cache pubkeys in browser memory

js/twister_io.js

@@ -23,6 +23,7 @@ var _dhtgetPendingMap = {};
 // memory cache for profile and avatar
 var _profileMap = {};
 var _avatarMap = {};
+var _pubkeyMap = {};
 
 // number of dhtgets in progress (requests to the daemon)
 var _dhtgetsInProgress = 0;
@@ -405,14 +406,22 @@ function checkPubkeyExists(username, cbFunc, cbArg) {
 // cbFunc is called as cbFunc(cbArg, pubkey)
 // if user doesn't exist then pubkey.length == 0
 function dumpPubkey(username, cbFunc, cbArg) {
+    if( username in _pubkeyMap ) {
+        if( cbFunc )
+            cbFunc(cbArg, _pubkeyMap[username]);
+    } else {
         twisterRpc("dumppubkey", [username],
                    function(args, ret) {
+                       if( ret.length > 0 ) {
+                            _pubkeyMap[username] = ret;
+                       }
                        args.cbFunc(args.cbArg, ret);
                    }, {cbFunc:cbFunc, cbArg:cbArg},
                    function(args, ret) {
                        alert(polyglot.t("error_connecting_to_daemon"));
                    }, {cbFunc:cbFunc, cbArg:cbArg});
     }
+}
 
 // privkey is obtained from wallet db
 // so privkey is returned even for unsent transactions