+++ /dev/null
-module ActionController
- # === Action Pack pagination for Active Record collections
- #
- # The Pagination module aids in the process of paging large collections of
- # Active Record objects. It offers macro-style automatic fetching of your
- # model for multiple views, or explicit fetching for single actions. And if
- # the magic isn't flexible enough for your needs, you can create your own
- # paginators with a minimal amount of code.
- #
- # The Pagination module can handle as much or as little as you wish. In the
- # controller, have it automatically query your model for pagination; or,
- # if you prefer, create Paginator objects yourself.
- #
- # Pagination is included automatically for all controllers.
- #
- # For help rendering pagination links, see
- # ActionView::Helpers::PaginationHelper.
- #
- # ==== Automatic pagination for every action in a controller
- #
- # class PersonController < ApplicationController
- # model :person
- #
- # paginate :people, :order => 'last_name, first_name',
- # :per_page => 20
- #
- # # ...
- # end
- #
- # Each action in this controller now has access to a <tt>@people</tt>
- # instance variable, which is an ordered collection of model objects for the
- # current page (at most 20, sorted by last name and first name), and a
- # <tt>@person_pages</tt> Paginator instance. The current page is determined
- # by the <tt>params[:page]</tt> variable.
- #
- # ==== Pagination for a single action
- #
- # def list
- # @person_pages, @people =
- # paginate :people, :order => 'last_name, first_name'
- # end
- #
- # Like the previous example, but explicitly creates <tt>@person_pages</tt>
- # and <tt>@people</tt> for a single action, and uses the default of 10 items
- # per page.
- #
- # ==== Custom/"classic" pagination
- #
- # def list
- # @person_pages = Paginator.new self, Person.count, 10, params[:page]
- # @people = Person.find :all, :order => 'last_name, first_name',
- # :limit => @person_pages.items_per_page,
- # :offset => @person_pages.current.offset
- # end
- #
- # Explicitly creates the paginator from the previous example and uses
- # Paginator#to_sql to retrieve <tt>@people</tt> from the model.
- #
- module Pagination
- unless const_defined?(:OPTIONS)
- # A hash holding options for controllers using macro-style pagination
- OPTIONS = Hash.new
-
- # The default options for pagination
- DEFAULT_OPTIONS = {
- :class_name => nil,
- :singular_name => nil,
- :per_page => 10,
- :conditions => nil,
- :order_by => nil,
- :order => nil,
- :join => nil,
- :joins => nil,
- :count => nil,
- :include => nil,
- :select => nil,
- :group => nil,
- :parameter => 'page'
- }
- else
- DEFAULT_OPTIONS[:group] = nil
- end
-
- def self.included(base) #:nodoc:
- super
- base.extend(ClassMethods)
- end
-
- def self.validate_options!(collection_id, options, in_action) #:nodoc:
- options.merge!(DEFAULT_OPTIONS) {|key, old, new| old}
-
- valid_options = DEFAULT_OPTIONS.keys
- valid_options << :actions unless in_action
-
- unknown_option_keys = options.keys - valid_options
- raise ActionController::ActionControllerError,
- "Unknown options: #{unknown_option_keys.join(', ')}" unless
- unknown_option_keys.empty?
-
- options[:singular_name] ||= ActiveSupport::Inflector.singularize(collection_id.to_s)
- options[:class_name] ||= ActiveSupport::Inflector.camelize(options[:singular_name])
- end
-
- # Returns a paginator and a collection of Active Record model instances
- # for the paginator's current page. This is designed to be used in a
- # single action; to automatically paginate multiple actions, consider
- # ClassMethods#paginate.
