-
Notifications
You must be signed in to change notification settings - Fork 1.3k
/
FeedServlet.java
436 lines (400 loc) · 15.2 KB
/
FeedServlet.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
/**
* The contents of this file are subject to the license and copyright
* detailed in the LICENSE and NOTICE files at the root of the source
* tree and available online at
*
* http://www.dspace.org/license/
*/
package org.dspace.app.webui.servlet;
import java.io.IOException;
import java.sql.SQLException;
import java.text.MessageFormat;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.ResourceBundle;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.Logger;
import org.dspace.app.util.SyndicationFeed;
import org.dspace.app.webui.util.JSPManager;
import org.dspace.authorize.AuthorizeException;
import org.dspace.authorize.AuthorizeManager;
import org.dspace.browse.BrowseEngine;
import org.dspace.browse.BrowseException;
import org.dspace.browse.BrowseIndex;
import org.dspace.browse.BrowseInfo;
import org.dspace.browse.BrowserScope;
import org.dspace.sort.SortOption;
import org.dspace.sort.SortException;
import org.dspace.content.Collection;
import org.dspace.content.Community;
import org.dspace.content.DCDate;
import org.dspace.content.DSpaceObject;
import org.dspace.content.Item;
import org.dspace.core.ConfigurationManager;
import org.dspace.core.Constants;
import org.dspace.core.Context;
import org.dspace.core.LogManager;
import org.dspace.handle.HandleManager;
import org.dspace.search.Harvest;
import org.dspace.eperson.Group;
import com.sun.syndication.io.FeedException;
/**
* Servlet for handling requests for a syndication feed. The Handle of the collection
* or community is extracted from the URL, e.g: <code>/feed/rss_1.0/1234/5678</code>.
* Currently supports only RSS feed formats.
*
* @author Ben Bosman, Richard Rodgers
* @version $Revision$
*/
public class FeedServlet extends DSpaceServlet
{
// key for site-wide feed
public static final String SITE_FEED_KEY = "site";
// one hour in milliseconds
private static final long HOUR_MSECS = 60 * 60 * 1000;
/** log4j category */
private static Logger log = Logger.getLogger(FeedServlet.class);
private String clazz = "org.dspace.app.webui.servlet.FeedServlet";
// are syndication feeds enabled?
private static boolean enabled = false;
// number of DSpace items per feed
private static int itemCount = 0;
// optional cache of feeds
private static Map<String, CacheFeed> feedCache = null;
// maximum size of cache - 0 means caching disabled
private static int cacheSize = 0;
// how many days to keep a feed in cache before checking currency
private static int cacheAge = 0;
// supported syndication formats
private static List<String> formats = null;
// Whether to include private items or not
private static boolean includeAll = true;
static
{
enabled = ConfigurationManager.getBooleanProperty("webui.feed.enable");
// read rest of config info if enabled
if (enabled)
{
String fmtsStr = ConfigurationManager.getProperty("webui.feed.formats");
if ( fmtsStr != null )
{
formats = new ArrayList<String>();
String[] fmts = fmtsStr.split(",");
for (int i = 0; i < fmts.length; i++)
{
formats.add(fmts[i]);
}
}
itemCount = ConfigurationManager.getIntProperty("webui.feed.items");
cacheSize = ConfigurationManager.getIntProperty("webui.feed.cache.size");
if (cacheSize > 0)
{
feedCache = new HashMap<String, CacheFeed>();
cacheAge = ConfigurationManager.getIntProperty("webui.feed.cache.age");
}
}
}
protected void doDSGet(Context context, HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException,
SQLException, AuthorizeException
{
includeAll = ConfigurationManager.getBooleanProperty("harvest.includerestricted.rss", true);
String path = request.getPathInfo();
String feedType = null;
String handle = null;
// build label map from localized Messages resource bundle
Locale locale = request.getLocale();
ResourceBundle msgs = ResourceBundle.getBundle("Messages", locale);
