Author: jonathan
Date: Thu Jun 26 18:06:26 2008
New Revision: 18665
URL: http://wso2.org/svn/browse/wso2?view=rev&revision=18665
Log:
Added feedCache mashup.
Added:
trunk/mashup/java/modules/samples/feedCache/
trunk/mashup/java/modules/samples/feedCache/feedCache.js
trunk/mashup/java/modules/samples/feedCache/feedCache.resources/
trunk/mashup/java/modules/samples/feedCache/feedCache.tags
- copied, changed from r18661,
/trunk/mashup/java/modules/samples/digit2image/digit2image.tags
Added: trunk/mashup/java/modules/samples/feedCache/feedCache.js
URL:
http://wso2.org/svn/browse/wso2/trunk/mashup/java/modules/samples/feedCache/feedCache.js?pathrev=18665
==============================================================================
--- (empty file)
+++ trunk/mashup/java/modules/samples/feedCache/feedCache.js Thu Jun 26
18:06:26 2008
@@ -0,0 +1,166 @@
+/*
+ * Copyright 2008 WSO2, Inc. http://www.wso2.org
+ *
+ * Licensed 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.
+
+ Created 2008-05 Jonathan Marsh; [EMAIL PROTECTED]
+
+ */
+
+this.documentation = <div>Cache feeds according to per-feed cache settings,
including whether to prefetch or not, and the lifespan of the cached
feed.</div>;
+this.init = function () {
+ // look for stuff to prefetch every 5 min
+ system.setInterval(fetch, 5*60*1000);
+}
+
+cacheSettings.documentation = <div>Set the caching properties for a feed.
+ <b>prefetch</b> determines whether the feed
should be fetched regularly in the background (true), or only on demand (false).
+ <b>lifespan</b> is the number of milliseconds
that the feed should be cached; when prefetch=true, this is the refresh
interval,
+ when prefetch=false, this is how long a cached
version should be used until it is considered stale.</div>;
+cacheSettings.inputTypes = {"feedUrl" : "xs:anyURI", "lifespan" : "number",
"prefetch" : "boolean"};
+cacheSettings.outputType = "boolean";
+function cacheSettings(feedUrl, lifespan, prefetch) {
+ // read database.
+ var cachedb = readXML("db");
+ if (cachedb == null) cachedb = <cache/>;
+
+ // if this url isn't being tracked in the cache, add it to the cache with
default settings
+ if (cachedb.feed.(@url == feedUrl).length() == 0) {
+ cachedb.appendChild(<feed url={feedUrl} prefetch="false"
lifespan={24*60*60*1000} timestamp="0" />);
+ }
+
+ // find the settings for the requested feed
+ var feedInfo = cachedb.feed.(@url == feedUrl);
+
+ // record the prefetch and lifespam settings. Only change the automatic
refresh interval if it's shorter than someone else has asked for.
+ [EMAIL PROTECTED] = prefetch;
+ if (prefetch && parseInt([EMAIL PROTECTED]) > lifespan) {
+ [EMAIL PROTECTED] = lifespan;
+ }
+
+ // save the database
+ writeXML("db", cachedb);
+
+ // force an immediate cache refresh. This should execute the prefetch on
the new feed item (and any others that are stale)
+ system.setTimeout(fetch, 1);
+
+ return true;
+}
+
+feedReference.documentation = <div>Return a local reference to a cached feed.
If the feed is stale, it will be refreshed.
+ If the feed has not been cached before, it will
be using the default settings of no prefetching, cache lifespan 24 hours.</div>;
+feedReference.inputTypes = {"feedUrl" : "xs:anyURI"};
+feedReference.outputType = "xs:anyURI";
+feedReference.safe = true;
+function feedReference(feedUrl) {
+ // read database.
+ var cachedb = readXML("db");
+ if (cachedb == null) cachedb = <cache/>;
+
+ // if this url isn't being tracked in the cache, add it to the cache with
default settings
+ if (cachedb.feed.(@url == feedUrl).length() == 0) {
+ cachedb.appendChild(<feed url={feedUrl} prefetch="false"
lifespan={24*60*60*1000} timestamp="0" />);
+ }
+
+ // find the settings for the requested feed
+ var feedInfo = cachedb.feed.(@url == feedUrl);
+
+ var cacheURL = system.wwwURL + "/" + escapePathSegment(feedUrl) + ".xml";
+ var now = new Date().valueOf();
+ // if cache is stale, refresh it
+ if (parseInt([EMAIL PROTECTED]) + parseInt([EMAIL PROTECTED]) < now) {
+ // record the attempt. Somebody might make use of this for diagnostic
information.
