609 lines
20 KiB
Ruby
609 lines
20 KiB
Ruby
require 'rubygems'
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require 'extlib'
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require 'digest/md5'
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require File.dirname(__FILE__) + '/document'
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require 'mime/types'
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# = CouchRest::Model - Document modeling, the CouchDB way
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module CouchRest
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# = CouchRest::Model - Document modeling, the CouchDB way
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#
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# CouchRest::Model provides an ORM-like interface for CouchDB documents. It
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# avoids all usage of <tt>method_missing</tt>, and tries to strike a balance
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# between usability and magic. See CouchRest::Model#view_by for
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# documentation about the view-generation system.
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#
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# ==== Example
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#
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# This is an example class using CouchRest::Model. It is taken from the
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# spec/couchrest/core/model_spec.rb file, which may be even more up to date
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# than this example.
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#
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# class Article < CouchRest::Model
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# use_database CouchRest.database!('http://127.0.0.1:5984/couchrest-model-test')
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# unique_id :slug
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#
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# view_by :date, :descending => true
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# view_by :user_id, :date
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#
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# view_by :tags,
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# :map =>
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# "function(doc) {
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# if (doc['couchrest-type'] == 'Article' && doc.tags) {
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# doc.tags.forEach(function(tag){
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# emit(tag, 1);
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# });
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# }
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# }",
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# :reduce =>
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# "function(keys, values, rereduce) {
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# return sum(values);
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# }"
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#
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# key_writer :date
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# key_reader :slug, :created_at, :updated_at
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# key_accessor :title, :tags
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#
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# timestamps!
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#
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# before(:create, :generate_slug_from_title)
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# def generate_slug_from_title
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# self['slug'] = title.downcase.gsub(/[^a-z0-9]/,'-').squeeze('-').gsub(/^\-|\-$/,'')
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# end
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# end
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#
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# ==== Examples of finding articles with these views:
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#
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# * All the articles by Barney published in the last 24 hours. Note that we
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# use <tt>{}</tt> as a special value that sorts after all strings,
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# numbers, and arrays.
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#
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# Article.by_user_id_and_date :startkey => ["barney", Time.now - 24 * 3600], :endkey => ["barney", {}]
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#
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# * The most recent 20 articles. Remember that the <tt>view_by :date</tt>
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# has the default option <tt>:descending => true</tt>.
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#
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# Article.by_date :limit => 20
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#
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# * The raw CouchDB view reduce result for the custom <tt>:tags</tt> view.
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# In this case we'll get a count of the number of articles tagged "ruby".
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#
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# Article.by_tags :key => "ruby", :reduce => true
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#
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class Model < Document
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# instantiates the hash by converting all the keys to strings.
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def initialize keys = {}
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super(keys)
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apply_defaults
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cast_keys
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unless self['_id'] && self['_rev']
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self['couchrest-type'] = self.class.to_s
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end
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end
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# this is the CouchRest::Database that model classes will use unless
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# they override it with <tt>use_database</tt>
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cattr_accessor :default_database
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class_inheritable_accessor :casts
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class_inheritable_accessor :default_obj
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class_inheritable_accessor :class_database
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class_inheritable_accessor :design_doc
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class_inheritable_accessor :design_doc_slug_cache
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class_inheritable_accessor :design_doc_fresh
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class << self
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# override the CouchRest::Model-wide default_database
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def use_database db
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self.class_database = db
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end
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# returns the CouchRest::Database instance that this class uses
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def database
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self.class_database || CouchRest::Model.default_database
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end
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# Load a document from the database by id
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def get id
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doc = database.get id
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new(doc)
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end
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# Load all documents that have the "couchrest-type" field equal to the
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# name of the current class. Take the standard set of
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# CouchRest::Database#view options.
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def all opts = {}, &block
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self.design_doc ||= Design.new(default_design_doc)
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unless design_doc_fresh
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refresh_design_doc
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end
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view :all, opts, &block
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end
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# Load the first document that have the "couchrest-type" field equal to
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# the name of the current class.
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#
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# ==== Returns
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# Object:: The first object instance available
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# or
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# Nil:: if no instances available
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#
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# ==== Parameters
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# opts<Hash>::
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# View options, see <tt>CouchRest::Database#view</tt> options for more info.
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def first opts = {}
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first_instance = self.all(opts.merge!(:limit => 1))
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first_instance.empty? ? nil : first_instance.first
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end
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# Cast a field as another class. The class must be happy to have the
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# field's primitive type as the argument to it's constuctur. Classes
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# which inherit from CouchRest::Model are happy to act as sub-objects
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# for any fields that are stored in JSON as object (and therefore are
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# parsed from the JSON as Ruby Hashes).
