From 25e48f1b9fff10866e4d6a0f875912527a5160bc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C4=93teris=20Caune?= <cuu508@gmail.com>
Date: Fri, 14 Dec 2018 18:58:35 +0200
Subject: [PATCH] croniter.is_valid() throws exceptions for some bad inputs, so
 must use try ... except

---
 hc/front/tests/test_cron_preview.py   |  9 ++++++++-
 hc/front/tests/test_update_timeout.py | 21 ++++++++++++---------
 hc/front/validators.py                |  4 +++-
 hc/front/views.py                     | 26 +++++++++++++-------------
 4 files changed, 36 insertions(+), 24 deletions(-)

diff --git a/hc/front/tests/test_cron_preview.py b/hc/front/tests/test_cron_preview.py
index 5ed68d0e..791ebc9d 100644
--- a/hc/front/tests/test_cron_preview.py
+++ b/hc/front/tests/test_cron_preview.py
@@ -16,7 +16,14 @@ class CronPreviewTestCase(BaseTestCase):
         self.assertContains(r, "cron-preview-title", status_code=200)
 
     def test_it_rejects_invalid_cron_expression(self):
-        for schedule in [None, "", "*", "100 100 100 100 100", "* * * * * *"]:
+        samples = [None,
+                   "",
+                   "*",
+                   "100 100 100 100 100",
+                   "* * * * * *",
+                   "1,2 3,* * * *"]
+
+        for schedule in samples:
             payload = {"schedule": schedule, "tz": "UTC"}
             r = self.client.post("/checks/cron_preview/", payload)
             self.assertContains(r, "Invalid cron expression", status_code=200)
diff --git a/hc/front/tests/test_update_timeout.py b/hc/front/tests/test_update_timeout.py
index c4a03933..d90ba1de 100644
--- a/hc/front/tests/test_update_timeout.py
+++ b/hc/front/tests/test_update_timeout.py
@@ -67,16 +67,19 @@ class UpdateTimeoutTestCase(BaseTestCase):
         self.assertEqual(self.check.schedule, "5 * * * *")
 
     def test_it_validates_cron_expression(self):
-        payload = {
-            "kind": "cron",
-            "schedule": "* invalid *",
-            "tz": "UTC",
-            "grace": 60
-        }
-
         self.client.login(username="alice@example.org", password="password")
-        r = self.client.post(self.url, data=payload)
-        self.assertEqual(r.status_code, 400)
+        samples = ["* invalid *", "1,2 3,* * * *"]
+
+        for sample in samples:
+            payload = {
+                "kind": "cron",
+                "schedule": sample,
+                "tz": "UTC",
+                "grace": 60
+            }
+
+            r = self.client.post(self.url, data=payload)
+            self.assertEqual(r.status_code, 400)
 
         # Check should still have its original data:
         self.check.refresh_from_db()
diff --git a/hc/front/validators.py b/hc/front/validators.py
index 89750ff9..0b5fc8f2 100644
--- a/hc/front/validators.py
+++ b/hc/front/validators.py
@@ -24,7 +24,9 @@ class CronExpressionValidator(object):
         if len(value.split()) != 5:
             raise ValidationError(message=self.message)
 
-        if not croniter.is_valid(value):
+        try:
+            croniter(value)
+        except:
             raise ValidationError(message=self.message)
 
 
diff --git a/hc/front/views.py b/hc/front/views.py
index 29700479..71a7b442 100644
--- a/hc/front/views.py
+++ b/hc/front/views.py
@@ -325,21 +325,21 @@ def cron_preview(request):
     tz = request.POST.get("tz")
     ctx = {"tz": tz, "dates": []}
 
-    if len(schedule.split()) != 5:
-        ctx["bad_schedule"] = True
-    elif not croniter.is_valid(schedule):
+    try:
+        zone = pytz.timezone(tz)
+        now_local = timezone.localtime(timezone.now(), zone)
+
+        if len(schedule.split()) != 5:
+            raise ValueError()
+
+        it = croniter(schedule, now_local)
+        for i in range(0, 6):
+            ctx["dates"].append(it.get_next(datetime))
+    except UnknownTimeZoneError:
+        ctx["bad_tz"] = True
+    except:
         ctx["bad_schedule"] = True
 
-    if "bad_schedule" not in ctx:
-        try:
-            zone = pytz.timezone(tz)
-            now_local = timezone.localtime(timezone.now(), zone)
-            it = croniter(schedule, now_local)
-            for i in range(0, 6):
-                ctx["dates"].append(it.get_next(datetime))
-        except UnknownTimeZoneError:
-            ctx["bad_tz"] = True
-
     return render(request, "front/cron_preview.html", ctx)