Merge pull request #11 from backupify/read_support_for_ttls

adds tests and read ttl functionality

lib/cassava/client.rb

@@ -31,6 +31,14 @@ def select(table, columns = nil)
       StatementBuilder.new(executor).select(table, columns)
     end
 
+    # @param table [Symbol] the table name
+    # @param target_attr [String] The attribute to select the TTL for
+    # @param where_arguments [Hash] Pairs of keys and values for the where clause
+    def select_ttl(table, target_attr, where_arguments)
+      statement = select_ttl_statement(table, target_attr, where_arguments)
+      executor.execute(statement).rows.first["ttl(#{target_attr})"]
+    end
+
     # @param table [Symbol] the table name
     # @param columns [Array<String] A list of columns that will be deleted. If nil, all columns will be deleted.
     # @return [StatementBuilder] A statement builder representing the partially completed statement.
@@ -60,6 +68,22 @@ def insert_statement(table, data, ttl = nil)
       statement_cql += " USING TTL #{ttl}" if ttl
       executor.prepare(statement_cql)
     end
+
+    # @param table [Symbol] the table name
+    # @param target_attr [Symbol] The attribute to select the TTL for
+    # @param where_arguments [Hash] Pairs of keys and values for the where clause
+    def select_ttl_statement(table, target_attr, where_arguments)
+      statement = "SELECT ttl(#{target_attr}) FROM #{table} WHERE "
+      where_clause = where_arguments.map do |(key, val)|
+        if val.is_a? Integer
+          "#{key} = #{val}"
+        else
+          "#{key} = '#{val}'"
+        end
+      end
+
+      statement + where_clause.join(" AND ")
+    end
   end
 
   class StatementBuilder

lib/cassava/version.rb

@@ -1,3 +1,3 @@
 module Cassava
-  VERSION = "0.1.2"
+  VERSION = "0.1.3"
 end

test/cassava/client_test.rb

@@ -161,6 +161,33 @@ def string_keys(hash)
       end
     end
 
+    context 'select_ttl' do
+      should 'allow an existing ttl to be read' do
+        ttl = 12345
+        item = { :id => 'i', :a => 1, :b => 'b', :c => "'\"item(", :d => 1, :ttl => ttl }
+        @client.insert(:test, item)
+
+        resulting_ttl = @client.select_ttl(:test, :d, {:id => 'i'})
+        assert (1..ttl).include? resulting_ttl
+      end
+
+      should 'return nil if there is no ttl set on a cell' do
+        item = { :id => 'i', :a => 1, :b => 'b', :c => "'\"item(", :d => 1 }
+        @client.insert(:test, item)
+
+        resulting_ttl = @client.select_ttl(:test, :d, {:id => 'i'})
+        assert resulting_ttl.nil?
+      end
+
+      should 'handle string vs integer arguments properly' do
+        where_args = { :id => 'i', :a => 1, :b => 'b', :c => "'\"item(" }
+        statement = @client.send(:select_ttl_statement, :test, :c, where_args)
+
+        assert_match /a\s=\s1/, statement
+        assert_match /b\s=\s'b'/, statement
+      end
+    end
+
     context 'delete' do
       setup do
         @client.insert(:test, :id => 'i', :a => 2, :b => 'a', :c => '1', :d => 1)