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#
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# Example:
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#
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# class Post < CouchRest::Model
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#
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# key_accessor :title, :body, :author
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#
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# cast :author, :as => 'Author'
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#
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# end
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#
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# post.author.class #=> Author
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#
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# Using the same example, if a Post should have many Comments, we
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# would declare it like this:
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#
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# class Post < CouchRest::Model
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#
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# key_accessor :title, :body, :author, comments
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#
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# cast :author, :as => 'Author'
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# cast :comments, :as => ['Comment']
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#
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# end
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#
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# post.author.class #=> Author
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# post.comments.class #=> Array
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# post.comments.first #=> Comment
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#
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def cast field, opts = {}
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self.casts ||= {}
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self.casts[field.to_s] = opts
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end
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# Defines methods for reading and writing from fields in the document.
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# Uses key_writer and key_reader internally.
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def key_accessor *keys
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key_writer *keys
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key_reader *keys
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end
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# For each argument key, define a method <tt>key=</tt> that sets the
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# corresponding field on the CouchDB document.
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def key_writer *keys
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keys.each do |method|
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key = method.to_s
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define_method "#{method}=" do |value|
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self[key] = value
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end
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end
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end
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# For each argument key, define a method <tt>key</tt> that reads the
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# corresponding field on the CouchDB document.
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def key_reader *keys
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keys.each do |method|
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key = method.to_s
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define_method method do
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self[key]
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end
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end
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end
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def default
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self.default_obj
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end
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def set_default hash
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self.default_obj = hash
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end
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# Automatically set <tt>updated_at</tt> and <tt>created_at</tt> fields
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# on the document whenever saving occurs. CouchRest uses a pretty
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# decent time format by default. See Time#to_json
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def timestamps!
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before(:save) do
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self['updated_at'] = Time.now
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self['created_at'] = self['updated_at'] if new_document?
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end
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end
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# Name a method that will be called before the document is first saved,
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# which returns a string to be used for the document's <tt>_id</tt>.
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# Because CouchDB enforces a constraint that each id must be unique,
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# this can be used to enforce eg: uniq usernames. Note that this id
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# must be globally unique across all document types which share a
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# database, so if you'd like to scope uniqueness to this class, you
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# should use the class name as part of the unique id.
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def unique_id method = nil, &block
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if method
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define_method :set_unique_id do
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self['_id'] ||= self.send(method)
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end
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elsif block
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define_method :set_unique_id do
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uniqid = block.call(self)
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raise ArgumentError, "unique_id block must not return nil" if uniqid.nil?
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self['_id'] ||= uniqid
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end
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end
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end
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# Define a CouchDB view. The name of the view will be the concatenation
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# of <tt>by</tt> and the keys joined by <tt>_and_</tt>
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#
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# ==== Example views:
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#
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# class Post
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# # view with default options
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# # query with Post.by_date
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# view_by :date, :descending => true
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#
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# # view with compound sort-keys
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# # query with Post.by_user_id_and_date
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# view_by :user_id, :date
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#
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# # view with custom map/reduce functions
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# # query with Post.by_tags :reduce => true
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# view_by :tags,
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# :map =>
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# "function(doc) {
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# if (doc['couchrest-type'] == 'Post' && doc.tags) {
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# doc.tags.forEach(function(tag){
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# emit(doc.tag, 1);
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# });
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# }
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# }",
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# :reduce =>
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# "function(keys, values, rereduce) {
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# return sum(values);
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# }"
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# end
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#
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# <tt>view_by :date</tt> will create a view defined by this Javascript
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# function:
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#
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# function(doc) {
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# if (doc['couchrest-type'] == 'Post' && doc.date) {
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# emit(doc.date, null);
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# }
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# }
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#
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# It can be queried by calling <tt>Post.by_date</tt> which accepts all
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# valid options for CouchRest::Database#view. In addition, calling with
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# the <tt>:raw => true</tt> option will return the view rows
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# themselves. By default <tt>Post.by_date</tt> will return the
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# documents included in the generated view.
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#
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# CouchRest::Database#view options can be applied at view definition
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# time as defaults, and they will be curried and used at view query
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# time. Or they can be overridden at query time.
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#
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# Custom views can be queried with <tt>:reduce => true</tt> to return
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# reduce results. The default for custom views is to query with
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# <tt>:reduce => false</tt>.
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#
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# Views are generated (on a per-model basis) lazily on first-access.
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# This means that if you are deploying changes to a view, the views for
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# that model won't be available until generation is complete. This can
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# take some time with large databases. Strategies are in the works.
