Issue #22229 has been updated by byroot (Jean Boussier).
but what about a fixed Regexp with the characters to escape?
@Eregon please see the benchmark at https://github.com/ruby/cgi/pull/55, it doesn't compile a regexp every time and there's still a 5x difference. I only did it in this in this example for simplicity, but also because you can't always have a static list upfront.
I would say it's something to optimize in Regexp matching,
I'm sure Regexp matching could be optimized further, but that's far from my area of expertise, and I made the point that by being limited to single characters, `escapeHTML` can be much easier to optimize much further. ---------------------------------------- Feature #22229: Allow GCI.escapeHTML to take a custom escape table https://bugs.ruby-lang.org/issues/22229#change-118363 * Author: byroot (Jean Boussier) * Status: Open ---------------------------------------- ### Use case `CGI.escapeHTML` has a fixed escape table: ```c HTML_ESCAPE('\'', "'"), HTML_ESCAPE('&', "&"), HTML_ESCAPE('"', """), HTML_ESCAPE('<', "<"), HTML_ESCAPE('>', ">"), ``` But in some context you may want to escape more or less characters than that, or escape them differently. One example of this is Active Support JSON serialization, which by defaults escape `<>&` as `\u003e\u003c\u0026`, to ensure that the generated JSON can safely be interpolated inside a `<script>` tag without causing XSS vulnerabilities. There's likely other use case as evidenced by the popularity of the `htmlentities` gem, which support several more escape tables. ### Why not `gsub` ? Today, this sort of escaping is performed using `gsub`, it works but is very noticeably slower than `CGI.escapeHTML` (see benchmarks on the PoC PR). This is because the only way to use `gsub` with an escape table is to craft a regexp: ```ruby def escape(string, table) pattern = Regexp.union(table.keys) string.gsub(pattern, table) end puts escape("<script>", "<" => "<", ">" => ">") ``` If `gsub` could be used directly with the escape table it would certainly make it faster: ```ruby puts "<script>".gsub("<" => "<", ">" => ">") ``` But compared to `CGI.escapeHTML` it would still need to deal with noticeably more scenarios (multi character search, etc), so would always be slower than a dedicated escaping method. `CGI.escapeHTML` can be more restrictive (single character search, etc). ### Specification ```ruby GCI.escapeHTML("</script>", "<" => "<", ">" => ">") ``` - The escape table keys must be single characters (currently ASCII only, but could be muti-byte characters if deemed necessary). ### Implementation Pull Request: https://github.com/ruby/cgi/pull/55 (NB: it's at proof of concept / demo stage, if the feature is accepted I can polish it). -- https://bugs.ruby-lang.org/