FEATURE: task for global rewrite, used post migration to multisite

script/discourse

@@ -5,6 +5,39 @@ require "thor"
 class DiscourseCLI < Thor
   class_option :verbose, default: false, aliases: :v
 
+  desc "remap", "Remap a string sequence accross all tables"
+  def remap(from, to)
+    load_rails
+
+    puts "Rewriting all occurences of #{from} to #{to}"
+    puts "THIS TASK WILL REWRITE DATA, ARE YOU SURE (type YES)"
+    result = STDIN.gets
+    if result.strip != "YES"
+      puts "aborting."
+      exit
+    end
+
+    sql = "SELECT table_name, column_name
+FROM information_schema.columns
+WHERE table_schema='public' and (data_type like 'char%' or data_type like 'text%')"
+
+    cnn = ActiveRecord::Base.connection.raw_connection
+
+    results = cnn.async_exec(sql).to_a
+
+    results.each do |result|
+      table_name = result["table_name"]
+      column_name = result["column_name"]
+      puts "Reampping #{table_name} #{column_name}"
+      result = cnn.async_exec("UPDATE #{table_name}
+                      SET #{column_name} = replace(#{column_name}, $1, $2)
+                      WHERE NOT #{column_name} IS NULL
+                        AND #{column_name} <> replace(#{column_name}, $1, $2)", [from, to])
+      puts "#{result.cmd_tuples} rows affected!"
+    end
+
+  end
+
   desc "export", "Export a Discourse backup"
   def export(filename=nil)
     load_rails