src/main/java/net/pterodactylus/sone/web/ajax/JsonPage.java

   1 /*
   2  * Sone - JsonPage.java - Copyright © 2010–2013 David Roden
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 package net.pterodactylus.sone.web.ajax;
  19
  20 import static java.util.logging.Logger.getLogger;
  21
  22 import java.io.ByteArrayOutputStream;
  23 import java.io.IOException;
  24 import java.io.OutputStreamWriter;
  25 import java.io.PrintWriter;
  26 import java.net.URI;
  27 import java.util.logging.Level;
  28 import java.util.logging.Logger;
  29
  30 import net.pterodactylus.sone.data.LocalSone;
  31 import net.pterodactylus.sone.web.WebInterface;
  32 import net.pterodactylus.sone.web.page.FreenetPage;
  33 import net.pterodactylus.sone.web.page.FreenetRequest;
  34 import net.pterodactylus.util.io.Closer;
  35 import net.pterodactylus.util.web.Page;
  36 import net.pterodactylus.util.web.Response;
  37
  38 import com.fasterxml.jackson.databind.ObjectMapper;
  39 import com.google.common.base.Optional;
  40
  41 import freenet.clients.http.ToadletContext;
  42
  43 /**
  44  * A JSON page is a specialized {@link Page} that will always return a JSON
  45  * object to the browser, e.g. for use with AJAX or other scripting frameworks.
  46  *
  47  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  48  */
  49 public abstract class JsonPage implements FreenetPage {
  50
  51         /** The logger. */
  52         private static final Logger logger = getLogger("Sone.Web.Ajax");
  53
  54         /** The JSON serializer. */
  55         private static final ObjectMapper objectMapper = new ObjectMapper();
  56
  57         /** The path of the page. */
  58         private final String path;
  59
  60         /** The Sone web interface. */
  61         protected final WebInterface webInterface;
  62
  63         /**
  64          * Creates a new JSON page at the given path.
  65          *
  66          * @param path
  67          *            The path of the page
  68          * @param webInterface
  69          *            The Sone web interface
  70          */
  71         public JsonPage(String path, WebInterface webInterface) {
  72                 this.path = path;
  73                 this.webInterface = webInterface;
  74         }
  75
  76         //
  77         // ACCESSORS
  78         //
  79
  80         protected Optional<LocalSone> getCurrentSone(ToadletContext toadletContext) {
  81                 return webInterface.getCurrentSone(toadletContext);
  82         }
  83
  84         protected Optional<LocalSone> getCurrentSone(ToadletContext toadletContext, boolean createSession) {
  85                 return webInterface.getCurrentSone(toadletContext, createSession);
  86         }
  87
  88         //
  89         // METHODS FOR SUBCLASSES TO OVERRIDE
  90         //
  91
  92         /**
  93          * This method is called to create the JSON object that is returned back to
  94          * the browser.
  95          *
  96          * @param request
  97          *            The request to handle
  98          * @return The created JSON object
  99          */
 100         protected abstract JsonReturnObject createJsonObject(FreenetRequest request);
 101
 102         /**
 103          * Returns whether this command needs the form password for authentication
 104          * and to prevent abuse.
 105          *
 106          * @return {@code true} if the form password (given as “formPassword”) is
 107          *         required, {@code false} otherwise
 108          */
 109         @SuppressWarnings("static-method")
 110         protected boolean needsFormPassword() {
 111                 return true;
 112         }
 113
 114         /**
 115          * Returns whether this page requires the user to be logged in.
 116          *
 117          * @return {@code true} if the user needs to be logged in to use this page,
 118          *         {@code false} otherwise
 119          */
 120         @SuppressWarnings("static-method")
 121         protected boolean requiresLogin() {
 122                 return true;
 123         }
 124
 125         //
 126         // PROTECTED METHODS
 127         //
 128
 129         /**
 130          * Creates a success reply.
