Initial commit of making ar-extensions import Rails 3 friendly

lib/ar-extensions.rb

@@ -0,0 +1,7 @@
+require "active_record"
+require "active_record/version"
+
+module ActiveRecord::Extensions
+end
+
+require "ar-extensions/import"

lib/ar-extensions/import.rb

@@ -0,0 +1,351 @@
+require "ostruct"
+
+module ActiveRecord::Extensions::ConnectionAdapters ; end
+
+module ActiveRecord::Extensions::Import #:nodoc:
+  
+  module ImportSupport #:nodoc:
+    def supports_import? #:nodoc:
+      true
+    end
+  end
+  
+  module OnDuplicateKeyUpdateSupport #:nodoc:
+    def supports_on_duplicate_key_update? #:nodoc:
+      true
+    end
+  end
+  
+end
+
+class ActiveRecord::Base
+  class << self
+
+    # use tz as set in ActiveRecord::Base
+    tproc = @@default_timezone == :utc ? lambda { Time.now.utc } : lambda { Time.now }
+    AREXT_RAILS_COLUMNS = {
+      :create => { "created_on" => tproc ,
+                   "created_at" => tproc },
+      :update => { "updated_on" => tproc ,
+                   "updated_at" => tproc }
+    }
+    AREXT_RAILS_COLUMN_NAMES = AREXT_RAILS_COLUMNS[:create].keys + AREXT_RAILS_COLUMNS[:update].keys
+  
+    # Returns true if the current database connection adapter
+    # supports import functionality, otherwise returns false.
+    def supports_import?
+      connection.supports_import?
+    rescue NoMethodError
+      false
+    end
+
+    # Returns true if the current database connection adapter
+    # supports on duplicate key update functionality, otherwise
+    # returns false.
+    def supports_on_duplicate_key_update?
+      connection.supports_on_duplicate_key_update?
+    rescue NoMethodError
+      false
+    end
+    
+    # Imports a collection of values to the database.  
+    #
+    # This is more efficient than using ActiveRecord::Base#create or
+    # ActiveRecord::Base#save multiple times. This method works well if
+    # you want to create more than one record at a time and do not care
+    # about having ActiveRecord objects returned for each record
+    # inserted. 
+    #
+    # This can be used with or without validations. It does not utilize
+    # the ActiveRecord::Callbacks during creation/modification while
+    # performing the import.
+    #
+    # == Usage
+    #  Model.import array_of_models
+    #  Model.import column_names, array_of_values
+    #  Model.import column_names, array_of_values, options
+    # 
+    # ==== Model.import array_of_models
+    # 
+    # With this form you can call _import_ passing in an array of model
+    # objects that you want updated.
+    #
+    # ==== Model.import column_names, array_of_values
+    #
+    # The first parameter +column_names+ is an array of symbols or
+    # strings which specify the columns that you want to update.
+    #
+    # The second parameter, +array_of_values+, is an array of
+    # arrays. Each subarray is a single set of values for a new
+    # record. The order of values in each subarray should match up to
+    # the order of the +column_names+.
+    #
+    # ==== Model.import column_names, array_of_values, options
+    #
+    # The first two parameters are the same as the above form. The third
+    # parameter, +options+, is a hash. This is optional. Please see
+    # below for what +options+ are available.
+    #
+    # == Options
+    # * +validate+ - true|false, tells import whether or not to use \
+    #    ActiveRecord validations. Validations are enforced by default.
+    # * +on_duplicate_key_update+ - an Array or Hash, tells import to \
+    #    use MySQL's ON DUPLICATE KEY UPDATE ability. See On Duplicate\
+    #    Key Update below.
+    # * +synchronize+ - an array of ActiveRecord instances for the model
+    #   that you are currently importing data into. This synchronizes
+    #   existing model instances in memory with updates from the import.
+    # * +timestamps+ - true|false, tells import to not add timestamps \
+    #   (if false) even if record timestamps is disabled in ActiveRecord::Base
+    #
+    # == Examples  
+    #  class BlogPost < ActiveRecord::Base ; end
+    #  
+    #  # Example using array of model objects
+    #  posts = [ BlogPost.new :author_name=>'Zach Dennis', :title=>'AREXT',
+    #            BlogPost.new :author_name=>'Zach Dennis', :title=>'AREXT2',
+    #            BlogPost.new :author_name=>'Zach Dennis', :title=>'AREXT3' ]
+    #  BlogPost.import posts
+    #
+    #  # Example using column_names and array_of_values
+    #  columns = [ :author_name, :title ]
+    #  values = [ [ 'zdennis', 'test post' ], [ 'jdoe', 'another test post' ] ]
+    #  BlogPost.import columns, values 
+    #
+    #  # Example using column_names, array_of_value and options
+    #  columns = [ :author_name, :title ]
+    #  values = [ [ 'zdennis', 'test post' ], [ 'jdoe', 'another test post' ] ]
+    #  BlogPost.import( columns, values, :validate => false  )
+    #
+    #  # Example synchronizing existing instances in memory
+    #  post = BlogPost.find_by_author_name( 'zdennis' )
+    #  puts post.author_name # => 'zdennis'
+    #  columns = [ :author_name, :title ]
+    #  values = [ [ 'yoda', 'test post' ] ]
+    #  BlogPost.import posts, :synchronize=>[ post ]
+    #  puts post.author_name # => 'yoda'
+    #
+    # == On Duplicate Key Update (MySQL only)
+    #
+    # The :on_duplicate_key_update option can be either an Array or a Hash. 
