Class: HTTPX::Plugins::Cache::FileStore

Inherits:
Object
  • Object
show all
Includes:
_CacheStore
Defined in:
lib/httpx/plugins/cache/file_store.rb,
sig/plugins/cache/file_store.rbs

Overview

Implementation of a file system based cache store.

It stores cached responses in a file under a directory pointed by the dir variable (defaults to the default temp directory from the OS), in a custom format (similar but different from HTTP/1.1 request/response framing).

Constant Summary collapse

CRLF =

Returns:

  • (String) 
HTTPX::Connection::HTTP1::CRLF

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(dir = Dir.tmpdir) ⇒ FileStore

Returns a new instance of FileStore.

Parameters:

  • dir (path) (defaults to: Dir.tmpdir) 


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# File 'lib/httpx/plugins/cache/file_store.rb', line 17

def initialize(dir = Dir.tmpdir)
  @dir = Pathname.new(dir).join("httpx-response-cache")

  FileUtils.mkdir_p(@dir)
end

Instance Attribute Details

#dir ⇒ Object (readonly)

Returns the value of attribute dir.



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# File 'lib/httpx/plugins/cache/file_store.rb', line 15

def dir
  @dir
end

Instance Method Details

#clear ⇒ Object 



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# File 'lib/httpx/plugins/cache/file_store.rb', line 23

def clear
  FileUtils.rm_rf(@dir)
end

#file_path(request) ⇒ Pathname

Parameters:

  • request (cacheRequest)

Returns:

  • (Pathname) 


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# File 'lib/httpx/plugins/cache/file_store.rb', line 90

def file_path(request)
  @dir.join(request.response_cache_key)
end

#get(request) ⇒ Object 



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# File 'lib/httpx/plugins/cache/file_store.rb', line 27

def get(request)
  path = file_path(request)

  return unless File.exist?(path)

  File.open(path, mode: File::RDONLY | File::BINARY) do |f|
    f.flock(File::Constants::LOCK_SH)

    read_from_file(request, f)
  end
end

#read_from_file(request, f) ⇒ cacheResponse?

Parameters:

  • request (cacheRequest)
  • f (File)

Returns:

  • (cacheResponse, nil) 


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# File 'lib/httpx/plugins/cache/file_store.rb', line 94

def read_from_file(request, f)
  # if it's an empty file
  return if f.eof?

  # read request data
  verb = f.readline.delete_suffix!(CRLF)
  uri = f.readline.delete_suffix!(CRLF)

  request_headers = {}
  while (line = f.readline) != CRLF
    line.delete_suffix!(CRLF)
    sep_index = line.index(":")

    field = line.byteslice(0..(sep_index - 1))
    value = line.byteslice((sep_index + 1)..-1)

    request_headers[field] = value
  end

  status = f.readline.delete_suffix!(CRLF)
  version = f.readline.delete_suffix!(CRLF)

  response_headers = {}
  while (line = f.readline) != CRLF
    line.delete_suffix!(CRLF)
    sep_index = line.index(":")

    field = line.byteslice(0..(sep_index - 1))
    value = line.byteslice((sep_index + 1)..-1)

    response_headers[field] = value
  end

  original_request = request.options.request_class.new(verb, uri, request.options)
  original_request.merge_headers(request_headers)

  response = request.options.response_class.new(request, status, version, response_headers)
  response.original_request = original_request
  response.finish!
  response.mark_as_cached!

  IO.copy_stream(f, response.body)

  response
end

#set(request, response) ⇒ Object 



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# File 'lib/httpx/plugins/cache/file_store.rb', line 39

def set(request, response)
  path = file_path(request)

  file_exists = File.exist?(path)

  mode = file_exists ? File::RDWR : File::CREAT | File::Constants::WRONLY

  File.open(path, mode: mode | File::BINARY) do |f|
    f.flock(File::Constants::LOCK_EX)

    if file_exists
      cached_response = read_from_file(request, f)

      if cached_response
        next if cached_response == request.cached_response

        cached_response.close

        f.truncate(0)

        f.rewind
      end
    end
    # cache the request headers
    f << request.verb << CRLF
    f << request.uri << CRLF

    request.headers.each do |field, value|
      f << field << ":" << value << CRLF
    end

    f << CRLF

    # cache the response
    f << response.status << CRLF
    f << response.version << CRLF

    response.headers.each do |field, value|
      f << field << ":" << value << CRLF
    end

    f << CRLF

    response.body.rewind

    IO.copy_stream(response.body, f)
  end
end