it is alive

lib/load_data_infile.rb

@@ -0,0 +1,90 @@
+require 'erb'
+
+module LoadDataInfile
+  module MySql
+
+    # Deletes all rows in table very fast, but without calling +destroy+ method
+    # nor any hooks.
+    def truncate_table
+      connection.execute("TRUNCATE TABLE #{quoted_table_name}")
+    end
+
+    # Disables key updates for model table
+    def disable_keys
+      connection.execute("ALTER TABLE #{quoted_table_name} DISABLE KEYS")
+    end
+
+    # Enables key updates for model table
+    def enable_keys
+      connection.execute("ALTER TABLE #{quoted_table_name} ENABLE KEYS")
+    end
+
+    # Disables keys, yields block, enables keys.
+    def with_keys_disabled
+      disable_keys
+      yield
+      enable_keys
+    end
+
+    def load_data_infile(options = {})
+      c = Context.new
+
+      if options[:low_priority]
+        c.low_priority_or_concurrent = :LOW_PRIORITY
+      elsif options[:concurrent]
+        c.low_priority_or_concurrent = :CONCURRENT
+      end
+
+      c.local = :LOCAL if !options.member?(:local) || options[:local]
+
+      c.file_name = options[:path]
+
+      c.replace_or_ignore = options[:on_duplicates] if options[:on_duplicates] # REPLACE or IGNORE
+
+      c.table_name = options[:table] ? "`#{ options[:table] }`" : quoted_table_name
+
+      c.charset = "CHARACTER SET #{options[:charset]}" if options[:charset]
+
+      if options[:terminated_by] || options[:enclosed_by] || options[:optionally_enclosed_by] || options[:escaped_by]
+        c.fields_definitions = " FIELDS " # or COLUMNS
+        c.fields_definitions << " TERMINATED          BY '#{ options[:terminated_by] }' "          if options[:terminated_by]
+        c.fields_definitions << " ENCLOSED            BY '#{ options[:enclosed_by] }' "            if options[:enclosed_by]
+        c.fields_definitions << " OPTIONALLY ENCLOSED BY '#{ options[:optionally_enclosed_by] }' " if options[:optionally_enclosed_by]
+        c.fields_definitions << " ESCAPED             BY '#{ options[:escaped_by] }' "             if options[:escaped_by]
+      end
+
+      if options[:lines_terminated_by] || options[:lines_starting_by]
+        c.lines_defitions = " LINES "
+        c.lines_defitions << " STARTING BY '#{options[:lines_starting_by]}' "     if options[:lines_starting_by]
+        c.lines_defitions << " TERMINATED BY '#{options[:lines_terminated_by]}' " if options[:lines_terminated_by]
+      end
+
+      c.ignores = "IGNORE #{options[:ignore]} LINES" if options[:ignore]
+
+      c.columns = " (#{options[:columns].join(", ")}) " if options[:columns]
+
+      if options[:mappings] && options[:mappings].length > 0
+        s = options[:mapping].map{|column, mapping| "#{column} = #{mapping}" }.join(",")
+        c.mappings = "SET #{s}"
+      end
+
+      connection.execute(ERB.new(LOAD_DATA_INFILE_SQL).result(c.binding).gsub(/^\s*\n/, ""))
+    end
+
+    class Context < OpenStruct
+      public :binding
+    end
+
+    LOAD_DATA_INFILE_SQL = <<-SQL
+      LOAD DATA <%= low_priority_or_concurrent %> <%= local %> INFILE '<%= file_name %>'
+          <%= replace_or_ignore %>
+          INTO TABLE <%= table_name %>
+          <%= charset %>
+          <%= fields_definitions %>
+          <%= lines_defitions %>
+          <%= ignores %>
+          <%= columns %>
+          <%= mappings %> ;
+    SQL
+  end
+end

rails/init.rb

@@ -0,0 +1 @@
+ActiveRecord::Base.extend LoadDataInfile::MySql

spec/active_record_helper.rb

@@ -0,0 +1,13 @@
+ActiveRecord::Base.establish_connection(:adapter => "mysql", :database => "load_data_infile_test")
+
+ActiveRecord::Base.logger = Logger.new(STDOUT)
+
+ActiveRecord::Schema.define do
+  create_table "things", :force => true do |t|
+    t.string :field_a, :field_b
+    t.integer :field_c
+  end
+end
+
+class Thing < ActiveRecord::Base
+end

spec/fixtures/csv_with_headers.csv

@@ -0,0 +1,2 @@
+id,a,b,c
+71,Hello,Brother,42

spec/fixtures/csv_without_headers.csv

@@ -0,0 +1 @@
+61,live,from,2400

spec/load_data_infile_spec.rb

@@ -1,7 +1,40 @@
 require File.expand_path(File.dirname(__FILE__) + '/spec_helper')
 
-describe "LoadDataInfile" do
-  it "fails" do
-    fail "hey buddy, you should probably rename this file and start specing for real"
+describe LoadDataInfile do
+  before :each do
+    Thing.truncate_table
+  end
+
+  it "loads data from a csv file with headers into an ActiveRecord table" do
+    Thing.with_keys_disabled do
+      Thing.load_data_infile(
+        :path          => FIXTURE_WITH_HEADERS,
+        :columns       => %w|id field_a field_b field_c|,
+        :terminated_by => ",",
+        :ignore        => 1
+      )
+    end
+    Thing.all.map(&:attributes).should == [{
+      "id"      => 71,
+      "field_a" => "Hello",
+      "field_b" => "Brother",
+      "field_c" => 42
+    }]
+  end
+
+  it "loads data from a csv file without headers into an ActiveRecord table" do
+    Thing.with_keys_disabled do
+      Thing.load_data_infile(
+        :path          => FIXTURE_WITHOUT_HEADERS,
+        :terminated_by => ",",
+        :columns       => %w|id field_a field_b field_c|
+      )
+    end
+    Thing.all.map(&:attributes).should == [{
+      "id"      => 61,
+      "field_a" => "live",
+      "field_b" => "from",
+      "field_c" => 2400
+    }]
   end
 end

spec/spec_helper.rb

@@ -1,9 +1,16 @@
-$LOAD_PATH.unshift(File.dirname(__FILE__))
-$LOAD_PATH.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
+SPEC_PATH = File.dirname(__FILE__)
+$LOAD_PATH.unshift(SPEC_PATH)
+$LOAD_PATH.unshift(File.join(SPEC_PATH, '..', 'lib'))
 require 'load_data_infile'
 require 'spec'
 require 'spec/autorun'
+require 'rubygems'
+require 'active_record'
+require 'active_record_helper'
+require File.join(SPEC_PATH, "..", "rails", "init.rb")
+
+FIXTURE_WITH_HEADERS = File.join(SPEC_PATH, "fixtures", "csv_with_headers.csv")
+FIXTURE_WITHOUT_HEADERS = File.join(SPEC_PATH, "fixtures", "csv_without_headers.csv")
 
 Spec::Runner.configure do |config|
-
 end