| 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] ||= Inflector.singularize(collection_id.to_s) |
| options[:class_name] ||= 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 |