Rake is the ruby equivalent of make except it is much better in that you are scripting in ruby and not the nasty primeval make language. Rails uses rake a lot as a simple place to gather together a load of administration tasks such as running tests, running database migrations etc.
When I moved all my drupal blog posts from drupal over to PetersBlogger I decided to use a nice organised rake script rather than do my usual practise of having a directory full of utility scripts.
In my rails installation I created a file called lib/tasks/jobs.rake and in it I put my import code:
1 task (:import_drupal => :environment) do
2 print "Importing Drupal\n"
3 oTagTable = {}
4
5
6
7 Drupal::Article.find(:all, :conditions => "type <> 'image'").each do |oArticle|
8 print "#{oArticle.title}\n"
9 oTime = Time.at( oArticle.created)
10 oPost = Post.create( :nid => oArticle.nid,
11 :title => oArticle.title,
12 :body => oArticle.body,
13 :created => oTime)
14
15
16
17
18 oArticle.tags.each do |oTag|
19 if oTagTable[oTag.tag]
20 oNewTag = oTagTable[oTag.tag]
21 else
22 oNewTag = Tag.new( :tag=>oTag.tag)
23 oTagTable[oTag.tag] = oNewTag
24 end
25
26 oPost.tags << oNewTag
27 end
28
29
30
31
32 oArticle.comments.each do |oComment|
33 strWho = oComment.name
34 strComment = oComment.comment
35 if strWho == nil or strWho == ""
36 strWho = "Peter"
37 end
38 if strComment == nil or strComment.strip == ""
39 strComment = "{nothing to say}"
40 end
41 oPost.comments << Comment.create( :who => strWho,
42 :body => strComment,
43 :created => Time.at( oComment.timestamp), :published => 1)
44 if not oPost.comments[-1].valid?
45 p oPost.comments[-1]
46 p oPost.comments[-1].errors
47 end
48 end
49
50 oPost.save!
51 end
52 end
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This creates a rake task called 'import_drupal' which I can invoke simply by running
rake import_drupal
The task runs with the appropriate rails environment so all my models are in place. I had to create a model to access the records in the drupal database thus:
1 module Drupal
2 class Comment < ActiveRecord::Base
3 establish_connection configurations['drupal']
4 set_table_name 'comments'
5 end
6 class Tag < ActiveRecord::Base
7 establish_connection configurations['drupal']
8 set_primary_key 'tid'
9 has_and_belongs_to_many :articles,
10 :class_name => 'Drupal::Article',
11 :join_table => 'awtags_node',
12 :foreign_key => 'tid',
13 :association_foreign_key => 'nid'
14 set_table_name 'awtags'
15 end
16 class Article < ActiveRecord::Base
17 establish_connection configurations['drupal']
18 set_primary_key 'nid'
19 self.inheritance_column = 'poopy'
20 has_many :comments, :table_name => 'comments', :foreign_key => 'nid', :class_name => 'Drupal::Comment'
21 has_and_belongs_to_many :tags,
22 :class_name => 'Drupal::Tag',
23 :join_table => 'awtags_node',
24 :foreign_key => 'nid',
25 :association_foreign_key => 'tid'
26 set_table_name 'node'
27 end
28 end
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This model handles all the relationships between the records, including the has_and_belongs_to_many relationship between posts and tags (provided by awtags).
I needed an entry in config/database.yml to define the connection to the drupal database:
drupal:
adapter: mysql
database: petersblog
username: secret
password: doyouthinkidpostithere
and it all works nicely. If I invoke it thusly:
rake import_drupal RAILS_ENV=production
then it will import the posts into the rails production database.
I'm giving away a few of my schema secrets here which pedantic rails developers might leap on, specifically I have used my own fields called 'nid' and 'created' to perform roles that rails already provides 'id' and 'created_on' for. The reason for the duplication was that during development I was having problems setting these fields to the values from the drupal database, rails was insisting on giving them it's own values. By having my own fields I had total control. There are no doubt ways around this but I didn't have time to find them (although I did find other people moaning about the same problem).
And that's how I managed to save 1500 posts from the hell that is php.
Worked first time though 
Peter's Moblog
