/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.sling.servlets.get.impl.helpers;
import java.io.IOException;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.lang.StringUtils;
import org.apache.sling.api.SlingException;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.resource.ResourceNotFoundException;
import org.apache.sling.api.resource.ResourceUtil;
import org.apache.sling.api.servlets.SlingSafeMethodsServlet;
import org.apache.sling.commons.json.JSONException;
import org.apache.sling.commons.json.io.JSONRenderer;
import org.apache.sling.commons.json.io.JSONWriter;
import org.apache.sling.commons.json.sling.ResourceTraversor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The <code>JsonRendererServlet</code> renders the current resource in JSON
* on behalf of the {@link org.apache.sling.servlets.get.impl.DefaultGetServlet}.
*/
public class JsonRendererServlet extends SlingSafeMethodsServlet {
private final Logger log = LoggerFactory.getLogger(JsonRendererServlet.class);
private static final long serialVersionUID = 5577121546674133317L;
public static final String EXT_JSON = "json";
/** Recursion level selector that means "all levels" */
public static final String INFINITY = "infinity";
/** Selector that means "pretty-print the output */
public static final String TIDY = "tidy";
/** Selector that causes hierarchy to be rendered as arrays
* instead of child objects - useful to preserve the order of those
* child objects */
public static final String HARRAY = "harray";
/** How much to indent in tidy mode */
public static final int INDENT_SPACES = 2;
private long maximumResults;
private final JSONRenderer renderer = new JSONRenderer();
public JsonRendererServlet(long maximumResults) {
this.maximumResults = maximumResults;
}
@Override
protected void doGet(SlingHttpServletRequest req,
SlingHttpServletResponse resp) throws IOException {
// Access and check our data
final Resource r = req.getResource();
if (ResourceUtil.isNonExistingResource(r)) {
throw new ResourceNotFoundException("No data to render.");
}
int maxRecursionLevels = 0;
try {
maxRecursionLevels = getMaxRecursionLevel(req);
} catch(IllegalArgumentException iae) {
resp.sendError(HttpServletResponse.SC_BAD_REQUEST, iae.getMessage());
return;
}
resp.setContentType(req.getResponseContentType());
resp.setCharacterEncoding("UTF-8");
// We check the tree to see if the nr of nodes isn't bigger than the allowed nr.
boolean allowDump = true;
int allowedLevel = 0;
final boolean tidy = isTidy(req);
final boolean harray = hasSelector(req, HARRAY);
ResourceTraversor traversor = null;
try {
traversor = new ResourceTraversor(maxRecursionLevels, maximumResults, r, tidy);
allowedLevel = traversor.collectResources();
if ( allowedLevel != -1 ) {
allowDump = false;
}
} catch (final JSONException e) {
reportException(e);
}
try {
// Dump the resource if we can
if (allowDump) {
if (tidy || harray) {
final JSONRenderer.Options opt = renderer.options()
.withIndent(tidy ? INDENT_SPACES : 0)
.withArraysForChildren(harray);
resp.getWriter().write(renderer.prettyPrint(traversor.getJSONObject(), opt));
} else {
// If no rendering options, use the plain toString() method, for
// backwards compatibility. Output might be slightly different
// with prettyPrint and no options
resp.getWriter().write(traversor.getJSONObject().toString());
}
} else {
// We are not allowed to do the dump.
// Send a 300
String tidyUrl = (tidy) ? "tidy." : "";
resp.setStatus(HttpServletResponse.SC_MULTIPLE_CHOICES);
JSONWriter writer = new JSONWriter(resp.getWriter());
writer.array();
while (allowedLevel >= 0) {
writer.value(r.getResourceMetadata().getResolutionPath() + "." + tidyUrl + allowedLevel + ".json");
allowedLevel--;
}
writer.endArray();
}
} catch (JSONException je) {
reportException(je);
}
}
/** Get recursion level from selectors. as per SLING-167:
* the last selector, if present, gives the recursion
* level.
*/
protected int getMaxRecursionLevel(SlingHttpServletRequest req) throws IllegalArgumentException {
int maxRecursionLevels = 0;
final String[] selectors = req.getRequestPathInfo().getSelectors();
if (selectors != null && selectors.length > 0) {
final String level = selectors[selectors.length - 1];
if(!TIDY.equals(level) && !HARRAY.equals(level)) {
if (INFINITY.equals(level)) {
maxRecursionLevels = -1;
} else {
try {
maxRecursionLevels = Integer.parseInt(level);
} catch (NumberFormatException nfe) {
//SLING-2324
if (StringUtils.isNumeric(level)){
maxRecursionLevels = -1;
} else {
throw new IllegalArgumentException("Invalid recursion selector value '" + level + "'");
}
}
}
}
}
return maxRecursionLevels;
}
/** True if our request has the given selector */
protected boolean hasSelector(SlingHttpServletRequest req, String selectorToCheck) {
for(String selector : req.getRequestPathInfo().getSelectors()) {
if(selectorToCheck.equals(selector)) {
return true;
}
}
return false;
}
/** True if our request wants the "tidy" pretty-printed format */
protected boolean isTidy(SlingHttpServletRequest req) {
return hasSelector(req, TIDY);
}
/**
* @param e
* @throws SlingException wrapping the given exception
*/
private void reportException(Exception e) {
log.warn("Error in JsonRendererServlet: " + e.toString(), e);
throw new SlingException(e.toString(), e);
}
}