diff --git a/example/daemon/www/js/.eslintrc.js b/example/daemon/www/js/.eslintrc.js
index b5171ab..ccd1df7 100644
--- a/example/daemon/www/js/.eslintrc.js
+++ b/example/daemon/www/js/.eslintrc.js
@@ -234,7 +234,7 @@ module.exports = {
         "quotes": "off",
         "radix": "error",
         "require-atomic-updates": "error",
-        "require-await": "error",
+        "require-await": "off",
         "require-jsdoc": "off",
         "require-unicode-regexp": "off",
         "rest-spread-spacing": "error",
diff --git a/example/daemon/www/js/connection.js b/example/daemon/www/js/connection.js
deleted file mode 100644
index 991bb96..0000000
--- a/example/daemon/www/js/connection.js
+++ /dev/null
@@ -1,36 +0,0 @@
-export class Connection {
-
-    constructor() {
-        this.ws = null;
-        this.isConnected = false;
-        this.onopen = () => {};
-        this.onclose = () => {};
-        this.onmessage = () => {};
-    }
-
-    connectTo(url) {
-        if (this.ws) { this.close(); }
-
-        this.ws = new WebSocket(url, "fs");        
-        this.ws.onopen = () => { 
-            this.isConnected = true;
-            this.onopen();
-        };
-        this.ws.onclose = () => { 
-            this.isConnected = false;
-            this.onclose();
-         };
-         this.ws.onmessage = (message) => {
-             this.onmessage(message);
-         };
-    }
-
-    send(message) {
-        this.ws.send(message);
-    }
-
-    close() {
-        this.ws.close();
-    }
-
-}
\ No newline at end of file
diff --git a/example/daemon/www/js/connection_view.js b/example/daemon/www/js/connection_view.js
index 219803c..a75955e 100644
--- a/example/daemon/www/js/connection_view.js
+++ b/example/daemon/www/js/connection_view.js
@@ -1,8 +1,6 @@
 export class ConnectionView {
-    constructor(connection) {
-        this.connection = connection;
-        this.connection.onclose = () => { this.onConnectionClosed(); };
-        this.connection.onopen = () => { this.onConnectionOpened(); };
+    constructor(client) {
+        this.connection = client;
 
         this.element = document.createElement("div");
 
@@ -28,7 +26,7 @@ export class ConnectionView {
             this.connection.connectTo(url);
         }
         else {
-            this.connection.close();
+            this.connection.disconnect();
         }
     }
     onConnectionOpened() {
diff --git a/example/daemon/www/js/filesystem_handler.js b/example/daemon/www/js/filesystem_handler.js
deleted file mode 100644
index 017c047..0000000
--- a/example/daemon/www/js/filesystem_handler.js
+++ /dev/null
@@ -1,88 +0,0 @@
-/* eslint no-console: "off" */
-
-export class FileSystemHandler {
-
-    constructor(filesystem, connection) {
-        this._fs = filesystem;
-        this._connection = connection;
-        this._connection.onmessage = (message) => {
-            this._onmessage(message); 
-        };
-    }
-
-    _onmessage(message) {
-
-        try {
-            let request = JSON.parse(message.data);
-            let result = -42;
-            let response;
-    
-            console.log(request);
-            if (("string" === typeof(request.method)) && 
-                ("number" === typeof(request.id)) && 
-                            (request.params)) {
-                switch(request.method)
-                {
-                    case "lookup":
-                    {
-                        const parent = request.params[0];
-                        const name = request.params[1];
-                        result = this._fs.lookup(parent, name);
-                    }
-                    break;
-                    case "getattr":
-                    {
-                        const inode = request.params[0];
-                        result = this._fs.getattr(inode);
-                    }
-                    break;
-                    case "readdir":
-                    {
-                        const inode = request.params[0];
-                        result = this._fs.readdir(inode);
-                    }
-                    break;
-                    case "open":
-                    {
-                        const inode = request.params[0];
-                        const mode = request.params[1];
-                        result = this._fs.open(inode, mode);
-                    }
-                    break;
-                    case "close":
-                    {
-                        const inode = request.params[0];
-                        const handle = request.params[1];
-                        const mode = request.params[2];
-                        this._fs.close(inode, handle, mode);
-                    }
-                    break;
-                    case "read":
-                    {
-                        const inode = request.params[0];
-                        const handle = request.params[1];
-                        const offset = request.params[2];
-                        const length = request.params[3];
-                        result = this._fs.read(inode, handle, offset, length);
-                    }
-                    break;
-                    default:
-                        break;
-                }
-                
-                if ("number" == typeof(request.id))
-                {
-                    if ("number" !== typeof(result)) {
-                        response = {result: result, id: request.id};
-                    }
-                    else {
-                        response = {error: {code: result}, id: request.id};
-                    }
-                    console.log(response);
-                    this._connection.send(JSON.stringify(response));
-                }
-            }
-        }
-        catch (ex) { console.log(ex, message); }	
-    }   
-}
diff --git a/example/daemon/www/js/filesystem.js b/example/daemon/www/js/filesystem_provider.js
similarity index 57%
rename from example/daemon/www/js/filesystem.js
rename to example/daemon/www/js/filesystem_provider.js
index 8393026..be9a32b 100644
--- a/example/daemon/www/js/filesystem.js
+++ b/example/daemon/www/js/filesystem_provider.js
@@ -1,32 +1,31 @@
 /* eslint no-unused-vars: ["error", { "argsIgnorePattern": "^_" }] */
 
