Skip to content
This repository
Fetching contributors…

Cannot retrieve contributors at this time

file 320 lines (288 sloc) 12.597 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320
require 'will_paginate/core_ext'

module WillPaginate
  # = Will Paginate view helpers
  #
  # Currently there is only one view helper: +will_paginate+. It renders the
  # pagination links for the given collection. The helper itself is lightweight
  # and serves only as a wrapper around link renderer instantiation; the
  # renderer then does all the hard work of generating the HTML.
  #
  # == Global options for helpers
  #
  # Options for pagination helpers are optional and get their default values from the
  # WillPaginate::ViewHelpers.pagination_options hash. You can write to this hash to
  # override default options on the global level:
  #
  # WillPaginate::ViewHelpers.pagination_options[:prev_label] = 'Previous page'
  #
  # By putting this into your environment.rb you can easily translate link texts to previous
  # and next pages, as well as override some other defaults to your liking.
  module ViewHelpers
    # default options that can be overridden on the global level
    @@pagination_options = {
      :class => 'pagination',
      :prev_label => '« Previous',
      :next_label => 'Next »',
      :inner_window => 4, # links around the current page
      :outer_window => 1, # links around beginning and end
      :separator => ' ', # single space is friendly to spiders and non-graphic browsers
      :param_name => :page,
      :params => nil,
      :renderer => 'WillPaginate::LinkRenderer',
      :page_links => true,
      :container => true
    }
    mattr_reader :pagination_options

    # Renders Digg/Flickr-style pagination for a WillPaginate::Collection
    # object. Nil is returned if there is only one page in total; no point in
    # rendering the pagination in that case...
    #
    # ==== Options
    # * <tt>:class</tt> -- CSS class name for the generated DIV (default: "pagination")
    # * <tt>:prev_label</tt> -- default: "« Previous"
    # * <tt>:next_label</tt> -- default: "Next »"
    # * <tt>:inner_window</tt> -- how many links are shown around the current page (default: 4)
    # * <tt>:outer_window</tt> -- how many links are around the first and the last page (default: 1)
    # * <tt>:separator</tt> -- string separator for page HTML elements (default: single space)
    # * <tt>:param_name</tt> -- parameter name for page number in URLs (default: <tt>:page</tt>)
    # * <tt>:params</tt> -- additional parameters when generating pagination links
    # (eg. <tt>:controller => "foo", :action => nil</tt>)
    # * <tt>:renderer</tt> -- class name of the link renderer (default: WillPaginate::LinkRenderer)
    # * <tt>:page_links</tt> -- when false, only previous/next links are rendered (default: true)
    # * <tt>:container</tt> -- toggles rendering of the DIV container for pagination links, set to
    # false only when you are rendering your own pagination markup (default: true)
    # * <tt>:id</tt> -- HTML ID for the container (default: nil). Pass +true+ to have the ID automatically
    # generated from the class name of objects in collection: for example, paginating
    # ArticleComment models would yield an ID of "article_comments_pagination".
    #
    # All options beside listed ones are passed as HTML attributes to the container
    # element for pagination links (the DIV). For example:
    #
    # <%= will_paginate @posts, :id => 'wp_posts' %>
    #
    # ... will result in:
    #
    # <div class="pagination" id="wp_posts"> ... </div>
    #
    # ==== Using the helper without arguments
    # If the helper is called without passing in the collection object, it will
    # try to read from the instance variable inferred by the controller name.
    # For example, calling +will_paginate+ while the current controller is
    # PostsController will result in trying to read from the <tt>@posts</tt>
    # variable. Example:
    #
    # <%= will_paginate :id => true %>
    #
    # ... will result in <tt>@post</tt> collection getting paginated:
    #
    # <div class="pagination" id="posts_pagination"> ... </div>
    #
    def will_paginate(collection = nil, options = {})
      options, collection = collection, nil if collection.is_a? Hash
      unless collection or !controller
        collection_name = "@#{controller.controller_name}"
        collection = instance_variable_get(collection_name)
        raise ArgumentError, "The #{collection_name} variable appears to be empty. Did you " +
          "forget to pass the collection object for will_paginate?" unless collection
      end
      # early exit if there is nothing to render
      return nil unless WillPaginate::ViewHelpers.total_pages_for_collection(collection) > 1
      
      options = options.symbolize_keys.reverse_merge WillPaginate::ViewHelpers.pagination_options
      # create the renderer instance
      renderer_class = options[:renderer].to_s.constantize
      renderer = renderer_class.new collection, options, self
      # render HTML for pagination
      renderer.to_html
    end
    
    # Wrapper for rendering pagination links at both top and bottom of a block
    # of content.
    #
    # <% paginated_section @posts do %>
    # <ol id="posts">
    # <% for post in @posts %>
    # <li> ... </li>
    # <% end %>
    # </ol>
    # <% end %>
    #
    # will result in:
    #
    # <div class="pagination"> ... </div>
    # <ol id="posts">
    # ...
    # </ol>
    # <div class="pagination"> ... </div>
    #
    # Arguments are passed to a <tt>will_paginate</tt> call, so the same options
    # apply. Don't use the <tt>:id</tt> option; otherwise you'll finish with two
    # blocks of pagination links sharing the same ID (which is invalid HTML).
    def paginated_section(*args, &block)
      pagination = will_paginate(*args).to_s
      content = pagination + capture(&block) + pagination
      concat content, block.binding
    end

