Looking at some examples, I came across lines like:
output.safe_concat("<input type=\"hidden\" id=\"#{k}\" name=\"#{CGI.escape(k)}\" value=\"#{CGI.escape(v)}\"/>")
That rely on the CGI class. When I Googled CGI Rails I found the documentation that said:
CGI is a large class, providing several categories of methods, many of
which are mixed in from other modules. Some of the documentation is in
this class, some in the modules CGI::QueryExtension and
CGI::HtmlExtension. See CGI::Cookie for specific information on
handling cookies, and cgi/session.rb (CGI::Session) for information on
sessions.
Just out of curiosity, what does CGI stand for?
CGI stands for Common Gateway Interface.