index.js

'use strict';

var request = require('request');
var pid;

exports.resolve = function(doi, options, cb) {
  var r = {};

  exports.APIquery(doi, function(err, response) {
    if (err) {
      return cb(err);
    }
    if (response === null) { 
      return cb(null, {});
    }
    if (!response) {
      return cb(new Error('no response'));
    }
    if (typeof response !== 'object') {
      return cb(new Error('response is not a valid object'));
    }
    if (options.auth) {
      return cb(null, response);
    } else {
      if (!response.message) {
        return cb(new Error('response object has no message'));
      }
      if (response['message-type'] === 'work') {
        return cb(null, exports.APIgetInfo(response.message, options.extended))
      }
      if (response['message-type'] === 'work-list' && Array.isArray(response.message.items)) {
        var list = response.message.items.map(function(item) {
          return exports.APIgetInfo(item, options.extended);
        });
        return cb(null, list);
      }
      return cb(null, {});
    }
  }, options.auth);
};

/**
 * Query Crossref and get results
 * @param  {Object}   doi : doi to search metadata for
 * @param  {Function} callback(err, result)
 * @param  {Array}    auth : [ login, password ]
 */
exports.APIquery = function(doi, callback, auth) {
  var url = 'http://api.crossref.org/works';

  if (auth && !Array.isArray(doi)) {
    url = 'https://doi.crossref.org/search/doi?pid=' + auth.join(':') + '&format=json&doi=' + encodeURIComponent(doi)
  } else {
    if (Array.isArray(doi)) {
      url += '?rows=' + doi.length + '&filter=doi:' + doi.join(',doi:');
    } else {
      url += '/' + encodeURIComponent(doi);
    }
  }


  request.get(url, {
    'timeout': 120000
  }, function(err, res, body) {
    if (err) {
      return callback(err);
    }

    if (res.statusCode === 404) {
      // doi not found
      return callback(null, null);
    } else if (res.statusCode !== 200) {
      var error = new Error('Unexpected status code : ' + res.statusCode);
      error.url = url;
      error.response = res;
      return callback(error);
    }

    var info;

    try {
      info = JSON.parse(body);
    } catch (e) {
      return callback(e);
    }

    if (auth) {
      return callback(null, info);
    }

    // if an error is thrown, the json should contain the status code and a detailed message
    if (info.status !== 'ok') {
      var error = new Error('got an unknown error from the API');
      error.message = info.message;
      return callback(error);
    }

    callback(null, info);
  });
};

exports.APIgetPublicationDateYear = function(apiResult) {
  if (apiResult.message !== undefined && apiResult.message.issued !== undefined) {
    return apiResult.message.issued['date-parts'][0][0];
  }
  return {};
};

exports.APIgetPublicationTitle = function(apiResult) {
  if (apiResult.message !== undefined && typeof apiResult.message['container-title'] !== undefined) {
    return apiResult.message['container-title'][0];
  }
  return {};
};

exports.APIgetInfo = function(doc, extended) {
  var info = {
    'doi-publication-title': '',
    'doi-publication-date-year': '',
    'doi-publisher': '',
    'doi-type': '',
    'doi-ISSN': '',
    'doi-subject': '',
    'doi-author': '',
  };

  if (extended) {
    info['doi-license-content-version'] = '';
    info['doi-license-URL'] = '';
  }

  if (typeof doc !== 'object' || doc === null) {
    return info;
  }

  // search standard information
  info['doi-publication-title'] = doc['container-title'];
  info['doi-publisher'] = doc['publisher'];
  info['doi-type'] = doc['type'];
  info['doi-ISSN'] = doc['ISSN'];
  info['doi-DOI'] = doc['DOI'];
  info['doi-subject'] = doc['subject'];
  info['doi-author'] = doc['author'];

  if (typeof doc.issued === 'object' &&
    doc.issued['date-parts'] &&
    doc.issued['date-parts'][0] &&
    doc.issued['date-parts'][0][0]) {

    info['doi-publication-date-year'] = doc.issued['date-parts'][0][0];
  }

  // search licence informations
  if (extended && doc['license'] && doc['license'][0]) {
    info['doi-license-content-version'] = doc['license'][0]['content-version'];
    info['doi-license-URL'] = doc['license'][0]['URL'];
  }

  return info;
};


exports.DOIgetPublicationDateYear = function(doc) {
  var publication_date = doc.crossref_result.query_result.body.query.doi_record.crossref.journal.journal_article.publication_date;
  var publication_date_year;
  if (typeof publication_date === 'object') {
    if (typeof publication_date[0] === 'object') {
      publication_date_year = publication_date[0].year;
    } else if (publication_date.year === undefined) {
      publication_date_year = "unknown";
    } else {
      publication_date_year = publication_date.year;
    }
  } else {
    publication_date_year = "unknown";
  }
  return publication_date_year;
};