io.soabase.web.assets.InternalAssetServlet.java Source code

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Here is the source code for io.soabase.web.assets.InternalAssetServlet.java

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/**
 * Copyright 2016 Jordan Zimmerman
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.soabase.web.assets;

import com.github.jknack.handlebars.Handlebars;
import com.github.jknack.handlebars.Template;
import com.github.jknack.handlebars.helper.StringHelpers;
import com.google.common.base.Charsets;
import com.google.common.collect.Maps;
import com.google.common.io.CharStreams;
import com.google.common.io.Files;
import com.google.common.net.MediaType;
import io.dropwizard.servlets.assets.AssetServlet;
import io.dropwizard.setup.Environment;
import io.soabase.web.config.WebConfiguration;
import io.soabase.web.context.ContextCache;
import io.soabase.web.context.ContextFactory;
import io.soabase.web.language.RequestLanguage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.io.StringReader;
import java.net.URL;
import java.util.concurrent.ConcurrentMap;

public class InternalAssetServlet extends AssetServlet {
    private final Logger log = LoggerFactory.getLogger(getClass());
    private final WebConfiguration configuration;
    private final RequestLanguage requestLanguage;
    private final Handlebars handlebars;
    private final ConcurrentMap<String, Template> templateCache = Maps.newConcurrentMap();
    private final WebTemplateLoader templateLoader;
    private final ContextCache contextCache;

    public InternalAssetServlet(WebConfiguration configuration, ContextFactory contextFactory,
            RequestLanguage requestLanguage, Environment environment) {
        super("/", configuration.uriPath, configuration.defaultFile.substring(1), Charsets.UTF_8);
        this.configuration = configuration;
        this.requestLanguage = requestLanguage;

        File assetsFile;
        try {
            assetsFile = configuration.assetsFile.getCanonicalFile();
            if (!assetsFile.exists()) {
                throw new RuntimeException("File doesn't exist: " + assetsFile);
            }
        } catch (IOException e) {
            throw new RuntimeException("Could not resolve: " + configuration.assetsFile);
        }
        templateLoader = assetsFile.isFile() ? new WebZipTemplateLoader(configuration, assetsFile)
                : new WebFileTemplateLoader(configuration, assetsFile);
        handlebars = new Handlebars(templateLoader);
        StringHelpers.register(handlebars);
        handlebars.registerHelper("concat", new ConcatHelper(this::getTemplate));

        contextCache = new ContextCache(contextFactory, assetsFile, configuration.textDir, configuration.debug,
                configuration.modelCache.build(environment));
    }

    public Handlebars getHandlebars() {
        return handlebars;
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String path = pathFromRequest(request);
        String pathExtension = Files.getFileExtension(path);
        if (configuration.templateExtensions.contains(pathExtension)) {
            serveTemplate(request, response, path);
        } else {
            super.doGet(request, response);
        }
    }

    protected String pathFromRequest(HttpServletRequest request) {
        return (request.getPathInfo() != null) ? request.getPathInfo() : configuration.defaultFile;
    }

    private void serveTemplate(HttpServletRequest request, HttpServletResponse response, String path) {
        try {
            Template template = getTemplate(path);
            String content = template
                    .apply(contextCache.getContext(request, requestLanguage.getLanguageCode(request)));
            String mimeTypeOfExtension = request.getServletContext().getMimeType(request.getRequestURI());
            MediaType mediaType = MediaType.parse(mimeTypeOfExtension);
            response.setContentType(mediaType.type() + '/' + mediaType.subtype());
            if (mediaType.type().equals("text") || mediaType.subtype().equals("javascript")) {
                response.setCharacterEncoding(Charsets.UTF_8.name());
            }
            response.setContentLength(content.length());
            CharStreams.copy(new StringReader(content), response.getWriter());
        } catch (Exception e) {
            log.error("Could not serve template: " + path, e);
        }
    }

    private Template getTemplate(String path) {
        return configuration.debug ? compile(path) : templateCache.computeIfAbsent(path, key -> compile(path));
    }

    private Template compile(String path) {
        try {
            return handlebars.compile(path.substring(1));
        } catch (IOException e) {
            throw new RuntimeException("Could not compile: " + path, e);
        }
    }

    @Override
    protected URL getResourceUrl(String absoluteRequestedResourcePath) {
        return templateLoader.getResourceUrl(absoluteRequestedResourcePath);
    }
}