 131          *
 132          * @return A reply signaling success
 133          */
 134         protected static JsonReturnObject createSuccessJsonObject() {
 135                 return new JsonReturnObject(true);
 136         }
 137
 138         /**
 139          * Creates an error reply.
 140          *
 141          * @param error
 142          *            The error that has occured
 143          * @return The JSON object, signalling failure and the error code
 144          */
 145         protected static JsonReturnObject createErrorJsonObject(String error) {
 146                 return new JsonErrorReturnObject(error);
 147         }
 148
 149         //
 150         // PAGE METHODS
 151         //
 152
 153         /**
 154          * {@inheritDoc}
 155          */
 156         @Override
 157         public String getPath() {
 158                 return path;
 159         }
 160
 161         /**
 162          * {@inheritDoc}
 163          */
 164         @Override
 165         public boolean isPrefixPage() {
 166                 return false;
 167         }
 168
 169         /**
 170          * {@inheritDoc}
 171          */
 172         @Override
 173         public Response handleRequest(FreenetRequest request, Response response) throws IOException {
 174                 if (webInterface.getCore().getPreferences().isRequireFullAccess() && !request.getToadletContext().isAllowedFullAccess()) {
 175                         return response.setStatusCode(403).setStatusText("Forbidden").setContentType("application/json").write(objectMapper.writeValueAsString(new JsonErrorReturnObject("auth-required")));
 176                 }
 177                 if (needsFormPassword()) {
 178                         String formPassword = request.getHttpRequest().getParam("formPassword");
 179                         if (!webInterface.getFormPassword().equals(formPassword)) {
 180                                 return response.setStatusCode(403).setStatusText("Forbidden").setContentType("application/json").write(objectMapper.writeValueAsString(new JsonErrorReturnObject("auth-required")));
 181                         }
 182                 }
 183                 if (requiresLogin()) {
 184                         if (!getCurrentSone(request.getToadletContext(), false).isPresent()) {
 185                                 return response.setStatusCode(403).setStatusText("Forbidden").setContentType("application/json").write(objectMapper.writeValueAsString(new JsonErrorReturnObject("auth-required")));
 186                         }
 187                 }
 188                 try {
 189                         JsonReturnObject jsonObject = createJsonObject(request);
 190                         return response.setStatusCode(200).setStatusText("OK").setContentType("application/json").write(objectMapper.writeValueAsString(jsonObject));
 191                 } catch (Exception e1) {
 192                         logger.log(Level.WARNING, "Error executing JSON page!", e1);
 193                         return response.setStatusCode(500).setStatusText(e1.getMessage()).setContentType("text/plain").write(dumpStackTrace(e1));
 194                 }
 195         }
 196
 197         /**
 198          * {@inheritDoc}
 199          */
 200         @Override
 201         public boolean isLinkExcepted(URI link) {
 202                 return false;
 203         }
 204
 205         //
 206         // PRIVATE METHODS
 207         //
 208
 209         /**
 210          * Returns a byte array containing the stack trace of the given throwable.
 211          *
 212          * @param t
 213          *            The throwable whose stack trace to dump into an array
 214          * @return The array with the stack trace, or an empty array if the stack
 215          *         trace could not be dumped
 216          */
 217         private static byte[] dumpStackTrace(Throwable t) {
 218                 ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
 219                 OutputStreamWriter writer = null;
 220                 PrintWriter printWriter = null;
 221                 try {
 222                         writer = new OutputStreamWriter(byteArrayOutputStream, "uTF-8");
 223                         printWriter = new PrintWriter(writer);
 224                         t.printStackTrace(printWriter);
 225                         byteArrayOutputStream.flush();
 226                         return byteArrayOutputStream.toByteArray();
 227                 } catch (IOException ioe1) {
 228                         /* quite not possible. */
 229                         return new byte[0];
 230                 } finally {
 231                         Closer.close(printWriter);
 232                         Closer.close(writer);
 233                         Closer.close(byteArrayOutputStream);
 234                 }
 235         }
 236
 237 }