validate_feed.js

/**
 * Created by Akelaus on 11/25/13.
 */


var fs = require('fs');
var xmlParser = require('libxmljs');
var mongoose = require('mongoose');
var config = require('./config');
require('./model/schema/feed');
require('./db/mongo');

/**
 * main process routine for path passed into
 * @param vipFeedPath
 */
function process_feed(vipFeedPath){
  if (valid_source_path(vipFeedPath)) {
    parse_feed(vipFeedPath);
  }
  else {
    console.error("File Path invalid");
    process.exit();
  }
}

/**
 * confirms the presence of the path passed in as argument
 * @param file_path
 * @returns {boolean}
 */
function valid_source_path(file_path){
  console.log('verify source path');
  exists = fs.existsSync(file_path);
  console.log('Does path and file exist? ' + exists);
  return exists;
}

/**
 * parses text representation of VIP feed into XML format
 * @param vipFeedTxt
 */
function parse_feed(vipFeedTxt){
  console.log('feed to parse: ' + vipFeedTxt);
  var vipFeedDoc = xmlParser.parseXmlString(fs.readFileSync(vipFeedTxt.toString()));
  validFeed = is_valid_feed(vipFeedDoc);

  /*
   *  parse feed election element data..if the feed data's determined to be valid
   *  TODO: refactor the following blocks
   */
  //if(validFeed){
    election_node = vipFeedDoc.get("//election");
    var election_date = election_node.get("//date").text();
    var election_type = election_node.get("//election_type").text();
    var state_id = election_node.get("//state_id").text();
    var state_name = vipFeedDoc.get("//state/name").text();
    var feed_name = vipFeedTxt.substring(vipFeedTxt.lastIndexOf("/")+1, vipFeedTxt.lastIndexOf('.'));
    var election_id = vipFeedDoc.get("election").attr("id").value();
    var vip_id = election_node.get("//vip_id").text();
    var feed_path = vipFeedTxt.substring(0,vipFeedTxt.lastIndexOf("/")+1);

    /*
     * TODO: add the following to schema in Sprint 2 -nab
     * var state_wide = election_node.get("statewide").text();
     * //var registration_info = election_node.get("//election_info");
     */
  //}

  //build Feed object and capture all relevant element data from the XML (using lixmljs)
  var Feed = mongoose.model(config.mongoose.model.feed);

  var vipFeed = null;
  if(validFeed) {
    vipFeed = new Feed(
      {
        payload: vipFeedTxt,
        election_date: new Date(election_date), //Date()
        loaded_on: Date(),
        validation_status: validFeed,
        feed_status: "Undetermined",
        feed_type: election_type,
        name: feed_name,
        state: state_name,  //will eventually be a VIP ID (TODO: consider for sprint 2)
        date: Date(), //TODO: keep this entry or "loaded_on"
        election_id: election_id,
        vip_id: vip_id,
        feed_path: feed_path
      }
    );
  }
  else {
    vipFeed = new Feed(
      {
        payload: vipFeedTxt,
        loaded_on: Date(),
        validation_status: validFeed,
        name: feed_name,
        feed_path: feed_path,
        date: Date() //TODO: keep this entry or "loaded_on"
      }
    );
  }
  //save feed into MongoDB
  console.log("saving feed", feed_name, "to Mongo");
  save_model(vipFeed);
}

/**
 * validates VIP Feed doc (currently against 3.0 schema)
 * @param vipFeedDoc - text representation of the XML document
 */
function is_valid_feed(vipFeedDoc) {
  //validate VIP feed against schema v3.0
  console.log('attempting to validate against VIP schema v3.0');

  vipXSDPath = config.vipSchema.path;   //TODO: consider
  var vipXSDDoc = xmlParser.parseXmlString(fs.readFileSync(vipXSDPath.toString()));

  isValid = vipFeedDoc.validate(vipXSDDoc);
  console.log("Parsed feed value: " + isValid); //TODO: add schema for valid_status
  return isValid;
}


function save_model(vipModel){

  var saved = false;

  vipModel.save(function(err, vipModel) {
    if(err) {
      console.error("failed to save");

    }
    else {
      console.log("successful save");
      saved = true;
      process.exit();
    }
    //vipModel = vipModel;
  })

  //in case we want to do something clever with this one day, consider:  return [vipModel, saved];
}

module.exports = function(feed_path) {
  return {
    process_path: function(){
      return process_feed(feed_path);
    }
  };
}

/*
DONE: 1 Instantiate handler for file path
Done: 2 Error handling for filepath, name, format, etc
TODO: 3 Eliminate mongoose memory leaks
TODO: 4 Unit tests for mongoose, init and server functions
TODO: 5 Wrap processing method as Endpoint??
 */