R/plosword.R

In rplos: Interface to the Search API for 'PLoS' Journals

#' Search results on a keyword over all fields in PLoS Journals.
#'
#' @export
#' @param terms search terms (character)
#' @param vis visualize results in bar plot or not (TRUE or FALSE)
#' @param ... Optional additional curl options passed to
#' \code{\link[crul]{HttpClient}}
#'
#' @return Number of search results (vis = FALSE), or number of search in a
#' table and a histogram of results (vis = TRUE).
#' @examples \dontrun{
#' plosword('Helianthus')
#' plosword(list('monkey','replication','design','sunflower','whale'),
#'    vis = TRUE)
#' }

plosword <- function(terms, vis = FALSE, ...) {

  Term <- No_Articles <- NULL

  if (length(terms) == 1) {
    stats::setNames(search_(terms, ...), 'Number of articles with search term')
  } else {
    temp <- stats::setNames(ldply(terms, search_, ...), "No_Articles")
    temp$Term <- terms
    temp$Term <- as.character(temp$Term)
    if (vis) {
      p <- ggplot(temp, aes(x = Term, y = No_Articles)) +
        geom_bar(stat = "identity") +
        theme_grey(base_size = 18)
      return(list(table = temp, plot = p))
    }
    return( temp )
  }
}

search_ <- function(terms, ...){
  args <- ploscompact(list(q = terms, fl = "id", wt = "json"))
  cli <- HttpClient$new(url = pbase())
  tt <- cli$get(query = args, ...)
  tt$raise_for_status()
  jsonlite::fromJSON(tt$parse("UTF-8"), FALSE)$response$numFound
}