--- a/viewer.py	Sat Jun 18 18:56:40 2016 +0800
+++ b/viewer.py	Sat Jun 18 22:30:42 2016 +0800
@@ -4,10 +4,11 @@
 import logging
 import os
 
+from peewee import DoesNotExist
 from tornado.escape import json_decode
 from tornado.ioloop import IOLoop
 from tornado.options import define, options
-from tornado.web import Application, RequestHandler, URLSpec
+from tornado.web import Application, HTTPError, RequestHandler, URLSpec
 
 from candolint import uimodules
 from candolint.models import database, Project, Change, Check
@@ -22,6 +23,13 @@
 define('debug', metavar='True|False', default=False, type=bool)
 
 
+def get_or_404(query, *args, **kwargs):
+    try:
+        return query.get(*args, **kwargs)
+    except DoesNotExist:
+        raise HTTPError(404)
+
+
 class BaseHandler(RequestHandler):
     def prepare(self):
         database.connect()
@@ -45,10 +53,11 @@
 
 class ProjectHandler(BaseHandler):
     def get(self, domain, user, name):
-        project = Project.select().where(
+        pq = Project.select().where(
             Project.domain == domain,
             Project.user == (user if user != '-' else None),
-            Project.name == name).get()
+            Project.name == name)
+        project = get_or_404(pq)
         checks = (Check
                   .select(Check, Change)
                   .join(Change)
@@ -59,25 +68,27 @@
 
 class CheckHandler(BaseHandler):
     def get(self, domain, user, name, check_num):
-        project = Project.select().where(
+        pq = Project.select().where(
             Project.domain == domain,
             Project.user == (user if user != '-' else None),
-            Project.name == name).get()
+            Project.name == name)
+        project = get_or_404(pq)
         if check_num == 'latest':
-            check = Check.get(project=project)
+            check = get_or_404(Check, project=project)
         else:
-            check = Check.get(project=project, ordinal=check_num)
+            check = get_or_404(Check, project=project, ordinal=check_num)
         lines = json_decode(check.lines)
         self.render('check.html', project=project, check=check, lines=lines)
 
 
 class StatusHandler(BaseHandler):
     def get(self, domain, user, name):
-        project = Project.select().where(
+        pq = Project.select().where(
             Project.domain == domain,
             Project.user == (user if user != '-' else None),
-            Project.name == name).get()
-        check = Check.get(project=project)
+            Project.name == name)
+        project = get_or_404(pq)
+        check = get_or_404(Check, project=project)
         parts = [('#555', 30, 14.5, 'lint')]
         if not check.success:
             parts.append(('#777', 62, 30.5, 'unknown'))