initial version, mostly inspired from phpbb script

script/import_scripts/mybb.rb

@@ -0,0 +1,169 @@
+require File.expand_path(File.dirname(__FILE__) + "/base.rb")
+
+require "mysql2"
+
+# Call it like this:
+#   RAILS_ENV=production bundle exec ruby script/import_scripts/mybb.rb
+class ImportScripts::MyBB < ImportScripts::Base
+
+  MYBB_DB = "mybb_db"
+  BATCH_SIZE = 1000
+
+  def initialize
+    super
+
+    @client = Mysql2::Client.new(
+      host: "localhost",
+      username: "root",
+      #password: "",
+      database: MYBB_DB
+    )
+  end
+
+  def execute
+    import_users
+    import_categories
+    import_posts
+    import_private_messages
+    suspend_users
+  end
+
+  def import_users
+    puts '', "creating users"
+
+    total_count = mysql_query("SELECT count(*) count
+                                 FROM mybb_users u
+                                 JOIN mybb_usergroups g ON g.gid = u.usergroup
+                                WHERE g.title != 'Banned';").first['count']
+
+    batches(BATCH_SIZE) do |offset|
+      results = mysql_query(
+        "SELECT uid id, email email, username, regdate, g.title `group`
+           FROM mybb_users u
+           JOIN mybb_usergroups g ON g.gid = u.usergroup
+          WHERE g.title != 'Banned'
+          ORDER BY u.uid ASC
+          LIMIT #{BATCH_SIZE}
+         OFFSET #{offset};")
+
+      break if results.size < 1
+
+      create_users(results, total: total_count, offset: offset) do |user|
+        { id: user['id'],
+          email: user['email'],
+          username: user['username'],
+          created_at: Time.zone.at(user['regdate']),
+          moderator: user['group'] == 'Super Moderators',
+          admin: user['group'] == 'Administrators' }
+      end
+    end
+  end
+
+  def import_categories
+    results = mysql_query("
+      SELECT fid id, pid parent_id, left(name, 50) name, description
+        FROM mybb_forums
+    ORDER BY pid ASC, fid ASC
+    ")
+
+    create_categories(results) do |row|
+      h = {id: row['id'], name: CGI.unescapeHTML(row['name']), description: CGI.unescapeHTML(row['description'])}
+      if row['parent_id'].to_i > 0
+        parent = category_from_imported_category_id(row['parent_id'])
+        h[:parent_category_id] = parent.id if parent
+      end
+      h
+    end
+  end
+
+  def import_posts
+    puts "", "creating topics and posts"
+
+    total_count = mysql_query("SELECT count(*) count from mybb_posts").first["count"]
+
+    batches(BATCH_SIZE) do |offset|
+      results = mysql_query("
+        SELECT p.pid id,
+               p.tid topic_id,
+               t.fid category_id,
+               t.subject title,
+               t.firstpost first_post_id,
+               p.uid user_id,
+               p.message raw,
+               p.dateline post_time
+          FROM mybb_posts p,
+               mybb_threads t
+         WHERE p.tid = t.tid
+      ORDER BY id
+         LIMIT #{BATCH_SIZE}
+        OFFSET #{offset};
+      ")
+
+      break if results.size < 1
+
+      create_posts(results, total: total_count, offset: offset) do |m|
+        skip = false
+        mapped = {}
+
+        mapped[:id] = m['id']
+        mapped[:user_id] = user_id_from_imported_user_id(m['user_id']) || -1
+        mapped[:raw] = process_mybb_post(m['raw'], m['id'])
+        mapped[:created_at] = Time.zone.at(m['post_time'])
+
+        if m['id'] == m['first_post_id']
+          mapped[:category] = category_from_imported_category_id(m['category_id']).try(:name)
+          mapped[:title] = CGI.unescapeHTML(m['title'])
+        else
+          parent = topic_lookup_from_imported_post_id(m['first_post_id'])
+          if parent
+            mapped[:topic_id] = parent[:topic_id]
+          else
+            puts "Parent post #{m['first_post_id']} doesn't exist. Skipping #{m["id"]}: #{m["title"][0..40]}"
+            skip = true
+          end
+        end
+
+        skip ? nil : mapped
+      end
+    end
+  end
+
+  def import_private_messages
+    puts "", "private messages are not implemented"
+  end
+
+  def suspend_users
+    puts '', "banned users are not implemented"
+  end
+
+  def process_mybb_post(raw, import_id)
+    s = raw.dup
+
+    # :) is encoded as <!-- s:) --><img src="{SMILIES_PATH}/icon_e_smile.gif" alt=":)" title="Smile" /><!-- s:) -->
+    s.gsub!(/<!-- s(\S+) -->(?:.*)<!-- s(?:\S+) -->/, '\1')
+
+    # Some links look like this: <!-- m --><a class="postlink" href="http://www.onegameamonth.com">http://www.onegameamonth.com</a><!-- m -->
+    s.gsub!(/<!-- \w --><a(?:.+)href="(\S+)"(?:.*)>(.+)<\/a><!-- \w -->/, '[\2](\1)')
+
+    # Many phpbb bbcode tags have a hash attached to them. Examples:
+    #   [url=https&#58;//google&#46;com:1qh1i7ky]click here[/url:1qh1i7ky]
+    #   [quote=&quot;cybereality&quot;:b0wtlzex]Some text.[/quote:b0wtlzex]
+    s.gsub!(/:(?:\w{8})\]/, ']')
+
+    s = CGI.unescapeHTML(s)
+
+    # phpBB shortens link text like this, which breaks our markdown processing:
+    #   [http://answers.yahoo.com/question/index ... 223AAkkPli](http://answers.yahoo.com/question/index?qid=20070920134223AAkkPli)
+    #
+    # Work around it for now:
+    s.gsub!(/\[http(s)?:\/\/(www\.)?/, '[')
+
+    s
+  end
+
+  def mysql_query(sql)
+    @client.query(sql, cache_rows: false)
+  end
+end
+
+ImportScripts::MyBB.new.perform