Added RandomUniqueId::Util.set_initial_ids that helps with testing ap…

…ps that use rids.

CHANGELOG.md

@@ -1,9 +1,10 @@
 Authoritative changelog in README.md.
 
 ## Next version
+- Added RandomUniqueId::Util.set_initial_ids.
 - Started testing Ruby 2.1.2 and 2.1.3.
 - Started testing Rails 4.1 (fixed some deprecation warnings).
-- Improved documentation
+- Improved documentation.
 
 ## Version 0.2.1 (May 27, 2014)
 - Internal refactorings.

README.md

@@ -72,9 +72,10 @@ records. For example:
 ## Changelog
 
 ### Next version
+- Added RandomUniqueId::Util.set_initial_ids.
 - Started testing Ruby 2.1.2 and 2.1.3.
 - Started testing Rails 4.1 (fixed some deprecation warnings).
-- Improved documentation
+- Improved documentation.
 
 ### Version 0.2.1 (May 27, 2014)
 - Internal refactorings.

lib/random_unique_id/util.rb

@@ -0,0 +1,38 @@
+# Copyright © 2014, Watu
+
+# Some utilities that might be useful if you are using RandomUniqueId. This file needs to be explicitely included:
+#
+#   require "random_unique_id/util"
+module RandomUniqueId::Util
+  # Set the initial automatic ids on the database (also known as sequences) to a higher number than 1. The reason to use
+  # this is in case you want to test for id leakage in HTML. For example, you create a blog post, display it, and search
+  # the HTML for the id of the blog post, author, featured image, and so on. If these ids are low, like 1 or 10, the
+  # likelihood of false positives is very high, but if they are larger numbers, like 10001, then it becomes very
+  # unlikely (but not impossible).
+  #
+  # @param [Hash] options
+  # @option options [Boolean] :verbose whether to print messages to the console about what's going on or not.
+  # @option options [Integer] :initial_id initial id at which the sequences will be set.
+  def self.set_initial_ids(options={})
+    options.reverse_merge!(verbose: false, initial_id: 10000)
+    verbose = options[:verbose]
+    initial_id = options[:initial_id]
+
+    sql_connection = ActiveRecord::Base.connection
+    case sql_connection.adapter_name
+      when "PostgreSQL"
+        puts "==  Setting initial ids to #{initial_id} or the next available one".ljust(79, "=") if verbose
+        sequences = sql_connection.select_values("SELECT c.relname FROM pg_class c WHERE c.relkind = 'S'")
+        sequences.each do |sequence|
+          print "-- Setting initial id for #{sequence} to..." if verbose
+          next_id = [initial_id, sql_connection.select_values("SELECT nextval('#{sequence}')").first.to_i].max
+          print "#{next_id}..." if verbose
+          sql_connection.execute("SELECT setval('#{sequence}', #{next_id})")
+          puts " done." if verbose
+        end
+        puts "==  Setting initial ids to #{initial_id} (done)  ".ljust(79, "=") if verbose
+      else
+        raise "Don't know how to set initial ids for #{sql_connection.adapter_name}. Would you like to contribute? https://github.com/watu/random_unique_id"
+    end
+  end
+end

test/random_unique_id/util_test.rb

@@ -0,0 +1,28 @@
+# Copyright © 2014, Watu
+
+require_relative "../test_helper"
+
+require "random_unique_id/util"
+
+class RandomUniqueId::UtilTest < MiniTest::Unit::TestCase
+  should "raise an exception for unknown adapters" do
+    sql_connection = stub("connection", adapter_name: "dBASE")
+    ActiveRecord::Base.expects(:connection).returns(sql_connection)
+    assert_raises RuntimeError do
+      RandomUniqueId::Util.set_initial_ids
+    end
+  end
+
+  should "set initial ids in PostgreSQL" do
+    sql_connection = mock("connection")
+    sql_connection.stubs(:adapter_name).returns("PostgreSQL")
+    sequences = ["sequence_1", "sequence_2"]
+    sql_connection.expects(:select_values).with("SELECT c.relname FROM pg_class c WHERE c.relkind = 'S'").returns(sequences)
+    sql_connection.expects(:select_values).with("SELECT nextval('sequence_1')").returns(["1"])
+    sql_connection.expects(:execute).with("SELECT setval('sequence_1', 10000)")
+    sql_connection.expects(:select_values).with("SELECT nextval('sequence_2')").returns(["20000"])
+    sql_connection.expects(:execute).with("SELECT setval('sequence_2', 20000)")
+    ActiveRecord::Base.expects(:connection).returns(sql_connection)
+    RandomUniqueId::Util.set_initial_ids
+  end
+end