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#
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# To understand the capabilities of this view system more compeletly,
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# it is recommended that you read the RSpec file at
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# <tt>spec/core/model_spec.rb</tt>.
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def view_by *keys
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self.design_doc ||= Design.new(default_design_doc)
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opts = keys.pop if keys.last.is_a?(Hash)
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opts ||= {}
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ducktype = opts.delete(:ducktype)
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unless ducktype || opts[:map]
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opts[:guards] ||= []
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opts[:guards].push "(doc['couchrest-type'] == '#{self.to_s}')"
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end
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keys.push opts
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self.design_doc.view_by(*keys)
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self.design_doc_fresh = false
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end
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def method_missing m, *args
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if has_view?(m)
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query = args.shift || {}
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view(m, query, *args)
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else
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super
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end
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end
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# returns stored defaults if the there is a view named this in the design doc
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def has_view?(view)
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view = view.to_s
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design_doc && design_doc['views'] && design_doc['views'][view]
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end
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# Dispatches to any named view.
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def view name, query={}, &block
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unless design_doc_fresh
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refresh_design_doc
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end
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query[:raw] = true if query[:reduce]
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raw = query.delete(:raw)
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fetch_view_with_docs(name, query, raw, &block)
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end
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def all_design_doc_versions
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database.documents :startkey => "_design/#{self.to_s}-",
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:endkey => "_design/#{self.to_s}-\u9999"
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end
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# Deletes any non-current design docs that were created by this class.
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# Running this when you're deployed version of your application is steadily
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# and consistently using the latest code, is the way to clear out old design
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# docs. Running it to early could mean that live code has to regenerate
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# potentially large indexes.
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def cleanup_design_docs!
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ddocs = all_design_doc_versions
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ddocs["rows"].each do |row|
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if (row['id'] != design_doc_id)
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database.delete({
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"_id" => row['id'],
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"_rev" => row['value']['rev']
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})
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end
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end
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end
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private
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def fetch_view_with_docs name, opts, raw=false, &block
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if raw
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fetch_view name, opts, &block
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else
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begin
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view = fetch_view name, opts.merge({:include_docs => true}), &block
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view['rows'].collect{|r|new(r['doc'])} if view['rows']
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rescue
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# fallback for old versions of couchdb that don't
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# have include_docs support
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view = fetch_view name, opts, &block
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view['rows'].collect{|r|new(database.get(r['id']))} if view['rows']
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end
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end
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end
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def fetch_view view_name, opts, &block
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retryable = true
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begin
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design_doc.view(view_name, opts, &block)
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# the design doc could have been deleted by a rouge process
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rescue RestClient::ResourceNotFound => e
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if retryable
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refresh_design_doc
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retryable = false
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retry
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else
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raise e
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end
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end
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end
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def design_doc_id
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"_design/#{design_doc_slug}"
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end
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def design_doc_slug
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return design_doc_slug_cache if design_doc_slug_cache && design_doc_fresh
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funcs = []
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design_doc['views'].each do |name, view|
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funcs << "#{name}/#{view['map']}#{view['reduce']}"
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end
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md5 = Digest::MD5.hexdigest(funcs.sort.join(''))
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self.design_doc_slug_cache = "#{self.to_s}-#{md5}"
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end
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def default_design_doc
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{
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"language" => "javascript",
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"views" => {
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'all' => {
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'map' => "function(doc) {
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if (doc['couchrest-type'] == '#{self.to_s}') {
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emit(null,null);
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}
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}"
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}
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}
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}
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end
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def refresh_design_doc
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did = design_doc_id
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saved = database.get(did) rescue nil
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if saved
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design_doc['views'].each do |name, view|
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saved['views'][name] = view
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end
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database.save(saved)
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self.design_doc = saved
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else
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design_doc['_id'] = did
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design_doc.delete('_rev')
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design_doc.database = database
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design_doc.save
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end
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self.design_doc_fresh = true
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end
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end # class << self
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# returns the database used by this model's class
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def database
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self.class.database
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end
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# Takes a hash as argument, and applies the values by using writer methods
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# for each key. It doesn't save the document at the end. Raises a NoMethodError if the corresponding methods are
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# missing. In case of error, no attributes are changed.
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def update_attributes_without_saving hash
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hash.each do |k, v|
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raise NoMethodError, "#{k}= method not available, use key_accessor or key_writer :#{k}" unless self.respond_to?("#{k}=")
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end
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hash.each do |k, v|
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self.send("#{k}=",v)
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end
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end
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# Takes a hash as argument, and applies the values by using writer methods
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# for each key. Raises a NoMethodError if the corresponding methods are
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# missing. In case of error, no attributes are changed.
