Pattern for storing contents of a query in a server-side map in MarkLogic Server

server-side-map.xqy

xquery version "1.0-ml";

declare function local:get-map-by-name($name) {
    if (
        fn:exists(xdmp:get-server-field($name))
    ) then (
        xdmp:log(fn:concat("A server-side map with the following name (", $name, ") exists - returning it")), xdmp:get-server-field($name)
    ) else (
        xdmp:log(fn:concat("No server-side map was found with the name (", $name, ") - creating it")), xdmp:set-server-field($name, map:map())
    )
};

declare function local:get-docs-by-id-group($group as xs:string, $map-name as xs:string) {
    let $map := local:get-map-by-name($map-name)
    return
        let $_ :=
            for $x in cts:search(fn:doc(), cts:element-value-query(xs:QName("id"), $group))
            return
                if (
                    map:contains($map, xdmp:node-uri($x))
                ) then (
                    xdmp:log(fn:concat("Map: (", $map-name, ") contains uri: (", xdmp:node-uri($x), ")")),
                    map:get($map, xdmp:node-uri($x))
                ) else (
                    xdmp:log(fn:concat("Map: (", $map-name, ") does not contain uri: (", xdmp:node-uri($x), ")")),
                    map:put($map, xdmp:node-uri($x), xdmp:quote($x/node()))
                )
        return
            xdmp:set-server-field($map-name, $map)
};

local:get-docs-by-id-group("4", "my-map")