i was getting serious performance problem with one of my projects. so i came
up with a simple fragment cache implementation on ruby on rails.

after implementing this stuff, i replaced "render(:partial => ...)" with the
following method -

render_from_cache_or_render(:cache_key =>"cache key",
:cache_expire_after => ConstantHelper::TAG_CLOUD_EXPIRED_IN, # minutes
:partial => "....")

let's have a look on my implementation -

def render_from_cache_or_render(p_args)

return render(p_args) if true == p_args[:cache_off]

# check from cache
cache_key = p_args[:cache_key]
cached_content = CacheService.get_cache(cache_key)

if not cached_content.nil? and not cached_content.empty?
return cached_content
else
content = render(p_args)
# cache expire time if defined
cache_expire_time_in_minutes = p_args[:cache_expire_after] || 60
CacheService.add_cache(cache_key, cache_expire_time_in_minutes, content)
return content
end
end

actually, my implemented "CacheService" class is simply storing all cache in
a hash map.
when some cache was requested for peek, cache expiry was checked before
returning the cached value.

for CacheService implementation look at the bottom of my post.

anyway, after implementing and utilizing this stuff, i gained 70+ requests
capability per second. fyi, before applying cache it was around 10 per
second.

module Cache
class Item
attr_accessor :key, :expire_time, :content, :created_on

def initialize(p_key, p_expire_time, p_content)
@key = p_key
@expire_time = p_expire_time * 60 # in minutes
@content = p_content
@created_on = Time.now
end
end
end

class CacheService
@@CACHES = {}
@@CACHE_EXPIRE_TIMES = {}

def self.add_cache(p_key, p_expire_time, p_content)
cache_item = Cache::Item.new(p_key, p_expire_time, p_content)
@@CACHES[p_key.to_sym] = cache_item
end

def self.get_cache(p_key)
# load content from cache
cached_content = @@CACHES[p_key.to_sym]
return nil if cached_content.nil?

# verify cache validity
return cached_content.content if not expired?(cached_content)
return nil
end

private
def self.expired?(p_cache)
# find time difference
time_difference = Time.now - p_cache.created_on
return true if time_difference > p_cache.expire_time
end
end

best wishes,


--
----------------------------------------------------
nhm tanveer hossain khan (hasan)
http://hasan.we4tech.com
----------------------------------------------------
mobile: +880 1713 090 511
----------------------------------------------------
"work for fun"


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