Author: antelder
Date: Wed Aug 20 01:43:57 2008
New Revision: 687289
URL: http://svn.apache.org/viewvc?rev=687289&view=rev
Log:
TUSCANY-2537: Apply patch from Dan Becker for Demonstrate Atom Binding end to
end caching (ETag, Last-modified use) in
Modified:
tuscany/java/sca/modules/binding-atom-abdera/src/main/java/org/apache/tuscany/sca/binding/atom/provider/AtomBindingListenerServlet.java
Modified:
tuscany/java/sca/modules/binding-atom-abdera/src/main/java/org/apache/tuscany/sca/binding/atom/provider/AtomBindingListenerServlet.java
URL:
http://svn.apache.org/viewvc/tuscany/java/sca/modules/binding-atom-abdera/src/main/java/org/apache/tuscany/sca/binding/atom/provider/AtomBindingListenerServlet.java?rev=687289&r1=687288&r2=687289&view=diff
==============================================================================
---
tuscany/java/sca/modules/binding-atom-abdera/src/main/java/org/apache/tuscany/sca/binding/atom/provider/AtomBindingListenerServlet.java
(original)
+++
tuscany/java/sca/modules/binding-atom-abdera/src/main/java/org/apache/tuscany/sca/binding/atom/provider/AtomBindingListenerServlet.java
Wed Aug 20 01:43:57 2008
@@ -27,7 +27,9 @@
import java.io.Writer;
import java.net.URLDecoder;
import java.text.SimpleDateFormat;
+import java.util.ArrayList;
import java.util.Date;
+import java.util.List;
import java.util.StringTokenizer;
import java.util.logging.Logger;
@@ -51,6 +53,7 @@
import org.apache.abdera.writer.WriterFactory;
import org.apache.commons.codec.binary.Base64;
+import org.apache.tuscany.sca.binding.atom.CacheContext;
import org.apache.tuscany.sca.data.collection.Entry;
import org.apache.tuscany.sca.databinding.Mediator;
import org.apache.tuscany.sca.interfacedef.DataType;
@@ -157,6 +160,14 @@
// No authentication required for a get request
+ // Test for any cache info in the request
+ CacheContext cacheContext = null;
+ try {
+ cacheContext = getCacheContextFromRequest( request );
+ } catch ( java.text.ParseException e ) {
+ }
+ // System.out.println( "AtomBindingListener.doGet cache context=" +
cacheContext );
+
// Get the request path
int servletPathLength = request.getContextPath().length() +
request.getServletPath().length();
String path =
URLDecoder.decode(request.getRequestURI().substring(servletPathLength),
"UTF-8");
@@ -260,20 +271,20 @@
// All feeds must provide Id and updated elements.
// However, some do not, so provide some program
protection.
feed.setId( "Feed" + feed.hashCode());
- Date lastModified = new Date( 0 );
+ Date responseLastModified = new Date( 0 );
// Add entries to the feed
for (Entry<Object, Object> entry: collection) {
org.apache.abdera.model.Entry feedEntry =
feedEntry(entry, itemClassType, itemXMLType, mediator, abderaFactory);
// Use the most recent entry update as the feed update
Date entryUpdated = feedEntry.getUpdated();
- if (( entryUpdated != null ) &&
(entryUpdated.compareTo( lastModified ) > 0 ))
- lastModified = entryUpdated;
+ if (( entryUpdated != null ) &&
(entryUpdated.compareTo( responseLastModified ) > 0 ))
+ responseLastModified = entryUpdated;
feed.addEntry(feedEntry);
}
// If no entries were newly updated,
- if ( lastModified.compareTo( new Date( 0 ) ) == 0 )
- lastModified = new Date();
+ if ( responseLastModified.compareTo( new Date( 0 ) ) == 0
)
+ responseLastModified = new Date();
}
}
if (feed != null) {
@@ -320,6 +331,11 @@
}
}
}
+ // Provide Etag based on Id and time.
+ response.addHeader(ETAG, feedETag );
+ if ( feedUpdated != null )
+ response.addHeader(LASTMODIFIED,
dateFormat.format( feedUpdated ));
+
// Content negotiation
String acceptType = request.getHeader( "Accept" );
String preferredType = getContentPreference( acceptType );
@@ -339,10 +355,6 @@
} else {
// Write the Atom feed
response.setContentType("application/atom+xml;type=feed");
- // Provide Etag based on Id and time.
- response.addHeader(ETAG, feedETag );
- if ( feedUpdated != null )
- response.addHeader(LASTMODIFIED,
dateFormat.format( feedUpdated ));
try {
feed.getDocument().writeTo(response.getOutputStream());
} catch (IOException ioe) {
@@ -376,14 +388,13 @@
}
// Write the Atom entry
if (feedEntry != null) {
- IRI feedId = feedEntry.getId();
- if ( feedId != null )
- response.addHeader(ETAG, "\"" + feedId.toString() + "\"" );
+ String entryETag = "\"" + generateEntryETag( feedEntry ) +
"\"";
Date entryUpdated = feedEntry.getUpdated();
if ( entryUpdated != null )
response.addHeader(LASTMODIFIED, dateFormat.format(
entryUpdated ));
// TODO Check If-Modified-Since If-Unmodified-Since predicates
against LASTMODIFIED.
