Class: Prefab::CachingHttpConnection

Inherits:
Object
  • Object
show all
Defined in:
lib/prefab/caching_http_connection.rb

Defined Under Namespace

Classes: CacheEntry

Constant Summary collapse

CACHE_SIZE = 
2.freeze

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(uri, api_key) ⇒ CachingHttpConnection

Returns a new instance of CachingHttpConnection.



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# File 'lib/prefab/caching_http_connection.rb', line 18

def initialize(uri, api_key)
  @connection = HttpConnection.new(uri, api_key)
end

Class Method Details

.cache ⇒ Object 



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# File 'lib/prefab/caching_http_connection.rb', line 9

def cache
  @cache ||= FixedSizeHash.new(CACHE_SIZE)
end

.reset_cache! ⇒ Object 



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# File 'lib/prefab/caching_http_connection.rb', line 13

def reset_cache!
  @cache = FixedSizeHash.new(CACHE_SIZE)
end

Instance Method Details

#get(path) ⇒ Object 



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# File 'lib/prefab/caching_http_connection.rb', line 22

def get(path)
  now = Time.now.to_i
  cache_key = "#{@connection.uri}#{path}"
  cached = self.class.cache[cache_key]

  # Check if we have a valid cached response
  if cached&.data && cached.expires_at && now < cached.expires_at
    return Faraday::Response.new(
      status: 200,
      body: cached.data,
      response_headers: {
        'ETag' => cached.etag,
        'X-Cache' => 'HIT',
        'X-Cache-Expires-At' => cached.expires_at.to_s
      }
    )
  end

  # Make request with conditional GET if we have an ETag
  response = if cached&.etag
               @connection.get(path, { 'If-None-Match' => cached.etag })
             else
               @connection.get(path)
             end

  # Handle 304 Not Modified
  if response.status == 304 && cached&.data
    return Faraday::Response.new(
      status: 200,
      body: cached.data,
      response_headers: {
        'ETag' => cached.etag,
        'X-Cache' => 'HIT',
        'X-Cache-Expires-At' => cached.expires_at.to_s
      }
    )
  end

  # Parse caching headers
  cache_control = response.headers['Cache-Control'].to_s
  etag = response.headers['ETag']

  # Always add X-Cache header
  response.headers['X-Cache'] = 'MISS'

  # Don't cache if no-store is present
  return response if cache_control.include?('no-store')

  # Calculate expiration
  max_age = cache_control.match(/max-age=(\d+)/)&.captures&.first&.to_i
  expires_at = max_age ? now + max_age : nil

  # Cache the response if we have caching headers
  if etag || expires_at
    self.class.cache[cache_key] = CacheEntry.new(
      response.body,
      etag,
      expires_at
    )
  end

  response
end

#post(path, body) ⇒ Object

Delegate other methods to the underlying connection



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# File 'lib/prefab/caching_http_connection.rb', line 87

def post(path, body)
  @connection.post(path, body)
end

#uri ⇒ Object 



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# File 'lib/prefab/caching_http_connection.rb', line 91

def uri
  @connection.uri
end