-export class FileSystem {
-    static get GOOD() { return 0; }
-    static get BAD()  { return 1; }
-
-    static get BAD_NOTIMPLEMENTED()  { return 2; }
-    static get BAD_TIMEOUT()         { return 3; }
-    static get BAD_FORMAT()          { return 4; }
-
-    static get BAD_NOENTRY()  { return 101; }
-    static get BAD_NOACCESS() { return 102; }
-
-    static get O_ACCMODE() { return 0x003; }
-    static get O_RDONLY()  { return 0x000; }
-    static get O_WRONLY()  { return 0x001; }
-    static get O_RDWR()    { return 0x002; }
-    static get O_CREAT()   { return 0x040; }
-    static get O_EXCL()    { return 0x080; }
-    static get O_TRUNK()   { return 0x200; }
-    static get O_APPEND()  { return 0x400; }
+import { BadState } from "./wsfs/bad_state.js";
+import { FileMode } from "./wsfs/file_mode.js";
+import { Provider } from "./wsfs/provider.js";
 
+export class FileSystemProvider extends Provider {
     constructor(root) {
+        super();
+
         this.root = root;
         this._inodes = { };
         
         this._walk(this.root, (entry) => { this._inodes[entry.inode] = entry; });
     }
 
+    setView(view) {
+        this._view = view;
+    }
+
+    connected() {
+        if (this._view) { this._view.onConnectionOpened(); }
+    }
+
+    disconnected() {
+        if (this._view) { this._view.onConnectionClosed(); }
+    }
+
     _walk(node, callback) {
         callback(node);
 
@@ -39,7 +38,7 @@ export class FileSystem {
     }
    
     
-    lookup(parent, name) {
+    async lookup(parent, name) {
         const parentEntry = this._inodes[parent];
         const entry = (parentEntry && parentEntry.entries && parentEntry.entries[name]) || null;
         if (entry) {
@@ -54,12 +53,12 @@ export class FileSystem {
 			};
         }
         else {
-            return FileSystem.BAD_NOENTRY;
+            throw new BadState(BadState.NO_ENTRY);
         }
     }
 
 
-    getattr(inode) {
+    async getattr(inode) {
         let entry = this._inodes[inode];
         if (entry) {
 			return {
@@ -72,16 +71,15 @@ export class FileSystem {
 			};
         }
         else {
-            return FileSystem.BAD_NOENTRY;
+            throw new BadState(BadState.NO_ENTRY);
         }
     }
 
-    readdir(inode) {
-        let result = FileSystem.BAD_NOENTRY;
+    async readdir(inode) {
         let entry = this._inodes[inode];
 
         if ((entry) && ("dir" === entry.type)) {
-            result = [
+            let result = [
                 {name: ".", inode: entry.inode},
                 {name: "..", inode: entry.inode}
             ];
@@ -90,20 +88,29 @@ export class FileSystem {
                 const inode = subdir[1].inode;
                 result.push({name, inode});               
             }
+
+            return result;
+        }
+        else {
+            throw new BadState(BadState.NO_ENTRY);
         }
 
-        return result;
     }
 
-    open(inode, mode) {
-        let result = FileSystem.BAD_NOENTRY;
+    async open(inode, mode) {
         let entry = this._inodes[inode];
 
 		if (entry.type === "file") {
-			result = ((mode & FileSystem.O_ACCMODE) === FileSystem.O_RDONLY) ? {handle: 1337} : FileSystem.BAD_NOACCESS;			
-		}
-	
-		return result;
+			if ((mode & FileMode.ACCESS_MODE) === FileMode.READONLY) {
+                return {handle: 1337}; 
+            }
+            else {
+                throw new BadState(BadState.NO_ACCESS);                
+            }
+        }
+        else {
+            throw new BadState(BadState.NO_ENTRY);
+        }
     }
 
     close(_inode, _handle, _mode) {
@@ -111,20 +118,17 @@ export class FileSystem {
 		return true;
     }
 
