Add markdown utils

- External links open in a new tab
- Clicking on image open an image modal

judge/markdown.py

@@ -3,6 +3,8 @@ import bleach
 from django.utils.html import escape
 from bs4 import BeautifulSoup
 from pymdownx import superfences
+from django.conf import settings
+from urllib.parse import urlparse
 
 from judge.markdown_extensions import YouTubeExtension, EmoticonExtension
 
@@ -96,6 +98,35 @@ ALLOWED_ATTRS = [
 ]
 
 
+def _wrap_img_iframe_with_lazy_load(soup):
+    for img in soup.findAll("img"):
+        if img.get("src"):
+            img["loading"] = "lazy"
+    for img in soup.findAll("iframe"):
+        if img.get("src"):
+            img["loading"] = "lazy"
+    return soup
+
+
+def _wrap_images_with_featherlight(soup):
+    for img in soup.findAll("img"):
+        if img.get("src"):
+            link = soup.new_tag("a", href=img["src"], **{"data-featherlight": "image"})
+            img.wrap(link)
+    return soup
+
+
+def _open_external_links_in_new_tab(soup):
+    domain = settings.SITE_DOMAIN.lower()
+    for a in soup.findAll("a", href=True):
+        href = a["href"]
+        if href.startswith("http://") or href.startswith("https://"):
+            link_domain = urlparse(href).netloc.lower()
+            if link_domain != domain:
+                a["target"] = "_blank"
+    return soup
+
+
 def markdown(value, lazy_load=False):
     extensions = EXTENSIONS
     html = _markdown.markdown(
@@ -106,13 +137,13 @@ def markdown(value, lazy_load=False):
 
     if not html:
         html = escape(value)
+
+    soup = BeautifulSoup(html, features="html.parser")
     if lazy_load:
-        soup = BeautifulSoup(html, features="html.parser")
-        for img in soup.findAll("img"):
-            if img.get("src"):
-                img["loading"] = "lazy"
-        for img in soup.findAll("iframe"):
-            if img.get("src"):
-                img["loading"] = "lazy"
-        html = str(soup)
+        soup = _wrap_img_iframe_with_lazy_load(soup)
+
+    soup = _wrap_images_with_featherlight(soup)
+    soup = _open_external_links_in_new_tab(soup)
+    html = str(soup)
+
     return '<div class="md-typeset content-description">%s</div>' % html