Add support for behavior on undefined query parameters

[ahenket]

Roaster ignores query parameters. If you want to explicitly send a client error on undefined query parameters, you could write some middleware. It would be nicer if you could make it explicit using the OpenAPI definition.

Propose to add support for x-allow-unknown-query-parameters as boolean under the method. Default value = true

Support could look like:

declare function parameters:in-request ($request as map(*), $response as map(*)) as map(*)+ {
    if (not(map:contains($request?config, "parameters")))
    then ($request, $response) (: route expects no parameters, return request unchanged :)
    else if (not($request?config?parameters instance of array(*)))
    then error($errors:OPERATION, "Parameter definition must be an array: " || $request?pattern, $request)
    else (
        let $errorUnknownParams := 
            exists($request?config?x-allow-unknown-query-parameters[. = false()])
        let $unsupported-params := 
            if ($errorUnknownParams) then 
                request:get-parameter-names()[not(. = $request?config?parameters?*[?in = "query"]?name)] 
            else ()
        let $unsupported-params := 
            if (empty($unsupported-params)) then () else (
                error($errors:BAD_REQUEST, "Unsupported parameter(s): " || string-join($unsupported-params, ', '))
            )
        
        let $maps := for-each($request?config?parameters?*, parameters:retrieve#1)

        (: extend previous parameters map with new values :)
        let $merged := map:merge(($request?parameters, $maps))

        return (
            map:put($request, "parameters", $merged),
            $response
        )
    )
};