-    read(inode, handle, offset, length) {
-		let result = FileSystem.BAD_NOENTRY;
+    async read(inode, handle, offset, length) {
 		let entry = this._inodes[inode];
 				
 		if (entry.type === "file") {
-			let end = Math.min(offset + length, entry.contents.length);
-			let data = (offset < entry.contents.length) ? entry.contents.substring(offset, end) : "";	
-			result = {
-				data: btoa(data),
-				format: "base64",
-				count: data.length
-			};
-		}
-	
-		return result;
+			const end = Math.min(offset + length, entry.contents.length);
+            const data = (offset < entry.contents.length) ? entry.contents.substring(offset, end) : "";
+
+            return data;
+        }
+        else {
+            throw new BadState(BadState.NO_ENTRY);
+        }
     }
 }
\ No newline at end of file
diff --git a/example/daemon/www/js/startup.js b/example/daemon/www/js/startup.js
index 29ffab6..3118a74 100644
--- a/example/daemon/www/js/startup.js
+++ b/example/daemon/www/js/startup.js
@@ -1,7 +1,6 @@
-import { Connection } from "./connection.js";
+import { Client } from "./wsfs/client.js";
 import { ConnectionView } from "./connection_view.js";
-import { FileSystem } from "./filesystem.js";
-import { FileSystemHandler } from "./filesystem_handler.js";
+import { FileSystemProvider } from "./filesystem_provider.js";
 
 
 function mode(value) {
@@ -9,11 +8,7 @@ function mode(value) {
 }
 
 function startup() {
-    let connection = new Connection();
-    let connectionView = new ConnectionView(connection);
-    document.getElementById('connection').appendChild(connectionView.element);
-
-    let fs = new FileSystem({
+    let provider = new FileSystemProvider({
         inode: 1,
         mode: mode("0755"),
         type: "dir",
@@ -22,8 +17,10 @@ function startup() {
             "say_hello.sh": { inode: 3, mode: mode("0555"), type: "file", contents: "#!/bin/sh\necho hello\n"}
         }
     });
-
-    let handler = new FileSystemHandler(fs, connection);
+    let client = new Client(provider);
+    let connectionView = new ConnectionView(client);    
+    document.getElementById('connection').appendChild(connectionView.element);
+    provider.setView(connectionView);
 }
 
