R/auth_NLU.R

In johannesharmse/watsonNLU:

#' Watson Natural Language Understanding API Authentication
#'
#' See the \href{https://github.com/johannesharmse/watsonNLU/blob/master/README.md}{sign-up} documentation for step by step instructions to secure your own username and password to enable you to authenticate the Watson NLU API. The \strong{auth_NLU} function takes in a username and password as input to authenticate the users computer to use the Watson Natural Language Understanding API.
#'
#'
#' @param username Authentication IBM Watson Natural-Language-Understanding-3j \strong{username}
#' @param password Authentication IBM Watson Natural-Language-Understanding-3j \strong{password}
#'
#' @return If authentication is successful, there is no return value. If unsuccessful,
#'    the function will ask the user to ensure username and password combination are correct.
#'
#' @examples
#'
#' credentials <- readRDS("../tests/testthat/credentials.rds")
#' username <- credentials$username
#' password <- credentials$password
#'
#' # Authenticate using Watson NLU API Credentials
#' auth_NLU(username, password)
#'
#' @seealso \code{\link[watsonNLU]{keyword_sentiment}}, \code{\\link[watsonNLU]{keyword_relevance}}, \code{\\link[watsonNLU]{keyword_emotions}}, \code{\\link[watsonNLU]{text_categories}}
#'
#'
#' @import httr
#'
#' @export

auth_NLU <- function(username = NULL, password=NULL){
  # check that username and password have been specified as character arguments
  if (is.null(username) ||
      is.null(password) ||
      !is.character(username) ||
      !is.character(password)){
    stop("Please specify a valid username and password combination as string arguments.")
  }
    # base login url
    url_NLU = "https://gateway.watsonplatform.net/natural-language-understanding/api/v1/analyze"

    response <- GET(url=paste0(url_NLU),
         authenticate(username, password),
         add_headers("Content-Type"="application/json")
         )

    status <- status_code(response)

    if (status == 400){

      watson_credentials <<- new.env(parent = globalenv())
      assign("username", username, envir = watson_credentials)
      assign("password", password, envir = watson_credentials)

      return(print("Valid credentials provided."))

    }else if(status == 401){
      stop("Invalid credentials provided.")
    }else{
      stop(content(response))
    }
}