refactor: reduce redundancy in feed gen

backend/app/services/feed_generator.py

@@ -1,3 +1,5 @@
+from typing import List
+
 from dateutil import tz
 from feedgen.feed import FeedGenerator
 from sqlalchemy.orm import Session
@@ -5,6 +7,45 @@ from sqlalchemy.orm import Session
 from app.core.config import settings
 from app.crud.entries import get_all_entries, get_entries_by_newsletter
 from app.crud.newsletters import get_newsletter_by_identifier
+from app.models.entries import Entry
+
+
+def _create_feed_generator(
+    feed_id: str, title: str, feed_url: str, description: str
+) -> FeedGenerator:
+    """Initialize and configures a FeedGenerator instance."""
+    logo_url = f"{settings.app_base_url}/logo.png"
+    icon_url = f"{settings.app_base_url}/favicon.ico"
+
+    fg = FeedGenerator()
+    fg.id(feed_id)
+    fg.title(title)
+    fg.logo(logo_url)
+    fg.icon(icon_url)
+    fg.link(href=feed_url, rel="self")
+    fg.link(href=f"{settings.app_base_url}/", rel="alternate")
+    fg.description(description)
+    return fg
+
+
+def _add_entries_to_feed(
+    fg: FeedGenerator, entries: List[Entry], is_master_feed: bool = False
+):
+    """Add a list of entries to a FeedGenerator instance."""
+    for entry in entries:
+        fe = fg.add_entry()
+        fe.id(f"urn:letterfeed:entry:{entry.id}")
+        fe.title(
+            f"[{entry.newsletter.name}] {entry.subject}"
+            if is_master_feed
+            else entry.subject
+        )
+        fe.content(entry.body, type="html")
+        if entry.received_at.tzinfo is None:
+            timezone_aware_received_at = entry.received_at.replace(tzinfo=tz.tzutc())
+            fe.published(timezone_aware_received_at)
+        else:
+            fe.published(entry.received_at)
 
 
 def generate_feed(db: Session, feed_identifier: str):
@@ -16,29 +57,17 @@ def generate_feed(db: Session, feed_identifier: str):
     entries = get_entries_by_newsletter(db, newsletter.id)
 
     feed_url = f"{settings.app_base_url}/feeds/{newsletter.slug or newsletter.id}"
-    logo_url = f"{settings.app_base_url}/logo.png"
-    icon_url = f"{settings.app_base_url}/favicon.ico"
-
-    fg = FeedGenerator()
-    fg.id(f"urn:letterfeed:newsletter:{newsletter.id}")
-    fg.title(newsletter.name)
-    fg.logo(logo_url)
-    fg.icon(icon_url)
-    fg.link(href=feed_url, rel="self")
-    fg.link(href=f"{settings.app_base_url}/", rel="alternate")
     sender_emails = ", ".join([s.email for s in newsletter.senders])
-    fg.description(f"A feed of newsletters from {sender_emails}")
+    description = f"A feed of newsletters from {sender_emails}"
 
-    for entry in entries:
-        fe = fg.add_entry()
-        fe.id(f"urn:letterfeed:entry:{entry.id}")
-        fe.title(entry.subject)
-        fe.content(entry.body, type="html")
-        if entry.received_at.tzinfo is None:
-            timezone_aware_received_at = entry.received_at.replace(tzinfo=tz.tzutc())
-            fe.published(timezone_aware_received_at)
-        else:
-            fe.published(entry.received_at)
+    fg = _create_feed_generator(
+        feed_id=f"urn:letterfeed:newsletter:{newsletter.id}",
+        title=newsletter.name,
+        feed_url=feed_url,
+        description=description,
+    )
+
+    _add_entries_to_feed(fg, entries)
 
     return fg.atom_str(pretty=True)
 
@@ -48,27 +77,14 @@ def generate_master_feed(db: Session):
     entries = get_all_entries(db)
 
     feed_url = f"{settings.app_base_url}/feeds/all"
-    logo_url = f"{settings.app_base_url}/logo.png"
-    icon_url = f"{settings.app_base_url}/favicon.ico"
 
-    fg = FeedGenerator()
-    fg.id("urn:letterfeed:master")
-    fg.title("LetterFeed: All Newsletters")
-    fg.logo(logo_url)
-    fg.icon(icon_url)
-    fg.link(href=feed_url, rel="self")
-    fg.link(href=f"{settings.app_base_url}/", rel="alternate")
-    fg.description("A master feed of all your newsletters.")
+    fg = _create_feed_generator(
+        feed_id="urn:letterfeed:master",
+        title="LetterFeed: All Newsletters",
+        feed_url=feed_url,
+        description="A master feed of all your newsletters.",
+    )
 
-    for entry in entries:
-        fe = fg.add_entry()
-        fe.id(f"urn:letterfeed:entry:{entry.id}")
-        fe.title(f"[{entry.newsletter.name}] {entry.subject}")
-        fe.content(entry.body, type="html")
-        if entry.received_at.tzinfo is None:
-            timezone_aware_received_at = entry.received_at.replace(tzinfo=tz.tzutc())
-            fe.published(timezone_aware_received_at)
-        else:
-            fe.published(entry.received_at)
+    _add_entries_to_feed(fg, entries, is_master_feed=True)
 
     return fg.atom_str(pretty=True)