@NonNull
    public static Single<ObjectNode> requestJSON(final String uri, @Nullable final Parameters params) {
        return request("GET", uri, params, new Parameters("Accept", "application/json, text/javascript, */*; q=0.01"), null)
                .flatMap(getResponseData)
                .flatMap(stringToJson);
    }
Get the result of a GET HTTP request returning a JSON body.

@param uri    the base URI of the GET HTTP request
@param params the query parameters, or {@code null} if there are none
@return a Single with a JSON object if the request was successful and the body could be decoded, an error otherwise
main/src/main/java/cgeo/geocaching/network/Network.java