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def update_attributes hash
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update_attributes_without_saving hash
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save
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end
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# for compatibility with old-school frameworks
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alias :new_record? :new_document?
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# Overridden to set the unique ID.
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def save bulk = false
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set_unique_id if new_document? && self.respond_to?(:set_unique_id)
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super(bulk)
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end
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# Saves the document to the db using create or update. Raises an exception
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# if the document is not saved properly.
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def save!
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raise "#{self.inspect} failed to save" unless self.save
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end
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# Deletes the document from the database. Runs the :destroy callbacks.
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# Removes the <tt>_id</tt> and <tt>_rev</tt> fields, preparing the
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# document to be saved to a new <tt>_id</tt>.
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def destroy
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result = database.delete self
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if result['ok']
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self['_rev'] = nil
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self['_id'] = nil
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end
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result['ok']
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end
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# creates a file attachment to the current doc
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def create_attachment(args={})
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raise ArgumentError unless args[:file] && args[:name]
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return if has_attachment?(args[:name])
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self['_attachments'] ||= {}
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set_attachment_attr(args)
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rescue ArgumentError => e
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raise ArgumentError, 'You must specify :file and :name'
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end
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# reads the data from an attachment
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def read_attachment(attachment_name)
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Base64.decode64(database.fetch_attachment(self.id, attachment_name))
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end
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# modifies a file attachment on the current doc
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def update_attachment(args={})
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raise ArgumentError unless args[:file] && args[:name]
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return unless has_attachment?(args[:name])
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delete_attachment(args[:name])
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set_attachment_attr(args)
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rescue ArgumentError => e
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raise ArgumentError, 'You must specify :file and :name'
|
|
end
|
|
|
|
# deletes a file attachment from the current doc
|
|
def delete_attachment(attachment_name)
|
|
return unless self['_attachments']
|
|
self['_attachments'].delete attachment_name
|
|
end
|
|
|
|
# returns true if attachment_name exists
|
|
def has_attachment?(attachment_name)
|
|
!!(self['_attachments'] && self['_attachments'][attachment_name] && !self['_attachments'][attachment_name].empty?)
|
|
end
|
|
|
|
# returns URL to fetch the attachment from
|
|
def attachment_url(attachment_name)
|
|
return unless has_attachment?(attachment_name)
|
|
"#{database.root}/#{self.id}/#{attachment_name}"
|
|
end
|
|
|
|
private
|
|
|
|
def apply_defaults
|
|
return unless new_document?
|
|
if self.class.default
|
|
self.class.default.each do |k,v|
|
|
unless self.key?(k.to_s)
|
|
if v.class == Proc
|
|
self[k.to_s] = v.call
|
|
else
|
|
self[k.to_s] = Marshal.load(Marshal.dump(v))
|
|
end
|
|
end
|
|
end
|
|
end
|
|
end
|
|
|
|
def cast_keys
|
|
return unless self.class.casts
|
|
# TODO move the argument checking to the cast method for early crashes
|
|
self.class.casts.each do |k,v|
|
|
next unless self[k]
|
|
target = v[:as]
|
|
v[:send] || 'new'
|
|
if target.is_a?(Array)
|
|
klass = ::Extlib::Inflection.constantize(target[0])
|
|
self[k] = self[k].collect do |value|
|
|
(!v[:send] && klass == Time) ? Time.parse(value) : klass.send((v[:send] || 'new'), value)
|
|
end
|
|
else
|
|
self[k] = if (!v[:send] && target == 'Time')
|
|
Time.parse(self[k])
|
|
else
|
|
::Extlib::Inflection.constantize(target).send((v[:send] || 'new'), self[k])
|
|
end
|
|
end
|
|
end
|
|
end
|
|
|
|
def encode_attachment(data)
|
|
Base64.encode64(data).gsub(/\r|\n/,'')
|
|
end
|
|
|
|
def get_mime_type(file)
|
|
MIME::Types.type_for(file.path).empty? ?
|
|
'text\/plain' : MIME::Types.type_for(file.path).first.content_type.gsub(/\//,'\/')
|
|
end
|
|
|
|
def set_attachment_attr(args)
|
|
content_type = args[:content_type] ? args[:content_type] : get_mime_type(args[:file])
|
|
self['_attachments'][args[:name]] = {
|
|
'content-type' => content_type,
|
|
'data' => encode_attachment(args[:file].read)
|
|
}
|
|
end
|
|
|
|
include ::Extlib::Hook
|
|
register_instance_hooks :save, :destroy
|
|
|
|
end # class Model
|
|
end # module CouchRest
|