require "open-uri" class FileHelper def self.is_image?(filename) filename =~ images_regexp end def self.download(url, max_file_size, tmp_file_name, follow_redirect=false, read_timeout=5) raise Discourse::InvalidParameters.new(:url) unless url =~ /^https?:\/\// uri = parse_url(url) extension = File.extname(uri.path) tmp = Tempfile.new([tmp_file_name, extension]) File.open(tmp.path, "wb") do |f| downloaded = uri.open("rb", read_timeout: read_timeout, redirect: follow_redirect, allow_redirections: :all) while f.size <= max_file_size && data = downloaded.read(512.kilobytes) f.write(data) end # tiny files are StringIO, no close! on them downloaded.try(:close!) rescue nil end tmp end private def self.images @@images ||= Set.new ["jpg", "jpeg", "png", "gif", "tif", "tiff", "bmp", "svg", "webp", "ico"] end def self.images_regexp @@images_regexp ||= /\.(#{images.to_a.join("|")})$/i end # HACK to support underscores in URLs # cf. http://stackoverflow.com/a/18938253/11983 def self.parse_url(url) URI.parse(url) rescue URI::InvalidURIError host = url.match(".+\:\/\/([^\/]+)")[1] uri = URI.parse(url.sub(host, 'valid-host')) uri.instance_variable_set("@host", host) uri end end