How do I adjust findAll() _id or id param in a Mongoose base schema

I've created a Mongoose base schema to take care of encrypting _id and returning it as just id for my restify based API.

BaseSchema = () ->

  Schema.apply @, arguments

  # Ensure virtual fields are serialised.
  @set 'toJSON', {

    virtuals: true

  }

  @set 'toObject', {

    virtuals: true

  }

  # transform our JSON so its friendly for our API
  @options.toJSON.transform = ( doc, ret, options ) ->

    # remove _id and __v so we dont expose it in the API
    delete ret._id
    delete ret.__v

    return ret

  # encrypted _id in id using a virtual
  @virtual('id')

    .get ->

      id = hashids.encryptHex this._id.toHexString()
      return id 

    .set ( id ) ->

      console.log 'Setting', id
      @_id = mongoose.Types.ObjectId hashids.decryptHex(id) 
      return

  # some default and consistent schema fields
  @add {

      # when the document was created
      createdAt: {

        type: Date,
        default: Date.now

      },

      # when the document was modified
      modifiedAt: {

        type: Date,
        default: Date.now

      }
  }

And then in subsequent schemas:

PersonSchema = new BaseSchema {}, { id: false }

To alleviate the problem of transforming the id I receive in the API querying call I've created the following restify middleware:

server.use ( req, res, next ) ->

  if req.params.id

    req.params.id = hashids.decryptHex req.params.id

  next()

This works but I'm not happy with this.

I would like to know if there is a way of handling the decryption of the id and the translation to _id ObjectId in the Base Schema somewhere. I would like to be able to do:

server.get '/interfaces/:id', ( req, res, next ) ->

  # get the interface based on id
  iface = Interface.findOne { _id: req.params.id } , ( err, iface ) ->

    res.send iface
    next()

_id is part of the findOne {} query and so it should be translated before the actual query executes.

That would centralise the logic nicely.

Thanks !