R/credentials.R

In CDCgov/Rnssp: A Signature R package for the National Syndromic Surveillance Program (NSSP)

#' A \code{Credentials} Class Representing a Credentials object
#'
#' @description
#' A \code{Credentials} object has a username, a password and a key.
#'
#' @details
#' A \code{Credentials} object can get API data via an API URL.

Credentials <- R6::R6Class(
  "NSSPCredentials",
  private = list(
    ..username = NSSPContainer$new(NULL),
    ..password = NSSPContainer$new(NULL),
    ..__ = NSSPContainer$new(stringi::stri_rand_strings(1, 1024, pattern = "[A-Za-z0-9*-+=/_$@.?!%|;:#~<>()[]\`\']"))
  ),
  public = list(

    #' @description
    #' Initializes a new Credentials object.
    #' @param username a string for username
    #' @param password a string for password
    #' @return A new \code{Credentials} object
    initialize = function(username = NULL, password = NULL) {
      if (!missing(username)) {
        private$..username <- NSSPContainer$new(safer::encrypt_string(username, key = private$..__$value, ascii = FALSE))
      }
      if (!missing(password)) {
        private$..password <- NSSPContainer$new(safer::encrypt_string(password, key = private$..__$value, ascii = FALSE))
      }
    },

    #' @description
    #' Get API response
    #' @param url a character of API URL
    #' @return An object of class \code{response}
    #' @examples
    #' \dontrun{
    #' myProfile <- Credentials$new(askme("Enter my username: "), askme())
    #' url <- "https://httpbin.org/json"
    #' api_response <- myProfile$get_api_response(url)
    #' }
    get_api_response = function(url) {
      if (is.null(private$..password$value)) {
        assertions::assert_string(url)
        res <- httr::GET(url)
      } else {
        assertions::assert_string(url)
        res <- url %>%
          httr::GET(., httr::authenticate(
            private$..username$value %>% safer::decrypt_string(., private$..__$value),
            private$..password$value %>% safer::decrypt_string(., private$..__$value)
          ))
      }
      res$request$options$userpwd <- ""
      cli::cli_alert_info(httr::http_status(res$status_code)$message)
      return(res)
    },

    #' @description
    #' Get API data
    #' @param url a character ofAPI URL
    #' @param fromCSV a logical, defines whether data are returned in .csv format or .json format
    #' @param ... further arguments and CSV parsing parameters to be passed to \code{\link[readr]{read_csv}} when \code{fromCSV = TRUE}.
    #' @return a dataframe (\code{fromCSV = TRUE}) or a list containing a dataframe and its metadata (\code{fromCSV = TRUE})
    #' @examples
    #' \dontrun{
    #' myProfile <- Credentials$new(askme("Enter my username: "), askme())
    #' json_url <- "https://httpbin.org/json"
    #' api_data_json <- myProfile$get_api_data(json_url)
    #'
    #' csv_url <- "https://httpbin.org/robots.txt"
    #' api_data_csv <- myProfile$get_api_data(csv_url, fromCSV = TRUE)
    #' }
    get_api_data = function(url, fromCSV = FALSE, ...) {
      assertions::assert_string(url)
      apir <- self$get_api_response(url)
      if(apir$status_code == 200){
        if(any("data.frame" %in% class(httr::content(apir, as = "text")))){
          return(httr::content(apir, as = "text"))
        }
        apir %>% {
          if (fromCSV) {
            httr::content(., by = "text/csv") %>% readr::read_csv(...)
          } else {
            httr::content(., as = "text") %>% jsonlite::fromJSON()
          }
        }
      }
    },

    #' @description
    #' Get API graph
    #' @param url a character of API URL
    #' @param file_ext a non-empty character vector giving the file extension. Default is \code{.png}.
    #' @return A list containing an api_response object and a path to a time series graph in .png format
    #' @examples
    #' \dontrun{
    #' myProfile <- Credentials$new(askme("Enter my username: "), askme())
    #' url <- "<url>"
    #' api_data_graph <- myProfile$get_api_graph(url)
    #' names(api_data_graph)
    #' img <- png::readPNG(api_data_graph$graph)
    #' grid::grid.raster(img)
    #' }
    get_api_graph = function(url, file_ext = ".png") {
      assertions::assert_string(url)
      graph <- tempfile(fileext = file_ext)
      apir <- url %>%
        httr::GET(., httr::authenticate(
          private$..username$value %>% safer::decrypt_string(., private$..__$value),
          private$..password$value %>% safer::decrypt_string(., private$..__$value)
        ), httr::write_disk(graph, overwrite = TRUE))
      apir$request$options$userpwd <- ""
      cli::cli_alert_info(httr::http_status(apir$status_code)$message)
      list("api_response" = apir, "graph" = graph)
    }
  )
)