    # Renders a helpful message with numbers of displayed vs. total entries.
    # You can use this as a blueprint for your own, similar helpers.
    #
    # <%= page_entries_info @posts %>
    # #-> Displaying entries 6 - 10 of 26 in total
    def page_entries_info(collection)
      %{Displaying entries <b>%d&nbsp;-&nbsp;%d</b> of <b>%d</b> in total} % [
        collection.offset + 1,
        collection.offset + collection.length,
        collection.total_entries
      ]
    end

    def self.total_pages_for_collection(collection) #:nodoc:
      if collection.respond_to?('page_count') and !collection.respond_to?('total_pages')
        WillPaginate::Deprecation.warn <<-MSG
You are using a paginated collection of class #{collection.class.name}
which conforms to the old API of WillPaginate::Collection by using
`page_count`, while the current method name is `total_pages`. Please
upgrade yours or 3rd-party code that provides the paginated collection.
MSG
        class << collection
          def total_pages; page_count; end
        end
      end
      collection.total_pages
    end
  end

  # This class does the heavy lifting of actually building the pagination
  # links. It is used by +will_paginate+ helper internally.
  class LinkRenderer
    # * +collection+ is a WillPaginate::Collection instance or any other object
    # that conforms to that API
    # * +options+ are forwarded from +will_paginate+ view helper
    # * +template+ is the reference to the template being rendered
    def initialize(collection, options, template)
      @collection = collection
      @options = options
      @template = template
    end

    # Process it! This method returns the complete HTML string which contains
    # pagination links. Feel free to subclass LinkRenderer and change this
    # method as you see fit.
    def to_html
      links = @options[:page_links] ? windowed_links : []
      # previous/next buttons
      links.unshift page_link_or_span(@collection.previous_page, %w(disabled prev_page), @options[:prev_label])
      links.push page_link_or_span(@collection.next_page, %w(disabled next_page), @options[:next_label])
      
      html = links.join(@options[:separator])
      @options[:container] ? @template.content_tag(:div, html, html_attributes) : html
    end

    # Returns the subset of +options+ this instance was initialized with that
    # represent HTML attributes for the container element of pagination links.
    def html_attributes
      return @html_attributes if @html_attributes
      @html_attributes = @options.except *(WillPaginate::ViewHelpers.pagination_options.keys - [:class])
      # pagination of Post models will have the ID of "posts_pagination"
      if @options[:container] and @options[:id] === true
        @html_attributes[:id] = @collection.first.class.name.underscore.pluralize + '_pagination'
      end
      @html_attributes
    end
    
  protected

    # The gap in page links is represented by:
    #
    # <span class="gap">&hellip;</span>
    def gap_marker
      '<span class="gap">&hellip;</span>'
    end
    
    # Collects link items for visible page numbers.
    def windowed_links
      prev = nil

      visible_page_numbers.inject [] do |links, n|
        # detect gaps:
        links << gap_marker if prev and n > prev + 1
        links << page_link_or_span(n, 'current')
        prev = n
        links
      end
    end

    # Calculates visible page numbers using the <tt>:inner_window</tt> and
    # <tt>:outer_window</tt> options.
    def visible_page_numbers
      inner_window, outer_window = @options[:inner_window].to_i, @options[:outer_window].to_i
      window_from = current_page - inner_window
      window_to = current_page + inner_window
      
      # adjust lower or upper limit if other is out of bounds
      if window_to > total_pages
        window_from -= window_to - total_pages
        window_to = total_pages
      end
      if window_from < 1
        window_to += 1 - window_from
        window_from = 1
        window_to = total_pages if window_to > total_pages
      end
      
      visible = (1..total_pages).to_a
      left_gap = (2 + outer_window)...window_from
      right_gap = (window_to + 1)...(total_pages - outer_window)
      visible -= left_gap.to_a if left_gap.last - left_gap.first > 1
      visible -= right_gap.to_a if right_gap.last - right_gap.first > 1

      visible
    end
    
    def page_link_or_span(page, span_class, text = nil)
      text ||= page.to_s
      classnames = Array[*span_class]
      
      if page and page != current_page
        @template.link_to text, url_for(page), :rel => rel_value(page), :class => classnames[1]
      else
        @template.content_tag :span, text, :class => classnames.join(' ')
      end
    end

    # Returns URL params for +page_link_or_span+, taking the current GET params
    # and <tt>:params</tt> option into account.
    def url_for(page)
      unless @url_string
        @url_params = { :escape => false }
        # page links should preserve GET parameters
        stringified_merge @url_params, @template.params if @template.request.get?
        stringified_merge @url_params, @options[:params] if @options[:params]
        
        if param_name.index(/[^\w-]/)
          page_param = (defined?(CGIMethods) ? CGIMethods : ActionController::AbstractRequest).
            parse_query_parameters("#{param_name}=#{page}")
          
          stringified_merge @url_params, page_param
        else
          @url_params[param_name] = page
        end

        url = @template.url_for(@url_params)
        @url_string = url.sub(/([?&]#{CGI.escape param_name}=)#{page}/, '\1@')
        return url
      end
      @url_string.sub '@', page.to_s
    end

  private

    def rel_value(page)
      case page
      when @collection.previous_page; 'prev' + (page == 1 ? ' start' : '')
      when @collection.next_page; 'next'
      when 1; 'start'
      end
    end

    def current_page
      @collection.current_page
    end

    def total_pages
      @total_pages ||= WillPaginate::ViewHelpers.total_pages_for_collection(@collection)
    end

    def param_name
      @param_name ||= @options[:param_name].to_s
    end

    def stringified_merge(target, other)
      other.each do |key, value|
        key = key.to_s
        existing = target[key]

        if value.is_a?(Hash)
          target[key] = existing = {} if existing.nil?
          if existing.is_a?(Hash)
            stringified_merge(existing, value)
            return
          end
        end
        
        target[key] = value
      end
    end
  end
end
Something went wrong with that request. Please try again.