R/ct_build_request.R

In ropensci/comtradr: Interface with the United Nations Comtrade API

#' Build a valid request object from the checked parameters
#'
#' This is an internal function takes the necessary parameters
#' from `ct_check_params()` and creates a httr2 request to be performed.
#' This request can then be used in a second function, `ct_perform_request()`
#' to actually return the data. It is called internally ct `ct_get_data()`
#'
#' @param params a named vector of parameters for the comtrade request,
#' result from `ct_check_params()`.
#'
#' @noRd
#' @returns a httr2 request object
#' @inheritParams ct_get_data
ct_build_request <- function(params,
                             primary_token = NULL,
                             verbose = FALSE) {
  query_params <- params$query_params

  extra_params <- params$extra_params |>
    purrr::map(unlist) |>
    purrr::pluck(1) |>
    as.list()
  query_params <- c(query_params, extra_params)
  type <- params$url_params$type

  freq <- params$url_params$freq

  clCode <- params$url_params$clCode

  res <-
    httr2::request("https://comtradeapi.un.org/data/v1/get/") |>
    httr2::req_url_path_append(type) |>
    httr2::req_url_path_append(freq) |>
    httr2::req_url_path_append(clCode) |>
    httr2::req_headers(`Ocp-Apim-Subscription-Key` = primary_token) |>
    httr2::req_url_query(!!!query_params)

  if (stringr::str_length(res$url) > 4095) {
    rlang::abort("Your request exceeds 4KB or 4096 characters, which is the upper limit of the Comtrade API.") # nolint
  }

  if (verbose) {
    cli::cli_inform(c("i" = paste0("URL that will be queried: ", res$url)))
  }

  return(res)
}