Class: Racknga::Middleware::Cache — racknga - ラングバ

Class: Racknga::Middleware::Cache

Inherits:
Object
  • Object
show all
Defined in:
lib/racknga/middleware/cache.rb

Overview

This is a middleware that provides page cache.

This stores page contents into a groonga database. A groonga database can access by multi process. It means that your Rack application processes can share the same cache. For example, Passenger runs your Rack application with multi processes.

Cache key is the request URL by default. It can be customized by env[Racknga::Cache::KEY]. For example, Racknga::Middleware::PerUserAgentCache and Racknga::Middleware::JSONP use it.

This only caches the following responses:

  • 200 status response.

  • text/*, */json, */xml or /+xml content type response.

Usage:

use Racnkga::Middleware::Cache, :database_path => "var/cache/db"
run YourApplication

See Also:

Constant Summary

KEY = 
"racknga.cache.key"
START_TIME = 
"racknga.cache.start_time"

Instance Attribute Summary (collapse)

Instance Method Summary (collapse)

Constructor Details

- (Cache) initialize(application, options = {})

A new instance of Cache

Parameters:

  • options (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (options):

  • :database_path (String) —

    the database path to be stored caches.

Raises:

  • (ArgumentError) 


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# File 'lib/racknga/middleware/cache.rb', line 98

def initialize(application, options={})
  @application = application
  @options = Utils.normalize_options(options || {})
  database_path = @options[:database_path]
  raise ArgumentError, ":database_path is missing" if database_path.nil?
  @database = CacheDatabase.new(database_path)
end

Instance Attribute Details

- (Racknga::CacheDatabase) database (readonly)

The database used by this middleware.

Returns:



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# File 'lib/racknga/middleware/cache.rb', line 94

def database
  @database
end

Instance Method Details

- (Object) call(environment)

For Rack.



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# File 'lib/racknga/middleware/cache.rb', line 107

def call(environment)
  request = Rack::Request.new(environment)
  return @application.call(environment) unless use_cache?(request)
  age = @database.configuration.age
  key = normalize_key(environment[KEY] || request.fullpath)
  environment[START_TIME] = Time.now
  cache = @database.responses
  record = cache[key]
  if record and record.age == age
    handle_request_with_cache(cache, key, age, record, request)
  else
    handle_request(cache, key, age, request)
  end
end

- (Object) close_database

close the cache database.



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# File 'lib/racknga/middleware/cache.rb', line 128

def close_database
  @database.close_database
end

- (Object) ensure_database

ensures creating cache database.



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# File 'lib/racknga/middleware/cache.rb', line 123

def ensure_database
  @database.ensure_database
end