added usage of X-Real-IP http header

to identify request IPs which came through NGINX reverse proxy
configurations

source/net/yacy/cora/protocol/RequestHeader.java

@@ -76,6 +76,7 @@ public class RequestHeader extends HeaderFramework implements HttpServletRequest
 
     public static final String X_CACHE = "X-Cache";
     public static final String X_CACHE_LOOKUP = "X-Cache-Lookup";
+    public static final String X_Real_IP = "X-Real-IP";
 
     public static final String COOKIE = "Cookie";
 
@@ -706,12 +707,21 @@ public class RequestHeader extends HeaderFramework implements HttpServletRequest
     @Override
     public String getRemoteAddr() {
         if (this._request != null) {
-            return _request.getRemoteAddr();
+        	return client(_request);
         } else {
             return super.get(HeaderFramework.CONNECTION_PROP_CLIENTIP);
         }
     }
 
+    public static String client(final ServletRequest request) {
+        String clientHost = request.getRemoteAddr();
+        if (request instanceof HttpServletRequest) {
+        	String XRealIP = ((HttpServletRequest) request).getHeader(X_Real_IP);
+        	if (XRealIP != null && XRealIP.length() > 0) clientHost = XRealIP; // get IP through nginx config "proxy_set_header X-Real-IP $remote_addr;"
+        }
+		return clientHost;
+    }
+    
     @Override
     public String getRemoteHost() {
         if (_request != null) {

source/net/yacy/http/servlets/SolrSelectServlet.java

@@ -47,6 +47,8 @@ import net.yacy.cora.federate.solr.responsewriter.HTMLResponseWriter;
 import net.yacy.cora.federate.solr.responsewriter.OpensearchResponseWriter;
 import net.yacy.cora.federate.solr.responsewriter.SnapshotImagesReponseWriter;
 import net.yacy.cora.federate.solr.responsewriter.YJsonResponseWriter;
+import net.yacy.cora.protocol.RequestHeader;
+import net.yacy.cora.util.ConcurrentLog;
 import net.yacy.data.UserDB;
 import net.yacy.search.Switchboard;
 import net.yacy.search.SwitchboardConstants;
@@ -162,6 +164,8 @@ public class SolrSelectServlet extends HttpServlet {
                 */
             }
             String q = mmsp.get(CommonParams.Q, "");
+            ConcurrentLog.info("SolrSelect", "client=" + RequestHeader.client(request) + " q=" + q); // to detect bots and dos
+
             if (querystring.length() == 0) querystring = q;
             if (!mmsp.getMap().containsKey(CommonParams.START)) {
                 int startRecord = mmsp.getFieldInt("startRecord", null, CommonParams.START_DEFAULT);