R/pull.R

In dncnbrn/EmsiR: Emsi Episteme API from R

#' @export
pullquery <- function(country, content, release, constraints, metrics) {
    emsi_URL <- paste("http://episteme.economicmodeling.com/EMSI.", country, ".", content, "/", release, sep = "")
    body <- list(metrics = metrics, constraints = constraints)
    r <- httr::POST(emsi_URL, body = body, encode = "json", httr::add_headers(EpistemeSettings()))
    r2 <- jsonlite::fromJSON(httr::content(r, "text"), simplifyDataFrame = TRUE)
    outputdata <- as.data.frame(r2$data$rows) %>% dplyr::tbl_df()
    colnames(outputdata) <- r2$data$name
    rm(r)
    rm(r2)
    outputdata[, colnames(outputdata) %in% names(constraints)] <- apply(outputdata[, colnames(outputdata) %in% names(constraints)],
        2, function(x) factor(x))
    if(ncol(outputdata[, colnames(outputdata) %in% metrics$as])>1) {
      outputdata[, colnames(outputdata) %in% metrics$as] <- apply(outputdata[, colnames(outputdata) %in% metrics$as], 2, function(x) as.numeric(x))
    }
    return(outputdata)
}

#' Pull data from the Episteme API
#'
#' @description Pulls data from the Emsi Episteme API according to specified parameters and returns a prepared data frame for analysis.
#'
#' @param country The two-character country code.
#' @param content The Emsi Episteme dataset description (e.g. "Occupation").
#' @param release The release or version identifier for the dataset (e.g. "2016.1").
#' @param constraints A list of dimensional constraints relevant to the dataset, each of which has been prepared through
#' \code{\link{dimmaker}} or \code{\link{CoW}}.
#' @param metrics A set of metrics through which to quantify the data, prepared through \code{\link{metricmaker}}.
#' @return A data frame of dimensions and metrics, with dimensions classified as factors and metrics as doubles.
#' @examples
#' met1 <- data.frame(names=c("Jobs.2016","Jobs.2022"), as=c("Jobs.2016","Jobs.2022"))
#' met1 <- metricmaker(met1)
#' area1 <- data.frame(name=c("Great Britain", "Wales"), code=c("GB", "WAL"))
#' areadim <- dimmaker("Area", area1)
#' occdim <- dimmaker("Occupation", "asIdentity")
#' datapull("UK","Occupation","2016.1",list(CoW("A"),areadim,occsdim),met1)
#' @export
datapull <- function(country, content, release, constraints, metrics) {
    if (ncol(metrics) == 2) {
        outputdata <- pullquery(country, content, release, constraints, metrics)
    }
    if (ncol(metrics) > 2) {
        if (nrow(metrics[is.na(metrics$operation), ]) == 0) {
            outputdata <- pullquery(country, content, release, constraints, metrics)
        }
        if (nrow(metrics[is.na(metrics$operation), ]) > 0) {
            metrics1 <- metrics %>% dplyr::filter(is.na(operation)) %>% dplyr::select(-operation)
            metrics2 <- metrics %>% dplyr::filter(!is.na(operation))
            outputdata1 <- pullquery(country, content, release, constraints, metrics1)
            outputdata2 <- pullquery(country, content, release, constraints, metrics2)
            outputdata <- outputdata1 %>% dplyr::left_join(outputdata2)
            rm(outputdata1, outputdata2)
        }
    }
    return(outputdata)
}