TemplateServlet.java

package edu.gatech.oad.rocket.findmythings.server;

import com.google.common.base.Charsets;
import edu.gatech.oad.rocket.findmythings.server.model.AppMember;
import edu.gatech.oad.rocket.findmythings.server.model.MessageBean;
import edu.gatech.oad.rocket.findmythings.server.security.ProfileRealm;
import edu.gatech.oad.rocket.findmythings.server.util.HTTP;
import edu.gatech.oad.rocket.findmythings.server.util.HTTP.Status;
import edu.gatech.oad.rocket.findmythings.server.util.MimeTypes;
import org.apache.shiro.SecurityUtils;
import org.apache.shiro.mgt.RealmSecurityManager;
import org.apache.shiro.realm.Realm;
import org.apache.shiro.subject.PrincipalCollection;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.logging.Logger;

public abstract class TemplateServlet extends HttpServlet {

	private static final long serialVersionUID = 8526927539799303725L;

	@SuppressWarnings("unused")
	private static final Logger LOGGER = Logger.getLogger(TemplateServlet.class.getName());
	
	private PageGenerator generator;

	@Override
	public void init() throws ServletException {
		super.init();
		try {
			generator = new PageGenerator(getServletContext().getResource("/WEB-INF/templates/"), Locale.getDefault(), Charsets.UTF_8);
		} catch (IOException e) {
			throw new RuntimeException(e);
		}
	}

	private static int indexOfExtension(String filename) {
		if (filename == null) {
			return -1;
		}
		int extensionPos = filename.lastIndexOf(".");
		int lastUnixPos = filename.lastIndexOf('/');
		int lastWindowsPos = filename.lastIndexOf('\\');
		return (Math.max(lastUnixPos, lastWindowsPos) > extensionPos ? -1 : extensionPos);
	}

	private static String removeExtension(String filename) {
		if (filename == null) {
			return null;
		}
		int index = indexOfExtension(filename);
		if (index == -1) {
			return filename;
		} else {
			return filename.substring(0, index);
		}
	}

	private static String replaceExtensionWith(String filename, String extension) {
		return removeExtension(filename) + "." + extension;
	}

	protected static String getDefaultTemplateURI(HttpServletRequest request) {
		String URI = request.getRequestURI();
		if (URI.endsWith("/")) URI = URI.substring(0, URI.length() - 1);
		if (URI.length() == 0) URI = "index.html";
		return replaceExtensionWith(URI, "ftl");
	}

	protected String createDocument(String templateName, Map<String,Object> userArgs) throws IOException {
		return generator.createPage(templateName, userArgs);
	}

	protected String createDocument(String templateName, Object... args) throws IOException {
		return createDocument(templateName, PageGenerator.map(args));
	}

	protected void writeDocument(HttpServletResponse response, String templateName, Map<String,Object> args) throws IOException {
		HTTP.write(response, MimeTypes.HTML, Status.OK, createDocument(templateName, args));
	}

	protected void writeDocument(HttpServletResponse response, String templateName, Object... args) throws IOException {
		writeDocument(response, templateName, PageGenerator.map(args));
	}

	String getCurrentUserEmail() {
		PrincipalCollection principals = SecurityUtils.getSubject().getPrincipals();
		if (principals == null || principals.isEmpty()) return null;
		return (String)principals.getPrimaryPrincipal();
	}

	protected boolean memberExistsWithEmail(String email) {
		if (email == null || email.length() == 0) return false;
		RealmSecurityManager manager = (RealmSecurityManager)SecurityUtils.getSecurityManager();
		for (Realm realm : manager.getRealms()) {
			if (realm instanceof ProfileRealm) {
				if (((ProfileRealm) realm).accountExists(email)) return true;
			}
		}
		return false;
	}

	protected AppMember memberWithEmail(String email) {
		if (email == null || email.length() == 0) return null;
		RealmSecurityManager manager = (RealmSecurityManager)SecurityUtils.getSecurityManager();
		for (Realm realm : manager.getRealms()) {
			if (realm instanceof ProfileRealm) {
				AppMember potential = ((ProfileRealm) realm).getAccount(email);
				if (potential != null && potential.getEmail().equals(email)) return potential;
			}
		}

		return null;
	}

	protected final Map<String,Object> getParameterMap(HttpServletRequest request) {
		Map<String,Object> map = new HashMap<>();
		addParametersToMap(request, map);
		return map;
	}

	protected void addParametersToMap(HttpServletRequest request, Map<String, Object> params) {
		Object failureReason = request.getAttribute(MessageBean.FAILURE_REASON);
		if (failureReason != null) params.put(MessageBean.FAILURE_REASON, failureReason);
	}

}