Map<String, String> labelMap = new HashMap<String, String>();
labelMap.put(SyndicationFeed.MSG_UNTITLED, msgs.getString(clazz + ".notitle"));
labelMap.put(SyndicationFeed.MSG_LOGO_TITLE, msgs.getString(clazz + ".logo.title"));
labelMap.put(SyndicationFeed.MSG_FEED_DESCRIPTION, msgs.getString(clazz + ".general-feed.description"));
labelMap.put(SyndicationFeed.MSG_UITYPE, SyndicationFeed.UITYPE_JSPUI);
for (String selector : SyndicationFeed.getDescriptionSelectors())
{
labelMap.put("metadata." + selector, msgs.getString(SyndicationFeed.MSG_METADATA + selector));
}
if (path != null)
{
// substring(1) is to remove initial '/'
path = path.substring(1);
int split = path.indexOf('/');
if (split != -1)
{
feedType = path.substring(0,split);
handle = path.substring(split+1);
}
}
DSpaceObject dso = null;
//as long as this is not a site wide feed,
//attempt to retrieve the Collection or Community object
if(handle != null && !handle.equals(SITE_FEED_KEY))
{
// Determine if handle is a valid reference
dso = HandleManager.resolveToObject(context, handle);
if (dso == null)
{
log.info(LogManager.getHeader(context, "invalid_handle", "path=" + path));
JSPManager.showInvalidIDError(request, response, handle, -1);
return;
}
}
if (! enabled || (dso != null &&
(dso.getType() != Constants.COLLECTION && dso.getType() != Constants.COMMUNITY)) )
{
log.info(LogManager.getHeader(context, "invalid_id", "path=" + path));
JSPManager.showInvalidIDError(request, response, path, -1);
return;
}
// Determine if requested format is supported
if( feedType == null || ! formats.contains( feedType ) )
{
log.info(LogManager.getHeader(context, "invalid_syndformat", "path=" + path));
JSPManager.showInvalidIDError(request, response, path, -1);
return;
}
if (dso != null && dso.getType() == Constants.COLLECTION)
{
labelMap.put(SyndicationFeed.MSG_FEED_TITLE,
MessageFormat.format(msgs.getString(clazz + ".feed.title"),
new Object[]{ msgs.getString(clazz + ".feed-type.collection"),
((Collection)dso).getMetadata("short_description")}));
}
else if (dso != null && dso.getType() == Constants.COMMUNITY)
{
labelMap.put(SyndicationFeed.MSG_FEED_TITLE,
MessageFormat.format(msgs.getString(clazz + ".feed.title"),
new Object[]{ msgs.getString(clazz + ".feed-type.community"),
((Community)dso).getMetadata("short_description")}));
}
// Lookup or generate the feed
// Cache key is handle + locale
String cacheKey = (handle==null?"site":handle)+"."+locale.toString();
SyndicationFeed feed = null;
if (feedCache != null)
{
CacheFeed cFeed = feedCache.get(cacheKey);
if (cFeed != null) // cache hit, but...
{
// Is the feed current?
boolean cacheFeedCurrent = false;
if (cFeed.timeStamp + (cacheAge * HOUR_MSECS) < System.currentTimeMillis())
{
cacheFeedCurrent = true;
}
// Not current, but have any items changed since feed was created/last checked?
else if ( ! itemsChanged(context, dso, cFeed.timeStamp))
{
// no items have changed, re-stamp feed and use it
cFeed.timeStamp = System.currentTimeMillis();
cacheFeedCurrent = true;
}
if (cacheFeedCurrent)
{
feed = cFeed.access();
}
}
}
// either not caching, not found in cache, or feed in cache not current
if (feed == null)
{
feed = new SyndicationFeed(SyndicationFeed.UITYPE_JSPUI);
feed.populate(request, dso, getItems(context, dso), labelMap);
if (feedCache != null)
{
cache(cacheKey, new CacheFeed(feed));
}
}
// set the feed to the requested type & return it
try
{
feed.setType(feedType);
response.setContentType("text/xml; charset=UTF-8");
feed.output(response.getWriter());
}
catch( FeedException fex )
{
throw new IOException(fex.getMessage(), fex);
}
}
private boolean itemsChanged(Context context, DSpaceObject dso, long timeStamp)
throws SQLException
{
// construct start and end dates
DCDate dcStartDate = new DCDate( new Date(timeStamp) );
DCDate dcEndDate = new DCDate( new Date(System.currentTimeMillis()) );
// convert dates to ISO 8601, stripping the time
String startDate = dcStartDate.toString().substring(0, 10);