- #
- # +options+ are:
- # <tt>:singular_name</tt>:: the singular name to use, if it can't be inferred by singularizing the collection name
- # <tt>:class_name</tt>:: the class name to use, if it can't be inferred by
- # camelizing the singular name
- # <tt>:per_page</tt>:: the maximum number of items to include in a
- # single page. Defaults to 10
- # <tt>:conditions</tt>:: optional conditions passed to Model.find(:all, *params) and
- # Model.count
- # <tt>:order</tt>:: optional order parameter passed to Model.find(:all, *params)
- # <tt>:order_by</tt>:: (deprecated, used :order) optional order parameter passed to Model.find(:all, *params)
- # <tt>:joins</tt>:: optional joins parameter passed to Model.find(:all, *params)
- # and Model.count
- # <tt>:join</tt>:: (deprecated, used :joins or :include) optional join parameter passed to Model.find(:all, *params)
- # and Model.count
- # <tt>:include</tt>:: optional eager loading parameter passed to Model.find(:all, *params)
- # and Model.count
- # <tt>:select</tt>:: :select parameter passed to Model.find(:all, *params)
- #
- # <tt>:count</tt>:: parameter passed as :select option to Model.count(*params)
- #
- # <tt>:group</tt>:: :group parameter passed to Model.find(:all, *params). It forces the use of DISTINCT instead of plain COUNT to come up with the total number of records
- #
- def paginate(collection_id, options={})
- Pagination.validate_options!(collection_id, options, true)
- paginator_and_collection_for(collection_id, options)
- end
-
- # These methods become class methods on any controller
- module ClassMethods
- # Creates a +before_filter+ which automatically paginates an Active
- # Record model for all actions in a controller (or certain actions if
- # specified with the <tt>:actions</tt> option).
- #
- # +options+ are the same as PaginationHelper#paginate, with the addition
- # of:
- # <tt>:actions</tt>:: an array of actions for which the pagination is
- # active. Defaults to +nil+ (i.e., every action)
- def paginate(collection_id, options={})
- Pagination.validate_options!(collection_id, options, false)
- module_eval do
- before_filter :create_paginators_and_retrieve_collections
- OPTIONS[self] ||= Hash.new
- OPTIONS[self][collection_id] = options
- end
- end
- end
-
- def create_paginators_and_retrieve_collections #:nodoc:
- Pagination::OPTIONS[self.class].each do |collection_id, options|
- next unless options[:actions].include? action_name if
- options[:actions]
-
- paginator, collection =
- paginator_and_collection_for(collection_id, options)
-
- paginator_name = "@#{options[:singular_name]}_pages"
- self.instance_variable_set(paginator_name, paginator)
-
- collection_name = "@#{collection_id.to_s}"
- self.instance_variable_set(collection_name, collection)
- end
- end
-
- # Returns the total number of items in the collection to be paginated for
- # the +model+ and given +conditions+. Override this method to implement a
- # custom counter.
- def count_collection_for_pagination(model, options)
- model.count(:conditions => options[:conditions],
- :joins => options[:join] || options[:joins],
- :include => options[:include],
- :select => (options[:group] ? "DISTINCT #{options[:group]}" : options[:count]))
- end
-
- # Returns a collection of items for the given +model+ and +options[conditions]+,
- # ordered by +options[order]+, for the current page in the given +paginator+.
- # Override this method to implement a custom finder.
- def find_collection_for_pagination(model, options, paginator)
- model.find(:all, :conditions => options[:conditions],
- :order => options[:order_by] || options[:order],
- :joins => options[:join] || options[:joins], :include => options[:include],
- :select => options[:select], :limit => options[:per_page],
- :group => options[:group], :offset => paginator.current.offset)
- end
-
- protected :create_paginators_and_retrieve_collections,
- :count_collection_for_pagination,
- :find_collection_for_pagination
-
- def paginator_and_collection_for(collection_id, options) #:nodoc:
- klass = options[:class_name].constantize
- page = params[options[:parameter]]
- count = count_collection_for_pagination(klass, options)
- paginator = Paginator.new(self, count, options[:per_page], page)
- collection = find_collection_for_pagination(klass, options, paginator)
-
- return paginator, collection
- end
-
- private :paginator_and_collection_for
-
- # A class representing a paginator for an Active Record collection.
- class Paginator
- include Enumerable
-
- # Creates a new Paginator on the given +controller+ for a set of items
- # of size +item_count+ and having +items_per_page+ items per page.
- # Raises ArgumentError if items_per_page is out of bounds (i.e., less
- # than or equal to zero). The page CGI parameter for links defaults to
- # "page" and can be overridden with +page_parameter+.
- def initialize(controller, item_count, items_per_page, current_page=1)
- raise ArgumentError, 'must have at least one item per page' if
- items_per_page <= 0
-
- @controller = controller
- @item_count = item_count || 0
- @items_per_page = items_per_page
- @pages = {}
-
- self.current_page = current_page
- end
- attr_reader :controller, :item_count, :items_per_page
-
- # Sets the current page number of this paginator. If +page+ is a Page
- # object, its +number+ attribute is used as the value; if the page does
- # not belong to this Paginator, an ArgumentError is raised.
