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CouchRest::ExtendedDocument
CouchRest::ExtendedDocument is a DSL/ORM for CouchDB. Basically, ExtendedDocument seats on top of CouchRest Core to add the concept of Model.
ExtendedDocument offers a lot of the usual ORM tools such as optional yet defined schema, validation, callbacks, pagination, casting and much more.
Check spec/couchrest/more and spec/fixtures/more for more examples
class Article < CouchRest::ExtendedDocument use_database DB unique_id :slug view_by :date, :descending => true view_by :user_id, :date view_by :tags, :map => "function(doc) { if (doc['couchrest-type'] == 'Article' && doc.tags) { doc.tags.forEach(function(tag){ emit(tag, 1); }); } }", :reduce => "function(keys, values, rereduce) { return sum(values); }" property :date property :slug, :read_only => true property :title property :tags, :cast_as => ['String'] timestamps! set_callback :save, :before, :generate_slug_from_title def generate_slug_from_title self['slug'] = title.downcase.gsub(/[^a-z0-9]/,'-').squeeze('-').gsub(/^\-|\-$/,'') if new? end end
“CouchRest::ExtendedDocuments” instances have 4 callbacks already defined for you: “:validate”, “:create”, “:save”, “:update” and “:destroy”
“CouchRest::CastedModel” instances have 1 callback already defined for you: “:validate”
Define your callback as follows:
set_callback :save, :before, :generate_slug_from_name
CouchRest uses a mixin you can find in lib/mixins/callbacks which is extracted from Rails 3, here are some simple usage examples:
set_callback :save, :before, :before_method set_callback :save, :after, :after_method, :if => :condition set_callback :save, :around {|r| stuff; yield; stuff }Or the aliased short version:
before_save :before_method, :another_method after_save :after_method, :another_method, :if => :condition around_save {|r| stuff; yield; stuff }
To halt the callback, simply return a :halt symbol in your callback method.
Check the mixin or the ExtendedDocument class to see how to implement your own callbacks.
property :last_name, :alias => :family_name property :read_only_value, :read_only => true property :name, :length => 4...20 property :price, :type => Integer
Attribute protection from mass assignment to CouchRest properties. There are two modes of protection:
- Declare accessible properties, assume all the rest are protected
property :name, :accessible => true
property :admin # this will be automatically protected
- Declare protected properties, assume all the rest are accessible
property :name # this will not be protected
property :admin, :protected => true
Note: you cannot set both flags in a single class
Often, you will want to store multiple objects within a document, to be able to retrieve your objects when you load the document,
you can define some casting rules.
property :casted_attribute, :cast_as => 'WithCastedModelMixin' property :keywords, :cast_as => ["String"] property :occurs_at, :cast_as => 'Time', :init_method => 'parse property :end_date, :cast_as => 'Date', :init_method => 'parse
If you want to cast an array of instances from a specific Class, use the trick shown above [“ClassName”]
Pagination is available in any ExtendedDocument classes. Here are some usage examples:
basic usage:
Article.all.paginate(:page => 1, :per_page => 5)
note: the above query will look like: `GET /db/design/Article/_view/all?includedocs=true&skip=0&limit=5&reduce=false` and only fetch 5 documents.
Slightly more advance usage:
Article.by_name(:startkey => 'a', :endkey => {}).paginate(:page => 1, :per_page => 5)
note: the above query will look like: `GET /db/design/Article/view/byname?startkey=%22a%22&limit=5&skip=0&endkey=%7B%7D&includedocs=true`
Basically, you can paginate through the articles starting by the letter a, 5 articles at a time.
Low level usage:
Article.paginate(:design_doc => 'Article', :view_name => 'by_date', :per_page => 3, :page => 2, :descending => true, :key => Date.today, :include_docs => true)