Code highlighting

utils/highlight.py

@@ -0,0 +1,30 @@
+from functools import lru_cache
+
+from bs4 import BeautifulSoup
+from pygments import highlight as phighlight
+from pygments.formatters import HtmlFormatter
+from pygments.lexers import guess_lexer
+
+from config import THEME_STYLE
+from config import ThemeStyle
+
+_FORMATTER = HtmlFormatter(
+    style="default" if THEME_STYLE == ThemeStyle.LIGHT else "vim"
+)
+
+HIGHLIGHT_CSS = _FORMATTER.get_style_defs()
+
+
+@lru_cache(512)
+def highlight(html: str) -> str:
+    soup = BeautifulSoup(html, "html5lib")
+    for code in soup.find_all("code"):
+        if not code.parent.name == "pre":
+            continue
+        lexer = guess_lexer(code.text)
+        tag = BeautifulSoup(phighlight(code.text, lexer, _FORMATTER)).body.next
+        pre = code.parent
+        pre.replaceWith(tag)
+    out = soup.body
+    out.name = "div"
+    return str(out)

utils/template_filters.py

@@ -21,6 +21,7 @@ from config import ID
 from config import MEDIA_CACHE
 from core.activitypub import _answer_key
 from utils import parse_datetime
+from utils.highlight import highlight
 from utils.media import Kind
 from utils.media import _is_img
 
@@ -47,6 +48,11 @@ def visibility_is_public(v: str) -> bool:
     return v in [ap.Visibility.PUBLIC.name, ap.Visibility.UNLISTED.name]
 
 
+@filters.app_template_filter()
+def code_highlight(content):
+    return highlight(content)
+
+
 @filters.app_template_filter()
 def emojify(text):
     return emoji_unicode.replace(