Skip stripping of blob columns in the string_stripper plugin (Fixes #593

)

In addition to handling blob columns/values, this also allows
you to arbitrarily skip stripping of certain columns via
Model.skip_string_stripping.

CHANGELOG

@@ -1,5 +1,7 @@
 === HEAD
 
+* Skip stripping of blob columns in the string_stripper plugin (jeremyevans) (#593)
+
 * Allow Database#get to take an array to return multiple values, similar to map/select_map (jeremyevans)
 
 * Default :prefetch_rows to 100 in the Oracle adapter (andrewhr) (#592)

lib/sequel/plugins/string_stripper.rb

@@ -1,10 +1,18 @@
 module Sequel
   module Plugins
-    # StringStripper is a very simple plugin that strips all input strings
+    # StringStripper is a plugin that strips all input strings
     # when assigning to the model's values. Example:
     #
     #   album = Album.new(:name=>' A ')
     #   album.name # => 'A'
+    #
+    # SQL::Blob instances and all non-strings are not modified by
+    # this plugin.  Additionally, strings passed to a blob column
+    # setter are also not modified.  You can explicitly set
+    # other columns to skip the stripping:
+    #
+    #   Album.skip_string_stripping :foo
+    #   Album.new(:foo=>' A ').foo # => ' A '
     # 
     # Usage:
     #
@@ -14,11 +22,53 @@ module Plugins
     #   # Make the Album class strip strings
     #   Album.plugin :string_stripper
     module StringStripper
+      # Set blob columns as skipping stripping when plugin is loaded.
+      def self.configure(model)
+        model.instance_variable_set(:@skipped_string_stripping_columns, [])
+        model.send(:set_skipped_string_stripping_columns)
+      end
+
+      module ClassMethods
+        # Copy skipped stripping columns from superclass into subclass.
+        def inherited(subclass)
+          subclass.instance_variable_set(:@skipped_string_stripping_columns, @skipped_string_stripping_columns.dup)
+          super
+        end
+
+        # Set blob columns as skipping stripping when plugin is loaded.
+        def set_dataset(*)
+          super
+          set_skipped_string_stripping_columns
+        end
+
+        # Skip stripping for the given columns.
+        def skip_string_stripping(*columns)
+          @skipped_string_stripping_columns.concat(columns).uniq!
+        end
+
+        # Return true if the column should not have values stripped.
+        def skip_string_stripping?(column)
+          @skipped_string_stripping_columns.include?(column)
+        end
+
+        private
+
+        # Automatically skip stripping of blob columns
+        def set_skipped_string_stripping_columns
+          if @db_schema
+            blob_columns = @db_schema.map{|k,v| k if v[:type] == :blob}.compact
+            skip_string_stripping(*blob_columns)
+          end
+        end
+      end
+
       module InstanceMethods
-        # Strip value if it is a string, before attempting to assign
+        # Strip value if it is a non-blob string and the model hasn't been set
+        # to skip stripping for the column, before attempting to assign
         # it to the model's values.
         def []=(k, v)
-          v.is_a?(String) ? super(k, v.strip) : super
+          v = v.strip if v.is_a?(String) && !v.is_a?(SQL::Blob) && !model.skip_string_stripping?(k)
+          super(k, v)
         end
       end
     end

spec/extensions/string_stripper_spec.rb

@@ -3,9 +3,10 @@
 describe "Sequel::Plugins::StringStripper" do
   before do
     @db = Sequel::Database.new
-    @c = Class.new(Sequel::Model(@db))
+    @c = Class.new(Sequel::Model(@db[:test]))
+    @c.columns :name, :b
+    @c.db_schema[:b][:type] = :blob
     @c.plugin :string_stripper
-    @c.columns :name
     @o = @c.new
   end
 
@@ -20,4 +21,45 @@
     @o.name = Date.today
     @o.name.should == Date.today
   end
+
+  it "should not strip strings for blob arguments" do
+    v = Sequel.blob(' name ')
+    @o.name = v
+    @o.name.should equal(v)
+  end
+
+  it "should not strip strings for blob columns" do
+    @o.b = ' name '
+    @o.b.should be_a_kind_of(Sequel::SQL::Blob)
+    @o.b.should == Sequel.blob(' name ')
+  end
+
+  it "should allow skipping of columns using Model.skip_string_stripping" do
+    @c.skip_string_stripping :name
+    v = ' name '
+    @o.name = v
+    @o.name.should equal(v)
+  end
+
+  it "should work correctly in subclasses" do
+    o = Class.new(@c).new
+    o.name = ' name '
+    o.name.should == 'name'
+    o.b = ' name '
+    o.b.should be_a_kind_of(Sequel::SQL::Blob)
+    o.b.should == Sequel.blob(' name ')
+  end
+
+  it "should work correctly for dataset changes" do
+    c = Class.new(Sequel::Model(@db[:test]))
+    c.plugin :string_stripper
+    def @db.schema(*) [[:name, {}], [:b, {:type=>:blob}]] end
+    c.set_dataset(@db[:test2])
+    o = c.new
+    o.name = ' name '
+    o.name.should == 'name'
+    o.b = ' name '
+    o.b.should be_a_kind_of(Sequel::SQL::Blob)
+    o.b.should == Sequel.blob(' name ')
+  end
 end