discourse/lib/compression/strategy.rb

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# frozen_string_literal: true
module Compression
class Strategy
ExtractFailed = Class.new(StandardError)
DestinationFileExistsError = Class.new(StandardError)
def can_handle?(file_name)
file_name.include?(extension)
end
def decompress(dest_path, compressed_file_path, allow_non_root_folder: false)
sanitized_compressed_file_path = sanitize_path(compressed_file_path)
get_compressed_file_stream(sanitized_compressed_file_path) do |compressed_file|
available_size = calculate_available_size
entries_of(compressed_file).each do |entry|
entry_path = build_entry_path(
compressed_file, sanitize_path(dest_path),
sanitized_compressed_file_path, entry,
allow_non_root_folder
)
if is_file?(entry)
remaining_size = extract_file(entry, entry_path, available_size)
available_size = remaining_size
else
extract_folder(entry, entry_path)
end
end
end
end
def strip_directory(from, to, relative: false)
sanitized_from = sanitize_path(from)
sanitized_to = sanitize_path(to)
glob_path = relative ? "#{sanitized_from}/*/*" : "#{sanitized_from}/**"
FileUtils.mv(Dir.glob(glob_path), sanitized_to) if File.directory?(sanitized_from)
end
private
def sanitize_path(filename)
Pathname.new(filename).realpath.to_s
end
# https://guides.rubyonrails.org/security.html#file-uploads
def sanitize_filename(filename)
filename.strip.tap do |name|
# NOTE: File.basename doesn't work right with Windows paths on Unix
# get only the filename, not the whole path
name.sub! /\A.*(\\|\/)/, ''
# Finally, replace all non alphanumeric, underscore
# or periods with underscore
name.gsub! /[^\w\.\-]/, '_'
end
end
def calculate_available_size
1024**2 * (SiteSetting.decompressed_file_max_size_mb / 1.049) # Mb to Mib
end
def entries_of(compressed_file)
compressed_file
end
def is_file?(entry)
entry.file?
end
def chunk_size
@chunk_size ||= 1024**2 * 2 # 2MiB
end
def extract_file(entry, entry_path, available_size)
remaining_size = available_size
if ::File.exist?(entry_path)
raise DestinationFileExistsError, "Destination '#{entry_path}' already exists"
end
::File.open(entry_path, 'wb') do |os|
buf = ''.dup
while (buf = entry.read(chunk_size))
remaining_size -= chunk_size
raise ExtractFailed if remaining_size.negative?
os << buf
end
end
remaining_size
end
end
end