+ [EMAIL PROTECTED] = now;
+ try {
+ var feed = system.getXML(feedUrl);
+ writeXML(feedUrl, feed);
+ [EMAIL PROTECTED] = now;
+ } catch (e) {
+ // if the feed is unfetchable, return the url the user gave us and
let him deal with it
+ cacheURL = feedUrl;
+ }
+ }
+
+ // save the database
+ writeXML("db", cachedb);
+
+ return cacheURL;
+}
+
+feedContent.documentation = <div>Return the XML representation of the feed
directly (updating the cache in the process).
+ If the feed is stale, it will be refreshed.
+ If the feed has not been cached before, it will
be using the default settings of no prefetching, cache lifespan 24 hours.</div>;
+feedContent.inputTypes = {"feedUrl" : "xs:anyURI"};
+feedContent.outputType = "#raw";
+feedContent.safe = true;
+function feedContent(feedUrl) {
+ var cachedFeed = feedReference(feedUrl);
+ return system.getXML(cachedFeed);
+}
+
+// helper functions
+
+fetch.visible = false;
+function fetch(feedUrl) {
+ var cachedb = readXML("db");
+ if (cachedb == null) cachedb = <cache/>;
+
+ for each (var feedInfo in cachedb.feed) {
+ if (feedUrl == null || [EMAIL PROTECTED] == feedUrl) {
+ var now = new Date().valueOf();
+ if ([EMAIL PROTECTED] == "true" && parseInt([EMAIL PROTECTED]) +
parseInt([EMAIL PROTECTED]) < now) {
+ [EMAIL PROTECTED] = now;
+ try {
+ var feed = system.getXML([EMAIL PROTECTED]);
+ writeXML([EMAIL PROTECTED], feed);
+ [EMAIL PROTECTED] = now;
+ } catch (e) {}
+ }
+ }
+ }
+
+ writeXML("db", cachedb);
+}
+
+escapePathSegment.visible=false;
+function escapePathSegment (segment) {
+ segment = segment.replace(/\//g, "_");
+ segment = segment.replace(/:/g, "_");
+ segment = segment.replace(/\?/g, "_");
+ return segment;
+}
+
+readXML.visible=false;
+function readXML(fileId) {
+ var fileName = "www/" + escapePathSegment(fileId) + ".xml";
+ var f = new File(fileName);
+ var data;
+ if (f.exists) {
+ f.openForReading();
+ data = new XML(f.readAll());
+ }
+ f.close();
+ return data;
+}
+
+writeXML.visible=false;
+function writeXML(fileId, data) {
+ var fileName = "www/" + escapePathSegment(fileId) + ".xml";
+
+ var f = new File(fileName);
+ if (!f.exists)
+ f.createFile();
+ f.openForWriting();
+ f.write(data.toXMLString());
+ f.close();
+}
\ No newline at end of file
Copied: trunk/mashup/java/modules/samples/feedCache/feedCache.tags (from
r18661, /trunk/mashup/java/modules/samples/digit2image/digit2image.tags)
URL:
http://wso2.org/svn/browse/wso2/trunk/mashup/java/modules/samples/feedCache/feedCache.tags?rev=18665&r1=18661&r2=18665&view=diff
==============================================================================
--- /trunk/mashup/java/modules/samples/digit2image/digit2image.tags
(original)
+++ trunk/mashup/java/modules/samples/feedCache/feedCache.tags Thu Jun 26
18:06:26 2008
@@ -1,8 +1,9 @@
<tags>
<tag>built-in</tag>
- <tag>Flickr</tag>
- <tag>WSRequest</tag>
- <tag>storexml</tag>
- <tag>cache</tag>
+ <tag>feed</tag>
+ <tag>rss</tag>
+ <tag>atom</tag>
+ <tag>lifespan</tag>
+ <tag>prefetch</tag>
<tag>sample</tag>
</tags>
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