R/get_upw.R

In bvreede/OAmonitor: Scoring Open Accessibility of Publications at Dutch Universities

#' @import magrittr
NULL


####################################### API MINING ######################################

#' Get Unpaywall data from indicated source
#'
#' This function either kickstarts mining the Unpaywall API using the
#' doi columnn in a provided data frame, or loads saved Unpaywall data.
#'
#' @param df data frame with a doi column
#' @param source either "api" or the path of a saved unpaywall result
#' @param email email address of user (required by Unpaywall)
#' @param save_results Do you want to save the resulting data frame?
#' @return data frame with unpaywall results
#' @export
get_upw <- function(df, source="api", email="", save_results=F){
  if(source=="api"){
    if(email == ""){
      warning("Provide a valid email address to mine the Unpaywall API.")
    }
  df <- df %>%
    api_to_df("upw", email)
  if(save_results == T){
    save_df(df, "upw")
  }
  } else if(file.exists(source)){
    #TODO add a check if the dataframe provided matches the saved results
    #TODO rename df, this is confusing
    df <- readr::read_csv(source)
  } else{
    warning("Not sure what Unpaywall data to use. Please either use source='api' for use of the Unpaywall API,
or provide the path of saved data that was previously mined from the Unpaywall API.")
    stop
  }
  df <- df %>% dplyr::filter(!duplicated(doi)) # just in case any dois are inadvertently duplicated
  return(df)
}

#' Mining the Unpaywall API
#'
#' Collecting DOI results from Unpaywall using their REST API
#' (at http://api.unpaywall.org/v2/). The entry for the DOI in the
#' Unpaywall database is returned.
#'
#' @param doi DOI of paper that needs to be checked
#' @param email email address of user (required by Unpaywall)
#' @return list with Unpaywall results
#' @export

upw_api <- function(doi,email){
  Sys.sleep(0.2) # making sure the API does not get flooded
  # compile query to send to unpaywall
  api <- "https://api.unpaywall.org/v2/"
  email <- paste0("?email=",email)
  query <- paste0(api,doi,email)
  result <- httr::GET(query)
  # resolve query results and transform to a line that can be added to a df
  result_list <- httr::content(result, as="parsed", encoding="UTF-8")
  result_line <- tibble::tibble(x = list(result_list)) %>% tidyr::unnest_wider(x)
  #add variable 'oa_color' to extract from upw data later
  #classify bronze oa with repository copy as green
  result_line <- dplyr::mutate(result_line, oa_color = dplyr::case_when(
    (oa_status == "bronze" & has_repository_copy == TRUE) ~ "green",
    TRUE ~ oa_status))
    return(result_line)
}