R/DBConnection.R

In shinyChatR: R Shiny Chat Module

#' DBConnection R6 Class
#'
#' An R6 class representing a connection to a database for the chat module.
#'
#' @field connection A database connection object, created using a package such as RSQLite.
#' @field table The table that contains the chat information.
#'
#'
DBConnection <- R6::R6Class("DBConnection",
                            public = list(
                              connection = NULL,
                              table = NULL,
                              #' Initialize the R6 Object
                              #'
                              #' @param connection DB connection
                              #' @param table Table name
                              #'
                              #'
                              initialize = function(connection, table="chat_data") {
                                db.exists <- DBI::dbExistsTable(connection, table)
                                if(!db.exists) {
                                  df <- data.frame(
                                    user = character(),
                                    text = character(),
                                    time = double())
                                  DBI::dbWriteTable(connection, table, df)
                                }
                                self$connection <- connection
                                self$table <- table
                              },
                              #' @description Reads the full dataset
                              #'
                              #' @returns The full dataset
                              #'
                              get_data = function() {
                                DBI::dbGetQuery(self$connection, paste('SELECT * FROM', self$table))
                              },
                              #' Save a message to data source
                              #'
                              #' @param message The message to be stores
                              #' @param user The user who entered the message
                              #' @param time The time when message was submitted
                              #'
                              insert_message = function(message, user, time) {
                                DBI::dbExecute(self$connection, paste('INSERT INTO', self$table, '(user, text, time)
                                            VALUES (?, ?, ?);'),
                                               list(user, message, time))
                              }
                            )
)