added image link in search results

This should be a help to make a preview of search results.
The image is computed from the list of embedded images, it is
always the first image in that list.
In rss-type results the image is presented like
<media:content medium="image" url="https://abc.xyz/logo.png"/>
as defined in
http://www.rssboard.org/media-rss#media-content

htroot/yacysearchitem.java

@@ -153,7 +153,7 @@ public class yacysearchitem {
             prop.putJSON("content_title-json", result.title());
             prop.putHTML("content_showPictures_link", resultUrlstring);
             //prop.putHTML("content_link", resultUrlstring);
-
+            
 // START interaction
             if (sb.getConfigBool("proxyURL.useforresults", false) && sb.getConfigBool("proxyURL", false)) {
                 String modifyURL = resultUrlstring;
@@ -199,6 +199,19 @@ public class yacysearchitem {
             	prop.put("content_favicon", 1);
             }
             prop.putHTML("content_favicon_faviconUrl", processFaviconURL(ImageViewer.hasFullViewingRights(header, sb), faviconURL));
+            
+            if (result.limage() == 0) {
+            	if (faviconURL == null) {
+            		prop.put("content_image", 0);
+            	} else {
+            		prop.put("content_image", 1);
+                	prop.putXML("content_image_url", faviconURL.toNormalform(true));
+            	}
+            } else {
+            	prop.put("content_image", 1);
+            	prop.putXML("content_image_url", result.imageURL());
+            }
+            
             prop.put("content_urlhash", urlhash);
             prop.put("content_ranking", Float.toString(result.score()));
             Date[] events = result.events();

htroot/yacysearchitem.json

@@ -5,6 +5,7 @@
       "code": "#[code]#",
       "description": "#[description-json]#",
       "pubDate": "#[date822]#",
+      #(image)#::"image": "#[url]#",#(/image)#
       #(showEvent)#::"eventDate": "#[date822]#",#(/showEvent)#
       "size": "#[size]#",
       "sizename": "#[sizename]#",

htroot/yacysearchitem.xml

@@ -3,6 +3,7 @@
 <link>#[link]#</link>
 <description>#[description-xml]#</description>
 <pubDate>#[date822]#</pubDate>
+#(image)#::<media:content medium="image" url="#[url]#"/>#(/image)#
 #(showEvent)#::<ev:startdate>#[date822]#</ev:startdate><ev:enddate>#[date822]#</ev:enddate>#(/showEvent)#
 <dc:publisher><![CDATA[#[publisher]#]]></dc:publisher>
 <dc:creator><![CDATA[#[creator]#]]></dc:creator>

source/net/yacy/cora/federate/solr/responsewriter/OpensearchResponseWriter.java

@@ -40,6 +40,8 @@ import net.yacy.cora.lod.vocabulary.DublinCore;
 import net.yacy.cora.lod.vocabulary.Geo;
 import net.yacy.cora.lod.vocabulary.YaCyMetadata;
 import net.yacy.cora.protocol.HeaderFramework;
+import net.yacy.crawler.retrieval.Response;
+import net.yacy.search.schema.CollectionConfiguration;
 import net.yacy.search.schema.CollectionSchema;
 
 import org.apache.lucene.document.Document;
@@ -159,6 +161,7 @@ public class OpensearchResponseWriter implements QueryResponseWriter {
         SolrIndexSearcher searcher = request.getSearcher();
         DocIterator iterator = response.iterator();
         String urlhash = null;
+        MultiProtocolURL url = null;
         for (int i = 0; i < responseCount; i++) {
             openTag(writer, "item");
             int id = iterator.nextDoc();
@@ -168,6 +171,8 @@ public class OpensearchResponseWriter implements QueryResponseWriter {
             List<String> texts = new ArrayList<String>();
             List<String> descriptions = new ArrayList<String>();
             String title = "";
+            List<Object> images_protocol_obj = new ArrayList<>();
+        	List<String> images_stub = new ArrayList<>();
             for (int j = 0; j < fieldc; j++) {
                 IndexableField value = fields.get(j);
                 String fieldName = value.name();
@@ -184,7 +189,7 @@ public class OpensearchResponseWriter implements QueryResponseWriter {
                     String u = value.stringValue();
                     solitaireTag(writer, RSSMessage.Token.link.name(), u);
                     try {
-                        MultiProtocolURL url = new MultiProtocolURL(u);
+                        url = new MultiProtocolURL(u);
                         solitaireTag(writer, YaCyMetadata.host.getURIref(), url.getHost());
                         solitaireTag(writer, YaCyMetadata.path.getURIref(), url.getPath());
                         solitaireTag(writer, YaCyMetadata.file.getURIref(), url.getFileName());
@@ -232,6 +237,26 @@ public class OpensearchResponseWriter implements QueryResponseWriter {
                     texts.add(value.stringValue());
                     continue;
                 }
+                if (CollectionSchema.images_protocol_sxt.getSolrFieldName().equals(fieldName)) {
+                	images_protocol_obj.add(value.stringValue());
+                    continue;
+                }
+                if (CollectionSchema.images_urlstub_sxt.getSolrFieldName().equals(fieldName)) {
+                	images_stub.add(value.stringValue());
+                    continue;
+                }
+            }
+            
+            if (Math.min(images_protocol_obj.size(), images_stub.size()) > 0) {
+            	List<String> images_protocol = CollectionConfiguration.indexedList2protocolList(images_protocol_obj, images_protocol_obj.size());
+            	String imageurl = images_protocol.get(0) + "://" + images_stub.get(0);
+                 writer.write("<media:content medium=\"image\" url=\"");
+                 XML.escapeCharData(imageurl, writer); writer.write("\"/>\n");
+            } else {
+            	if (url != null && Response.docTypeExt(MultiProtocolURL.getFileExtension(url.getFile()).toLowerCase()) == Response.DT_IMAGE) {
+            		writer.write("<media:content medium=\"image\" url=\"");
+                    XML.escapeCharData(url.toNormalform(true), writer); writer.write("\"/>\n");
+            	}
             }
             
