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A Small Object Model for Redis in CoffeeScript

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Orpheus - Redis Little Helper

Orpheus is a Redis Object Model for CoffeeScript.

npm install orpheus

build status

  • Rails like models
  • Sexy DSL
  • simple relations
  • transactional spirit, with multi
  • Dynamic keys
  • Maps between strings and ids
  • Validations

A Small Taste

class User extends Orpheus
  constructor: ->
    @has 'book'

    @str 'about_me'
    @num 'points'
    @set 'likes'
    @zset 'ranking'

    @map @str 'fb_id'
    @str 'fb_secret'


    about_me: 'I like douchebags and watermelon'
    points: 5
  .books.add('dune','maybe some proust')
  .err (err) -> res.json err
  .exec ->
      # woho!


Orpheus supports all the basic types of Redis: @num, @str, @list, @set, @zset and @hash. Note that strings and numbers are stored inside the model hash. See the wiki for supported commands and key names for each type.


   client: redis.createClient()
   prefix: 'bookapp'


  • client: the Redis client.
  • prefix: optional prefix for keys. defaults to orpheus.

Issuing Commands with Orpheus

The Straightforward Way

    .points_by_time.zincrby(5, new Date().getTime())

Note you don't need to add the command prefix in this cases:

  str: 'h'
  num: 'h'
  list: 'l'
  set: 's'
  zset: 'z'
  hash: 'h'

So the commands above could have been just set, incrby and add.

Adding, Setting

    points: 20
    ranking: [1, 'best book ever!']
    name: 'sequel'
    num:  'hincrby'
    str:  'hset'
    set:  'sadd'
    zset: 'zincrby'
    list: 'lpush'

    num:  'hset'
    str:  'hset'
    set:  'sadd'
    zset: 'zadd'
    list: 'lpush'

Removing the Model

user('dune').delete (err, res) ->

Getting Stuff

Getting the entire model in Orpheus is pretty easy:

user.get (err, user) ->
  res.json user

Specific queries for getting stuff will also convert the response to an object, provided all the commands issued are for getting stuff (no incrby or lpush somewhere in the query).

get_user: (fn) ->
      @exec fn

Converting to object supports this commands:

getters: [
  # String, Number

  # List

  # Set

  # Zset

  # Hash

Getting stuff while updating stuff in the same query will return the results in an array, the same way a Redis multi() command will return the results.

Sometimes you need to do a few operations on the same property, like grabbing a few items off a list and getting the list length. In this case the returned propery will be an array, the first element of which is the response for the first request for that property and so on.

  .activites.range(0, 3)
  .exec (err, response) ->
    # response might be [20, ['item1', 'item2', 'item3']]

Err and Exec

Orpheus uses the .err() function for handling validation and unexpected errors. If .err() is not set the .exec() command receives errors as the first parameter.

user('sonic youth')
    name: 'modest mouse'
    points: 50
  .err (err) ->
    if err.type is 'validation'
      # phew, it's just a validation error
      res.json err.toResponse()
      # Redis Error, or a horrendous
      # bug in Orpheus
      log "Wake the sysadmins! #{err}"
      res.json status: 500
  .exec (res, id) ->
    # fun!

Without Err:

    name: 'putout'
  .exec (err, res, id) ->
    # err is the first parameter
    # everything else as usual

Getting the Model ID

When new models are created .exec() receives the model ID as the last argument.

  .exec (err, res, user_id) ->

Separate Callbacks

Just like with the multi command you can supply a separate callback for specific commands.

  .pokemons.push('pikachu', 'charizard', redis.print)
  .name.set('The Machine')
  .exec ->
    # ...

Conditional Commands

Sometimes you'll want to only issue specific commands based on a condition. If you don't want to break the chaining and clutter the code, use .when(fn). When executes fn immediately, with the context set to the model context. only is an alias for when.

info = get_mission_critical_information()
player('danny').when( ->
    if info is 'nah, never mind' then @name.set('oh YEAHH')
).points.incrby(5) # Business as usual

Default Values

Use the default option to pass a default value to all types:

class User extends Orpheus
  constructor: ->
    @str 'name', default: 'John Doe'

  user = User.create()

    .exec (err, res) ->
      log # 'John Doe'

Note that default values will be returned in all the get commands of the type. So if you have {someData: true} as a default for a zset, you will get that back when you request a zrank of a non-existent member:

# User Model
@zset 'visits', default: {'/': 0}

# Query
  .visits.rank('/404.html') # No such visit, default is returned
  .exec (err, res) ->
    log res.visits # unexpected default zset value: {'/': 0}


class User extends Orpheus
  constructor: ->
    @has 'book'

class Book extends Orpheus
  constructor: ->
    @has 'user'

user = User.create()
book = Book.create()

# Every relation means a set for that relation
user('chaplin').books.smembers().exec (err, book_ids) ->

  # With async functions for fun and profit
  user('chaplin') book_ids, (id, cb, i) ->
      book(id).get cb
    (err, books) ->
      # What? Did we just retrieved all the books from Redis?

Your can pass @has 'book', namespace: 'book' to create a different namespace than the relation. The default would be orpheus:us:{user_id}:bo:{book_id}. By passing the namespace option the key will map to orpheus:us:{user_id}:book:{book_id}

Dynamic Keys

class User extends Orpheus
  constructor: ->
    @zset 'monthly_ranking'
      key: ->
        d = new Date()
        # prefix:user:id:ranking:2012:5

user = User.create()
  .monthly_ranking.incrby(1, 'Midnight Oil - The Dead Heart')
  .exec ->
    res.json status: 200

Using arguments in dyanmic keys is easy:

@zset 'monthly_ranking'
  key: (year, month) ->
    "ranking:#{year || d.getFullYear()}:#{month || d.getMonth()+1}"

# later on, in a far away place...
  .monthly_ranking.incrby(1, 'Stoned Jesus - Im The Mountain', key: [2012, 12])

Everything inside key will be passed to the dynamic key function.

