDs or other metadata. When a database connection is provided, it implements session persistence - if a value already exists for the current session, storage is skipped to maintain consistency across page refreshes.

Usage

sd_store_value(value, id = NULL, db = NULL, auto_assign = TRUE)

Arguments

value: The value to be stored. This can be any R object that can be coerced to a character string.
id: (Optional) Character string. The id (name) of the value in the data. If not provided, the name of the value variable will be used.
db: (Optional) Database connection object created with sd_db_connect(). If provided, enables session persistence. If not provided, will automatically look for a variable named 'db' in the calling environment, or fall back to the database connection from the session.
auto_assign: Logical. If TRUE (default), automatically assigns the stored value back to the original variable in the calling environment. This eliminates the need for explicit assignment when session persistence is desired. If FALSE, the function only returns the value without modifying the original variable.

Value

The value that was stored (either the new value or existing value from database if session persistence applies). This allows the function to be used in variable assignments.

Examples

if (interactive()) {
  library(surveydown)

  # Get path to example survey file
  survey_path <- system.file("examples", "sd_ui.qmd",
                             package = "surveydown")

  # Copy to a temporary directory
  temp_dir <- tempdir()
  file.copy(survey_path, file.path(temp_dir, "basic_survey.qmd"))
  orig_dir <- getwd()
  setwd(temp_dir)

  # Define a minimal server
  server <- function(input, output, session) {
    # Set up database connection
    db <- sd_db_connect()

    # Generate and store values with automatic assignment (default behavior)
    respondentID <- sample(1:1000, 1)
    sd_store_value(respondentID, "respID", db)  # respondentID automatically updated

    completion_code <- sample(0:9, 6, replace = TRUE)
    sd_store_value(completion_code)  # completion_code automatically updated

    # Traditional assignment approach (auto_assign = FALSE)
    some_value <- sd_store_value(42, "some_value", auto_assign = FALSE)

    # The function ensures session persistence across page refreshes

    sd_server()
  }

  # Run the app
  shiny::shinyApp(ui = sd_ui(), server = server)

  # Clean up
  setwd(orig_dir)
}