String endDate = dcEndDate.toString().substring(0, 10);
// this invocation should return a non-empty list if even 1 item has changed
try {
return (Harvest.harvest(context, dso, startDate, endDate,
0, 1, !includeAll, false, false, includeAll).size() > 0);
}
catch (ParseException pe)
{
// This should never get thrown as we have generated the dates ourselves
return false;
}
}
// returns recently changed items, checking for accessibility
private Item[] getItems(Context context, DSpaceObject dso)
throws IOException, SQLException
{
try
{
// new method of doing the browse:
String idx = ConfigurationManager.getProperty("recent.submissions.sort-option");
if (idx == null)
{
throw new IOException("There is no configuration supplied for: recent.submissions.sort-option");
}
BrowseIndex bix = BrowseIndex.getItemBrowseIndex();
if (bix == null)
{
throw new IOException("There is no browse index with the name: " + idx);
}
BrowserScope scope = new BrowserScope(context);
scope.setBrowseIndex(bix);
if (dso != null)
{
scope.setBrowseContainer(dso);
}
for (SortOption so : SortOption.getSortOptions())
{
if (so.getName().equals(idx))
{
scope.setSortBy(so.getNumber());
}
}
scope.setOrder(SortOption.DESCENDING);
scope.setResultsPerPage(itemCount);
// gather & add items to the feed.
BrowseEngine be = new BrowseEngine(context);
BrowseInfo bi = be.browseMini(scope);
Item[] results = bi.getItemResults(context);
if (includeAll)
{
return results;
}
else
{
// Check to see if we can include this item
//Group[] authorizedGroups = AuthorizeManager.getAuthorizedGroups(context, results[i], Constants.READ);
//boolean added = false;
List<Item> items = new ArrayList<Item>();
for (Item result : results)
{
checkAccess:
for (Group group : AuthorizeManager.getAuthorizedGroups(context, result, Constants.READ))
{
if ((group.getID() == Group.ANONYMOUS_ID))
{
items.add(result);
break checkAccess;
}
}
}
return items.toArray(new Item[items.size()]);
}
}
catch (SortException se)
{
log.error("caught exception: ", se);
throw new IOException(se.getMessage(), se);
}
catch (BrowseException e)
{
log.error("caught exception: ", e);
throw new IOException(e.getMessage(), e);
}
}
/************************************************
* private cache management classes and methods *
************************************************/
/**
* Add a feed to the cache - reducing the size of the cache by 1 to make room if
* necessary. The removed entry has an access count equal to the minumum in the cache.
* @param feedKey
* The cache key for the feed
* @param newFeed
* The CacheFeed feed to be cached
*/
private static void cache(String feedKey, CacheFeed newFeed)
{
// remove older feed to make room if cache full
if (feedCache.size() >= cacheSize)
{
// cache profiling data
int total = 0;
String minKey = null;
CacheFeed minFeed = null;
CacheFeed maxFeed = null;
Iterator<String> iter = feedCache.keySet().iterator();
while (iter.hasNext())
{
String key = iter.next();
CacheFeed feed = feedCache.get(key);
if (minKey != null)
{
if (feed.hits < minFeed.hits)
{
minKey = key;
minFeed = feed;
}
if (feed.hits >= maxFeed.hits)
{
maxFeed = feed;
}
}
else
{
minKey = key;
minFeed = feed;
maxFeed = feed;
}
total += feed.hits;
}
// log a profile of the cache to assist administrator in tuning it
int avg = total / feedCache.size();
String logMsg = "feedCache() - size: " + feedCache.size() +
" Hits - total: " + total + " avg: " + avg +
" max: " + maxFeed.hits + " min: " + minFeed.hits;
log.info(logMsg);
// remove minimum hits entry
feedCache.remove(minKey);
}
// add feed to cache
feedCache.put(feedKey, newFeed);
}
/**
* Class to instrument accesses & currency of a given feed in cache
*/
private static class CacheFeed
{
// currency timestamp
public long timeStamp = 0L;
// access count
public int hits = 0;
// the feed
private SyndicationFeed feed = null;
public CacheFeed(SyndicationFeed feed)
{
this.feed = feed;
timeStamp = System.currentTimeMillis();
}
public SyndicationFeed access()
{
++hits;
return feed;
}
}
}