Faraday Http Cache

a Faraday middleware that respects HTTP cache, by checking expiration and validation of the stored responses.

Installation

Add it to your Gemfile:

gem 'faraday-http-cache'

Usage and configuration

You have to use the middleware in the Faraday instance that you want to. You can use the new shortcut using a symbol or passing the middleware class

client = Faraday.new do |builder|
  builder.use :http_cache
  # or
  builder.use Faraday::HttpCache

  builder.adapter Faraday.default_adapter
end

The middleware uses the ActiveSupport::Cache API to record the responses from the targeted endpoints, and any extra configuration option will be used to setup the cache store.

# Connect the middleware to a Memcache instance.
client = Faraday.new do |builder|
  builder.use :http_cache, store: :mem_cache_store, store_options: ['localhost:11211']
  builder.adapter Faraday.default_adapter
end

# Or use the Rails.cache instance inside your Rails app.
client = Faraday.new do |builder|
  builder.use :http_cache, store: Rails.cache
  builder.adapter Faraday.default_adapter
end

The default store provided by ActiveSupport is the MemoryStore one, so it's important to configure a proper one for your production environment.

MultiJson is used for serialization by default. If you expect to be dealing with images, you can use Marshal instead.

client = Faraday.new do |builder|
  builder.use :http_cache, serializer: Marshal
  builder.adapter Faraday.default_adapter
end

Logging

You can provide a :logger option that will be receive debug informations based on the middleware operations:

client = Faraday.new do |builder|
  builder.use :http_cache, logger: Rails.logger
  builder.adapter Faraday.default_adapter
end

client.get('http://site/api/users')
# logs "HTTP Cache: [GET users] miss, store"

See it live

You can clone this repository, install it's dependencies with Bundler (run bundle install) and execute the files under the examples directory to see a sample of the middleware usage.

What get's cached?

The middleware will use the following headers to make caching decisions:

• Cache-Control
• Age
• Last-Modified
• ETag
• Expires

Cache-Control

The max-age, must-revalidate, proxy-revalidate and s-maxage directives are checked.

Note: private caches are ignored.

License

Copyright (c) 2012-2013 Plataformatec. See LICENSE file.