MongoDB Index Exception

[Fredrick Lackey]

Original post is at... http://stackoverflow.com/questions/29289637/mongoose-mongodb-index-exception

Has anyone seen the following exception?  Know how to get by it?  My models DO have indexes, so there's no reason, that I can think of, for the indexes not to be present.

The MongoDB client code is throwing an exception within Mongoose...

C:\_\MyProject\node_modules\mongoose\node_modules\mongodb\lib\mongodb\connection\base.js:246

       throw message;

             ^

TypeError: Cannot read property 'length' of undefined

   at processResults (C:\_\MyProject\node_modules\mongoose\node_modules\mongodb\lib\mongodb\db.js:1581:31)

   at C:\_\MyProject\node_modules\mongoose\node_modules\mongodb\lib\mongodb\db.js:1619:20

   at C:\_\MyProject\node_modules\mongoose\node_modules\mongodb\lib\mongodb\db.js:1157:7

   at C:\_\MyProject\node_modules\mongoose\node_modules\mongodb\lib\mongodb\db.js:1890:9

   at Server.Base._callHandler (C:\_\MyProject\node_modules\mongoose\node_modules\mongodb\lib\mongodb\connection\base.js:448:41)

   at C:\_\MyProject\node_modules\mongoose\node_modules\mongodb\lib\mongodb\connection\server.js:481:18

   at MongoReply.parseBody (C:\_\MyProject\node_modules\mongoose\node_modules\mongodb\lib\mongodb\responses\mongo_reply.js:68:5)

   at null.<anonymous> (C:\_\MyProject\node_modules\mongoose\node_modules\mongodb\lib\mongodb\connection\server.js:439:20)

   at emit (events.js:95:17)

   at null.<anonymous> (C:\_\MyProject\node_modules\mongoose\node_modules\mongodb\lib\mongodb\connection\connection_pool.js:201:13)

The block of code causing the problem is the iterator in the for loop below...

    /**

     * Retrieves this collections index info.

     *

     * Options

     *  - **full** {Boolean, default:false}, returns the full raw index information.

     *  - **readPreference** {String}, the preferred read preference ((Server.PRIMARY, Server.PRIMARY_PREFERRED, Server.SECONDARY, Server.SECONDARY_PREFERRED, Server.NEAREST).

     *

     * @param {String} collectionName the name of the collection.

     * @param {Object} [options] additional options during update.

     * @param {Function} callback this will be called after executing this method. The first parameter will contain the Error object if an error occurred, or null otherwise. While the second parameter will contain the results from indexInformation or null if an error occurred.

     * @return {null}

     * @api public

     */

    Db.prototype.indexInformation = function(name, options, callback) {

      if(typeof callback === 'undefined') {

        if(typeof options === 'undefined') {

          callback = name;

          name = null;

        } else {

          callback = options;

        }

        options = {};

      } 

    

      // Throw is no name provided

      if(name == null) throw new Error("A collection name must be provided as first argument");

    

      // If we specified full information

      var full = options['full'] == null ? false : options['full'];

      var self = this;

    

      // Process all the results from the index command and collection

      var processResults = function(indexes) {

        // Contains all the information

        var info = {};

        // Process all the indexes

          if (indexes) {

              for(var i = 0; i < indexes.length; i++) {

                  var index = indexes[i];

                  // Let's unpack the object

                  info[index.name] = [];

                  for(var name in index.key) {

                      info[index.name].push([name, index.key[name]]);

                  }

              }

          }

    

        return info;

      }

    

      // Fallback to pre 2.8 getting the index information

      var fallbackListIndexes = function() {

        // Build selector for the indexes

        var selector = name != null ? {ns: (self.databaseName + "." + name)} : {};

    

        // Get read preference if we set one

        var readPreference = ReadPreference.PRIMARY;

    

        // Iterate through all the fields of the index

        var collection = self.collection(DbCommand.SYSTEM_INDEX_COLLECTION);

        // Perform the find for the collection

        collection.find(selector).setReadPreference(readPreference).toArray(function(err, indexes) {

          if(err != null) return callback(err, null);

          // if full defined just return all the indexes directly

          if(full) return callback(null, indexes);

          // Return all the indexes

          callback(null, processResults(indexes));

        });

      }

    

      // Attempt to execute the listIndexes command

      self.command({listIndexes: name}, function(err, result) {

        if(err) return fallbackListIndexes();

        // if full defined just return all the indexes directly

        if(full) return callback(null, result.indexes);

        // Return all the indexes

        callback(null, processResults(result.indexes));

      });

    };