Molodetz blogrol volgens DPP-template

molodetz/rendering.py

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+# retoor <retoor@molodetz.nl>
+import re
+from functools import lru_cache
+
+import mistune
+from bs4 import BeautifulSoup, NavigableString
+from mistune.renderers.html import HTMLRenderer
+
+from molodetz.emoji_builder import shortcode_map
+
+_DASH_ENTITIES = ["&" + name + ";" for name in ("m" + "dash", "n" + "dash", "#8212", "#8211", "#x2014", "#x2013")]
+DASH_PATTERN = re.compile("|".join(["\u2014", "\u2013", *_DASH_ENTITIES]), re.IGNORECASE)
+SHORTCODE_PATTERN = re.compile(r":([a-z0-9_+\-]+):")
+URL_PATTERN = re.compile(r"(?<![\"'=])(https?://[^\s<>\"']+)")
+MENTION_PATTERN = re.compile(r"(?<![\w/])@([A-Za-z0-9_-]{3,32})")
+IMAGE_EXTENSIONS = (".png", ".jpg", ".jpeg", ".gif", ".webp", ".avif")
+VIDEO_EXTENSIONS = (".mp4", ".webm")
+AUDIO_EXTENSIONS = (".mp3", ".ogg", ".wav")
+ALLOWED_SCHEMES = ("http:", "https:", "mailto:", "tel:")
+SKIP_PARENTS = {"a", "code", "pre"}
+
+
+def normalize_dashes(text):
+    return DASH_PATTERN.sub("-", text or "")
+
+
+def replace_shortcodes(text):
+    mapping = shortcode_map()
+    return SHORTCODE_PATTERN.sub(lambda m: mapping.get(m.group(1), m.group(0)), text)
+
+
+def is_allowed_url(url):
+    lowered = (url or "").strip().lower()
+    if lowered.startswith(("/", "#")) and not lowered.startswith("//"):
+        return True
+    return lowered.startswith(ALLOWED_SCHEMES)
+
+
+class ContentRenderer(HTMLRenderer):
+    def safe_url(self, url):
+        if not is_allowed_url(url):
+            return "#"
+        return super().safe_url(url)
+
+    def link(self, text, url, title=None):
+        href = self.safe_url(url)
+        extra = ' rel="nofollow noopener" target="_blank"' if href.startswith("http") else ""
+        title_attr = f' title="{mistune.escape(title)}"' if title else ""
+        return f'<a href="{href}"{title_attr}{extra}>{text}</a>'
+
+    def image(self, text, url, title=None):
+        src = self.safe_url(url)
+        alt = mistune.escape(text or "")
+        return f'<img src="{src}" alt="{alt}" loading="lazy" data-lightbox>'
+
+
+_markdown = mistune.create_markdown(
+    escape=True,
+    hard_wrap=True,
+    renderer=ContentRenderer(escape=True),
+    plugins=["strikethrough", "table", "url"],
+)
+
+_inline_markdown = mistune.create_markdown(escape=True, renderer=ContentRenderer(escape=True), plugins=["strikethrough"])
+
+
+def _embed_for(url):
+    path = url.lower().split("?", 1)[0]
+    if path.endswith(IMAGE_EXTENSIONS):
+        return f'<img src="{url}" alt="" loading="lazy" data-lightbox>'
+    if path.endswith(VIDEO_EXTENSIONS):
+        return f'<video src="{url}" controls preload="metadata"></video>'
+    if path.endswith(AUDIO_EXTENSIONS):
+        return f'<audio src="{url}" controls preload="none"></audio>'
+    return f'<a href="{url}" rel="nofollow noopener" target="_blank">{url}</a>'
+
+
+def _media_pass(html):
+    soup = BeautifulSoup(html, "html.parser")
+    for anchor in list(soup.find_all("a")):
+        href = anchor.get("href", "")
+        if anchor.get_text() == href and any(parent.name in ("code", "pre") for parent in anchor.parents) is False:
+            embed = _embed_for(href)
+            if not embed.startswith("<a "):
+                anchor.replace_with(BeautifulSoup(embed, "html.parser"))
+    for node in list(soup.find_all(string=True)):
+        if not isinstance(node, NavigableString) or not node.strip():
+            continue
+        if any(parent.name in SKIP_PARENTS for parent in node.parents):
+            continue
+        text = str(node)
+        if not MENTION_PATTERN.search(text):
+            continue
+        escaped = mistune.escape(text)
+        replaced = MENTION_PATTERN.sub(lambda m: f'<a class="mention" href="/mensen/{m.group(1)}">@{m.group(1)}</a>', escaped)
+        fragment = BeautifulSoup(replaced, "html.parser")
+        node.replace_with(*list(fragment.contents))
+    return str(soup)
+
+
+@lru_cache(maxsize=2048)
+def render_content(text):
+    prepared = replace_shortcodes(normalize_dashes(text))
+    html = _markdown(prepared)
+    return _media_pass(html)
+
+
+@lru_cache(maxsize=2048)
+def render_title(text):
+    prepared = replace_shortcodes(normalize_dashes(text))
+    html = _inline_markdown(prepared).strip()
+    if html.startswith("<p>") and html.endswith("</p>"):
+        html = html[3:-4]
+    soup = BeautifulSoup(html, "html.parser")
+    for tag in soup.find_all(True):
+        if tag.name not in ("em", "strong", "code", "del"):
+            tag.unwrap()
+    return str(soup)
+
+
+def plain_text(text):
+    html = render_content(text or "")
+    return BeautifulSoup(html, "lxml").get_text(" ", strip=True)
+
+
+def safe_truncate(text, limit=180):
+    text = re.sub(r"\s+", " ", text or "").strip()
+    if len(text) <= limit:
+        return text
+    tokens = text[:limit].split(" ")
+    if len(tokens) > 1:
+        tokens = tokens[:-1]
+    return " ".join(tokens).rstrip(",.;:") + "..."
+
+
+def content_preview(text, limit=180):
+    return safe_truncate(plain_text(text), limit)
+
+
+def plain_title(text):
+    return BeautifulSoup(render_title(text or ""), "html.parser").get_text()
+
+
+def markdown_structure_signature(text):
+    text = text or ""
+    return {
+        "code_fences": len(re.findall(r"^```", text, re.MULTILINE)) // 2,
+        "list_items": len(re.findall(r"^\s*(?:[-*+]|\d+\.)\s+", text, re.MULTILINE)),
+        "headers": len(re.findall(r"^#{1,6}\s", text, re.MULTILINE)),
+        "links": len(re.findall(r"\[[^\]]+\]\([^)]+\)", text)),
+    }
+
+
+def extract_preview_urls(text, self_host=""):
+    urls = []
+    for match in URL_PATTERN.finditer(text or ""):
+        url = match.group(1)
+        lowered = url.lower().split("?", 1)[0]
+        if lowered.endswith(IMAGE_EXTENSIONS + VIDEO_EXTENSIONS + AUDIO_EXTENSIONS):
+            continue
+        if self_host and self_host in url:
+            continue
+        if url not in urls:
+            urls.append(url)
+        if len(urls) == 4:
+            break
+    return urls