feat: add oschina topic (#2570)

* feat: add oschina topic

* remove ua

* format

docs/programming.md

@@ -367,6 +367,7 @@ GitHub 官方也提供了一些 RSS:
 | xxiaobian |
 
 </Route>
+
 ### 数字型账号用户博客
 
 <Route author="dxmpalb" example="/oschina/u/3920392" path="/oschina/u/:id" :paramsDesc="['用户 id, 可通过查看用户博客网址得到，以 u/数字结尾，数字即为 id']">
@@ -377,6 +378,10 @@ GitHub 官方也提供了一些 RSS:
 
 </Route>
 
+### 问答主题
+
+<Route author="loveely7" example="/oschina/topic/weekly-news" path="/oschina/topic/:topic" :paramsDesc="['主题名, 可从[全部主题](https://www.oschina.net/question/topics)进入主题页, 在 URL 中找到']"/>
+
 ## 看雪
 
 ### 论坛

lib/router.js

@@ -420,6 +420,7 @@ router.get('/linkedkeeper/:type/:id?', require('./routes/linkedkeeper/index'));
 router.get('/oschina/news/:category?', require('./routes/oschina/news'));
 router.get('/oschina/user/:id', require('./routes/oschina/user'));
 router.get('/oschina/u/:id', require('./routes/oschina/u'));
+router.get('/oschina/topic/:topic', require('./routes/oschina/topic'));
 
 // 安全客
 router.get('/aqk/vul', require('./routes/aqk/vul'));

lib/routes/oschina/topic.js

@@ -0,0 +1,54 @@
+const url = require('url');
+const got = require('@/utils/got');
+const date = require('@/utils/date');
+const cheerio = require('cheerio');
+
+async function load(link) {
+    const res = await got({
+        method: 'get',
+        url: link,
+    });
+    const content = cheerio.load(res.data);
+    content('.ad-wrap').remove();
+    return content;
+}
+
+module.exports = async (ctx) => {
+    const topic = ctx.params.topic;
+    const topicUrl = `https://www.oschina.net/question/topic/${topic}?show=time`;
+
+    const $ = await load(topicUrl);
+    const topicName = $('.topic-info > .topic-header > h3').text();
+    const list = $('#questionList').find('.question-item');
+    const count = [];
+    for (let i = 0; i < Math.min(list.length, 10); i++) {
+        count.push(i);
+    }
+
+    const resultItem = await Promise.all(
+        count.map(async (i) => {
+            const each = $(list[i]);
+            const originalUrl = each.find('.header').attr('href');
+
+            const item = {
+                title: each.find('.header').text(),
+                link: url.resolve('https://www.oschina.net', encodeURI(originalUrl)),
+                author: date(each.find('.extra > .list > .item:nth-of-type(1)').text()),
+                pubDate: date(each.find('.extra > .list > .item:nth-of-type(2)').text()),
+            };
+
+            item.description = await ctx.cache.tryGet(originalUrl, async () => {
+                const content = await load(item.link);
+                return content('#articleContent').html();
+            });
+
+            return Promise.resolve(item);
+        })
+    );
+
+    ctx.state.data = {
+        title: `开源中国-${topicName}`,
+        link: topicUrl,
+        item: resultItem,
+    };
+};