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# frozen_string_literal: true
require 'time'
require_relative 'constants'
require_relative 'head'
require_relative 'utils'
require_relative 'request'
require_relative 'mime'
module Rack
# Rack::Files serves files below the +root+ directory given, according to the
# path info of the Rack request.
# e.g. when Rack::Files.new("/etc") is used, you can access 'passwd' file
# as http://localhost:9292/passwd
#
# Handlers can detect if bodies are a Rack::Files, and use mechanisms
# like sendfile on the +path+.
class Files
ALLOWED_VERBS = %w[GET HEAD OPTIONS]
ALLOW_HEADER = ALLOWED_VERBS.join(', ')
MULTIPART_BOUNDARY = 'AaB03x'
attr_reader :root
def initialize(root, headers = {}, default_mime = 'text/plain')
@root = (::File.expand_path(root) if root)
@headers = headers
@default_mime = default_mime
@head = Rack::Head.new(lambda { |env| get env })
end
def call(env)
# HEAD requests drop the response body, including 4xx error messages.
@head.call env
end
def get(env)
request = Rack::Request.new env
unless ALLOWED_VERBS.include? request.request_method
return fail(405, "Method Not Allowed", { 'allow' => ALLOW_HEADER })
end
path_info = Utils.unescape_path request.path_info
return fail(400, "Bad Request") unless Utils.valid_path?(path_info)
clean_path_info = Utils.clean_path_info(path_info)
path = ::File.join(@root, clean_path_info)
available = begin
::File.file?(path) && ::File.readable?(path)
rescue SystemCallError
# Not sure in what conditions this exception can occur, but this
# is a safe way to handle such an error.
# :nocov:
false
# :nocov:
end
if available
serving(request, path)
else
fail(404, "File not found: #{path_info}")
end
end
def serving(request, path)
if request.options?
return [200, { 'allow' => ALLOW_HEADER, CONTENT_LENGTH => '0' }, []]
end
last_modified = ::File.mtime(path).httpdate
return [304, {}, []] if request.get_header('HTTP_IF_MODIFIED_SINCE') == last_modified
headers = { "last-modified" => last_modified }
mime_type = mime_type path, @default_mime
headers[CONTENT_TYPE] = mime_type if mime_type
# Set custom headers
headers.merge!(@headers) if @headers
status = 200
size = filesize path
ranges = Rack::Utils.get_byte_ranges(request.get_header('HTTP_RANGE'), size)
if ranges.nil?
# No ranges:
ranges = [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
partial_content = true
if ranges.size == 1
range = ranges[0]
headers["content-range"] = "bytes #{range.begin}-#{range.end}/#{size}"
else
headers[CONTENT_TYPE] = "multipart/byteranges; boundary=#{MULTIPART_BOUNDARY}"
end
status = 206
body = BaseIterator.new(path, ranges, mime_type: mime_type, size: size)
size = body.bytesize
end
headers[CONTENT_LENGTH] = size.to_s
if request.head?
body = []
elsif !partial_content
body = Iterator.new(path, ranges, mime_type: mime_type, size: size)
end
[status, headers, body]
end
class BaseIterator
attr_reader :path, :ranges, :options
def initialize(path, ranges, options)
@path = path
@ranges = ranges
@options = options
end
def each
::File.open(path, "rb") do |file|
ranges.each do |range|
yield multipart_heading(range) if multipart?
each_range_part(file, range) do |part|
yield part
end
end
yield "\r\n--#{MULTIPART_BOUNDARY}--\r\n" if multipart?
end
end
def bytesize
size = ranges.inject(0) do |sum, range|
sum += multipart_heading(range).bytesize if multipart?
sum += range.size
end
size += "\r\n--#{MULTIPART_BOUNDARY}--\r\n".bytesize if multipart?
size
end
def close; end
private
def multipart?
ranges.size > 1
end
def multipart_heading(range)
<<-EOF
\r
--#{MULTIPART_BOUNDARY}\r
content-type: #{options[:mime_type]}\r
content-range: bytes #{range.begin}-#{range.end}/#{options[:size]}\r
\r
EOF
end
def each_range_part(file, range)
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
class Iterator < BaseIterator
alias :to_path :path
end
private
def fail(status, body, headers = {})
body += "\n"
[
status,
{
CONTENT_TYPE => "text/plain",
CONTENT_LENGTH => body.size.to_s,
"x-cascade" => "pass"
}.merge!(headers),
[body]
]
end
# The MIME type for the contents of the file located at @path
def mime_type(path, default_mime)
Mime.mime_type(::File.extname(path), default_mime)
end
def filesize(path)
# 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.
::File.size?(path) || ::File.read(path).bytesize
end
end
end