kad.js : implement store api using kademlia

storage/kad.js

@@ -0,0 +1,73 @@
+var kad=require("kad");
+var levelup=require("levelup");
+
+module.exports.create=function(conf,cb){
+    var dht= kad({
+        address:conf.kadAddress,
+        port:conf.kadPort,
+        storage:levelup(conf.kadStore),
+        seeds:conf.kadSeeds,
+        transport: kad.transports.UDP,
+    });
+
+    var dht2=kad({
+        address: conf.kadAddress,
+        port:conf.kadPort+1,
+        storage:levelup('./kadstore2.db'),
+        seeds:[],
+        transport: kad.transports.UDP,
+    });
+
+    var indices={},
+        Channel={};
+
+    var makeChannel=function(cName){
+        Channel[cName]={
+            lastModified:0,
+            messages:[],
+        };
+    },
+    makeIndex=function(cName){
+        indices[cName]=-1;
+    },
+    loadIndex=function(cName,out){
+        indices[cName]=parseInt(out);
+        typeof indices[cName] !== 'number' &&
+            console.error('FOUND A NON-NUMERIC INDEX for channel: %s',cName);
+    },
+    getIndex=function(cName,f){
+        if(typeof indices[cName] !== 'undefined'){
+            f(indices[cName]);
+        }else{
+            dht.get(cName+'=>index',function(e,out){
+                e?  makeIndex(cName): loadIndex(cName,out);
+                f(indices[cName]);
+            });
+        }
+    };
+
+    cb({
+        message:function(cName, content, cb){
+            getIndex(cName, function(index){
+                var index = ++indices[cName];
+                dht.put(cName+'=>index', ''+index,function(e){
+                    e && console.error(e);
+                });
+                dht.put(cName+'=>'+index, content, function(e){
+                    e && console.error(e);
+                    cb();
+                });
+            });
+        },
+        getMessages: function(cName, cb){
+            getIndex(cName, function(index){
+                for(var i=index;i>=0;i--){
+                    dht.get(cName+'=>'+i,function(e,out){
+                        if(e) return console.error(e);
+                        cb(out);
+                    });
+                }
+            });
+        },
+    });
+};