FEATURE: support email attachments

lib/file_helper.rb

@@ -0,0 +1,34 @@
+class FileHelper
+
+  def self.is_image?(filename)
+    filename =~ images_regexp
+  end
+
+  def self.download(url, max_file_size, tmp_file_name)
+    raise Discourse::InvalidParameters unless url =~ /^https?:\/\//
+
+    extension = File.extname(URI.parse(url).path)
+    tmp = Tempfile.new([tmp_file_name, extension])
+
+    File.open(tmp.path, "wb") do |f|
+      avatar = open(url, "rb", read_timeout: 5)
+      while f.size <= max_file_size && data = avatar.read(max_file_size)
+        f.write(data)
+      end
+      avatar.close!
+    end
+
+    tmp
+  end
+
+  private
+
+  def self.images
+    @@images ||= Set.new ["jpg", "jpeg", "png", "gif", "tif", "tiff", "bmp"]
+  end
+
+  def self.images_regexp
+    @@images_regexp ||= /\.(#{images.to_a.join("|").gsub(".", "\.")})$/i
+  end
+
+end