diff --git a/NetfluxWebsocketSrv.js b/NetfluxWebsocketSrv.js
index d3ba89694..b8c4f5a2a 100644
--- a/NetfluxWebsocketSrv.js
+++ b/NetfluxWebsocketSrv.js
@@ -230,7 +230,7 @@ const handleMessage = function (ctx, user, msg) {
                 var rpc_call = parsed.slice(1);
 
                 // slice off the sequence number and pass in the rest of the message
-                ctx.rpc(rpc_call, function (err, output) {
+                ctx.rpc(ctx, rpc_call, function (err, output) {
                     if (err) {
                         console.error('[' + err + ']', output); // TODO make this disableable
                         sendMsg(ctx, user, [seq, 'ACK']);
diff --git a/rpc.js b/rpc.js
index 66973039b..cff3dfeb0 100644
--- a/rpc.js
+++ b/rpc.js
@@ -11,11 +11,15 @@ var getHash = function (ctx, cb) { };
 var getTotalSize = function (ctx, cb) { };
 var getFileSize = function (ctx, cb) { };
 
+var isValidChannel = function (chan) {
+    return /^[a-fA-F0-9]/.test(chan);
+};
+
 RPC.create = function (config, cb) {
     // load pin-store...
 
     console.log('loading rpc module...');
-    rpc = function (msg, respond) {
+    var rpc = function (ctx, msg, respond) {
         switch (msg[0]) {
             case 'ECHO':
                 respond(void 0, msg);
@@ -25,7 +29,14 @@ RPC.create = function (config, cb) {
             case 'GET_HASH':
             case 'GET_TOTAL_SIZE':
             case 'GET_FILE_SIZE':
-
+                if (!isValidChannel(msg[1])) {
+                    return void respond('INVALID_CHAN');
+                }
+
+                return void ctx.store.getChannelSize(msg[1], function (e, size) {
+                    if (e) { return void respond(e.code); }
+                    respond(void 0, size);
+                });
             default:
                 respond('UNSUPPORTED_RPC_CALL', msg);
                 break;
diff --git a/storage/file.js b/storage/file.js
index 1584f4a59..ab2bce617 100644
--- a/storage/file.js
+++ b/storage/file.js
@@ -216,6 +216,14 @@ var getMessages = function (env, chanName, handler, cb) {
     });
 };
 
+var channelBytes = function (env, chanName, cb) {
+    var path = mkPath(env, chanName);
+    Fs.stat(path, function (err, stats) {
+        if (err) { return void cb(err); }
+        cb(void 0, stats.size);
+    });
+};
+
 module.exports.create = function (conf, cb) {
     var env = {
         root: conf.filePath || './datastore',
@@ -248,6 +256,9 @@ module.exports.create = function (conf, cb) {
             flushUnusedChannels: function (cb) {
                 flushUnusedChannels(env, cb);
             },
+            getChannelSize: function (chanName, cb) {
+                channelBytes(env, chanName, cb);
+            },
         });
     });
     setInterval(function () {
diff --git a/www/common/cryptpad-common.js b/www/common/cryptpad-common.js
index 625568a24..65c7a7fa1 100644
--- a/www/common/cryptpad-common.js
+++ b/www/common/cryptpad-common.js
@@ -987,6 +987,28 @@ define([
         });
         */
     };
+
+    var getUserChannelList = common.getUserChannelList = function () {
+        var store = common.getStore();
+        var proxy = store.getProxy();
+        var fo = proxy.fo;
+
+        var list = fo.getFilesDataFiles().map(function (href) {
+            var parsed = common.parsePadUrl(href);
+            if (!parsed || !parsed.hash) { return; }
+
+            parsed = common.parseHash(parsed.hash);
+
+            var channel = parsed.channel;
+            if (!channel) { return; }
+
+            var hex = common.base64ToHex(channel);
+            return hex;
+        }).filter(function (x) { return x; }).sort();
+
+        return list;
+    };
+
     var createButton = common.createButton = function (type, rightside, data, callback) {
         var button;
         var size = "17px";
diff --git a/www/examples/rpc/main.js b/www/examples/rpc/main.js
index 528290d66..37b1751d7 100644
--- a/www/examples/rpc/main.js
+++ b/www/examples/rpc/main.js
@@ -30,6 +30,20 @@ define([
                 if (e) { return void console.error(e); }
                 console.log(msg);
             });
+
+            var list = Cryptpad.getUserChannelList();
+            if (list.length) {
+                rpc.send('GET_FILE_SIZE', list[0], function (e, msg) {
+                    if (e) {
+                        return void console.error(e);
+                    }
+                    console.log(msg);
+                });
+            }
+            rpc.send('GET_FILE_SIZE', 'pewpew', function (e, msg) {
+                if (e) { return void console.error(e); }
+                console.log(msg);
+            });
         });
     });
 });