redis_store.rb in pupa-0.0.9

- old
+ new

@@ -6,20 +6,21 @@
       # Pupa flushes the JSON document store before scraping. If you use Redis,
       # **DO NOT** share a Redis database with Pupa and other applications. You
       # can select a different database than the default `0` for use with Pupa
       # by passing an argument like `redis://localhost:6379/0`.
       #
-      # @note Redis support depends on the `redis` gem. For better performance,
-      #   use the `hiredis` gem as well.
+      # @note Redis support depends on the `redis-store` gem. You may optionally
+      #   use the `hiredis` gem to further improve performance.
       class RedisStore
         # @param [String] address the address (e.g. `redis://localhost:6379/0`)
         #   in which to dump JSON documents
-        def initialize(address)
-          options = {}
-          if defined?(Hiredis)
-            options.update(driver: :hiredis)
-          end
+        # @param [Boolean] pipelined whether to enable
+        #   [pipelining](http://redis.io/topics/pipelining)
+        def initialize(address, pipelined: false)
+          @pipelined = pipelined
+          options = {marshalling: false}
+          options.update(driver: :hiredis) if defined?(Hiredis)
           @redis = Redis::Store::Factory.create(address, options)
         end
 
         # Returns whether database contains an entry for the given key.
         #
@@ -39,38 +40,70 @@
         # Returns, as JSON, the value of the given key.
         #
         # @param [String] name a key
         # @return [Hash] the value of the given key
         def read(name)
-          JSON.load(@redis.get(name))
+          MultiJson.load(@redis.get(name))
         end
 
         # Returns, as JSON, the values of the given keys.
         #
         # @param [String] names keys
         # @return [Array<Hash>] the values of the given keys
         def read_multi(names)
-          @redis.mget(*names).map{|value| JSON.load(value)}
+          @redis.mget(*names).map{|value| MultiJson.load(value)}
         end
 
         # Writes, as JSON, the value to a key.
         #
         # @param [String] name a key
         # @param [Hash] value a value
         def write(name, value)
-          @redis.set(name, JSON.dump(value))
+          @redis.set(name, MultiJson.dump(value))
         end
 
+        # Writes, as JSON, the value to a key, unless the key exists.
+        #
+        # @param [String] name a key
+        # @param [Hash] value a value
+        # @return [Boolean] whether the key was set
+        def write_unless_exists(name, value)
+          @redis.setnx(name, MultiJson.dump(value))
+        end
+
+        # Writes, as JSON, the values to keys.
+        #
+        # @param [Hash] pairs key-value pairs
+        def write_multi(pairs)
+          args = []
+          pairs.each do |key,value|
+            args << key
+            args << MultiJson.dump(value)
+          end
+          @redis.mset(*args)
+        end
+
         # Delete a key.
         #
         # @param [String] name a key
         def delete(name)
           @redis.del(name)
         end
 
         # Deletes all keys in the database.
         def clear
           @redis.flushdb
+        end
+
+        # Collects commands to run all at once.
+        def pipelined
+          if @pipelined
+            @redis.pipelined do
+              yield
+            end
+          else
+            yield
+          end
         end
       end
     end
   end
 end