WebConfigurer.java

package com.worktajm.config;

import com.codahale.metrics.MetricRegistry;
import com.codahale.metrics.servlet.InstrumentedFilter;
import com.codahale.metrics.servlets.MetricsServlet;
import com.hazelcast.core.HazelcastInstance;
import com.worktajm.web.filter.CachingHttpHeadersFilter;
import com.worktajm.web.filter.StaticResourcesProductionFilter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer;
import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
import org.springframework.boot.context.embedded.MimeMappings;
import org.springframework.boot.context.embedded.ServletContextInitializer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
import org.springframework.web.filter.CorsFilter;

import java.util.*;
import javax.inject.Inject;
import javax.servlet.*;

/**
 * Configuration of web application with Servlet 3.0 APIs.
 */
@Configuration
public class WebConfigurer implements ServletContextInitializer, EmbeddedServletContainerCustomizer {

    private final Logger log = LoggerFactory.getLogger(WebConfigurer.class);

    @Inject
    private Environment env;

    @Inject
    private JHipsterProperties props;

    @Autowired(required = false)
    private MetricRegistry metricRegistry;

    // Hazelcast instance is injected to force its initialization before the Servlet filter uses it.
    @Inject
    private HazelcastInstance hazelcastInstance;

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        log.info("Web application configuration, using profiles: {}", Arrays.toString(env.getActiveProfiles()));
        EnumSet<DispatcherType> disps = EnumSet.of(DispatcherType.REQUEST, DispatcherType.FORWARD, DispatcherType.ASYNC);
        if (!env.acceptsProfiles(Constants.SPRING_PROFILE_FAST)) {
            initMetrics(servletContext, disps);
        }
        if (env.acceptsProfiles(Constants.SPRING_PROFILE_PRODUCTION)) {
            initCachingHttpHeadersFilter(servletContext, disps);
            initStaticResourcesProductionFilter(servletContext, disps);
        }
        if (env.acceptsProfiles(Constants.SPRING_PROFILE_DEVELOPMENT)) {
            initH2Console(servletContext);
        }
        log.info("Web application fully configured");
    }

    /**
     * Set up Mime types.
     */
    @Override
    public void customize(ConfigurableEmbeddedServletContainer container) {
        MimeMappings mappings = new MimeMappings(MimeMappings.DEFAULT);
        // IE issue, see https://github.com/jhipster/generator-jhipster/pull/711
        mappings.add("html", "text/html;charset=utf-8");
        // CloudFoundry issue, see https://github.com/cloudfoundry/gorouter/issues/64
        mappings.add("json", "text/html;charset=utf-8");
        container.setMimeMappings(mappings);
    }

    /**
     * Initializes the static resources production Filter.
     */
    private void initStaticResourcesProductionFilter(ServletContext servletContext,
                                                     EnumSet<DispatcherType> disps) {

        log.debug("Registering static resources production Filter");
        FilterRegistration.Dynamic staticResourcesProductionFilter =
            servletContext.addFilter("staticResourcesProductionFilter",
                new StaticResourcesProductionFilter());

        staticResourcesProductionFilter.addMappingForUrlPatterns(disps, true, "/");
        staticResourcesProductionFilter.addMappingForUrlPatterns(disps, true, "/index.html");
        staticResourcesProductionFilter.addMappingForUrlPatterns(disps, true, "/assets/*");
        staticResourcesProductionFilter.addMappingForUrlPatterns(disps, true, "/scripts/*");
        staticResourcesProductionFilter.setAsyncSupported(true);
    }

    /**
     * Initializes the caching HTTP Headers Filter.
     */
    private void initCachingHttpHeadersFilter(ServletContext servletContext,
                                              EnumSet<DispatcherType> disps) {
        log.debug("Registering Caching HTTP Headers Filter");
        FilterRegistration.Dynamic cachingHttpHeadersFilter =
            servletContext.addFilter("cachingHttpHeadersFilter",
                new CachingHttpHeadersFilter(env));

        cachingHttpHeadersFilter.addMappingForUrlPatterns(disps, true, "/dist/assets/*");
        cachingHttpHeadersFilter.addMappingForUrlPatterns(disps, true, "/dist/scripts/*");
        cachingHttpHeadersFilter.setAsyncSupported(true);
    }

    /**
     * Initializes Metrics.
     */
    private void initMetrics(ServletContext servletContext, EnumSet<DispatcherType> disps) {
        log.debug("Initializing Metrics registries");
        servletContext.setAttribute(InstrumentedFilter.REGISTRY_ATTRIBUTE,
            metricRegistry);
        servletContext.setAttribute(MetricsServlet.METRICS_REGISTRY,
            metricRegistry);

        log.debug("Registering Metrics Filter");
        FilterRegistration.Dynamic metricsFilter = servletContext.addFilter("webappMetricsFilter",
            new InstrumentedFilter());

        metricsFilter.addMappingForUrlPatterns(disps, true, "/*");
        metricsFilter.setAsyncSupported(true);

        log.debug("Registering Metrics Servlet");
        ServletRegistration.Dynamic metricsAdminServlet =
            servletContext.addServlet("metricsServlet", new MetricsServlet());

        metricsAdminServlet.addMapping("/metrics/metrics/*");
        metricsAdminServlet.setAsyncSupported(true);
        metricsAdminServlet.setLoadOnStartup(2);
    }

    @Bean
    public CorsFilter corsFilter() {
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        CorsConfiguration config = props.getCors();
        if (config.getAllowedOrigins() != null && !config.getAllowedOrigins().isEmpty()) {
            source.registerCorsConfiguration("/api/**", config);
            source.registerCorsConfiguration("/v2/api-docs", config);
            source.registerCorsConfiguration("/oauth/**", config);
        }
        return new CorsFilter(source);
    }

    /**
     * Initializes H2 console
     */
    private void initH2Console(ServletContext servletContext) {
        log.debug("Initialize H2 console");
        ServletRegistration.Dynamic h2ConsoleServlet = servletContext.addServlet("H2Console", new org.h2.server.web.WebServlet());
        h2ConsoleServlet.addMapping("/console/*");
        h2ConsoleServlet.setInitParameter("-properties", "src/main/resources");
        h2ConsoleServlet.setLoadOnStartup(1);
    }
}