R/plot_run_vars.R

In PecanProject/rpecanapi: R Library that interacts with the PEcAn API

##' Plot the desired variables from the results of a PEcAn run.
##' Hits the `/api/run/{run_id}/graph/{year}/{y_var}` API endpoint
##' @name plot_run_vars
##' @title Plot the desired variables from the results of a PEcAn run
##' @param server Server object obtained using the connect() function
##' @param run_id ID of the PEcAn run whose details are needed
##' @param year the year this data is for
##' @param yvar the variable to plot along the y-axis.
##' @param xvar the variable to plot along the x-axis, by default time is used.
##' @param width the width of the image generated, default is 800 pixels.
##' @param height the height of the image generated, default is 600 pixels.
##' @param filename File name to save the generated plot, default is 'plot.png'.
##' @return Response obtained from the `/api/run/{run_id}/graph/{year}/{y_var}` endpoint
##' @author Tezan Sahu
##' @export
##' @examples
##' server <- connect(url="http://pecan.localhost:80", username="carya", password="illinois")
##' 
##' # Plot the Gross Primary Productivity vs Time for the run with ID '99000000282' for the year 2002
##' plot_run_vars(server, run_id=99000000282, year=2002, y_var="GPP")
##' 
##' # Plot the Total Respiration vs Soil Respiration for the run with ID '99000000283' for the year 2002 of custom size
##' plot_run_vars(server, run_id=99000000283, year=2002, y_var="TotalResp", x_var="SoilResp", width=500, height=400)

plot_run_vars <- function(server, run_id, year, y_var, x_var="time", width=800, height=600, filename="plot.png"){
  res <- NULL
  tryCatch(
    expr = {
      url <- paste0(server$url, "/api/runs/", run_id, "/graph/", year, "/", y_var, "?x_var=", x_var, "&width=", width, "&height=", height)
      
      if(! is.null(server$username) && ! is.null(server$password)){
        res <- httr::GET(
          url,
          httr::authenticate(server$username, server$password)
        )
      }
      else{
        res <- httr::GET(url)
      }
    },
    error = function(e) {
      message("Sorry! Server not responding.")
    }
  )
  
  if(! is.null(res)) {
    if(res$status_code == 200){
      writeBin(res$content, filename)
    }
    else if(res$status_code == 401){
      stop("Invalid credentials")
    }
    else if(res$status_code == 404){
      stop("Run details not found")
    }
    else if(res$status_code == 500){
      stop("Internal server error")
    }
    else{
      stop("Unidentified error")
    }
  }
}