From 4b224f0a1f24b008a7c259062163c6d98acc2be2 Mon Sep 17 00:00:00 2001
From: Gabriel Augendre <gabriel@augendre.info>
Date: Sun, 3 Jan 2021 21:46:41 +0100
Subject: [PATCH] Minify custom css before rendering

---
 articles/models.py                            | 14 ++++++-
 .../templates/articles/article_detail.html    |  2 +-
 articles/templates/articles/article_list.html |  2 +-
 articles/tests/test_models.py                 | 40 +++++++++++++++++++
 4 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/articles/models.py b/articles/models.py
index 8401d80..11ec6fa 100644
--- a/articles/models.py
+++ b/articles/models.py
@@ -1,7 +1,7 @@
 import random
 import re
 import uuid
-from functools import cached_property
+from functools import cached_property, reduce
 
 import html2text
 import markdown
@@ -153,3 +153,15 @@ class Article(AdminUrlMixin, models.Model):
         return list(
             filter(None, map(lambda k: k.strip().lower(), self.keywords.split(",")))
         )
+
+    @cached_property
+    def get_minified_custom_css(self):
+        def reducer(res, next_char):
+            if len(res) == 0:
+                return next_char
+            if res[-1] == next_char == " ":
+                return res
+            return res + next_char
+
+        css = self.custom_css.replace("\n", " ")
+        return reduce(reducer, css, "")
diff --git a/articles/templates/articles/article_detail.html b/articles/templates/articles/article_detail.html
index 053c2ec..72f9fa9 100644
--- a/articles/templates/articles/article_detail.html
+++ b/articles/templates/articles/article_detail.html
@@ -2,7 +2,7 @@
 
 {% block append_header %}
     <style>
-        {{ article.custom_css }}
+        {{ article.get_minified_custom_css }}
     </style>
 {% endblock %}
 
diff --git a/articles/templates/articles/article_list.html b/articles/templates/articles/article_list.html
index 4a9e436..8eb3f5a 100644
--- a/articles/templates/articles/article_list.html
+++ b/articles/templates/articles/article_list.html
@@ -2,7 +2,7 @@
 
 {% block append_header %}
     <style>
-        {{ article.custom_css }}
+        {{ article.get_minified_custom_css }}
     </style>
     <style>
         .pagination {
diff --git a/articles/tests/test_models.py b/articles/tests/test_models.py
index 7a80f96..0f48f12 100644
--- a/articles/tests/test_models.py
+++ b/articles/tests/test_models.py
@@ -39,3 +39,43 @@ def test_save_article_doesnt_change_existing_slug(published_article: Article):
     published_article.title = "This is a brand new title"
     published_article.save()
     assert published_article.slug == original_slug
+
+
+@pytest.mark.django_db
+def test_empty_custom_css_minified(published_article):
+    published_article.custom_css = ""
+    assert published_article.get_minified_custom_css == ""
+
+
+@pytest.mark.django_db
+def test_simple_custom_css_minified(published_article):
+    published_article.custom_css = ".cls {\n    background-color:  red;\n}"
+    assert (
+        published_article.get_minified_custom_css == ".cls { background-color: red; }"
+    )
+
+
+@pytest.mark.django_db
+def test_larger_custom_css_minified(published_article):
+    published_article.custom_css = """\
+.profile {
+    display: flex;
+    justify-content: space-evenly;
+    flex-wrap: wrap;
+}
+
+.profile img {
+    max-width: 200px;
+    min-width: 100px;
+    max-height: 200px;
+    min-height: 100px;
+    border-radius: 10%;
+    padding: 1rem;
+    flex-shrink: 1;
+    flex-grow: 0;
+    padding: 0;
+}"""
+    assert (
+        published_article.get_minified_custom_css
+        == """.profile { display: flex; justify-content: space-evenly; flex-wrap: wrap; } .profile img { max-width: 200px; min-width: 100px; max-height: 200px; min-height: 100px; border-radius: 10%; padding: 1rem; flex-shrink: 1; flex-grow: 0; padding: 0; }"""
+    )