Add better support for WireMock's RequestMatcherExtension

[marcingrzejszczak]

With RequestMatcherExtension we could consider allowing giving the users the option to pass in their own, custom matching options. Sth like this:

class DefaultRequestMatcher extends RequestMatcherExtension {

	private static final String GROOVY_EXPRESSION = "groovy-expression";

	@Override
	public MatchResult match(Request request, Parameters parameters) {
		if (!parameters.containsKey(GROOVY_EXPRESSION)) {
			return MatchResult.exactMatch();
		}
		String expression = parameters.getString(GROOVY_EXPRESSION);
		GroovyShell groovyShell = new GroovyShell();
		groovyShell.setVariable("body", request.getBody());
		return MatchResult.of(groovyShell.evaluate(expression) != null);
	}

	@Override
	public String getName() {
		return GROOVY_EXPRESSION;
	}
}

the WireMock stub could look like this:

{
    "request" : {
        "customMatcher" : {
            "name" : "groovy-expression",
            "parameters" : {
                "groovy-expression" : "new JsonSlurper(body.asString()).findAll {it.name == 'foo'}"
            }
        }
    },
    "response" : {
        "status" : 422
    }
}

then in the DSL one could call:

bodyMatchers {
    expression('new JsonSlurper(body.asString()).findAll {it.name == 'foo'}')
}

To consider:

• security issues (you can run an arbitrary Groovy code)
• maybe SPeL would be enough
• passing in slurped body (either json or xml) instead of WireMock's body

[TYsewyn]

As per our (@marcingrzejszczak and I) discussion yesterday:

Tim: I’d suggest to start with a custom matcher based on SPeL, and make a separate one for groovy? Like you said, it has a lot of security implications. Marcin: I wonder if Spel is actually good enough to do the slurping etc. cause the body would need to be converted to a map or sth for spel to work. otoh we already parse groovy scripts that can contain all sort of crap. Tim: That’s also true 😂 But passing the slurped body to both custom matchers should make your life easier I guess. Marcin: I think that it could be a map - then Spel would work Tim: Let me add these comments to github later today, so others can see our new thoughts :)