plugins/org.eclipse.sirius.server.frontend.workflow/src/org/eclipse/sirius/server/frontend/workflow/internal/SiriusServerWorkflowFrontendConfigurator.java

/*******************************************************************************
 * Copyright (c) 2018 Obeo.
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *    Obeo - initial API and implementation
 *******************************************************************************/
package org.eclipse.sirius.server.frontend.workflow.internal;

import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.util.EnumSet;

import javax.servlet.DispatcherType;

import org.eclipse.core.runtime.FileLocator;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.URIUtil;
import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.handler.HandlerCollection;
import org.eclipse.jetty.servlet.DefaultServlet;
import org.eclipse.jetty.servlet.ServletContextHandler;
import org.eclipse.jetty.servlet.ServletHolder;
import org.eclipse.sirius.server.api.ISiriusServerConfigurator;
import org.osgi.framework.Bundle;

/**
 * The entry point of the workflow front-end used to configure the Sirius server.
 *
 * @author sbegaudeau
 */
public class SiriusServerWorkflowFrontendConfigurator implements ISiriusServerConfigurator {

    /**
     * The context path of the Sirius front-end.
     */
    private static final String CONTEXT_PATH = "/workflow"; //$NON-NLS-1$

    /**
     * The default servlet holder name.
     */
    private static final String SERVLET_HOLDER_NAME = "SiriusWorkflowFrontendServletHolder"; //$NON-NLS-1$

    /**
     * The path of the front end resources.
     */
    private static final String FRONTEND_RESOURCES_PATH = "./workflow-frontend"; //$NON-NLS-1$

    /**
     * The path of the default servlet used to expose the static resources.
     */
    private static final String SERVLET_PATH = "/"; //$NON-NLS-1$

    @Override
    public void configure(Server server) {
        ServletContextHandler servletContextHandler = new ServletContextHandler(ServletContextHandler.SESSIONS | ServletContextHandler.GZIP);
        servletContextHandler.setContextPath(CONTEXT_PATH);

        servletContextHandler.addFilter(SiriusServerWorkflowFrontendFilter.class, "/*", EnumSet.of(DispatcherType.REQUEST, DispatcherType.INCLUDE)); //$NON-NLS-1$

        try {
            Bundle bundle = SiriusServerWorkflowFrontendPlugin.getPlugin().getBundle();
            URL frontendResourcesURL = bundle.getResource(FRONTEND_RESOURCES_PATH);
            URL resolvedURL = FileLocator.resolve(frontendResourcesURL);
            URI frontendResourcesURI = URIUtil.toURI(resolvedURL);
            String frontendResourcesPath = new File(frontendResourcesURI).getAbsolutePath();

            ServletHolder servletHolder = new ServletHolder(SERVLET_HOLDER_NAME, new DefaultServlet());
            servletHolder.setInitParameter("resourceBase", frontendResourcesPath); //$NON-NLS-1$
            servletHolder.setInitParameter("dirAllowed", "false"); //$NON-NLS-1$ //$NON-NLS-2$
            servletContextHandler.addServlet(servletHolder, SERVLET_PATH);

            Handler handler = server.getHandler();
            if (handler instanceof HandlerCollection) {
                HandlerCollection handlerCollection = (HandlerCollection) handler;
                handlerCollection.addHandler(servletContextHandler);
            }
        } catch (URISyntaxException | IOException exception) {
            IStatus status = new Status(IStatus.ERROR, SiriusServerWorkflowFrontendPlugin.PLUGIN_ID, exception.getMessage(), exception);
            SiriusServerWorkflowFrontendPlugin.getPlugin().log(status);
        }
    }
}