Class: Wrest::CacheProxy::DefaultCacheProxy

Inherits:
Object
  • Object
show all
Defined in:
lib/wrest/cache_proxy.rb

Constant Summary collapse

HOP_BY_HOP_HEADERS = 
%w[connection
keep-alive
proxy-authenticate
proxy-authorization
te
trailers
transfer-encoding
upgrade].freeze

Instance Method Summary collapse

Constructor Details

#initialize(get, cache_store) ⇒ DefaultCacheProxy

Returns a new instance of DefaultCacheProxy.



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# File 'lib/wrest/cache_proxy.rb', line 35

def initialize(get, cache_store)
  @get         = get
  @cache_store = cache_store
end

Instance Method Details

#cache(response) ⇒ Object 



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# File 'lib/wrest/cache_proxy.rb', line 63

def cache(response)
  @cache_store[@get.full_uri_string] = response.clone if response&.cacheable?
end

#fresh_get_response ⇒ Object

:nodoc:



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# File 'lib/wrest/cache_proxy.rb', line 68

def fresh_get_response
  @cache_store.delete @get.full_uri_string

  response = @get.invoke_without_cache_check

  cache(response)

  response
end

#get ⇒ Object 



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# File 'lib/wrest/cache_proxy.rb', line 44

def get
  cached_response = @cache_store[@get.full_uri_string]
  return fresh_get_response if cached_response.nil?

  if cached_response.expired?
    expired_cached_response(cached_response)
  else
    log_cached_response
    cached_response
  end
end

#get_validated_response_for(cached_response) ⇒ Object

:nodoc:



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# File 'lib/wrest/cache_proxy.rb', line 79

def get_validated_response_for(cached_response)
  new_response = send_validation_request_for(cached_response)
  if new_response.code == '304'
    update_cache_headers_for(cached_response, new_response)
    log_cached_response
    cached_response
  else
    cache(new_response)
    new_response
  end
end

#log_cached_response ⇒ Object 



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# File 'lib/wrest/cache_proxy.rb', line 40

def log_cached_response
  Wrest.logger.debug "<*> (GET #{@get.hash}) #{@get.uri.protocol}://#{@get.uri.host}:#{@get.uri.port}#{@get.http_request.path}"
end

#send_validation_request_for(cached_response) ⇒ Object

:nodoc: Send a cache-validation request to the server. This would be the actual Get request with extra cache-validation headers. If a 304 (Not Modified) is received, Wrest would use the cached_response itself. Otherwise the new response is cached and used.



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# File 'lib/wrest/cache_proxy.rb', line 94

def send_validation_request_for(cached_response)
  last_modified            = cached_response.last_modified
  etag                     = cached_response.headers['etag']

  cache_validation_headers = {}
  cache_validation_headers['if-modified-since'] = last_modified unless last_modified.nil?
  cache_validation_headers['if-none-match'] = etag unless etag.nil?

  new_request = @get.build_request_without_cache_store(cache_validation_headers)

  new_request.invoke
end

#update_cache_headers_for(cached_response, new_response) ⇒ Object 



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# File 'lib/wrest/cache_proxy.rb', line 56

def update_cache_headers_for(cached_response, new_response)
  # RFC 2616 13.5.3 (Combining Headers)
  cached_response.headers.merge!(new_response.headers.reject do |key, _value|
                                   (HOP_BY_HOP_HEADERS.include? key.downcase)
                                 end)
end