End find_node crawl early if node is found

closes #281

Author: cpacia

dht/crawling.py

@@ -160,6 +160,10 @@ def _handleFoundValues(self, values):
 
 class NodeSpiderCrawl(SpiderCrawl):
 
+    def __init__(self, protocol, node, peers, ksize, alpha, find_exact=False):
+        SpiderCrawl.__init__(self, protocol, node, peers, ksize, alpha)
+        self.find_exact = find_exact
+
     def find(self):
         """
         Find the closest nodes.
@@ -176,7 +180,12 @@ def _nodesFound(self, responses):
             if not response.happened():
                 toremove.append(peerid)
             else:
-                self.nearest.push(response.getNodeList())
+                node_list = response.getNodeList()
+                self.nearest.push(node_list)
+                if self.find_exact:
+                    for node in node_list:
+                        if node.id == self.node.id:
+                            return [node]
         self.nearest.remove(toremove)
 
         if self.nearest.allBeenContacted():

dht/network.py

@@ -354,7 +354,7 @@ def check_for_node(nodes):
             self.log.warning("there are no known neighbors to find node %s" % node_to_find.id.encode("hex"))
             return defer.succeed(None)
 
-        spider = NodeSpiderCrawl(self.protocol, node_to_find, nearest, self.ksize, self.alpha)
+        spider = NodeSpiderCrawl(self.protocol, node_to_find, nearest, self.ksize, self.alpha, True)
         return spider.find().addCallback(check_for_node)
 
     def saveState(self, fname):