 window.onload = startup;
diff --git a/example/daemon/www/js/wsfs/bad_state.js b/example/daemon/www/js/wsfs/bad_state.js
new file mode 100644
index 0000000..fdb05d9
--- /dev/null
+++ b/example/daemon/www/js/wsfs/bad_state.js
@@ -0,0 +1,15 @@
+export class BadState extends Error {
+    static get BAD()  { return 1; }
+
+    static get NOT_IMPLEMENTED()  { return 2; }
+    static get TIMEOUT()         { return 3; }
+    static get FORMAT()          { return 4; }
+
+    static get NO_ENTRY()  { return 101; }
+    static get NO_ACCESS() { return 102; }
+
+    constructor(code) {
+        super("Bad State");
+        this.code = code;
+    }
+}
\ No newline at end of file
diff --git a/example/daemon/www/js/wsfs/client.js b/example/daemon/www/js/wsfs/client.js
new file mode 100644
index 0000000..f6428d6
--- /dev/null
+++ b/example/daemon/www/js/wsfs/client.js
@@ -0,0 +1,156 @@
+import { BadState } from "./bad_state.js";
+
+export class Client {
+    static get _PROTOCOL() { return "fs"; }
+
+    constructor(provider) {
+        this._provider = provider;
+        this._ws = null;
+        this.isConnected = false;
+    }
+
+    connectTo(url) {
+        this.disconnect();
+
+        this._ws = new WebSocket(url, Client._PROTOCOL);
+        this._ws.onopen = () => {
+            this.isConnected = true;
+            this._provider.connected(); 
+        };
+        this._ws.onclose = () => {
+            this.isConnected = false;
+            this._provider.disconnected();
+        };
+        this._ws.onmessage = (message) => {
+            this._onmessage(message);
+        };
+    }
+
+    disconnect() {
+        if (this._ws) {
+            this._ws.close();
+        }
+    }
+
+    _onmessage(message) {
+        try {
+            const request = JSON.parse(message.data);
+            const method = request.method;
+            const id = request.id;
+            const params = request.params;
+
+            if ("string" !== typeof(method)) {
+                throw new Error("parse error: missing field: \"method\"");
+            }
+
+            if (!params) {
+                throw new Error("parse error: missing field: \"params\"");
+            }
+
+            if ("number" === typeof(request.id)) {
+                this._invoke(method, params, id);
+            }
+            else {
+                this._notify(method, params);
+            }
+        }
+        catch (ex) {
+            // swallow
+        }
+    }
+
+    _invoke(method, params, id) {
+        this._invokeAsync(method, params).then((result) => {
+            const response = { result, id };
+            this._ws.send(JSON.stringify(response));
+        }).
+        catch((ex) => {
+            const code = ex.code || BadState.BAD;
+            const response = {error: {code}, id};
+            this._ws.send(JSON.stringify(response));
+        });
+
+    }
+
+    async _invokeAsync(method, params) {
+        switch(method)
+        {
+            case "lookup":
+                return this._lookup(params);
+            case "getattr":
+                return this._getattr(params);
+            case "readdir":
+                return this._readdir(params);
+            case "open":
+                return this._open(params);
+            case "read":
+                return this._read(params);
+            default:
+                throw new BadState(BadState.NOT_IMPLEMENTED);
+        }
+    }
+
+    _notify(method, params) {
+        switch(method) {
+            case 'close':
+                this._close(params);
+                break;
+            default:
+                throw new Error(`Invalid method: "${method}"`);
+        }
+    }
+
+    async _lookup(params) {
+        const parent = params[0];
+        const name = params[1];
+        
+        return this._provider.lookup(parent, name);
+    }
+
+    async _getattr(params) {
+        const inode = params[0];
+
+        return this._provider.getattr(inode);
+    }
+
+    async _readdir(params) {
+        const inode = params[0];
+
+        return this._provider.readdir(inode);
+    }
+
+    async _open(params) {
+        const inode = params[0];
+        const mode = params[1];
+
+        return this._provider.open(inode, mode);
+    }
+
+    _close(params) {
+        const inode = params[0];
+        const handle = params[1];
+        const mode = params[2];
+
+        this._provider.close(inode, handle, mode);
+    }
+
+    async _read(params) {
+        const inode = params[0];
+        const handle = params[1];
+        const offset = params[2];
+        const length = params[3];
+
+        const data = await this._provider.read(inode, handle, offset, length);
+
+        if ("string" === typeof(data)) {
+			return {
+				data: btoa(data),
+				format: "base64",
+				count: data.length
+			};
+        }
+        else {
+            throw new BadState(BadState.BAD);
+        }
+    }    
+} 
\ No newline at end of file
diff --git a/example/daemon/www/js/wsfs/file_mode.js b/example/daemon/www/js/wsfs/file_mode.js
new file mode 100644
index 0000000..b81a1ea
--- /dev/null
+++ b/example/daemon/www/js/wsfs/file_mode.js
@@ -0,0 +1,10 @@
+export class FileMode {
+    static get ACCESS_MODE() { return 0x003; }
+    static get READONLY()    { return 0x000; }
+    static get WRITEONLY()   { return 0x001; }
+    static get READWRITE()   { return 0x002; }
+    static get CREATE()      { return 0x040; }
+    static get EXCLUSIVE()   { return 0x080; }
+    static get TRUNKATE()    { return 0x200; }
+    static get APPEND()      { return 0x400; }    
+}
\ No newline at end of file
diff --git a/example/daemon/www/js/wsfs/provider.js b/example/daemon/www/js/wsfs/provider.js
new file mode 100644
index 0000000..c9008f9
--- /dev/null
+++ b/example/daemon/www/js/wsfs/provider.js
@@ -0,0 +1,38 @@
+/* eslint no-unused-vars: ["error", { "argsIgnorePattern": "^_" }] */
+
+import { BadState } from "./bad_state.js";
+
+export class Provider {
+
+    connected() {
+        // empty
+    }
+
+    disconnected() {
+        // empty
+    }
+
+    async lookup(_parent, _name) {
+        throw new BadState(BadState.NOT_IMPLEMENTED);
+    }
+
+    async getattr(_inode) {
+        throw new BadState(BadState.NOT_IMPLEMENTED);
+    }
+
+    async readdir(_inode) {
+        throw new BadState(BadState.NOT_IMPLEMENTED);
+    }
+
+    async open(_inode, _mode) {
+        throw new BadState(BadState.NOT_IMPLEMENTED);
+    }
+
+    close(_inode, _handle, _mode) {
+        // empty
+    }
+
+    async read(_inode, _handle, _offset, _length) {
+        throw new BadState(BadState.NOT_IMPLEMENTED);
+    }
+}