From 951703550197b165ab7c8ebe335b6a2e572a6d1e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C4=93teris=20Caune?= <cuu508@gmail.com>
Date: Thu, 9 Sep 2021 10:56:23 +0300
Subject: [PATCH] Fix N+1 queries issue in "My Checks" and clean up Check.url()

---
 hc/api/models.py                       | 22 +++++++++++-----------
 hc/front/templatetags/hc_extras.py     | 14 ++++++++++++++
 hc/front/views.py                      |  1 +
 templates/front/my_checks_desktop.html |  8 ++------
 4 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/hc/api/models.py b/hc/api/models.py
index 98aca553..ccc9ccb5 100644
--- a/hc/api/models.py
+++ b/hc/api/models.py
@@ -115,23 +115,23 @@ class Check(models.Model):
 
         return str(self.code)
 
-    def relative_url(self):
+    def url(self):
+        """ Return check's ping url in user's preferred style.
+
+        Note: this method reads self.project. If project is not loaded already,
+        this causes a SQL query.
+
+        """
+
         if self.project_id and self.project.show_slugs:
             if not self.slug:
                 return None
 
-            key = self.project.ping_key
             # If ping_key is not set, use dummy placeholder
-            if key is None:
-                key = "{ping_key}"
-            return key + "/" + self.slug
-
-        return str(self.code)
+            key = self.project.ping_key or "{ping_key}"
+            return settings.PING_ENDPOINT + key + "/" + self.slug
 
-    def url(self):
-        s = self.relative_url()
-        if s:
-            return settings.PING_ENDPOINT + s
+        return settings.PING_ENDPOINT + str(self.code)
 
     def details_url(self):
         return settings.SITE_ROOT + reverse("hc-details", args=[self.code])
diff --git a/hc/front/templatetags/hc_extras.py b/hc/front/templatetags/hc_extras.py
index 9de2207e..2d7b7d53 100644
--- a/hc/front/templatetags/hc_extras.py
+++ b/hc/front/templatetags/hc_extras.py
@@ -213,3 +213,17 @@ def guess_schedule(check):
     hours, seconds = divmod(v, 3600)
     if hours in (2, 3, 4, 6, 8, 12) and seconds == 0:
         return f"0 */{hours} * * *"
+
+
+FORMATTED_PING_ENDPOINT = (
+    f"""<span class="base hidden-md">{settings.PING_ENDPOINT}</span>"""
+)
+
+
+@register.filter
+def format_ping_endpoint(ping_url):
+    """ Wrap the ping endpoint in span tags for styling with CSS. """
+
+    assert ping_url.startswith(settings.PING_ENDPOINT)
+    tail = ping_url[len(settings.PING_ENDPOINT) :]
+    return mark_safe(FORMATTED_PING_ENDPOINT + escape(tail))
diff --git a/hc/front/views.py b/hc/front/views.py
index 6314b145..d64d0d07 100644
--- a/hc/front/views.py
+++ b/hc/front/views.py
@@ -182,6 +182,7 @@ def my_checks(request, code):
         request.session["last_project_id"] = project.id
 
     q = Check.objects.filter(project=project)
+    q = q.select_related("project")
     checks = list(q.prefetch_related("channel_set"))
     sortchecks(checks, request.profile.sort)
 
diff --git a/templates/front/my_checks_desktop.html b/templates/front/my_checks_desktop.html
index 2e7cad21..7b7b56ec 100644
--- a/templates/front/my_checks_desktop.html
+++ b/templates/front/my_checks_desktop.html
@@ -84,12 +84,8 @@
             {% if project.show_slugs and not check.slug %}
             <span class="unavailable">unavailable, set name first</span>
             {% else %}
-            <span class="my-checks-url">
-                <span class="base hidden-md">{{ ping_endpoint }}</span>{{ check.relative_url }}
-            </span>
-            <button class="copy-link" data-clipboard-text="{{ check.url }}">
-                copy
-            </button>
+            <span class="my-checks-url">{{ check.url|format_ping_endpoint }}</span>
+            <button class="copy-link" data-clipboard-text="{{ check.url }}">copy</button>
             {% endif %}
         </td>
         <td class="hidden-xs">