feat(route): add langchain dev blog (#17415)

fix(route): fix pr issue

lib/routes/langchain/index.ts

@@ -0,0 +1,74 @@
+import { Route, DataItem } from '@/types';
+import got from '@/utils/got';
+import { load } from 'cheerio';
+import cache from '@/utils/cache';
+
+export const route: Route = {
+    path: '/blog',
+    categories: ['blog'],
+    example: '/langchain/blog',
+    radar: [
+        {
+            source: ['blog.langchain.dev/'],
+        },
+    ],
+    url: 'blog.langchain.dev/',
+    name: 'Blog',
+    maintainers: ['liyaozhong'],
+    handler,
+    description: 'LangChain Blog Posts',
+};
+
+async function handler() {
+    const rootUrl = 'https://blog.langchain.dev';
+    const currentUrl = rootUrl;
+
+    const response = await got(currentUrl);
+    const $ = load(response.data);
+
+    const items = await Promise.all(
+        $('.posts-feed .post-card')
+            .toArray()
+            .map((item) => {
+                const $item = $(item);
+                const $link = $item.find('.post-card__content-link').first();
+
+                const href = $link.attr('href');
+                const title = $item.find('.post-card__title').text().trim();
+                const excerpt = $item.find('.post-card__excerpt').text().trim();
+
+                if (!href || !title) {
+                    return null;
+                }
+
+                const link = new URL(href, rootUrl).href;
+
+                return {
+                    title,
+                    description: excerpt,
+                    link,
+                } as DataItem;
+            })
+            .filter((item): item is DataItem => item !== null)
+            .map((item) =>
+                cache.tryGet(item.link as string, async () => {
+                    try {
+                        const detailResponse = await got(item.link);
+                        const $detail = load(detailResponse.data);
+
+                        item.description = $detail('.article-content').html() || item.description;
+
+                        return item as DataItem;
+                    } catch {
+                        return item;
+                    }
+                })
+            )
+    );
+
+    return {
+        title: 'LangChain Blog',
+        link: rootUrl,
+        item: items.filter((item): item is DataItem => item !== null),
+    };
+}

lib/routes/langchain/namespace.ts

@@ -0,0 +1,7 @@
+import type { Namespace } from '@/types';
+
+export const namespace: Namespace = {
+    name: 'LangChain Blog',
+    url: 'blog.langchain.dev',
+    lang: 'en',
+};