+    # 
+    # ==== Using an Array
+    #
+    # The :on_duplicate_key_update option can be an array of column
+    # names. The column names are the only fields that are updated if
+    # a duplicate record is found. Below is an example:
+    #
+    #   BlogPost.import columns, values, :on_duplicate_key_update=>[ :date_modified, :content, :author ]
+    #
+    # ====  Using A Hash
+    #
+    # The :on_duplicate_key_update option can be a hash of column name
+    # to model attribute name mappings. This gives you finer grained
+    # control over what fields are updated with what attributes on your
+    # model. Below is an example:
+    #   
+    #   BlogPost.import columns, attributes, :on_duplicate_key_update=>{ :title => :title } 
+    #  
+    # = Returns
+    # This returns an object which responds to +failed_instances+ and +num_inserts+.
+    # * failed_instances - an array of objects that fails validation and were not committed to the database. An empty array if no validation is performed.
+    # * num_inserts - the number of insert statements it took to import the data
+    def import( *args )
+      @logger = Logger.new(STDOUT)
+      @logger.level = Logger::DEBUG
+      options = { :validate=>true, :timestamps=>true }
+      options.merge!( args.pop ) if args.last.is_a? Hash
+      
+      # assume array of model objects
+      if args.last.is_a?( Array ) and args.last.first.is_a? ActiveRecord::Base
+        if args.length == 2
+          models = args.last
+          column_names = args.first
+        else
+          models = args.first
+          column_names = self.column_names.dup
+        end
+        
+        array_of_attributes  = []
+        models.each do |model|
+          # this next line breaks sqlite.so with a segmentation fault
+          # if model.new_record? || options[:on_duplicate_key_update]
+            attributes = []
+            column_names.each do |name| 
+              attributes << model.send( "#{name}_before_type_cast" ) 
+            end
+            array_of_attributes << attributes
+          # end
+        end
+        # supports 2-element array and array
+      elsif args.size == 2 and args.first.is_a?( Array ) and args.last.is_a?( Array )
+        column_names, array_of_attributes = args
+      else
+        raise ArgumentError.new( "Invalid arguments!" )
+      end
+
+      # Force the primary key col into the insert if it's not
+      # on the list and we are using a sequence and stuff a nil
+      # value for it into each row so the sequencer will fire later
+      if !column_names.include?(primary_key) && sequence_name && connection.prefetch_primary_key?
+         column_names << primary_key
+         array_of_attributes.each { |a| a << nil }
+      end
+
+      is_validating = options.delete( :validate )
+
+      # dup the passed in array so we don't modify it unintentionally
+      array_of_attributes = array_of_attributes.dup
+
+      # record timestamps unless disabled in ActiveRecord::Base
+      if record_timestamps && options.delete( :timestamps )
+         add_special_rails_stamps column_names, array_of_attributes, options
+      end
+
+      return_obj = if is_validating
+        import_with_validations( column_names, array_of_attributes, options )
+      else
+        num_inserts = import_without_validations_or_callbacks( column_names, array_of_attributes, options )
+        OpenStruct.new :failed_instances=>[], :num_inserts=>num_inserts
+      end
+
+      if options[:synchronize]
+        synchronize( options[:synchronize] )
+      end
+
+      return_obj.num_inserts = 0 if return_obj.num_inserts.nil?
+      return_obj
+    end
+    
+    # TODO import_from_table needs to be implemented. 
+    def import_from_table( options ) # :nodoc:
+    end
+    
+    # Imports the passed in +column_names+ and +array_of_attributes+
+    # given the passed in +options+ Hash with validations. Returns an
+    # object with the methods +failed_instances+ and +num_inserts+. 
+    # +failed_instances+ is an array of instances that failed validations. 
+    # +num_inserts+ is the number of inserts it took to import the data. See
+    # ActiveRecord::Base.import for more information on
+    # +column_names+, +array_of_attributes+ and +options+.
