Create our own HTML to Markdown converter

discord_rss_bot/markdown.py

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+from functools import lru_cache
+
+from bs4 import BeautifulSoup
+
+
+@lru_cache(maxsize=2048)
+def convert_html_to_md(html: str) -> str:
+    """Convert HTML to Markdown.
+
+    Discord supports:
+    - Bold with **text**
+    - Italic with *text*
+    - Blockquote with >>> text
+    - Code with `text`
+        - Fence code with ```text```
+    - Links with [text](url)
+    - Syntax highlighting with ```language
+    - Strikethrough with ~~text~~
+    """
+    soup: BeautifulSoup = BeautifulSoup(html, features="lxml")
+
+    # Bold
+    for bold in soup.find_all("b") + soup.find_all("strong"):
+        bold.replace_with(f"**{bold.text}**")
+
+    # Italic
+    for italic in soup.find_all("i") + soup.find_all("em"):
+        italic.replace_with(f"*{italic.text}*")
+
+    # Blockquote
+    for blockquote in soup.find_all("blockquote") + soup.find_all("q"):
+        blockquote.replace_with(f">>> {blockquote.text}")
+
+    # Code
+    for code in soup.find_all("code") + soup.find_all("pre"):
+        code.replace_with(f"`{code.text}`")
+
+    # Links
+    for link in soup.find_all("a") + soup.find_all("link"):
+        link_text = link.text or link.get("href") or "Link"
+        link.replace_with(f"[{link_text}]({link.get('href')})")
+
+    # Strikethrough
+    for strikethrough in soup.find_all("s") + soup.find_all("del") + soup.find_all("strike"):
+        strikethrough.replace_with(f"~~{strikethrough.text}~~")
+
+    # <br> tags
+    for br in soup.find_all("br"):
+        br.replace_with("\n")
+
+    # Remove all other tags
+    for tag in soup.find_all(True):
+        tag.replace_with(tag.text)
+
+    # If the text ends with a newline, remove it
+    # return soup.text[:-1] if soup.text.endswith("\n") else soup.text
+    return soup.text
+
+
+# Test the function
+if __name__ == "__main__":
+    html: str = """
+    <p><b>bold</b> <i>italic</i> <a href="https://example.com">link</a> <code>code</code> <s>strikethrough</s></p>
+    <blockquote>blockquote</blockquote>
+    <pre><code>pre code</code></pre>
+    <strong>strong</strong>
+    """
+    print(convert_html_to_md(html))