Check packages for broken links when submitting for approval

Half of #546

app/tasks/pkgtasks.py

@@ -16,12 +16,15 @@
 
 import datetime
 import re
+from typing import Optional
 
+import requests
 from sqlalchemy import or_, and_
 
+from app.markdown import get_links, render_markdown
 from app.models import Package, db, PackageState, AuditLogEntry
-from app.tasks import celery
-from app.utils import post_bot_message
+from app.tasks import celery, TaskError
+from app.utils import post_bot_message, post_to_approval_thread, get_system_user
 
 
 @celery.task()
@@ -103,3 +106,59 @@ def clear_removed_packages(all_packages: bool):
 	db.session.commit()
 
 	return f"Deleted {count} soft deleted packages packages"
+
+
+def _url_exists(url: str) -> bool:
+	try:
+		with requests.get(url, stream=True) as response:
+			try:
+				response.raise_for_status()
+				return True
+			except requests.exceptions.HTTPError:
+				return False
+	except requests.exceptions.ConnectionError:
+		return False
+
+
+def check_for_dead_links(package: Package) -> set[str]:
+	links: list[Optional[str]] = [
+		package.repo,
+		package.website,
+		package.issueTracker,
+		package.forums_url,
+		package.video_url,
+		package.donate_url_actual,
+		package.translation_url,
+	]
+
+	if package.desc:
+		links.extend(get_links(render_markdown(package.desc), package.get_url("packages.view", absolute=True)))
+
+	bad_urls = set()
+
+	for link in links:
+		if link is None:
+			continue
+
+		if not _url_exists(link):
+			bad_urls.add(link)
+
+	return bad_urls
+
+
+@celery.task()
+def check_package_on_submit(package_id: int):
+	package = Package.query.get(package_id)
+	if package is None:
+		raise TaskError("No such package")
+
+	bad_urls = check_for_dead_links(package)
+	if len(bad_urls) > 0:
+		marked = f"Marked {package.title} as Changed Needed"
+		msg = "The following broken links were found on your package:\n\n" + "\n".join([f"- {x}" for x in bad_urls])
+
+		system_user = get_system_user()
+		post_to_approval_thread(package, system_user, marked, is_status_update=True, create_thread=True)
+		post_to_approval_thread(package, system_user, msg, is_status_update=False, create_thread=True)
+		package.state = PackageState.CHANGES_NEEDED
+		db.session.commit()