@wbg-mde/r-script/index.js

A simple little module for passing data from NodeJS to R (and back again). Panapps customized version of r-script package for WBG-metadata-editor.

var _ = require("underscore"),
    child_process = require("child_process");

function init(path) {
    var obj = new R(path);
    return _.bindAll(obj, "data", "call", "callSync", "start");
}

function R(path) {
    this.d = {};
    this.path = path;
    this.options = {
        env: _.extend({ DIRNAME: __dirname }, process.env),
        encoding: "utf8"
    };
    this.idCounter = 0;
    this.args = ["--vanilla", __dirname + "/R/launch.R"];
}

R.prototype.data = function() {
    for (var i = 0; i < arguments.length; i++) {
        this.d[++this.idCounter] = arguments[i];
    }
    return this;
};

R.prototype.call = function(_opts, _callback) {
    var callback = _callback || _opts;
    var opts = _.isFunction(_opts) ? {} : _opts;
    this.options.env.input = JSON.stringify([this.d, this.path, opts]);
    var child = child_process.spawn("Rscript", this.args, this.options);
    child.on('error', function(err) {
        callback(err, null);
    });
    child.stderr.on("data", callback);
    child.stdout.on("data", function(d) {
		// handle json parse error
        var returnValue = 0;
        try {
            returnValue = JSON.parse(d);
        } catch (e) {

        }
        callback(null, returnValue);
    });
};

R.prototype.callSync = function(_opts) {
    var opts = _opts || {};
    this.options.env.input = JSON.stringify([this.d, this.path, opts]);
    var child = child_process.spawnSync("Rscript", this.args, this.options);
    if (child.stderr) throw child.stderr;
    return (JSON.parse(child.stdout));
};

R.prototype.start = function(_opts, _callback) {
    var callback = _callback || _opts;
    var opts = _.isFunction(_opts) ? {} : _opts;
    this.options.env.input = JSON.stringify([this.d, this.path, opts]);
    var child = child_process.spawn("Rscript", this.args, this.options);
    child.on('error', function(err) {        
        callback(err, null, null);
    });
    child.stderr.on("data", function(err, data){
        callback(err, data, child.pid);
    });
    child.stdout.on("data", function(d) {
		// handle json parse error
        var returnValue = 0;
        try {
            returnValue = JSON.parse(d);
        } catch (e) {

        }
        callback(null, returnValue, child.pid);
    });
};

module.exports = init;