- // If true return 304 and null body.
+ // If true return 304 and null body.
+
Link link = feedEntry.getSelfLink();
if (link != null) {
response.addHeader(LOCATION, link.getHref().toString());
@@ -394,6 +405,52 @@
}
}
+ // Test request for predicates.
+ String predicate = request.getHeader( "If-Match" );
+ if (( predicate != null ) && ( !predicate.equals(entryETag) ))
{
+ // No match, should short circuit
+
response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED);
+ return;
+ }
+ predicate = request.getHeader( "If-None-Match" );
+ if (( predicate != null ) && ( predicate.equals(entryETag) )) {
+ // Match, should short circuit
+ response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
+ return;
+ }
+ if ( entryUpdated != null ) {
+ predicate = request.getHeader( "If-Unmodified-Since" );
+ if ( predicate != null ) {
+ try {
+ Date predicateDate = dateFormat.parse(
predicate );
+ if ( predicateDate.compareTo(
entryUpdated ) < 0 ) {
+ // Match, should short circuit
+
response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
+ return;
+ }
+ } catch ( java.text.ParseException e ) {
+ // Ignore and move on
+ }
+ }
+ predicate = request.getHeader( "If-Modified-Since" );
+ if ( predicate != null ) {
+ try {
+ Date predicateDate = dateFormat.parse(
predicate );
+ if ( predicateDate.compareTo(
entryUpdated ) > 0 ) {
+ // Match, should short circuit
+
response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
+ return;
+ }
+ } catch ( java.text.ParseException e ) {
+ // Ignore and move on
+ }
+ }
+ }
+ // Provide Etag based on Id and time.
+ response.addHeader(ETAG, entryETag );
+ if ( entryUpdated != null )
+ response.addHeader(LASTMODIFIED,
dateFormat.format( entryUpdated ));
+
// Content negotiation
String acceptType = request.getHeader( "Accept" );
String preferredType = getContentPreference( acceptType );
@@ -726,6 +783,8 @@
/**
* Generate ETag based on feed Id and updated fields.
+ * Note that the feed id should be unique per feed, immutable, and
unchanging,
+ * but the ETag should change whenever the feed contents change.
* @param feed
* @return ETag
*/
@@ -748,6 +807,32 @@
return feedId + "-" + feedUpdated.hashCode();
}
+ /**
+ * Generate ETag based on entry Id and updated fields.
+ * Note that the entry id should be unique per entry, immutable, and
unchanging,
+ * but the ETag should change whenever the entry contents change.
+ * @param feed
+ * @return ETag
+ */
+ public static String generateEntryETag( org.apache.abdera.model.Entry
entry ) {
+ if ( entry == null ) {
+ return null;
+ }
+
+ IRI entryIdIRI = entry.getId();
+ String entryId = "ID";
+ if ( entryIdIRI != null ) {
+ entryId = entryIdIRI.toString();
+ }
+
+ Date entryUpdated = entry.getUpdated();
+ if ( entryUpdated == null ) {
+ return entryId;
+ }
+
+ return entryId + "-" + entryUpdated.hashCode();
+ }
+
public static String getContentPreference( String acceptType ) {
if (( acceptType == null ) || ( acceptType.length() < 1 )) {
return "application/atom+xml";
@@ -757,4 +842,40 @@
return st.nextToken();
return "application/atom+xml";
}
+
+ /**
+ * Gets the cache context information (ETag, LastModified, predicates)
from the Http request.
+ * @param request
+ * @return
+ */
+ public CacheContext getCacheContextFromRequest( HttpServletRequest request
) throws java.text.ParseException {
+ CacheContext context = new CacheContext();
+ List<String> predicates = new ArrayList<String>();
+
+ String eTag = request.getHeader( "If-Match" );
+ if ( eTag != null ) {
+ context.setETag( eTag );
+ predicates.add( "If-Match" );
+ }
+ eTag = request.getHeader( "If-None-Match" );
+ if ( eTag != null ) {
+ context.setETag( eTag );
+ predicates.add( "If-None-Match" );
+ }
+ String lastModifiedString = request.getHeader( "If-Modified-Since" );
+ if ( lastModifiedString != null ) {
+ context.setLastModified( lastModifiedString );
+ predicates.add( "If-Modified-Since" );
+ }
+ lastModifiedString = request.getHeader( "If-Unmodified-Since" );
+ if ( lastModifiedString != null ) {
+ context.setLastModified( lastModifiedString );
+ predicates.add( "If-Unmodified-Since" );
+ }
+ if ( predicates.size() > 0 ) {
+ context.setPredicates( predicates.toArray( new String[ 0 ] ) );
+ }
+ return context;
+ }
+
}
