TagsServlet.java

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/*
 * Turró i Cutiller Foundation. License notice.
 * Copyright (C) 2022 Lluis Turró Cutiller <http://www.turro.org/>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
package org.turro.elephant.web.tags;
 
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.turro.collections.KeyValueMap;
import org.turro.elephant.context.ElephantContext;
import org.turro.elephant.context.IConstructor;
import org.turro.elephant.web.ElContext;
import org.turro.elephant.web.ElContextMap;
import org.turro.marker.MarkerHelper;
import org.turro.path.Path;
import org.turro.string.Strings;
 
@WebServlet(name = "TagsEl", urlPatterns = {"/tag_/*"})
public class TagsServlet extends HttpServlet {
 
  private static final String CONTEXT_TO = "elctxnav";
  
  public static String navigateFromTo(String fromTag, String toTag) {
    return ElephantContext.getRootWebPath() + "/tag_/" + toTag + "?" + MarkerHelper.setObfuscatedPars("tag=" + fromTag);
  }
  
  public static String navigateAndSet(String fromTag, String path) {
    return ElephantContext.getRootWebPath() + "/tag_/" + CONTEXT_TO + "?" + 
            MarkerHelper.setObfuscatedPars("tag=" + fromTag + ";path=" + path);
  }
  
  public static String navigateBack(IConstructor constructor, String path) {
    if(Strings.isBlank(path)) {
      String backTag = SessionTags.get(constructor).previous();
      if(!Strings.isBlank(backTag)) {
        return ElephantContext.getRootWebPath() + "/tag_/" + backTag + "?" + 
                MarkerHelper.setObfuscatedPars("back=true");
      }
    } else {
      return ElephantContext.getRootWebPath() + "/tag_/" + CONTEXT_TO + "?" + 
              MarkerHelper.setObfuscatedPars("back=true;path=" + path);
    }
    return null;
  }
  
  protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    KeyValueMap kvm = MarkerHelper.getObfuscatedParameters(request);
    if(kvm != null) {
      if(kvm.containsKey("tag")) SessionTags.get(request, response).add(kvm.get("tag"));
      if(kvm.containsKey("back")) SessionTags.get(request, response).removeLast();
      if(kvm.containsKey("path")) {
        response.sendRedirect(request.getContextPath() + kvm.get("path"));
        return;
      }
    }
    Path path = Path.pathFrom(request.getPathInfo());
    ElContext context = ElContextMap.getContextFromWebTag(path.getRoot());
    if(context != null) {
      response.setStatus(HttpServletResponse.SC_FOUND);
      response.sendRedirect(request.getContextPath() + context.getPath());
    }
  }
 
  @Override
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    processRequest(request, response);
  }
  
  @Override
  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    processRequest(request, response);
  }
  
  @Override
  public String getServletInfo() {
    return "WebTags for Elephant";
  }
 
}