mloughran · November 4, 2011 19:36 · Nov 4, 2011
diff --git a/fiber_cache.rb b/fiber_cache.rb
@@ -0,0 +1,45 @@
+require 'eventmachine'
+require 'em-hiredis'
+require 'fiber'
+
+class Cache
+  include EM::Deferrable
+
+  def initialize(key)
+    $redis.get(key) { |v|
+      @value = v
+      succeed
+    }
+  end
+
+  def value
+    if @value
+      puts "Returning cached value"
+      @value
+    else
+      puts "Blocking the current fiber till result"
+      start = Time.now
+      f = Fiber.current
+      callback {
+        puts "Fiber blocked for #{Time.now - start}s"
+        f.resume(@value)
+      }
+      return Fiber.yield
+    end
+  end
+end
+
+EM.run {
+  $redis = EM::Hiredis.connect
+
+  Fiber.new {
+    $redis.set('foo', 'hello folks')
+
+    c = Cache.new('foo')
+    p c.value # Not populated yet - will block fiber
+
+    EM.add_timer(1) {
+      p c.value # Will return from cache
+    }
+  }.resume
+}