From b5775c2b3efb3ae5ef9074d26f6fc3e302a4f6f0 Mon Sep 17 00:00:00 2001
From: Pratik Naik <pratiknaik@gmail.com>
Date: Sun, 21 Jun 2009 14:35:14 +0100
Subject: [PATCH] Add expiry support File cache store [#1693 state:resolved]
 [Roman Shterenzon, Pratik Naik]

---
 activesupport/lib/active_support/cache.rb          | 12 ++++++++++--
 .../lib/active_support/cache/file_store.rb         | 14 +++++++++++++-
 .../lib/active_support/cache/mem_cache_store.rb    |  4 ----
 activesupport/test/caching_test.rb                 | 10 ++++++++++
 4 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/activesupport/lib/active_support/cache.rb b/activesupport/lib/active_support/cache.rb
index feb6b1f2cf217..192a82e74f0b4 100644
--- a/activesupport/lib/active_support/cache.rb
+++ b/activesupport/lib/active_support/cache.rb
@@ -129,8 +129,8 @@ def silence!
       #
       # For example, MemCacheStore's #write method supports the +:expires_in+
       # option, which tells the memcached server to automatically expire the
-      # cache item after a certain period. We can use this option with #fetch
-      # too:
+      # cache item after a certain period. This options is also supported by
+      # FileStore's #read method. We can use this option with #fetch too:
       #
       #   cache = ActiveSupport::Cache::MemCacheStore.new
       #   cache.fetch("foo", :force => true, :expires_in => 5.seconds) do
@@ -169,6 +169,10 @@ def fetch(key, options = {})
       # You may also specify additional options via the +options+ argument.
       # The specific cache store implementation will decide what to do with
       # +options+.
+      #
+      # For example, FileStore supports the +:expires_in+ option, which
+      # makes the method return nil for cache items older than the specified
+      # period.
       def read(key, options = nil)
         log("read", key, options)
       end
@@ -223,6 +227,10 @@ def decrement(key, amount = 1)
       end
 
       private
+        def expires_in(options)
+          (options && options[:expires_in]) || 0
+        end
+
         def log(operation, key, options)
           logger.debug("Cache #{operation}: #{key}#{options ? " (#{options.inspect})" : ""}") if logger && !@silence && !@logger_off
         end
diff --git a/activesupport/lib/active_support/cache/file_store.rb b/activesupport/lib/active_support/cache/file_store.rb
index 3217350d58e88..75eed5ed94216 100644
--- a/activesupport/lib/active_support/cache/file_store.rb
+++ b/activesupport/lib/active_support/cache/file_store.rb
@@ -10,11 +10,23 @@ def initialize(cache_path)
         @cache_path = cache_path
       end
 
+      # Reads a value from the cache.
+      #
+      # Possible options:
+      # - +:expires_in+ - the number of seconds that this value may stay in
+      #   the cache.
       def read(name, options = nil)
         super
-        File.open(real_file_path(name), 'rb') { |f| Marshal.load(f) } rescue nil
+
+        file_name = real_file_path(name)
+        expires = expires_in(options)
+
+        if File.exist?(file_name) && (expires <= 0 || Time.now - File.mtime(file_name) < expires)
+          File.open(file_name, 'rb') { |f| Marshal.load(f) }
+        end
       end
 
+      # Writes a value to the cache.
       def write(name, value, options = nil)
         super
         ensure_cache_path(File.dirname(real_file_path(name)))
diff --git a/activesupport/lib/active_support/cache/mem_cache_store.rb b/activesupport/lib/active_support/cache/mem_cache_store.rb
index 38b3409ca6a6d..954d0f5423db4 100644
--- a/activesupport/lib/active_support/cache/mem_cache_store.rb
+++ b/activesupport/lib/active_support/cache/mem_cache_store.rb
@@ -130,10 +130,6 @@ def stats
       end
 
       private
-        def expires_in(options)
-          (options && options[:expires_in]) || 0
-        end
-
         def raw?(options)
           options && options[:raw]
         end
diff --git a/activesupport/test/caching_test.rb b/activesupport/test/caching_test.rb
index 51d04d9388397..e6e220570813b 100644
--- a/activesupport/test/caching_test.rb
+++ b/activesupport/test/caching_test.rb
@@ -146,6 +146,16 @@ def teardown
   end
 
   include CacheStoreBehavior
+
+  def test_expires_in
+    @cache.write('foo', 'bar')
+    cache_read = lambda { @cache.read('foo', :expires_in => 2) }
+    assert_equal 'bar', cache_read.call
+    sleep(1)
+    assert_equal 'bar', cache_read.call
+    sleep(1)
+    assert_nil cache_read.call
+  end
 end
 
 class MemoryStoreTest < ActiveSupport::TestCase