added feature as requested in

http://forum.yacy-websuche.de/viewtopic.php?f=18&t=3461
The search can now be configured with a non-display host list.
the search will always exlude the given list of host unless they are
requested directly using the host navigation

defaults/yacy.init

@@ -762,6 +762,9 @@ search.navigation=hosts,authors,namespace,topics,filetype,protocol
              all search results are valid without verification
 search.verify = iffresh
 
+search.excludehosts=
+search.excludehosth=
+
 # in case that a link verification fails then the corresponding index reference can be
 # deleted to clean up the index. If this property is set then failed index verification in
 # the cases of nocache, iffresh and ifexist causes an index deletion

htroot/ConfigPortal.html

@@ -109,12 +109,18 @@
           </select>
           </dd>
           
+          <dt>Exclude Hosts</dt>
+          <dd>List of hosts that shall be excluded from search results by default but can be included using the site:&lt;host&gt; operator:<br/>
+          <input type="text" name="search.excludehosts" value="#[search.excludehosts]#" size="60" /><br/>
+          #[search.excludehosth]#
+          </dd>
+          
           <dt>'About' Column<br/>(shown in a column alongside<br/>with the search result page)</dt>
           <dd><input type="text" name="about.headline" value="#[about.headline]#" size="60" />(Headline)</br>
           <textarea name="about.body" cols="60" rows="8">#[about.body]#</textarea>(Content)
           </dd>
           
-          <dt>&nbsp;</dt>
+         <dt>&nbsp;</dt>
           <dd>
             <input type="submit" name="searchpage_set" value="Change Search Page" />&nbsp;&nbsp;
             <input type="submit" name="searchpage_default" value="Set to Default Values" />

htroot/ConfigPortal.java

@@ -26,6 +26,7 @@
 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
 import net.yacy.cora.protocol.RequestHeader;
+import net.yacy.kelondro.data.meta.DigestURI;
 import net.yacy.search.Switchboard;
 import net.yacy.search.SwitchboardConstants;
 import de.anomic.data.WorkTables;
@@ -93,6 +94,10 @@ public class ConfigPortal {
                 sb.setConfig("about.headline", post.get("about.headline", ""));
                 sb.setConfig("about.body", post.get("about.body", ""));
                 
+                String excludehosts = post.get("search.excludehosts", "");
+                sb.setConfig("search.excludehosts", excludehosts);
+                sb.setConfig("search.excludehosth", DigestURI.hosthashes(excludehosts));
+                
                 // construct navigation String
                 String nav = "";
                 if (post.getBoolean("search.navigation.hosts", false)) nav += "hosts,";
@@ -126,8 +131,10 @@ public class ConfigPortal {
                 sb.setConfig("search.result.show.pictures", false);
                 sb.setConfig(SwitchboardConstants.SEARCH_VERIFY, "iffresh");
                 sb.setConfig(SwitchboardConstants.SEARCH_VERIFY_DELETE, "true");
-                prop.put("about.headline", "");
+                sb.setConfig("about.headline", "");
-                prop.put("about.body", "");
+                sb.setConfig("about.body", "");
+                sb.setConfig("search.excludehosts", "");
+                sb.setConfig("search.excludehosth", "");
             }
         }
 
@@ -167,6 +174,9 @@ public class ConfigPortal {
         prop.put("about.headline", sb.getConfig("about.headline", ""));
         prop.put("about.body", sb.getConfig("about.body", ""));
 
+        prop.put("search.excludehosts", sb.getConfig("search.excludehosts", ""));
+        prop.put("search.excludehosth", sb.getConfig("search.excludehosth", ""));
+
         final String  browserPopUpPage = sb.getConfig(SwitchboardConstants.BROWSER_POP_UP_PAGE, "ConfigBasic.html");
         prop.put("popupFront", 0);
         prop.put("popupSearch", 0);

htroot/yacy/search.java

@@ -244,6 +244,7 @@ public final class search {
                     null,
                     false,
                     sitehash,
+                    null,
                     authorhash,
                     DigestURI.TLD_any_zone_filter,
                     client,
@@ -305,6 +306,7 @@ public final class search {
                     constraint,
                     false,
                     sitehash,
+                    null,
                     authorhash,
                     DigestURI.TLD_any_zone_filter,
                     client,

htroot/yacysearch.java

@@ -618,6 +618,7 @@ public class yacysearch {
                     constraint,
                     true,
                     sitehash,
+                    DigestURI.hosthashess(sb.getConfig("search.excludehosth", "")),
                     authorhash,
                     DigestURI.TLD_any_zone_filter,
                     client,

