flaskr/blog.py

@@ -5,6 +5,7 @@ from werkzeug.exceptions import abort
 
 from flaskr.auth import login_required
 from flaskr.db import get_db
+from flaskr.generate_rss import generate_feed
 
 import markdown
 import datetime
@@ -66,6 +67,7 @@ def create():
                 (title, body, g.user['id'])
             )
             db.commit()
+            generate_feed(db)
             return redirect(url_for('blog.index'))
 
     return render_template('blog/create.html')
@@ -119,6 +121,7 @@ def update(id):
                 (title, body, created, id)
             )
             db.commit()
+            generate_feed(db)
             return redirect(url_for('blog.index'))
 
     return render_template('blog/update.html', post=post)
@@ -131,3 +134,7 @@ def delete(id):
     db.execute('DELETE FROM post WHERE id = ?',(id,))
     db.commit()
     return redirect(url_for('blog.index'))
+
+@bp.route('/rss/', methods=('GET',))
+def redirect_rss():
+    return redirect(url_for('static', filename='rss.xml'))

flaskr/generate_rss.py

@@ -0,0 +1,69 @@
+from datetime import datetime
+import sqlite3
+
+from bs4 import BeautifulSoup
+from markdown import markdown
+
+def soup_append_multiple_tags(soup: BeautifulSoup, children: dict) -> None:
+    for name, string in children.items():
+        soup.append(soup.new_tag(name))
+        soup.find_all(name)[-1].string = string
+
+def post_find_first_plain_line(post: str) -> str:
+    while post:
+        if post[0].isalnum():
+            break
+        end = post.find("\n")
+        post = post[end+1:]
+    end = post.find("\n")
+    return post[:end]
+
+def generate_feed(db):
+    soup = BeautifulSoup(features="xml")
+
+    soup.append(soup.new_tag("rss", version="2.0"))
+    rss = soup.rss
+    rss["xmlns:atom"] = "http://www.w3.org/2005/Atom"
+    rss["xmlns:content"] = "http://purl.org/rss/1.0/modules/content/"
+
+    rss.append(soup.new_tag("channel"))
+    channel = rss.channel
+
+    channel_children = {
+        "description": "Blog posts from allsparkinfinite's blog",
+        "link": "https://blog.allsparkinfinite.name",
+        "title": "blogsparkinfinite",
+        "docs": "https://rssboard.org/rss-specification",
+        "language": "en-IN",
+        "lastBuildDate": datetime.now().strftime("%a, %d %b %Y %T +0530"),
+        "ttl": "240",
+    }
+    soup_append_multiple_tags(channel, channel_children)
+
+    channel.append(channel.new_tag("atom:link"))
+    channel.find_all("atom:link")[-1]["href"] = "https://blog.allsparkinfinite.name/rss/"
+    channel.find_all("atom:link")[-1]["rel"] = "self"
+    channel.find_all("atom:link")[-1]["type"] = "application/rss+xml"
+
+    channel.append(channel.new_tag("atom:link"))
+    channel.find_all("atom:link")[-1]["href"] = "https://blog.allsparkinfinite.name/"
+    channel.find_all("atom:link")[-1]["rel"] = "alternate"
+    channel.find_all("atom:link")[-1]["type"] = "text/html"
+
+    posts = db.execute("SELECT * FROM post").fetchall()
+    posts.reverse()
+
+    for post in posts:
+        channel.append(soup.new_tag("item"))
+        item = channel.find_all("item")[-1]
+        item_children = {
+            "description": post_find_first_plain_line(post[4]),
+            "guid": f"https://blog.allsparkinfinite.name/{post[0]}/",
+            "pubDate": post[2].strftime("%a, %d %b %Y %T GMT"),
+            "title": post[3],
+            "content:encoded": markdown(post[4]),
+        }
+        soup_append_multiple_tags(item, item_children)
+
+    with open("flaskr/static/rss.xml", "w") as f:
+        f.write(soup.prettify())