improved OutOfRangeError exception (storing the failed Pagy object)

ddnexus · Jun 18, 2018 · 9817659 · 9817659
1 parent c6d0cb3
commit 9817659
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Showing 3 changed files with 18 additions and 4 deletions.
diff --git a/docs/how-to.md b/docs/how-to.md
@@ -392,3 +392,16 @@ def redirect_to_page_20
   redirect_to url_for(page: 20), notice: %(Page ##{params[:page]} is out of range. Showing page #20 instead.)
 end
 ```
+
+**Notice**: The `Pagy::OutOfRangeError` exception object contain the failed Pagy object as it was during the initialization process. You can get some useful information from it. For example:
+
+```ruby
+# in a controller
+rescue_from Pagy::OutOfRangeError, :with => :redirect_to_last_page
+
+private
+
+def redirect_to_last_page(exception)
+  redirect_to url_for(page: exception.pagy.last), notice: %(Page ##{exception.pagy.page} is out of range. Showing the last page instead.)
+end
+```
diff --git a/lib/pagy.rb b/lib/pagy.rb
@@ -4,13 +4,13 @@
 
 class Pagy ; VERSION = '0.9.1'
 
-  class OutOfRangeError < StandardError; end
+  class OutOfRangeError < StandardError; attr_reader :pagy; def initialize(pagy) @pagy = pagy end; end
 
   # Root pathname to get the path of Pagy files like templates or dictionaries
   def self.root; Pathname.new(__FILE__).dirname end
 
   # default vars
-  VARS = { page:1, items:20, outset:0, size:[1,4,4,1], page_param: :page, params: {}, anchor: ''.freeze, link_extra: ''.freeze, item_path: 'pagy.info.item_name'.freeze }
+  VARS = { page:1, items:20, outset:0, size:[1,4,4,1], page_param: :page, params:{}, anchor:''.freeze, link_extra:''.freeze, item_path:'pagy.info.item_name'.freeze }
 
   attr_reader :count, :page, :items, :vars, :pages, :last, :offset, :from, :to, :prev, :next
 
@@ -22,7 +22,7 @@ def initialize(vars)
          or raise(ArgumentError, "expected :#{k} >= #{min}; got #{instance_variable_get(:"@#{k}").inspect}")
     end
     @pages  = @last = [(@count.to_f / @items).ceil, 1].max                # cardinal and ordinal meanings
-    @page >= 1 && @page <= @last or raise(OutOfRangeError, "expected :page in 1..#{@last}; got #{@page.inspect}")
+    @page >= 1 && @page <= @last or raise(OutOfRangeError.new(self), "expected :page in 1..#{@last}; got #{@page.inspect}")
     @offset = @items * (@page - 1) + @outset                              # pagination offset + outset (initial offset)
     @items  = @count - ((@pages-1) * @items) if @page == @last            # adjust items for last page
     @from   = @count == 0 ? 0 : @offset+1 - @outset                       # page begins from item

diff --git a/test/pagy_test.rb b/test/pagy_test.rb
@@ -23,7 +23,8 @@ def test_initialization
       assert_raises(ArgumentError) { Pagy.new(count: 100, page: 2, size: [1, 2, 3]).series }
       assert_raises(ArgumentError) { Pagy.new(count: 100, page: 2, size: [1, 2, 3, '4']).series }
       assert_raises(Pagy::OutOfRangeError) { Pagy.new(count: 100, page: '11') }
-      assert_raises(Pagy::OutOfRangeError) { Pagy.new(count: 100, page: 12) }
+      e = assert_raises(Pagy::OutOfRangeError) { Pagy.new(count: 100, page: 12) }
+      assert_instance_of Pagy, e.pagy
     end
   end