             // compute snippet from texts

source/net/yacy/cora/federate/solr/responsewriter/YJsonResponseWriter.java

@@ -35,6 +35,8 @@ import net.yacy.cora.federate.solr.responsewriter.OpensearchResponseWriter.ResHe
 import net.yacy.cora.protocol.HeaderFramework;
 import net.yacy.cora.util.ConcurrentLog;
 import net.yacy.cora.util.JSONObject;
+import net.yacy.crawler.retrieval.Response;
+import net.yacy.search.schema.CollectionConfiguration;
 import net.yacy.search.schema.CollectionSchema;
 
 import org.apache.lucene.document.Document;
@@ -141,6 +143,9 @@ public class YJsonResponseWriter implements QueryResponseWriter {
             List<String> descriptions = new ArrayList<String>();
             String title = "";
             StringBuilder path = new StringBuilder(80);
+            List<Object> images_protocol_obj = new ArrayList<>();
+        	List<String> images_stub = new ArrayList<>();
+        	
             for (int j = 0; j < fieldc; j++) {
                 IndexableField value = fields.get(j);
                 String fieldName = value.name();
@@ -193,9 +198,32 @@ public class YJsonResponseWriter implements QueryResponseWriter {
                     solitaireTag(writer, "sizename", sizemb > 0 ? (Integer.toString(sizemb) + " mbyte") : sizekb > 0 ? (Integer.toString(sizekb) + " kbyte") : (Integer.toString(size) + " byte"));
                     continue;
                 }
+                if (CollectionSchema.last_modified.getSolrFieldName().equals(fieldName)) {
+                    Date d = new Date(Long.parseLong(value.stringValue()));
+                    solitaireTag(writer, "pubDate", HeaderFramework.formatRFC1123(d));
+                    continue;
+                }
+                if (CollectionSchema.images_protocol_sxt.getSolrFieldName().equals(fieldName)) {
+                	images_protocol_obj.add(value.stringValue());
+                    continue;
+                }
+                if (CollectionSchema.images_urlstub_sxt.getSolrFieldName().equals(fieldName)) {
+                	images_stub.add(value.stringValue());
+                    continue;
+                }
 
                 //missing: "code","faviconCode"
             }
+
+            if (Math.min(images_protocol_obj.size(), images_stub.size()) > 0) {
+            	List<String> images_protocol = CollectionConfiguration.indexedList2protocolList(images_protocol_obj, images_protocol_obj.size());
+            	String imageurl = images_protocol.get(0) + "://" + images_stub.get(0);
+            	solitaireTag(writer, "image", imageurl);
+            } else {
+            	if (url != null && Response.docTypeExt(MultiProtocolURL.getFileExtension(url.getFile()).toLowerCase()) == Response.DT_IMAGE) {
+            		solitaireTag(writer, "image", url.toNormalform(true));
+            	}
+            }
             
             // compute snippet from texts            
             solitaireTag(writer, "path", path.toString());

source/net/yacy/kelondro/data/meta/URIMetadataNode.java

@@ -451,6 +451,20 @@ public class URIMetadataNode extends SolrDocument /* implements Comparable<URIMe
         return getInt(CollectionSchema.wordcount_i);
     }
 
+    /**
+     * in case that images are embedded in the document, get one image which can be used as thumbnail
+     * @return
+     */
+    public String imageURL() {
+    	if (limage() == 0) throw new UnsupportedOperationException();
+    	List<String> images_protocol = CollectionConfiguration.indexedList2protocolList(getFieldValues(CollectionSchema.images_protocol_sxt.getSolrFieldName()), limage());
+    	List<String> images_stub = getStringList(CollectionSchema.images_urlstub_sxt);
+    	int c = Math.min(images_protocol.size(), images_stub.size());
+    	if (c == 0) throw new UnsupportedOperationException();
+    	String url = images_protocol.get(0) + "://" + images_stub.get(0);
+    	return url;
+    }
+    
     public int llocal() {
         return getInt(CollectionSchema.inboundlinkscount_i);
     }