cray/epub/helpers.js

Epub parser

/**
 * @author: Akshay Kr Singh.
 * @date:   20/11/15.
 * @github: https://github.com/akshayKrSingh
 */
var util = require('util');
var xml2js = require('xml2js');
var _ = require('lodash');
var EpubErrors = require('./errors');

var Epub = function() {
  if (!(this instanceof Epub)) {
    return new Epub();
  }
};

Epub.prototype.generateContainerInfo = function(xml) {
  var self = this;
  var opfRegEx = xml.match(/<rootfile.*full\-path=["|'](.*?)["|']/),
    opfPath = root = opfRegEx ? opfRegEx[1] : -1, opsRoot = '';

  if (root === -1) {return self.error = EpubErrors['EPUB#container'].format;}

  if (root.match(/\//)) { // not at top level
    opsRoot = root.replace(/\/([^\/]+)\.opf/i, '');

    if (!opsRoot.match(/\/$/)) { // does not end in slash, but we want it to
      opsRoot += '/';
    }

    if (opsRoot.match(/^\//)) {
      opsRoot = opsRoot.replace(/^\//, '');
    }

  } else { // at top level
    opsRoot = '';

  }

  self.opfRoot = opsRoot;
  self.opfPath = opfPath;
};

Epub.prototype.generateOpfInfo = function(xml) {
  var epub = this;

  epub.error = null;

  function parseMeta(metadata) {
    var metaProp = {
      arr: ['language', 'title', 'date', 'creator', 'contributor', 'publisher', 'rights'],
      prefix: 'dc:'
    };

    _.each(metaProp.arr, function(meta) {
      if (meta === 'contributor') {
        var contributors = metadata[metaProp.prefix + meta] ? metadata[metaProp.prefix + meta] : '';
        return epub.metadata[meta] = (_.isArray(contributors)) ? contributors : [contributors];
      }

      if (metadata[metaProp.prefix + meta]) {
        epub.metadata[meta] = (_.isObject(metadata[metaProp.prefix + meta][0])) ?
          metadata[metaProp.prefix + meta][0]._ : metadata[metaProp.prefix + meta][0];

      } else {
        epub.metadata[meta] = "";

      }
    });
  }

  function parseManifest(manifest) {
    var items = [];

    _.each(manifest, function(item) {
      var temp = item.$;
      if (temp.properties) {
        if (temp.properties === 'nav') {
          return epub.nav = temp;
        }

        if (temp.properties === 'cover-image') {
          return epub.cover = {
            imagePath: temp.href
          }
        }

        return '';
      }

      items.push(temp);
    });

    epub.manifest = items;
  }

  function parseSpine(spine) {
    var spines = [], invalid = false;

    _.each(spine, function(item) {
      var manifest = _.find(epub.manifest, {id: item.$.idref});

      //TODO validate spine entries authentically
      if (manifest) {spines.push(manifest);}
    });

    epub.spines = spines;
  }

  function parseOpf(fileString) {
    xml2js.parseString(fileString, function (err, opfJson) {
      if (err) {
        return epub.error = EpubErrors['EPUB#opf'].format;
      }

      var temp = {
        metadata: opfJson.package.metadata[0],
        manifest: opfJson.package.manifest[0],
        spine: opfJson.package.spine[0]
      };

      epub.metadata = {};
      parseMeta(temp.metadata);
      parseManifest(temp.manifest.item);
      parseSpine(temp.spine.itemref);

      epub.isValid = true;
    });
  }

  parseOpf(xml);

};

module.exports = Epub;