Class: HTTPDisk::Cache

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

Overview

Disk cache for cache_keys => response. Files are compressed.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ Cache

Returns a new instance of Cache.



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# File 'lib/httpdisk/cache.rb', line 8

def initialize(options)
  @options = options
end

Instance Attribute Details

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/httpdisk/cache.rb', line 6

def options
  @options
end

Instance Method Details

#delete(cache_key) ⇒ Object

Delete existing response, if any



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# File 'lib/httpdisk/cache.rb', line 54

def delete(cache_key)
  path = diskpath(cache_key)
  FileUtils.rm(path) if File.exist?(path)
end

#diskpath(cache_key) ⇒ Object

Relative path for this cache_key based on the cache key



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# File 'lib/httpdisk/cache.rb', line 60

def diskpath(cache_key)
  File.join(dir, cache_key.diskpath)
end

#read(cache_key) ⇒ Object

Get cached response. If there is a cached error it will be raised.



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# File 'lib/httpdisk/cache.rb', line 21

def read(cache_key)
  payload_or_status = read0(cache_key)
  payload_or_status.is_a?(Symbol) ? nil : payload_or_status
end

#status(cache_key) ⇒ Object

Cache status for a cache_key, %i[error force hit miss stale]



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# File 'lib/httpdisk/cache.rb', line 27

def status(cache_key)
  payload_or_status = read0(cache_key, peek: true)
  return payload_or_status if payload_or_status.is_a?(Symbol)

  payload_or_status.error? ? :error : :hit
end

#write(cache_key, payload) ⇒ Object

Write response to the disk cache



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# File 'lib/httpdisk/cache.rb', line 35

def write(cache_key, payload)
  path = diskpath(cache_key)
  FileUtils.mkdir_p(File.dirname(path))

  # Atomically write gzipped payload. Put our underlying Tempfile into
  # binmode to avoid accidental newline conversion or string encoding. Not
  # required for *nix systems, but I've heard rumors it's helpful for
  # Windows.
  Tempfile.new(binmode: true).tap do |tmp|
    Zlib::GzipWriter.new(tmp).tap do |gzip|
      payload.write(gzip)
      gzip.close
    end
    tmp.close
    FileUtils.mv(tmp.path, path)
  end
end