One to One Maps

Maps are used to map between a unique attribute of the model and the model ID.

Internally maps use a hash prefix:users:map:fb_ids.

This example uses the excellent PassportJS.

fb_connect = (req, res, next) ->
  fb = req.account
  fb_details =
    fb_name:  fb.displayName
    fb_token: fb.token
    fb_gener: fb.gender
    fb_url:   fb.profileUrl

  id = if req.user then else fb_id:
  player id, (err, player, is_new) ->
    next err if err
    # That's it, we just handled autorization,
    # new users and authentication in one go
      .exec (err, res, user_id) ->
        req.session.passport.user = user_id if user_id
        next err

What Just Happened?

There are two scenarios:

  1. Authentication: req.user is undefined, so the user is not logged in. We create an object {fb_id:} to use in the map. Orpheus requests hget prefix:users:map:fb_ids fb_id. If a match is found we continue as usual. Otherwise a new user is created. In both cases, the user's Facebook information is updated.

  2. Authorization: req.user is defined. The anonymous function is called right away and the user's Facebook information is updated.


Validations are based on the input, not on the object itself. For example, hincrby 5 will validate the number 5 itself, not the accumulated value in the object.

Validations run synchronously.

class User extends Orpheus
  constructor: ->
    @str 'name'
    @validate 'name', (s) -> if s is 'something' then true else 'name should be "something".'

player = Player.create()
  name: 'james!!!'
.err (err) ->
  if err.type is 'validation'
    log err # <OrpheusValidationErrors>
    # something is wrong with redis
.exec (res) ->
  # Never ever land

OrpheusValidationErrors has a few convenience functions:

  • add: adds an error
  • empty: clears the errors
  • toResponse: returns a JSON:
  status: 400, # Bad Request
    name: ['name should be "something".']

errors contains the actual error objects:

  name: [
    msg: 'name should be "something".',
    command: 'hset',
    args: ['james!!!'],
    value: 'james!!!',
    date: 1338936463054 # new Date().getTime()
  # ...

Customizing Message

@validate 'legacy_code',
    format: /^[a-zA-Z]+$/
    message: (val) -> "#{val} must be only A-Za-z"

Will do the trick. Number validations do not support customized messages yet.

Custom Validations

class Player extends Orpheus
    constructor: ->
        @str 'name'
        @validate 'name', (s) -> if s is 'babomb' then true else 'String should be babomb.'

Number Validations

@num 'points'

@validate 'points',
        only_integer: true
        greater_than: 3
        greater_than_or_equal_to: 3
        equal_to: 3
        less_than_or_equal_to: 3
        odd: true


  • only_integer: "#{n} must be an integer."
  • greater_than: "#{a} must be greater than #{b}."
  • greater_than_or_equal_to: "#{a} must be greater than or equal to #{b}."
  • equal_to: "#{a} must be equal to #{b}."
  • less_than: "#{a} must be less than #{b}."
  • less_than_or_equal_to: "#{a} must be less than or equal to #{b}."
  • odd: "#{a} must be odd."
  • even: "#{a} must be even."

Exclusion and Inclusion Validations

@str 'subdomain'
@str 'size'
@validate 'subdomain',
    exclusion: ['www', 'us', 'ca', 'jp']
@validate 'size',
    inclusion: ['small', 'medium', 'large']


@str 'content'
@validate 'content'
        tokenizer: (s) -> s.match(/\w+/g).length
        is: 5
        minimum: 5
        maximum: 5
        in: [1,5]


  • minimum: "'#{field}' length is #{len}. Must be bigger than #{min}.
  • maximum: "'#{field}' length is #{len}. Must be smaller than #{max}."
  • in: "'#{field}' length is #{len}. Must be between #{range[0]} and #{range[1]}."
  • is: "'#{field}' length is #{len1}. Must be #{len2}."
  • tokenizer: useful for splitting the field in different ways. The default is field.length.

Regex Validations

class Player extends Orpheus
    constructor: ->
        @str 'legacy_code'
        @validate 'legacy_code', format: /^[a-zA-Z]+$/

Error Handling

  • Undefined Attributes: Using set, add and del on undefined attributes will throw an error "Orpheus :: No Such Model Attribute: #{k}". Trying to no_such_attribute.incrby(1) will result in TypeError: Object #<Object> has no method 'incrby'. The call stack will directly tell you where the misbehaving attribute sits.

Remove a Relationship

A dynamic function, called "un#{relationship}"(), is available for removing already declared relationships. For example, a user with a books relationship will have an unbook() function available.

This is helpful when trying to abstract away common queries that happen in a lot of requests and denormalize data across relations. Think: points, counters.

class User extends Orpheus
      constructor: ->
        @has 'issue'
        @num 'comments'
        @num 'email_replies'

      add_comment: (issue_id) ->
        @comments.incrby 1
        @comments.incrby 1

      add_email_reply: (issue_id, fn) ->
        @add_comment issue_id
        @email_replies.incrby 1
        @email_replies.incrby 1
        @exec fn

    user = User.create()
    user('rada').add_email_reply '#142', ->
      # everything went better than expected...


  • Test - Make sure you got jasmine-node installed (npm install jasmine-node -g) then run cake test.

  • Build - Use cake bake to compile the code to JavaScript.

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