fix: add missing request handler for rss feeds (#2006)

* fix: add missing request handler for rss feeds

* fix: ci issues

packages/request-handler/src/rss-feeds.ts

@@ -0,0 +1,127 @@
+import type { FeedData, FeedEntry } from "@extractus/feed-extractor";
+import { extract } from "@extractus/feed-extractor";
+import dayjs from "dayjs";
+import { z } from "zod";
+
+import type { Modify } from "@homarr/common/types";
+import { logger } from "@homarr/log";
+
+import { createCachedWidgetRequestHandler } from "./lib/cached-widget-request-handler";
+
+export const rssFeedsRequestHandler = createCachedWidgetRequestHandler({
+  queryKey: "rssFeedList",
+  widgetKind: "rssFeed",
+  async requestAsync(input: { url: string; count: number }) {
+    const result = (await extract(input.url, {
+      getExtraEntryFields: (feedEntry) => {
+        const media = attemptGetImageFromEntry(input.url, feedEntry);
+        if (!media) {
+          return {};
+        }
+        return {
+          enclosure: media,
+        };
+      },
+    })) as ExtendedFeedData;
+
+    return {
+      ...result,
+      entries: result.entries?.slice(0, input.count) ?? [],
+    };
+  },
+  cacheDuration: dayjs.duration(5, "minutes"),
+});
+
+const attemptGetImageFromEntry = (feedUrl: string, entry: object) => {
+  const media = getFirstMediaProperty(entry);
+  if (media !== null) {
+    return media;
+  }
+  return getImageFromStringAsFallback(feedUrl, JSON.stringify(entry));
+};
+
+const getImageFromStringAsFallback = (feedUrl: string, content: string) => {
+  const regex = /https?:\/\/\S+?\.(jpg|jpeg|png|gif|bmp|svg|webp|tiff)/i;
+  const result = regex.exec(content);
+
+  if (result == null) {
+    return null;
+  }
+
+  console.debug(
+    `Falling back to regex image search for '${feedUrl}'. Found ${result.length} matches in content: ${content}`,
+  );
+  return result[0];
+};
+
+const mediaProperties = [
+  {
+    path: ["enclosure", "@_url"],
+  },
+  {
+    path: ["media:content", "@_url"],
+  },
+];
+
+/**
+ * The RSS and Atom standards are poorly adhered to in most of the web.
+ * We want to show pretty background images on the posts and therefore need to extract
+ * the enclosure (aka. media images). This function uses the dynamic properties defined above
+ * to search through the possible paths and detect valid image URLs.
+ * @param feedObject The object to scan for.
+ * @returns the value of the first path that is found within the object
+ */
+const getFirstMediaProperty = (feedObject: object) => {
+  for (const mediaProperty of mediaProperties) {
+    let propertyIndex = 0;
+    let objectAtPath: object = feedObject;
+    while (propertyIndex < mediaProperty.path.length) {
+      const key = mediaProperty.path[propertyIndex];
+      if (key === undefined) {
+        break;
+      }
+      const propertyEntries = Object.entries(objectAtPath);
+      const propertyEntry = propertyEntries.find(([entryKey]) => entryKey === key);
+      if (!propertyEntry) {
+        break;
+      }
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
+      const [_, propertyEntryValue] = propertyEntry;
+      objectAtPath = propertyEntryValue as object;
+      propertyIndex++;
+    }
+
+    const validationResult = z.string().url().safeParse(objectAtPath);
+    if (!validationResult.success) {
+      continue;
+    }
+
+    logger.debug(`Found an image in the feed entry: ${validationResult.data}`);
+    return validationResult.data;
+  }
+  return null;
+};
+
+/**
+ * We extend the feed with custom properties.
+ * This interface adds properties on top of the default ones.
+ */
+interface ExtendedFeedEntry extends FeedEntry {
+  enclosure?: string;
+}
+
+/**
+ * We extend the feed with custom properties.
+ * This interface omits the default entries with our custom definition.
+ */
+type ExtendedFeedData = Modify<
+  FeedData,
+  {
+    entries?: ExtendedFeedEntry[];
+  }
+>;
+
+export interface RssFeed {
+  feedUrl: string;
+  feed: ExtendedFeedData;
+}