R/get_comment_threads.R

In tuber: Client for the YouTube API

#' Get Comments Threads
#'
#' @param filter string; Required.
#' named vector of length 1
#' potential names of the entry in the vector: 
#' \code{video_id}: video ID.
#' \code{channel_id}: channel ID.
#' \code{thread_id}: comma-separated list of comment thread IDs
#' \code{threads_related_to_channel}: channel ID.
#'  
#' @param part  Comment resource requested. Required. Comma separated list of one or more of the 
#' following: \code{id, snippet}. e.g., \code{"id, snippet"}, \code{"id"}, etc. Default: \code{snippet}.  
#' @param max_results  Maximum number of items that should be returned. Integer. Optional. Default is 100.
#' If the value is greater than 100 then the function fetches all the results. The outcome is a simplified \code{data.frame}.
#' @param page_token  Specific page in the result set that should be returned. Optional.
#' @param text_format Data Type: Character. Default is \code{"html"}. Only takes \code{"html"} or \code{"plainText"}. Optional. 
#' @param simplify Data Type: Boolean. Default is \code{TRUE}. If \code{TRUE}, the function returns a data frame. Else a list with all the information returned.
#' @param \dots Additional arguments passed to \code{\link{tuber_GET}}.
#'  
#' @return 
#' Nested named list. The entry \code{items} is a list of comments along with meta information. 
#' Within each of the \code{items} is an item \code{snippet} which has an item \code{topLevelComment$snippet$textDisplay}
#' that contains the actual comment.
#' 
#' If simplify is \code{TRUE}, a \code{data.frame} with the following columns:
#' \code{authorDisplayName, authorProfileImageUrl, authorChannelUrl, authorChannelId.value, videoId, textDisplay,          
#' canRate, viewerRating, likeCount, publishedAt, updatedAt}
#' 
#' @export
#' @references \url{https://developers.google.com/youtube/v3/docs/commentThreads/list}
#' 
#' @examples
#' \dontrun{
#' 
#' # Set API token via yt_oauth() first
#' 
#' get_comment_threads(filter = c(video_id = "N708P-A45D0"))
#' get_comment_threads(filter = c(video_id = "N708P-A45D0"), max_results = 101)
#' }

get_comment_threads <- function (filter = NULL, part = "snippet",
                                text_format = "html", simplify = TRUE,
                                max_results = 100, page_token = NULL, ...) {

  if (max_results < 20) {
    stop("max_results only takes a value over 20.
          Above 100, it outputs all the results.")
  }

  if (text_format != "html" & text_format != "plainText") {
    stop("Provide a legitimate value of textFormat.")
  }

  if (!(names(filter) %in%
    c("video_id", "channel_id", "thread_id", "threads_related_to_channel"))) {
    stop("filter can only take one of values: channel_id, video_id, parent_id,
      threads_related_to_channel.")
  }

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

  orig_filter <- filter
  translate_filter <- c(video_id = "videoId", thread_id = "id",
                    threads_related_to_channel = "allThreadsRelatedToChannelId",
                    channel_id = "channelId", page_token = "pageToken")

  yt_filter_name     <- as.vector(translate_filter[match(names(filter),
                                                      names(translate_filter))])
  names(filter)      <- yt_filter_name

  querylist <- list(part = part, maxResults =
                                 ifelse(max_results > 100, 100, max_results),
                                 textFormat = text_format,
                                 pageToken = page_token)
  querylist <- c(querylist, filter)

  res <- tuber_GET("commentThreads", querylist, ...)

  if (simplify == TRUE & part == "snippet" & max_results < 101) {
    simple_res  <- lapply(res$items, function(x) {
                                     unlist(x$snippet$topLevelComment$snippet)
                                     }
                                     )
    simpler_res <- ldply(simple_res, rbind)

    return(simpler_res)

  } else if (simplify == TRUE & part == "snippet" & max_results > 100) {

    simple_res  <- lapply(res$items, function(x) {
                                     unlist(x$snippet$topLevelComment$snippet)
                                     }
                                     )
    simpler_res <- ldply(simple_res, rbind)

    agg_res <- simpler_res
    page_token  <- res$nextPageToken

    while ( is.character(page_token)) {

      a_res <- get_comment_threads(orig_filter,
                                 part = part,
                                 text_format = text_format,
                                 simplify = FALSE,
                                 max_results = 100,
                                 page_token = page_token
                                )
      simple_res  <- lapply(res$items, function(x) {
                                     unlist(x$snippet$topLevelComment$snippet)
                                     }
                                     )
      simpler_res <- ldply(simple_res, rbind)

      agg_res <- rbind(simpler_res, agg_res)
      page_token  <- a_res$nextPageToken
    }
    return(agg_res)
  }
  res
}