diff -r b0659c867226 -r 5990b188c54b pvl/verkko/hosts.py
--- a/pvl/verkko/hosts.py	Wed Oct 10 22:10:16 2012 +0300
+++ b/pvl/verkko/hosts.py	Wed Oct 10 22:45:50 2012 +0300
@@ -64,14 +64,14 @@
     #_name   = db.dhcp_hosts.c.name,
 ))
 
-HOST_SORT = {
+HOST_ATTRS = {
     'id':   Host.id,
     'ip':   Host.ip,
     'mac':  Host.mac,
     'name': Host.name,
     'seen': Host.last_seen,
-    None:   Host.last_seen.desc(),
 }
+HOST_SORT = Host.last_seen.desc()
 
 def render_hosts (hosts, title=None) :
     COLS = (
@@ -135,62 +135,86 @@
         html.a(href='/hosts')(html('«'), 'Back'),
     )
 
-def respond (request, db, path) :
-    """
-        Handle request
-    """
-
-    hosts = db.query(Host)
-
-    # sort ?
-    sort = request.args.get('sort')
-    sort = HOST_SORT[sort]
-    log.debug("sort: %s", sort)
-
-    hosts = hosts.order_by(sort)
+class Handler (web.Handler) :
+    TITLE = "DHCP Hosts"
     
-    # index
-    if not path :
-        title = "DHCP Hosts"
-        html = render_hosts(hosts)
-    
-    # id
-    elif len(path) == 1 :
-        id, = path
-        id = int(id)
+    def index (self) :
+        return render_hosts(self.hosts)
 
-        host = hosts.get(id)
-        hosts = hosts.filter((Host.ip == host.ip) | (Host.mac == host.mac))
+    def host (self, id) :
+        host = self.hosts.get(id)
         
-        # render
-        title = "DHCP Host: {host}".format(host=unicode(host))
-        html = render_host(host, hosts)
+        if not host :
+            raise web.NotFound("No such host: {id}".format(id=id))
+
+        hosts = self.hosts.filter((Host.ip == host.ip) | (Host.mac == host.mac))
+        
+        # XXX
+        #self.title = "DHCP Host: {host}".format(host=unicode(host))
+
+        return render_host(host, hosts)
     
-    # query
-    elif len(path) == 2 :
-        attr, value = path
-        
+    def list (self, attr, value) :
         # fake host
         host = { 'ip': None, 'mac': None, 'name': None }
+
+        if attr not in HOST_ATTRS :
+            raise web.BadRequest("Invalid attribute: {attr}".format(attr=attr))
+
         host[attr] = value
 
         host = Host(**host)
 
         # query
-        attr = HOST_SORT[attr]
+        attr = HOST_ATTRS[attr]
         log.debug("%s == %s", attr, value)
 
-        hosts = hosts.filter(attr == value)
+        hosts = self.hosts.filter(attr == value)
         
-        # render
-        title = "DHCP Hosts: {value}".format(value=value)
-        html = render_host(host, hosts)
+        # XXX
+        #self.title = "DHCP Hosts: {value}".format(value=value)
 
-    else :
-        return Response("Not Found", status=404)
+        return render_host(host, hosts)
+    
+    def process (self) :
+        hosts = self.db.query(Host)
 
-    # render
-    html = web.render_layout(title, html)
+        # sort ?
+        sort = self.request.args.get('sort')
 
-    return web.Response(html, content_type='text/html; charset=UTF-8')
+        if sort :
+            sort = HOST_ATTRS[sort]
+        else :
+            sort = HOST_SORT
 
+        log.debug("sort: %s", sort)
+
+        hosts = hosts.order_by(sort)
+        
+        # store
+        self.hosts = hosts
+    
+    def render (self) :
+        # index
+        if not self.path :
+            return self.index()
+        
+        # id
+        elif len(self.path) == 1 :
+            try :
+                id, = self.path
+                id = int(id)
+            except ValueError as ex :
+                raise web.BadRequest("Invalid host ID: {id}: {ex}".format(id=id, ex=ex))
+
+            return self.host(id)
+
+        # query
+        elif len(self.path) == 2 :
+            attr, value = self.path
+            
+            return self.list(attr, value)
+
+        else :
+            raise web.NotFound
+