- def current_page=(page)
- if page.is_a? Page
- raise ArgumentError, 'Page/Paginator mismatch' unless
- page.paginator == self
- end
- page = page.to_i
- @current_page_number = has_page_number?(page) ? page : 1
- end
-
- # Returns a Page object representing this paginator's current page.
- def current_page
- @current_page ||= self[@current_page_number]
- end
- alias current :current_page
-
- # Returns a new Page representing the first page in this paginator.
- def first_page
- @first_page ||= self[1]
- end
- alias first :first_page
-
- # Returns a new Page representing the last page in this paginator.
- def last_page
- @last_page ||= self[page_count]
- end
- alias last :last_page
-
- # Returns the number of pages in this paginator.
- def page_count
- @page_count ||= @item_count.zero? ? 1 :
- (q,r=@item_count.divmod(@items_per_page); r==0? q : q+1)
- end
-
- alias length :page_count
-
- # Returns true if this paginator contains the page of index +number+.
- def has_page_number?(number)
- number >= 1 and number <= page_count
- end
-
- # Returns a new Page representing the page with the given index
- # +number+.
- def [](number)
- @pages[number] ||= Page.new(self, number)
- end
-
- # Successively yields all the paginator's pages to the given block.
- def each(&block)
- page_count.times do |n|
- yield self[n+1]
- end
- end
-
- # A class representing a single page in a paginator.
- class Page
- include Comparable
-
- # Creates a new Page for the given +paginator+ with the index
- # +number+. If +number+ is not in the range of valid page numbers or
- # is not a number at all, it defaults to 1.
- def initialize(paginator, number)
- @paginator = paginator
- @number = number.to_i
- @number = 1 unless @paginator.has_page_number? @number
- end
- attr_reader :paginator, :number
- alias to_i :number
-
- # Compares two Page objects and returns true when they represent the
- # same page (i.e., their paginators are the same and they have the
- # same page number).
- def ==(page)
- return false if page.nil?
- @paginator == page.paginator and
- @number == page.number
- end
-
- # Compares two Page objects and returns -1 if the left-hand page comes
- # before the right-hand page, 0 if the pages are equal, and 1 if the
- # left-hand page comes after the right-hand page. Raises ArgumentError
- # if the pages do not belong to the same Paginator object.
- def <=>(page)
- raise ArgumentError unless @paginator == page.paginator
- @number <=> page.number
- end
-
- # Returns the item offset for the first item in this page.
- def offset
- @paginator.items_per_page * (@number - 1)
- end
-
- # Returns the number of the first item displayed.
- def first_item
- offset + 1
- end
-
- # Returns the number of the last item displayed.
- def last_item
- [@paginator.items_per_page * @number, @paginator.item_count].min
- end
-
- # Returns true if this page is the first page in the paginator.
- def first?
- self == @paginator.first
- end
-
- # Returns true if this page is the last page in the paginator.
- def last?
- self == @paginator.last
- end
-
- # Returns a new Page object representing the page just before this
- # page, or nil if this is the first page.
- def previous
- if first? then nil else @paginator[@number - 1] end
- end
-
- # Returns a new Page object representing the page just after this
- # page, or nil if this is the last page.
- def next
- if last? then nil else @paginator[@number + 1] end
- end
-
- # Returns a new Window object for this page with the specified
- # +padding+.
- def window(padding=2)
- Window.new(self, padding)
- end
-
- # Returns the limit/offset array for this page.
- def to_sql
- [@paginator.items_per_page, offset]
- end
-
- def to_param #:nodoc:
- @number.to_s
- end
- end
-
- # A class for representing ranges around a given page.
- class Window
- # Creates a new Window object for the given +page+ with the specified
- # +padding+.
- def initialize(page, padding=2)
- @paginator = page.paginator
- @page = page
- self.padding = padding
- end
- attr_reader :paginator, :page
-
- # Sets the window's padding (the number of pages on either side of the
- # window page).
- def padding=(padding)
- @padding = padding < 0 ? 0 : padding
- # Find the beginning and end pages of the window
- @first = @paginator.has_page_number?(@page.number - @padding) ?
- @paginator[@page.number - @padding] : @paginator.first
- @last = @paginator.has_page_number?(@page.number + @padding) ?
- @paginator[@page.number + @padding] : @paginator.last
- end
- attr_reader :padding, :first, :last
-
- # Returns an array of Page objects in the current window.
- def pages
- (@first.number..@last.number).to_a.collect! {|n| @paginator[n]}
- end
- alias to_a :pages
- end
- end
-
- end
-end
projects / rails.git / blobdiff