Class: OpenURI::Cache

Inherits:
Object
  • Object
show all
Defined in:
lib/open-uri/cached.rb

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.cache_path ⇒ Object

Returns the value of attribute cache_path.



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# File 'lib/open-uri/cached.rb', line 28

def cache_path
  @cache_path
end

Class Method Details

.get(key) ⇒ StringIO

Retrieve file content and meta data from cache

Parameters:

  • key (String)

Returns:

  • (StringIO) 


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# File 'lib/open-uri/cached.rb', line 34

def get(key)
  filename = filename_from_url(key)
  # TODO: head request to determine last_modified vs file modtime

  # Read metadata, if it exists
  meta = YAML::load(File.read("#{filename}.meta")) if File.exists?("#{filename}.meta")

  f = File.exists?(filename) ? StringIO.new(File.open(filename, "rb") { |f| f.read }) : nil

  # Add meta accessors
  if meta && f
    f.instance_variable_set(:"@meta", meta)

    def f.meta
      @meta
    end
    def f.base_uri
      @meta[:base_uri]
    end
    def f.content_type
      @meta[:content_type]
    end
    def f.charset
      @meta[:charset]
    end
    def f.content_encoding
      @meta[:content_encoding]
    end
    def f.last_modified
      @meta[:last_modified]
    end
    def f.status
      @meta[:status]
    end
  end

  f
end

.invalidate(key, time = Time.now) ⇒ Object

Invalidate cache for a key, optionally if older than time givan

Parameters:

  • key (String) —

    URL of content to be invalidated

  • time (Time) (defaults to: Time.now) —

    (optional): the maximum age at which the cached value is still acceptable

Returns:

  • Returns 1 if a cached value was invalidated, false otherwise



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# File 'lib/open-uri/cached.rb', line 107

def invalidate(key, time = Time.now)
  filename = filename_from_url(key)
  File.delete(filename) if File.stat(filename).mtime < time
rescue Errno::ENOENT
  false
end

.set(key, value) ⇒ StringIO

Cache file content and metadata

Parameters:

  • key (String) —

    URL of content to be cached

  • value (StringIO) —

    value to be cached, typically StringIO returned from ‘original_open_uri`

Returns:

  • (StringIO) —

    Returns value



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# File 'lib/open-uri/cached.rb', line 80

def set(key, value)
  filename = filename_from_url(key)
  mkpath(filename)

  # Save metadata in a parallel file
  if value.respond_to?(:meta)
    filename_meta = "#{filename}.meta"
    meta = value.meta
    meta[:status] = value.status if value.respond_to?(:status)
    meta[:content_type] = value.content_type if value.respond_to?(:content_type)
    meta[:base_uri] = value.base_uri if value.respond_to?(:base_uri)
    File.open(filename_meta, 'wb') {|f| YAML::dump(meta, f)}
  end

  # Save file contents
  File.open(filename, 'wb'){|f| f.write value.read }
  value.rewind
  value
end