148 lines
4.3 KiB
Ruby
148 lines
4.3 KiB
Ruby
# frozen_string_literal: true
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# Downloads a remote file. If no filename is given, it'll use the remote filename
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module BulkImports
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class FileDownloadService
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ServiceError = Class.new(StandardError)
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REMOTE_FILENAME_PATTERN = %r{filename="(?<filename>[^"]+)"}.freeze
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FILENAME_SIZE_LIMIT = 255 # chars before the extension
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def initialize(configuration:, relative_url:, dir:, file_size_limit:, allowed_content_types:, filename: nil)
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@configuration = configuration
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@relative_url = relative_url
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@filename = filename
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@dir = dir
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@file_size_limit = file_size_limit
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@allowed_content_types = allowed_content_types
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end
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def execute
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validate_dir
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validate_url
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validate_content_type
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validate_content_length
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download_file
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validate_symlink
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filepath
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end
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private
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attr_reader :configuration, :relative_url, :dir, :file_size_limit, :allowed_content_types
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def download_file
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File.open(filepath, 'wb') do |file|
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bytes_downloaded = 0
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http_client.stream(relative_url) do |chunk|
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bytes_downloaded += chunk.size
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validate_size!(bytes_downloaded)
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raise(ServiceError, "File download error #{chunk.code}") unless chunk.code == 200
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file.write(chunk)
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end
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end
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rescue StandardError => e
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File.delete(filepath) if File.exist?(filepath)
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raise e
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end
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def http_client
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@http_client ||= BulkImports::Clients::HTTP.new(
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uri: configuration.url,
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token: configuration.access_token
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)
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end
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def allow_local_requests?
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::Gitlab::CurrentSettings.allow_local_requests_from_web_hooks_and_services?
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end
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def headers
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@headers ||= http_client.head(relative_url).headers
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end
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def validate_dir
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raise(ServiceError, 'Invalid target directory') unless dir.start_with?(Dir.tmpdir)
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end
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def validate_symlink
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if File.lstat(filepath).symlink?
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File.delete(filepath)
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raise(ServiceError, 'Invalid downloaded file')
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end
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end
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def validate_url
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::Gitlab::UrlBlocker.validate!(
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http_client.resource_url(relative_url),
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allow_localhost: allow_local_requests?,
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allow_local_network: allow_local_requests?,
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schemes: %w(http https)
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)
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end
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def validate_content_length
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validate_size!(headers['content-length'])
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end
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def validate_size!(size)
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if size.blank?
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raise ServiceError, 'Missing content-length header'
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elsif size.to_i > file_size_limit
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raise ServiceError, "File size %{size} exceeds limit of %{limit}" % {
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size: ActiveSupport::NumberHelper.number_to_human_size(size),
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limit: ActiveSupport::NumberHelper.number_to_human_size(file_size_limit)
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}
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end
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end
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def validate_content_type
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content_type = headers['content-type']
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raise(ServiceError, 'Invalid content type') if content_type.blank? || allowed_content_types.exclude?(content_type)
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end
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def filepath
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@filepath ||= File.join(@dir, filename)
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end
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def filename
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@filename.presence || remote_filename
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end
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# Fetch the remote filename information from the request content-disposition header
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# - Raises if the filename does not exist
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# - If the filename is longer then 255 chars truncate it
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# to be a total of 255 chars (with the extension)
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def remote_filename
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@remote_filename ||=
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headers['content-disposition'].to_s
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.match(REMOTE_FILENAME_PATTERN) # matches the filename pattern
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.then { |match| match&.named_captures || {} } # ensures the match is a hash
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.fetch('filename') # fetches the 'filename' key or raise KeyError
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.then(&File.method(:basename)) # Ensures to remove path from the filename (../ for instance)
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.then(&method(:ensure_filename_size)) # Ensures the filename is within the FILENAME_SIZE_LIMIT
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rescue KeyError
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raise ServiceError, 'Remote filename not provided in content-disposition header'
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end
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def ensure_filename_size(filename)
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if filename.length <= FILENAME_SIZE_LIMIT
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filename
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else
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extname = File.extname(filename)
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basename = File.basename(filename, extname)[0, FILENAME_SIZE_LIMIT]
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"#{basename}#{extname}"
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end
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end
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end
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end
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