Add rss.xml and feed.json endpoints

app/feed.json/route.ts

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+import { getPhotosCached } from '@/photo/cache';
+import { INFINITE_SCROLL_FEED_INITIAL } from '@/photo';
+import { formatPhotoForFeed } from '@/app/feed';
+import {
+  BASE_URL,
+  PUBLIC_FEED_ENABLED,
+  META_TITLE,
+} from '@/app/config';
+
+export const dynamic = 'force-static';
+
+export async function GET() {
+  if (PUBLIC_FEED_ENABLED) {
+    const photos = await getPhotosCached({
+      limit: INFINITE_SCROLL_FEED_INITIAL,
+      sortBy: 'createdAt',
+    });
+    return Response.json({
+      meta: {
+        title: META_TITLE,
+        url: BASE_URL,
+      },
+      photos: photos.map(formatPhotoForFeed),
+    });
+  } else {
+    return new Response('Feed disabled', { status: 404 });
+  }
+}

app/rss.xml/route.ts

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+import { INFINITE_SCROLL_FEED_INITIAL } from '@/photo';
+import { getPhotosCached } from '@/photo/cache';
+import {
+  BASE_URL,
+  META_DESCRIPTION,
+  META_TITLE,
+  PUBLIC_FEED_ENABLED,
+} from '@/app/config';
+import { feedPhotoToXml, formatPhotoForFeed } from '@/app/feed';
+
+export const dynamic = 'force-static';
+
+export async function GET() {
+  if (PUBLIC_FEED_ENABLED) {
+    const photos = await getPhotosCached({
+      limit: INFINITE_SCROLL_FEED_INITIAL,
+      sortBy: 'createdAt',
+    });
+    const items = photos.map(formatPhotoForFeed).map(feedPhotoToXml);
+
+    return new Response(
+      `<?xml version="1.0" encoding="UTF-8"?>
+  <rss version="2.0" xmlns:content="http://purl.org/rss/1.0/modules/content/"
+    xmlns:atom="http://www.w3.org/2005/Atom"
+    xmlns:media="http://search.yahoo.com/mrss/">
+
+    <channel>
+      <title>${META_TITLE}</title>
+      <atom:link href="${BASE_URL}/rss.xml"
+        rel="self" type="application/rss+xml" />
+      <link>${BASE_URL}</link>
+      <description>${META_DESCRIPTION}</description>
+
+      ${items.join('\n\n    ')}
+
+    </channel>
+
+  </rss>`,
+      {
+        headers: {
+          'Content-Type': 'text/xml',
+        },
+      },
+    );
+  } else {
+    return new Response('RSS feed access disabled', { status: 404 });
+  }
+}

src/app/feed.ts

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+import { Photo } from '@/photo';
+import { absolutePathForPhoto } from './paths';
+import { getNextImageUrlForRequest } from '@/platforms/next-image';
+import { formatDate } from '@/utility/date';
+
+export const FEED_PHOTO_WIDTH_CONTENT = 1080;
+export const FEED_PHOTO_WIDTH_THUMB = 640;
+
+export interface PublicFeed {
+  meta: {
+    title: string
+    url: string
+  }
+  photos: PublicFeedPhoto[]
+}
+
+interface PublicFeedMedia {
+  url: string
+  width: number
+  height: number
+}
+
+interface PublicFeedPhoto {
+  id: string
+  title?: string
+  description?: string
+  link: string
+  publicationDate: Date
+  media: Record<
+    'content' | 'thumb',
+    PublicFeedMedia
+  >
+}
+
+export const formatPhotoForFeed = (photo: Photo): PublicFeedPhoto => ({
+  id: photo.id,
+  title: photo.title,
+  description: photo.caption,
+  link: absolutePathForPhoto({ photo }),
+  publicationDate: photo.createdAt,
+  media: {
+    content: {
+      url: getNextImageUrlForRequest({
+        imageUrl: photo.url,
+        size: FEED_PHOTO_WIDTH_CONTENT,
+      }),
+      width: FEED_PHOTO_WIDTH_CONTENT,
+      height: Math.round(FEED_PHOTO_WIDTH_CONTENT / photo.aspectRatio),
+    },
+    thumb: {
+      url: getNextImageUrlForRequest({
+        imageUrl: photo.url,
+        size: FEED_PHOTO_WIDTH_THUMB,
+      }),
+      width: FEED_PHOTO_WIDTH_THUMB,
+      height: Math.round(FEED_PHOTO_WIDTH_THUMB / photo.aspectRatio),
+    },
+  },
+});
+
+export const feedPhotoToXml = (photo: PublicFeedPhoto): string => {
+  const formattedDate = formatDate({
+    date: photo.publicationDate,
+    length: 'rss',
+  });
+  const description = photo.description ?
+    `<description>
+      <![CDATA[${photo.description}]]>
+    </description>` : '';
+
+  return `  <item>
+        <title>${photo.title}</title>
+        <link>${photo.link}</link>
+        <pubDate>${formattedDate}</pubDate>
+        <guid isPermaLink="true">${photo.link}</guid>
+        ${description}
+        <media:content url="${photo.media.content.url.replace(/&/g, '&amp;')}"
+          type="image/jpeg"
+          medium="image"
+          width="${photo.media.content.width}"
+          height="${photo.media.content.height}">
+          <media:thumbnail url="${photo.media.thumb.url.replace(/&/g, '&amp;')}"
+            width="${photo.media.thumb.width}"
+            height="${photo.media.thumb.height}" />
+        </media:content>
+      </item>`;
+};