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

@@ -30,6 +30,8 @@ package net.yacy.kelondro.data.meta;
 import java.io.File;
 import java.io.Serializable;
 import java.net.MalformedURLException;
+import java.util.HashSet;
+import java.util.Set;
 
 import net.yacy.cora.document.ASCII;
 import net.yacy.cora.document.MultiProtocolURI;
@@ -71,6 +73,37 @@ public class DigestURI extends MultiProtocolURI implements Serializable {
         }
         return (url == null) ? null : ASCII.String(url.hash(), 6, 6);
     }
+    
+    /**
+     * from a given list of hosts make a list of host hashes
+     * the list is separated by comma
+     * @param hostlist
+     * @return list of host hashes without separation
+     */
+    public static String hosthashes(final String hostlist) {
+        String[] hs = hostlist.split(",");
+        StringBuilder sb = new StringBuilder(hostlist.length());
+        for (String h: hs) {
+            if (h == null) continue;
+            h = h.trim();
+            if (h.length() == 0) continue;
+            h = hosthash(h);
+            if (h == null || h.length() != 6) continue;
+            sb.append(h);
+        }
+        return sb.toString();
+    }
+    
+    public static Set<String> hosthashess(String hosthashes) {
+        if (hosthashes == null || hosthashes.length() == 0) return null;
+        HashSet<String> h = new HashSet<String>();
+        assert hosthashes.length() % 6 == 0;
+        for (int i = 0; i < hosthashes.length(); i = i + 6) {
+            h.add(hosthashes.substring(i, i + 6));
+        }
+        return h;
+    }
+    
 
     /**
      * DigestURI from File

source/net/yacy/search/query/QueryParams.java

@@ -29,8 +29,10 @@ package net.yacy.search.query;
 import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Map;
+import java.util.Set;
 import java.util.SortedSet;
 import java.util.TreeSet;
 import java.util.regex.Matcher;
@@ -124,6 +126,7 @@ public final class QueryParams {
     private final Segment indexSegment;
     public final String host; // this is the client host that starts the query, not a site operator
     public final String sitehash; // this is a domain hash, 6 bytes long or null
+    public final Set<String> siteexcludes; // set of domain hashes that are excluded if not included by sitehash
     public final String authorhash;
     public final String tenant;
     public final Modifier modifier;
@@ -182,6 +185,7 @@ public final class QueryParams {
         this.snippetCacheStrategy = null;
         this.host = null;
         this.sitehash = null;
+        this.siteexcludes = null;
         this.authorhash = null;
         this.remotepeer = null;
         this.time = Long.valueOf(System.currentTimeMillis());
@@ -208,6 +212,7 @@ public final class QueryParams {
         final Searchdom domType, final int domMaxTargets,
         final Bitfield constraint, final boolean allofconstraint,
         final String site,
+        final Set<String> siteexcludes,
         final String authorhash,
         final int domainzone,
         final String host,
@@ -250,6 +255,7 @@ public final class QueryParams {
         this.constraint = constraint;
         this.allofconstraint = allofconstraint;
         this.sitehash = site; assert site == null || site.length() == 6;
+        this.siteexcludes = siteexcludes != null && siteexcludes.size() == 0 ? null: siteexcludes;
         this.authorhash = authorhash; assert authorhash == null || !authorhash.isEmpty();
         this.snippetCacheStrategy = snippetCacheStrategy;
         this.host = host;
@@ -491,6 +497,8 @@ public final class QueryParams {
         context.append(asterisk);
         context.append(this.sitehash);
         context.append(asterisk);
+        context.append(this.siteexcludes);
+        context.append(asterisk);
         context.append(this.authorhash);
         context.append(asterisk);
         context.append(this.targetlang);

source/net/yacy/search/query/RWIProcess.java

@@ -311,6 +311,9 @@ public final class RWIProcess extends Thread
                 // check site constraints
                 final String hosthash = iEntry.hosthash();
                 if ( this.query.sitehash == null ) {
+                    if (this.query.siteexcludes != null && this.query.siteexcludes.contains(hosthash)) {
+                        continue pollloop;
+                    }
                     // no site constraint there; maybe collect host navigation information
                     if ( nav_hosts && this.query.urlMask_isCatchall ) {
                         this.hostNavigator.inc(hosthash);