it.bz.opendatahub.alpinebits.routing.middleware.RoutingMiddleware Maven / Gradle / Ivy
// SPDX-FileCopyrightText: NOI Techpark
//
// SPDX-License-Identifier: MPL-2.0
/*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
package it.bz.opendatahub.alpinebits.routing.middleware;
import it.bz.opendatahub.alpinebits.common.context.RequestContextKey;
import it.bz.opendatahub.alpinebits.middleware.Context;
import it.bz.opendatahub.alpinebits.middleware.Middleware;
import it.bz.opendatahub.alpinebits.middleware.MiddlewareChain;
import it.bz.opendatahub.alpinebits.routing.Router;
import it.bz.opendatahub.alpinebits.routing.RouterContextKey;
import it.bz.opendatahub.alpinebits.routing.UndefinedRouteException;
import java.util.Optional;
/**
* This {@link Middleware} provides routing capabilities for AlpineBits requests.
*
* It tries to match the version and action of the
* current AlpineBits request, taken from the {@link Context}.
*
* The version information is read using the
* {@link RequestContextKey#REQUEST_VERSION} key. The action
* information is read using the {@link RequestContextKey#REQUEST_ACTION} key.
*
* If a match was found, the corresponding middleware is invoked. A
* {@link UndefinedRouteException} is thrown otherwise.
*
* This middleware doesn't invoke {@link MiddlewareChain#next()}, i.e.
* no other middlewares will be invoked after this one.
*/
public class RoutingMiddleware implements Middleware {
private final Router router;
public RoutingMiddleware(Router router) {
if (router == null) {
throw new IllegalArgumentException("The router must not be null");
}
this.router = router;
}
@Override
public void handleContext(Context ctx, MiddlewareChain chain) {
String version = ctx.getOrThrow(RequestContextKey.REQUEST_VERSION);
String action = ctx.getOrThrow(RequestContextKey.REQUEST_ACTION);
// Try to find a middleware for the given AlpineBits version and action
Middleware middleware = this.findMiddleware(version, action);
// Add router to context, such that other middlewares may use its information
ctx.put(RouterContextKey.ALPINEBITS_ROUTER, this.router);
// Invoke middleware
middleware.handleContext(ctx, () -> {
});
}
private Middleware findMiddleware(String version, String actionRequestParam) {
Optional optional = this.router.findMiddleware(version, actionRequestParam);
if (!optional.isPresent()) {
throw new UndefinedRouteException("No route found for version " + version + " and action " + actionRequestParam);
}
return optional.get();
}
}