R/authenticate.R

In MSUDenver-Stats-Science-Club/Spotify-EDA:

#' @title Authenticate with Spotify's API
#'
#' @description A function to allow the user to authenticate with Spotify's API. This will refresh expired tokens. In order to interact with the Spotify API, please be sure to create an app within their system. See additional references to get started.
#'
#' @seealso Get started with the Spotify API here: https://developer.spotify.com/documentation/web-api/quick-start/
#'
#' @return `NULL`.
#' @export
authenticate <- function() {

  ## Adding in code that informs the user of what's happening
  usethis::ui_info("Attempting to authenticate...")

  ## Path required to authenticate in Spotify's web service
  auth_path <- "https://accounts.spotify.com/api/token"

  ## Check to see if required environment variables are present
  if (nchar(Sys.getenv("SPOTIFY_APP_ID")) == 0 | is.null(Sys.getenv("SPOTIFY_APP_ID"))) {
    rlang::abort("Global environment variable 'SPOTIFY_APP_ID' not found. Please create variable in global environment using 'usethis::edit_r_environ()'.")
  }

  if (nchar(Sys.getenv("SPOTIFY_APP_SECRET")) == 0 | is.null(Sys.getenv("SPOTIFY_APP_SECRET"))) {
    rlang::abort("Global environment variable 'SPOTIFY_APP_SECRET' not found. Please create variable in global environment using 'usethis::edit_r_environ()'.")
  }

  usethis::ui_info("Creating required headers...")

  ## Authentication headers
  auth_header <- httr::add_headers(
    "Authorization" = paste0("Basic ", RCurl::base64(
      paste0(
        Sys.getenv("SPOTIFY_APP_ID"),
        ":",
        Sys.getenv("SPOTIFY_APP_SECRET")
        )
      )
    )
  )

  usethis::ui_info("Making API Request...")

  ## Request to authenticate
  request <- httr::POST(
    auth_path,
    auth_header,
    body = list("grant_type" = "client_credentials"),
    encode = "form"
  )

  ## Check response to get valid token and expiration time limit
  if (request$status_code == 200) {

    usethis::ui_info("Request Successful!")

    request_content <- request %>% httr::content()

    token_header <- httr::add_headers(
      "Authorization" = paste0("Bearer ", request_content$access_token)
    )

    usethis::ui_info("Setting headers for future requests...")

    ## Set default headers for future requests made
    httr::set_config(
      token_header
    )

  } else {

    rlang::abort(glue::glue("Request unsuccessful... Returned status code {request$status_code}, please check variables used to create request!"))

  }

  usethis::ui_done("Finished!")

  return(invisible())

}