Orpheus

A Small CoffeeScript Object Model for Redis

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Orpheus - Redis Little Helper

Orpheus is a Redis Object Model for CoffeeScript.

npm install orpheus

If you are using Orpheus please ping me on Twitter or EngineZombie. It will make me happy.

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'

  user = Player.create()

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

Types

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.

Configuration

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

Options:

Issuing Commands with Orpheus

The Straightforward Way

  user('rada')
    .name.hset('radagaisus')
    .points.hincrby(5)
    .points_by_time.zincrby(5, new Date().getTime())
    .books.sadd('dune')

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

shorthands:
  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, Deleting

user('dune')
  .add
    points: 20
    ranking: [1, 'best book ever!']
  .set
    name: 'sequel'
  .exec()
add:
    num:  'hincrby'
    str:  'hset'
    set:  'sadd'
    zset: 'zincrby'
    list: 'lpush'

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

Getting Stuff

Getting the entire model in Orpheus is pretty easy:

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

Here's how get asks for different types:

switch type
  when 'str', 'num'
    @[key].get()
  when 'list'
    @[key].range 0, -1
  when 'set'
    @[key].members()
  when 'zset'
    @[key].range 0, -1, 'withscores'
  when 'hash'
    @[key].hgetall()

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) ->
      @name.get()
      @fb_id.get()
      @fb_friends.get()
      @member_since.get()
      @exec fn

Converting to object supports this commands:

getters: [
  # String, Number
  'hget',

  # List
  'lrange',

  # Set
  'smembers',
  'scard',

  # Zset
  'zrange',
  'zrangebyscore',
  'zrevrange',
  'zrevrangebyscore'

  # Hash
  'hget',
  'hgetall',
  'hmget'
]

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.

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

Without Err:

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

Separate Callbacks

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

user('mgmt')
  .pokemons.push('pikachu', 'charizard', redis.print)
  .err
    -> # ...
  .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
.exec()

Relations

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 (err, book_ids) ->

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

Dynamic Keys

class User extends Orpheus
  constructor: ->
    @zset 'monthly_ranking'
      key: ->
        d = new Date()
        # prefix:user:id:ranking:2012:5
        "ranking:#{d.getFullYear()}:#{d.getMonth()+1}"

user = User.create()
user('jackson')
  .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...
user('bean')
  .monthly_ranking.incrby(1, 'Stoned Jesus - I'm 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_id:    fb.id
    fb_name:  fb.displayName
    fb_token: fb.token
    fb_gener: fb.gender
    fb_url:   fb.profileUrl

  id = if req.user then req.user.id else fb_id: 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
    player
      .set(fb_details)
      .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: 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

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

OrpheusValidationErrors has a few convenience functions:

{
  status: 400, # Bad Request
  errors:
    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',
    numericality:
        only_integer: true
        greater_than: 3
        greater_than_or_equal_to: 3
        equal_to: 3
        less_than_or_equal_to: 3
        odd: true

Options:

Exclusion and Inclusion Validations

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

Size

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

Options:

Regex Validations

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

Error Handling

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
        @issue(issue_id)
        @comments.incrby 1
        @unissue()


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

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

Development

Test

cake test

Contribute