Patch StaticFileHandler to serve files from memory

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Omar Roth 2019-06-23 12:54:46 -05:00
parent 47ef74a1bb
commit 6cd884555c
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2 changed files with 203 additions and 8 deletions

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# Since systems have a limit on number of open files (`ulimit -a`),
# we serve them from memory to avoid 'Too many open files' without needing
# to modify ulimit.
#
# Very heavily re-used:
# https://github.com/kemalcr/kemal/blob/master/src/kemal/helpers/helpers.cr
# https://github.com/kemalcr/kemal/blob/master/src/kemal/static_file_handler.cr
#
# Changes:
# - A `send_file` overload is added which supports sending a Slice, file_path, filestat
# - `StaticFileHandler` is patched to cache to and serve from @cached_files
private def multipart(file, env : HTTP::Server::Context)
# See http://httpwg.org/specs/rfc7233.html
fileb = file.size
startb = endb = 0
if match = env.request.headers["Range"].match /bytes=(\d{1,})-(\d{0,})/
startb = match[1].to_i { 0 } if match.size >= 2
endb = match[2].to_i { 0 } if match.size >= 3
end
endb = fileb - 1 if endb == 0
if startb < endb < fileb
content_length = 1 + endb - startb
env.response.status_code = 206
env.response.content_length = content_length
env.response.headers["Accept-Ranges"] = "bytes"
env.response.headers["Content-Range"] = "bytes #{startb}-#{endb}/#{fileb}" # MUST
if startb > 1024
skipped = 0
# file.skip only accepts values less or equal to 1024 (buffer size, undocumented)
until (increase_skipped = skipped + 1024) > startb
file.skip(1024)
skipped = increase_skipped
end
if (skipped_minus_startb = skipped - startb) > 0
file.skip skipped_minus_startb
end
else
file.skip(startb)
end
IO.copy(file, env.response, content_length)
else
env.response.content_length = fileb
env.response.status_code = 200 # Range not satisfable, see 4.4 Note
IO.copy(file, env.response)
end
end
# Set the Content-Disposition to "attachment" with the specified filename,
# instructing the user agents to prompt to save.
private def attachment(env : HTTP::Server::Context, filename : String? = nil, disposition : String? = nil)
disposition = "attachment" if disposition.nil? && filename
if disposition && filename
env.response.headers["Content-Disposition"] = "#{disposition}; filename=\"#{File.basename(filename)}\""
end
end
def send_file(env : HTTP::Server::Context, file_path : String, data : Slice(UInt8), filestat : File::Info, filename : String? = nil, disposition : String? = nil)
config = Kemal.config.serve_static
mime_type = MIME.from_filename(file_path, "application/octet-stream")
env.response.content_type = mime_type
env.response.headers["Accept-Ranges"] = "bytes"
env.response.headers["X-Content-Type-Options"] = "nosniff"
minsize = 860 # http://webmasters.stackexchange.com/questions/31750/what-is-recommended-minimum-object-size-for-gzip-performance-benefits ??
request_headers = env.request.headers
filesize = data.bytesize
attachment(env, filename, disposition)
Kemal.config.static_headers.try(&.call(env.response, file_path, filestat))
file = IO::Memory.new(data)
if env.request.method == "GET" && env.request.headers.has_key?("Range")
return multipart(file, env)
end
condition = config.is_a?(Hash) && config["gzip"]? == true && filesize > minsize && Kemal::Utils.zip_types(file_path)
if condition && request_headers.includes_word?("Accept-Encoding", "gzip")
env.response.headers["Content-Encoding"] = "gzip"
Gzip::Writer.open(env.response) do |deflate|
IO.copy(file, deflate)
end
elsif condition && request_headers.includes_word?("Accept-Encoding", "deflate")
env.response.headers["Content-Encoding"] = "deflate"
Flate::Writer.open(env.response) do |deflate|
IO.copy(file, deflate)
end
else
env.response.content_length = filesize
IO.copy(file, env.response)
end
return
end
module Kemal
class StaticFileHandler < HTTP::StaticFileHandler
CACHE_LIMIT = 5_000_000 # 5MB
@cached_files = {} of String => {data: Bytes, filestat: File::Info}
def call(context : HTTP::Server::Context)
return call_next(context) if context.request.path.not_nil! == "/"
case context.request.method
when "GET", "HEAD"
else
if @fallthrough
call_next(context)
else
context.response.status_code = 405
context.response.headers.add("Allow", "GET, HEAD")
end
return
end
config = Kemal.config.serve_static
original_path = context.request.path.not_nil!
request_path = URI.unescape(original_path)
# File path cannot contains '\0' (NUL) because all filesystem I know
# don't accept '\0' character as file name.
if request_path.includes? '\0'
context.response.status_code = 400
return
end
expanded_path = File.expand_path(request_path, "/")
is_dir_path = if original_path.ends_with?('/') && !expanded_path.ends_with? '/'
expanded_path = expanded_path + '/'
true
else
expanded_path.ends_with? '/'
end
file_path = File.join(@public_dir, expanded_path)
if file = @cached_files[file_path]?
last_modified = file[:filestat].modification_time
add_cache_headers(context.response.headers, last_modified)
if cache_request?(context, last_modified)
context.response.status_code = 304
return
end
puts "Sending cached file, #{@cached_files.sum { |element| element[1][:data].bytesize }}"
send_file(context, file_path, file[:data], file[:filestat])
else
is_dir = Dir.exists? file_path
if request_path != expanded_path
redirect_to context, expanded_path
elsif is_dir && !is_dir_path
redirect_to context, expanded_path + '/'
end
if Dir.exists?(file_path)
if config.is_a?(Hash) && config["dir_listing"] == true
context.response.content_type = "text/html"
directory_listing(context.response, request_path, file_path)
else
call_next(context)
end
elsif File.exists?(file_path)
last_modified = modification_time(file_path)
add_cache_headers(context.response.headers, last_modified)
if cache_request?(context, last_modified)
context.response.status_code = 304
return
end
if @cached_files.sum { |element| element[1][:data].bytesize } + (size = File.size(file_path)) < CACHE_LIMIT
data = Bytes.new(size)
File.open(file_path) do |file|
file.read(data)
end
filestat = File.info(file_path)
@cached_files[file_path] = {data: data, filestat: filestat}
send_file(context, file_path, data, filestat)
else
send_file(context, file_path)
end
else
call_next(context)
end
end
end
end
end