Log4j RegexFilter, How to configure PatternFlags?

Question

I want to use RegexFilter (https://logging.apache.org/log4j/2.x/manual/filters.html#RegexFilter) in order to filter URLs. But in order to do so i need to config the regex pattern with Pattern.DOTALL flag. How do I config the RegexFilter to construct his pattern with this flag ? I tried this :

<RegexFilter regex=".*https://[-A-Za-z0-9+&amp;@#/%?=~_()|!:,.;]*[-A-Za-z0-9+&amp;@#/%=~_()|].*" onMatch="DENY" onMismatch="ACCEPT" PatternFlags="DOTALL"/>

But the PatternFlags is ignored.

Looking at the RegexFilter code, It does read the PatternFlags property :

   @PluginFactory
    public static RegexFilter createFilter(@PluginAttribute("regex") String regex, @PluginElement("PatternFlags") String[] patternFlags, @PluginAttribute("useRawMsg") Boolean useRawMsg, @PluginAttribute("onMatch") Result match, @PluginAttribute("onMismatch") Result mismatch) throws IllegalArgumentException, IllegalAccessException {
        if (regex == null) {
            LOGGER.error("A regular expression must be provided for RegexFilter");
            return null;
        } else {
            return new RegexFilter(useRawMsg.booleanValue(), Pattern.compile(regex, toPatternFlags(patternFlags)), match, mismatch);
        }
    }

Try `regex="[\s\S]*https://[-A-Za-z0-9+&@#/%?=~_()|!:,.;]*[-A-Za-z0-9+&@#/%=~_()|][\s\S]*"` — Wiktor Stribiżew, Jul 03 '18 at 13:24
BTW, This is not duplicated question, your answer is a work-around. I asked How do I configure log4j. — Saar peer, Jul 03 '18 at 13:43
You just make `.` match a newline char. It is a solution. `regex="(?s)..."` should also work. In the docs, there is no `PatternFlags` attribute. — Wiktor Stribiżew, Jul 03 '18 at 13:45
So - The answer should be, This is impossible. But you can work around it for this specific case — Saar peer, Jul 04 '18 at 05:32

Log4j RegexFilter, How to configure PatternFlags?

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