Class: Butler::Asset

Inherits:
Object
  • Object
show all
Defined in:
lib/butler/asset.rb

Overview

Butler::Asset

Sends a single requested file out to the user The code has been largely taken from Rack::File but adjusted to support sending custuom HTTP headers

Usage:

Butler::Asset.new(root_directory, headers: {
  'Cache-Control' => 'public, max-age=31536000',
  'Some custom header' => 'Content for some custom header'
})

Constant Summary collapse

SEPS = 
Regexp.union(*[File::SEPARATOR, File::ALT_SEPARATOR].compact)
ALLOWED_VERBS = 
%w[GET HEAD]
F = 
File

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(root, options = {}) ⇒ Asset

Returns a new instance of Asset.



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# File 'lib/butler/asset.rb', line 26

def initialize(root, options={})
  @root = root
  @headers = options[:headers] || {}
end

Instance Attribute Details

#path ⇒ Object Also known as: to_path

Returns the value of attribute path.



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# File 'lib/butler/asset.rb', line 23

def path
  @path
end

#root ⇒ Object

Returns the value of attribute root.



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# File 'lib/butler/asset.rb', line 23

def root
  @root
end

Instance Method Details

#_call(env) ⇒ Object 



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# File 'lib/butler/asset.rb', line 37

def _call(env)
  unless ALLOWED_VERBS.include? env["REQUEST_METHOD"]
    return fail(405, "Method Not Allowed")
  end

  path_info = Rack::Utils.unescape(env["PATH_INFO"])
  parts = path_info.split SEPS

  parts.inject(0) do |depth, part|
    case part
    when '', '.'
      depth
    when '..'
      return fail(404, "Not Found") if depth - 1 < 0
      depth - 1
    else
      depth + 1
    end
  end

  @path = F.join(@root, *parts)

  available = begin
    F.file?(@path) && F.readable?(@path)
  rescue SystemCallError
    false
  end

  if available
    serving(env)
  else
    fail(404, "File not found: #{path_info}")
  end
end

#call(env) ⇒ Object 



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# File 'lib/butler/asset.rb', line 31

def call(env)
  dup._call(env)
end

#each ⇒ Object 



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# File 'lib/butler/asset.rb', line 117

def each
  F.open(@path, "rb") do |file|
    file.seek(@range.begin)
    remaining_len = @range.end-@range.begin+1
    while remaining_len > 0
      part = file.read([8192, remaining_len].min)
      break unless part
      remaining_len -= part.length

      yield part
    end
  end
end

#serving(env) ⇒ Object 



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# File 'lib/butler/asset.rb', line 72

def serving(env)
  last_modified = F.mtime(@path).httpdate
  return [304, {}, []] if env['HTTP_IF_MODIFIED_SINCE'] == last_modified
  response = [
    200,
    {
      "Last-Modified"  => last_modified,
      "Content-Type"   => Rack::Mime.mime_type(F.extname(@path), 'text/plain')
    },
    env["REQUEST_METHOD"] == "HEAD" ? [] : self
  ]

  # Set headers
  @headers.each { |field, content| response[1][field] = content } if @headers

  # NOTE:
  #   We check via File::size? whether this file provides size info
  #   via stat (e.g. /proc files often don't), otherwise we have to
  #   figure it out by reading the whole file into memory.
  size = F.size?(@path) || Utils.bytesize(F.read(@path))

  ranges = Rack::Utils.byte_ranges(env, size)
  if ranges.nil? || ranges.length > 1
    # No ranges, or multiple ranges (which we don't support):
    # TODO: Support multiple byte-ranges
    response[0] = 200
    @range = 0..size-1
  elsif ranges.empty?
    # Unsatisfiable. Return error, and file size:
    response = fail(416, "Byte range unsatisfiable")
    response[1]["Content-Range"] = "bytes */#{size}"
    return response
  else
    # Partial content:
    @range = ranges[0]
    response[0] = 206
    response[1]["Content-Range"] =
      "bytes #{@range.begin}-#{@range.end}/#{size}"
    size = @range.end - @range.begin + 1
  end

  response[1]["Content-Length"] = size.to_s
  response
end