R/bearer_token.R

In mkearney/rtw: Collecting Twitter Data

http_req <- function(x) {
  handle <- curl::new_handle()
  if ("options" %in% names(x)) {
    curl::handle_setopt(handle, .list = x[["options"]])
  }
  if ("fields" %in% names(x)) {
    curl::handle_setform(handle, .list = x[["fields"]])
  }
  if ("headers" %in% names(x)) {
    curl::handle_setheaders(handle, .list = x[["headers"]])
  }
  on.exit(curl::handle_reset(handle), add = TRUE)
  curl::curl_fetch_memory(x[["url"]], handle = handle)
}

create_bearer_token <- function(token = NULL) {
  if (is.null(token)) {
    token <- get_token()
  }
  app_keys <- openssl::base64_encode(
    paste0(get_app_key(token), ":", get_app_secret(token))
  )
  req <- list(
    url = "https://api.twitter.com/oauth2/token",
    headers = c(Accept = "application/json, text/xml, application/xml, */*",
      Authorization = paste0("Basic ",  app_keys)),
    fields = c(grant_type = "client_credentials"),
    options = list(post = 1L)
  )
  r <- http_req(req)
  bearer <- from_js(r)
  bearer_env <- new.env()
  assign(".bearer_env", bearer_env, envir = .state)
  assign("bearer", bearer, envir = bearer_env)
  invisible()
}
#' Bearer token
#'
#' Convert default token into bearer token for application only (user-free)
#' authentication method
#'
#' @param token Oauth token
#' @return A bearer token
#'
#' @examples
#' \dontrun{
#' ## use bearer token to search for >18k tweets (up to 45k) w/o hitting rate limit
#' verified_user_tweets <- search_tweets("filter:verified", n = 30000, token = bearer_token())
#'
#' ## get followers (user == app)
#' ### - USER (normal) token – rate limit 15req/15min
#' cnn_flw <- get_followers("cnn", n = 75000)
#' ### - APP (bearer) token – rate limit 15req/15min
#' cnn_flw <- get_followers("cnn", n = 75000, token = bearer_token())
#'
#' ## get timelines (user < app)
#' ### - USER (normal) token – rate limit 900req/15min
#' cnn_flw_data <- get_timelines(cnn_flw$user_id[1:900])
#' ### - APP (bearer) token – rate limit 1500req/15min
#' cnn_flw_data <- get_timelines(cnn_flw$user_id[1:1500], token = bearer_token())
#'
#' ## lookup statuses (user > app)
#' ### - USER (normal) token – rate limit 900req/15min
#' cnn_flw_data2 <- lookup_tweets(cnn_flw_data$status_id[1:90000])
#' ### - APP (bearer) token – rate limit 300req/15min
#' cnn_flw_data2 <- lookup_tweets(cnn_flw_data$status_id[1:30000], token = bearer_token())
#'
#' }
#' @export
bearer_token <- function(token = NULL) {
  bearer <- get_bearer(token)
  if (is.null(bearer)) {
    stop("couldn't find bearer token")
  }
  r <- request(headers = c(Authorization = paste0("Bearer ", bearer$access_token)) )
  structure(r, bearer = bearer, class = c("bearer", "list"))
}


get_bearer <- function(token = NULL) {
  ## create if necessary
  if (!exists(".bearer_env", envir = .state)) {
    create_bearer_token(token)
  }
  ## retrieve
  bearer_env <- get(".bearer_env", envir = .state)
  bearer <- tryCatch(get("bearer", envir = bearer_env), error = function(e) NULL)
  if (is.null(bearer)) {
    stop("couldn't find bearer token")
  }
  bearer
}

get_app_key <- function(token) {
  token$app$key
}

get_app_secret <- function(token) {
  token$app$secret
}

get_oauth_key <- function(token) {
  token$credentials$oauth_token
}

get_oauth_secret <- function(token) {
  token$credentials$oauth_token_secret
}

print.bearer <- function(bearer) {
  cat(paste0("Bearer token: ", attr(bearer, "bearer")$access_token), fill = TRUE)
}