R/list_channel_resources.R

In soodoku/tuber: Client for the YouTube API

#' Returns List of Requested Channel Resources
#'
#' @param filter string; Required.
#' named vector of length 1
#' potential names of the entry in the vector:
#' \code{category_id}: YouTube guide category that returns channels associated
#' with that category
#' \code{username}:  YouTube username that returns channel associated with that
#'  username.
#' \code{channel_id}: a comma-separated list of the YouTube channel ID(s) for
#' the resource(s) that are being retrieved
#'
#' @param part a comma separated list of channel resource properties that
#' response will include string. Required.
#' One of the following: \code{auditDetails, brandingSettings, contentDetails,
#' contentOwnerDetails, id, invideoPromotion, localizations, snippet,
#' statistics, status, topicDetails}.
#' Default is \code{contentDetails}.
#' @param hl  Language used for text values. Optional. Default is \code{en-US}.
#' For other allowed language codes, see \code{\link{list_langs}}.
#' @param max_results Maximum number of items that should be returned. Integer.
#'  Optional. Can be between 0 and 50. Default is 50.
#' @param page_token specific page in the result set that should be returned,
#' optional
#' @param \dots Additional arguments passed to \code{\link{tuber_GET}}.
#'
#' @return list
#' @export
#' @references \url{https://developers.google.com/youtube/v3/docs/channels/list}
#'
#' @examples
#'
#' \dontrun{
#'
#' # Set API token via yt_oauth() first
#'
#' list_channel_resources(filter = c(channel_id = "UCT5Cx1l4IS3wHkJXNyuj4TA"))
#' list_channel_resources(filter = c(username = "latenight"), part = "id, contentDetails")
#' list_channel_resources(filter = c(username = "latenight"), part = "id, contentDetails",
#' max_results = 10)
#' }

list_channel_resources <- function(filter = NULL, part = "contentDetails",
                         max_results = 50, page_token = NULL, hl = "en-US", ...) {

  if (max_results < 0 | max_results > 50) {
    stop("max_results only takes a value between 0 and 50.")
  }

  if (!(names(filter) %in% c("category_id", "username", "channel_id"))) {
    stop("filter can only take one of three values: category_id,
      username or channel_id.")
  }

  if (length(filter) != 1) stop("filter must be a vector of length 1.")

  translate_filter   <- c(channel_id = "id", category_id = "categoryId",
                          username = "forUsername")
  yt_filter_name     <- as.vector(translate_filter[match(names(filter),
                                                      names(translate_filter))])
  names(filter)      <- yt_filter_name

  if (is.character(filter$username)) {
    usernames <- filter$username
    num_usernames <- length(usernames)
    channel_ids <- vector("list", length = num_usernames)
    
    for (i in seq_along(usernames)) {
      querylist <- list(part = part, maxResults = max_results,
                        pageToken = page_token, hl =  hl, forUsername = usernames[i])
      
      res <- tuber_GET("channels", querylist, ...)
      
      if (length(res$items) == 0) {
        warning("No details available for username: ", usernames[i])
      } else {
        channel_ids[[i]] <- res$items[[1]]$id
      }
      
      print(i)
    }
    
    return(channel_ids)
  }
  
  querylist <- list(part = part, maxResults = max_results,
                    pageToken = page_token, hl = hl)
  querylist <- c(querylist, filter)
  
  res <- tuber_GET("channels", querylist, ...)
  
  res
}