Class: Her::Middleware::CacheUnmodified

Inherits:
Faraday::Middleware
  • Object
show all
Defined in:
lib/her_cache_unmodified.rb

Overview

Easy way to begin support 304 status, so on ther side if data was not changed You will load it from local cache. Of course, other side must support Of course, other side must support 304 status also. Here is Rails controller example with this support:

class Post < ApplicationController

before_action :check_changes

private

def check_changes
  return unless request.headers['HTTP_IF_MODIFIED_SINCE']
  return if request.headers['HTTP_IF_MODIFIED_SINCE'].to_datetime > resource.updated_at
  render body: nil, status: 304
end

end

Constant Summary collapse

SAVE_METHODS = 
[:get, :head].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app, options = {}) ⇒ CacheUnmodified

apply with optinos: cache # default value is Rails.cache if Rails is used cache_key_prefix # defauilt is nil



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# File 'lib/her_cache_unmodified.rb', line 27

def initialize(app, options={})
  @app = app
  @cache = options[:cache] 
  @cache ||= Rails.cache if defined?(Rails)
  @options = options
end

Instance Attribute Details

#cache ⇒ Object (readonly)

Returns the value of attribute cache.



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# File 'lib/her_cache_unmodified.rb', line 20

def cache
  @cache
end

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/her_cache_unmodified.rb', line 20

def options
  @options
end

#url ⇒ Object

Returns the value of attribute url.



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# File 'lib/her_cache_unmodified.rb', line 21

def url
  @url
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/her_cache_unmodified.rb', line 34

def call(env)
  return @app.call(env) unless SAVE_METHODS.include?(env[:method])
  self.url = env.url.to_s
  env[:request_headers]["If-Modified-Since"] ||= cached_time if cached_time

  @app.call(env).on_complete do
    if env[:status] == 304
      if cached_body
        env[:body] = cached_body
        # with out this hack Her crushes
        env[:status] = 200
      end
    elsif env[:status] == 200
      cache.write cache_key_body, env[:body], expires_in: cache_key_ttl
      cache.write cache_key_time, Time.zone.now.httpdate, expires_in: cache_key_ttl
    end
  end
end