module CouchRest module Mixins module Collection def self.included(base) base.extend(ClassMethods) end module ClassMethods # Creates a new class method, find_all_, that will # execute the view specified with the design_doc and view_name # parameters, along with the specified view_options. This method will # return the results of the view as an Array of objects which are # instances of the class. # # This method is handy for objects that do not use the view_by method # to declare their views. def provides_collection(collection_name, design_doc, view_name, view_options) class_eval <<-END, __FILE__, __LINE__ + 1 def self.find_all_#{collection_name}(options = {}) view_options = #{view_options.inspect} || {} CollectionProxy.new(@database, "#{design_doc}", "#{view_name}", view_options.merge(options), Kernel.const_get('#{self}')) end END end # Fetch a group of objects from CouchDB. Options can include: # :page - Specifies the page to load (starting at 1) # :per_page - Specifies the number of objects to load per page # # Defaults are used if these options are not specified. def paginate(options) proxy = create_collection_proxy(options) proxy.paginate(options) end # Iterate over the objects in a collection, fetching them from CouchDB # in groups. Options can include: # :page - Specifies the page to load # :per_page - Specifies the number of objects to load per page # # Defaults are used if these options are not specified. def paginated_each(options, &block) proxy = create_collection_proxy(options) proxy.paginated_each(options, &block) end # Create a CollectionProxy for the specified view and options. # CollectionProxy behaves just like an Array, but offers support for # pagination. def collection_proxy_for(design_doc, view_name, view_options = {}) options = view_options.merge(:design_doc => design_doc, :view_name => view_name) create_collection_proxy(options) end private def create_collection_proxy(options) design_doc, view_name, view_options = parse_view_options(options) CollectionProxy.new(@database, design_doc, view_name, view_options, self) end def parse_view_options(options) design_doc = options.delete(:design_doc) raise ArgumentError, 'design_doc is required' if design_doc.nil? view_name = options.delete(:view_name) raise ArgumentError, 'view_name is required' if view_name.nil? default_view_options = (design_doc.class == Design && design_doc['views'][view_name.to_s] && design_doc['views'][view_name.to_s]["couchrest-defaults"]) || {} view_options = default_view_options.merge(options) [design_doc, view_name, view_options] end end class CollectionProxy alias_method :proxy_respond_to?, :respond_to? instance_methods.each { |m| undef_method m unless m =~ /(^__|^nil\?$|^send$|proxy_|^object_id$)/ } DEFAULT_PAGE = 1 DEFAULT_PER_PAGE = 30 # Create a new CollectionProxy to represent the specified view. If a # container class is specified, the proxy will create an object of the # given type for each row that comes back from the view. If no # container class is specified, the raw results are returned. # # The CollectionProxy provides support for paginating over a collection # via the paginate, and paginated_each methods. def initialize(database, design_doc, view_name, view_options = {}, container_class = nil) raise ArgumentError, "database is a required parameter" if database.nil? @database = database @container_class = container_class strip_pagination_options(view_options) @view_options = view_options if design_doc.class == Design @view_name = "#{design_doc.name}/#{view_name}" else @view_name = "#{design_doc}/#{view_name}" end end # See Collection.paginate def paginate(options = {}) page, per_page = parse_options(options) results = @database.view(@view_name, pagination_options(page, per_page)) remember_where_we_left_off(results, page) convert_to_container_array(results) end # See Collection.paginated_each def paginated_each(options = {}, &block) page, per_page = parse_options(options) begin collection = paginate({:page => page, :per_page => per_page}) collection.each(&block) page += 1 end until collection.size < per_page end def respond_to?(*args) proxy_respond_to?(*args) || (load_target && @target.respond_to?(*args)) end # Explicitly proxy === because the instance method removal above # doesn't catch it. def ===(other) load_target other === @target end private def method_missing(method, *args) if load_target if block_given? @target.send(method, *args) { |*block_args| yield(*block_args) } else @target.send(method, *args) end end end def load_target unless loaded? results = @database.view(@view_name, @view_options) @target = convert_to_container_array(results) end @loaded = true @target end def loaded? @loaded end def reload reset load_target self unless @target.nil? end def reset @loaded = false @target = nil end def inspect load_target @target.inspect end def convert_to_container_array(results) if @container_class.nil? results else results['rows'].collect { |row| @container_class.new(row['doc']) } unless results['rows'].nil? end end def pagination_options(page, per_page) view_options = @view_options.clone if @last_key && @last_docid && @last_page == page - 1 view_options.delete(:key) options = { :startkey => @last_key, :startkey_docid => @last_docid, :limit => per_page, :skip => 1 } else options = { :limit => per_page, :skip => per_page * (page - 1) } end view_options.merge(options) end def parse_options(options) page = options.delete(:page) || DEFAULT_PAGE per_page = options.delete(:per_page) || DEFAULT_PER_PAGE [page.to_i, per_page.to_i] end def strip_pagination_options(options) parse_options(options) end def remember_where_we_left_off(results, page) last_row = results['rows'].last if last_row @last_key = last_row['key'] @last_docid = last_row['id'] end @last_page = page end end end end end