rbeer/nodebb-plugin-smoothshorts

'use strict';

var async = require.main.require('async');
var nconf = require.main.require('nconf');
var winston = require.main.require('winston');
var db = require.main.require('./src/database');
var xxh = require('xxhash');

var hashing = {};

var hashType = {
  topics: {
    idName: 'tid',
    redirect: '/topic/:id'
  },
  posts: {
    idName: 'pid',
    redirect: '/post/:id'
  }
};

hashing.getHashForId = function(id, type, cb) {
  db.getSortedSetRangeByScore(type + ':smoothshorts', 0, -1, id, id,
    function(err, hash) {
      if (err) {
        return cb(err);
      }
      var res = { hash: hash[0] };
      res[hashType[type].idName] = id;
      cb(null, res);
    });
};

hashing.getHashDelegate = function(type) {
  return function(id, cb) {
    hashing.getHashForId.call(this, id, type, cb);
  };
};

hashing.shortenPost = function(postData, cb) {
  shorten(postData, 'posts', cb);
};

hashing.shortenTopic = function(topicData, cb) {
  shorten(topicData, 'topics', cb);
};

hashing.purgePost = function(id) {
  purge(id, 'posts');
};

hashing.purgeTopic = function(id) {
  purge(id, 'topics');
};

hashing.resolveHash = function(req, res, cb) {
  var hash = req.params.hash;

  async.parallel({
    isPost: function(next) {
      db.isSortedSetMember('posts:smoothshorts', hash, next);
    },
    isTopic: function(next) {
      db.isSortedSetMember('topics:smoothshorts', hash, next);
    }
  }, function(err, result) {
    if (err) {
      return cb(err);
    }
    let type = result.isPost ? 'posts' : result.isTopic ? 'topics' : '';
    if (!type) {
      winston.warn('[plugins:SmoothShorts] Couldn\'t resolve ' + hash);
      return cb(null);
    }
    db.sortedSetScore(type + ':smoothshorts', hash, function getId(err, id) {
      if(err) {
        return cb(err);
      }
      let uri = hashType[type].redirect.replace(':id', id);
      winston.verbose('[plugins:SmoothShorts] Redirecting ' + hash +
                      ' to ' + uri);
      res.redirect(uri);
    });
  });
};

function shorten(data, type, cb) {
  var hash = hashData(data);
  db.sortedSetAdd(type + ':smoothshorts', data[hashType[type].idName], hash, function(err) {
    if (err) {
      winston.error('[plugin:smoothshorts] Writing hash to DB failed.' +
                    '(' + hashType[type].idName + '=' + data[hashType[type].idName] + ')');
      winston.error(err);
      return cb ? cb(err) : void 0;
    }
    winston.verbose(type === 'posts' ?
                    '[plugin:smoothshorts] Hashed post ID ' + data.pid :
                    '[plugin:smoothshorts] Hashed \'' + data.title + '\' (ID: ' + data.tid + ')');
    return cb ? cb() : void 0;
  });
}

function purge(id, type) {
  db.sortedSetsRemoveRangeByScore([type + ':smoothshorts'], id, id, function(err) {
    if (err) {
      return winston.error('[plugin:smoothshorts] Deleting hash from DB failed.' +
                    '(' + hashType[type].idName + '=' + id + ')');
    }
    winston.verbose('[plugin:smoothshorts] Deleted hash for ' + type.substring(0, type.length - 1) + ' ID ' + id);
  });
}

function hashData(data) {
  var key = nconf.get('secret');
  key = parseInt('0x' + key.substring(0, key.indexOf('-')), 16);
  var hash = xxh.hash(new Buffer(JSON.stringify(data)), key).toString(16);
  key = null;
  return hash;
}

module.exports = hashing;