+    def import_with_validations( column_names, array_of_attributes, options={} )
+      failed_instances = []
+    
+      # create instances for each of our column/value sets
+      arr = validations_array_for_column_names_and_attributes( column_names, array_of_attributes )    
+
+      # keep track of the instance and the position it is currently at. if this fails
+      # validation we'll use the index to remove it from the array_of_attributes
+      arr.each_with_index do |hsh,i|
+        instance = new( hsh )
+        if not instance.valid?
+          array_of_attributes[ i ] = nil
+          failed_instances << instance
+        end    
+      end
+      array_of_attributes.compact!
+      
+      num_inserts = array_of_attributes.empty? ? 0 : import_without_validations_or_callbacks( column_names, array_of_attributes, options )
+      OpenStruct.new :failed_instances=>failed_instances, :num_inserts => num_inserts
+    end
+    
+    # Imports the passed in +column_names+ and +array_of_attributes+
+    # given the passed in +options+ Hash. This will return the number
+    # of insert operations it took to create these records without
+    # validations or callbacks. See ActiveRecord::Base.import for more
+    # information on +column_names+, +array_of_attributes_ and
+    # +options+.
+    def import_without_validations_or_callbacks( column_names, array_of_attributes, options={} )
+      escaped_column_names = quote_column_names( column_names )
+      columns = []
+      array_of_attributes.first.each_with_index { |arr,i| columns << columns_hash[ column_names[i] ] }
+      
+      if not supports_import?
+        columns_sql = "(" + escaped_column_names.join( ',' ) + ")"
+        insert_statements, values = [], []
+        number_inserted = 0
+        array_of_attributes.each do |arr|
+          my_values = []
+          arr.each_with_index do |val,j|
+            if !sequence_name.blank? && column_names[j] == primary_key && val.nil?
+               my_values << connection.next_value_for_sequence(sequence_name)
+            else
+               my_values << connection.quote( val, columns[j] )
+            end
+          end
+          insert_statements << "INSERT INTO #{quoted_table_name} #{columns_sql} VALUES(" + my_values.join( ',' ) + ")"
+          connection.execute( insert_statements.last )
+          number_inserted += 1
+        end
+      else
+        # generate the sql
+        insert_sql = connection.multiple_value_sets_insert_sql( quoted_table_name, escaped_column_names, options )
+        values_sql = connection.values_sql_for_column_names_and_attributes( columns, array_of_attributes )
+        post_sql_statements = connection.post_sql_statements( quoted_table_name, options )
+        
+        # perform the inserts
+        number_inserted = connection.insert_many( [ insert_sql, post_sql_statements ].flatten, 
+                                                  values_sql,
+                                                  "#{self.class.name} Create Many Without Validations Or Callbacks" )
+      end
+      
+      number_inserted
+    end
+    
+    # Returns an array of quoted column names
+    def quote_column_names( names ) 
+      names.map{ |name| connection.quote_column_name( name ) }
+    end
+
+    
+    private
+
+    
+    def add_special_rails_stamps( column_names, array_of_attributes, options )
+      AREXT_RAILS_COLUMNS[:create].each_pair do |key, blk|
+        if self.column_names.include?(key)
+          value = blk.call
+          if index=column_names.index(key)
+             # replace every instance of the array of attributes with our value
+             array_of_attributes.each{ |arr| arr[index] = value }
+          else
+            column_names << key
+            array_of_attributes.each { |arr| arr << value }
+          end
+        end
+      end
+
+      AREXT_RAILS_COLUMNS[:update].each_pair do |key, blk|
+        if self.column_names.include?(key)
+          value = blk.call
+          if index=column_names.index(key)
+             # replace every instance of the array of attributes with our value
+             array_of_attributes.each{ |arr| arr[index] = value }
+          else
+            column_names << key
+            array_of_attributes.each { |arr| arr << value }
+          end
+          
+          if options[:on_duplicate_key_update]
+            options[:on_duplicate_key_update] << key.to_sym if options[:on_duplicate_key_update].is_a?(Array)
+            options[:on_duplicate_key_update][key.to_sym] = key.to_sym if options[:on_duplicate_key_update].is_a?(Hash)
+          else
+            options[:on_duplicate_key_update] = [ key.to_sym ]
+          end
+        end
+      end
+    end
+    
+    # Returns an Array of Hashes for the passed in +column_names+ and +array_of_attributes+.
+    def validations_array_for_column_names_and_attributes( column_names, array_of_attributes ) # :nodoc:
+      arr = []
+      array_of_attributes.each do |attributes|
+        c = 0
+        hsh = attributes.inject( {} ){|hsh,attr| hsh[ column_names[c] ] = attr ; c+=1 ; hsh }
+        arr << hsh
+      end
+      arr
+    end
+    
+  end
+end