README.md in second_level_cache-1.6.0 vs README.md in second_level_cache-1.6.1
- old
+ new
@@ -1,17 +1,19 @@
# SecondLevelCache
+[](http://badge.fury.io/rb/second_level_cache)
+[](https://gemnasium.com/csdn-dev/second_level_cache)
+[](https://travis-ci.org/csdn-dev/second_level_cache)
+[](https://codeclimate.com/github/csdn-dev/second_level_cache)
+
SecondLevelCache is a write-through and read-through caching library inspired by Cache Money and cache_fu, support only Rails3 and ActiveRecord.
Read-Through: Queries by ID, like `current_user.articles.find(params[:id])`, will first look in cache store and then look in the database for the results of that query. If there is a cache miss, it will populate the cache.
Write-Through: As objects are created, updated, and deleted, all of the caches are automatically kept up-to-date and coherent.
-## Risk
-SecondLevelCache is not fully test and verify in production enviroment right now. Use it at your own risk.
-
## Install
In your gem file:
```ruby
@@ -47,42 +49,117 @@
```ruby
user = User.find 1
user.second_level_cache_key # We will get the key looks like "slc/user/1/0"
```
+Expires cache:
+
+```ruby
+user = User.find(1)
+user.expire_second_level_cache
+```
+or expires cache using class method:
+```ruby
+User.expire_second_level_cache(1)
+```
+
Disable SecondLevelCache:
```ruby
- User.without_second_level_cache do
- user = User.find 1
- # ...
- end
+User.without_second_level_cache do
+ user = User.find 1
+ # ...
+end
```
Only `SELECT *` query will be cached:
```ruby
- # this query will NOT be cached
- User.select("id, name").find(1)
+# this query will NOT be cached
+User.select("id, name").find(1)
```
Notice:
* SecondLevelCache cache by model name and id, so only find_one query will work.
-* only equal conditions query WILL get cache; and SQL string query like `User.where("name = 'Hooopo'").find(1)` WILL NOT work.
+* Only equal conditions query WILL get cache; and SQL string query like `User.where("name = 'Hooopo'").find(1)` WILL NOT work.
+* SecondLevelCache sync cache after transaction commit:
-## configure
+```ruby
+# user and account's write_second_level_cache operation will invoke after the logger.
+ActiveRecord::Base.transaction do
+ user.save
+ account.save
+ Rails.logger.info "info"
+end # <- Cache write
-cache_store: Default is Rails.cache
-logger: Default is Rails.logger
-cache_key_prefix: Avoid cache key conflict with other application, Default is 'slc'
+# if you want to do something after user and account's write_second_level_cache operation, do this way:
+ActiveRecord::Base.transaction do
+ user.save
+ account.save
+end # <- Cache write
+Rails.logger.info "info"
+```
-You can config like this:
+## Configure
+In production env, we recommend to use [Dalli](https://github.com/mperham/dalli) as Rails cache store.
```ruby
-# config/initializers/second_level_cache.rb
-SecondLevelCache.configure do |config|
- config.cache_store = ActiveSupport::Cache::MemoryStore.new
- config.logger = Logger.new($stdout)
- config.cache_key_prefix = 'domain'
+ config.cache_store = [:dalli_store, APP_CONFIG["memcached_host"], {:namespace => "ns", :compress => true}]
+```
+
+## Tips:
+
+* When you want to clear only second level cache apart from other cache for example fragment cache in cache store,
+you can only change the `cache_key_prefix`:
+
+```ruby
+SecondLevelCache.configure.cache_key_prefix = "slc1"
+```
+* When schema of your model changed, just change the `version` of the speical model, avoding clear all the cache.
+
+```ruby
+class User < ActiveRecord::Base
+ acts_as_cached(:version => 2, :expires_in => 1.week)
end
```
+
+* It provides a great feature, not hits db when fetching record via unique key(not primary key).
+
+```ruby
+# this will fetch from cache
+user = User.fetch_by_uniq_key("hooopo", :nick_name)
+
+# this also fetch from cache
+user = User.fetch_by_uniq_key!("hooopo", :nick_name) # this will raise `ActiveRecord::RecordNotFound` Exception when nick name not exists.
+```
+
+## Contributors
+
+* [chloerei](https://github.com/chloerei)
+* [reyesyang](https://github.com/reyesyang)
+* [hooopo](https://github.com/hooopo)
+* [sishen](https://github.com/sishen)
+
+## License
+
+MIT License
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+