encodings/xml_escaping.rb

tests/_examples/encodings/xml_escaping.rb in the metorex repository.

# `xml: :text` escapes the characters XML content cannot hold as they are,
# and writes each character the destination cannot spell as a hexadecimal
# character reference. `xml: :attr` also escapes the double quote and quotes
# the whole value.
p "<a & b>".encode "UTF-8", xml: :text
p "say \"hi\"".encode "UTF-8", xml: :text
p "<ü>".encode xml: :text
p "<ü>\"".encode "US-ASCII", xml: :attr
p "\u{1F600}&".encode "ISO-8859-1", xml: :text
p "<".encode("UTF-16LE", xml: :attr).bytes

# A character reference is written ahead of any other replacement.
p "ü".encode "US-ASCII", xml: :text, undef: :replace
p "ü".encode "US-ASCII", xml: :text, fallback: { "ü" => "u" }

# Anything but `:text` or `:attr` is refused.
def refusal
  yield
rescue ArgumentError => problem
  problem.message
end

p refusal { "".encode "UTF-8", xml: :other }
p refusal { "".encode "UTF-8", xml: "text" }

Output:

"<a & b>"
"say \"hi\""
"<ü>"
"\"<ü>"\""
"😀&"
[34, 0, 38, 0, 108, 0, 116, 0, 59, 0, 34, 0]
"ü"
"ü"
"unexpected value for xml option: other"
"unexpected value for xml option"