增加：商务印书馆新书速递 (#928)

- 实现 #894 
- 考虑到资源消耗的问题，目前只输出了最近两个月(比如现在是2018年9、10月这一项)下按时间排序(最新的在最前)的第一页新书（看到有些月份有近10页的，全部轮一遍意义不大。没有使用新书信息首页的数据是因为上面貌似是按添加顺序来的，最早添加的在最前面。。。

docs/README.md

@@ -444,6 +444,8 @@ RSSHub 提供下列 API 接口:
 
 <route name="热门同城活动" author="xyqfer" example="/douban/event/hot/118172" path="/douban/event/hot/:locationId" :paramsDesc="['位置 id, [同城首页](https://www.douban.com/location)打开控制台执行 `window.__loc_id__` 获取']"/>
 
+<route name="商务印书馆新书速递" author="xyqfer" example="/douban/commercialpress/latest" path="/douban/commercialpress/latest"/>
+
 ### Disqus
 
 <route name="评论" author="DIYgod" example="/disqus/posts/diygod-me" path="/disqus/posts/:forum" :paramsDesc="['网站的 disqus name']"/>

router.js

@@ -192,6 +192,7 @@ router.get('/douban/explore', require('./routes/douban/explore'));
 router.get('/douban/music/latest', require('./routes/douban/latest_music'));
 router.get('/douban/book/latest', require('./routes/douban/latest_book'));
 router.get('/douban/event/hot/:locationId', require('./routes/douban/event/hot'));
+router.get('/douban/commercialpress/latest', require('./routes/douban/commercialpress/latest'));
 
 // 煎蛋
 router.get('/jandan/:sub_model', require('./routes/jandan/pic'));

routes/douban/commercialpress/latest.js

@@ -0,0 +1,58 @@
+const axios = require('../../../utils/axios');
+const cheerio = require('cheerio');
+
+module.exports = async (ctx) => {
+    const link = 'https://site.douban.com/commercialpress/room/827243/';
+    const { data: roomResponse } = await axios({
+        method: 'get',
+        url: link,
+        headers: {
+            Referer: 'https://site.douban.com/commercialpress/',
+        },
+    });
+    let $ = cheerio.load(roomResponse);
+    const $mod = $('.mod').eq(0);
+    const title = $mod
+        .find('.hd > h2 span')
+        .eq(0)
+        .text();
+    const newBookUrl = $mod.find('.pl a').attr('href');
+
+    const newBookLandingPage = await axios({
+        method: 'get',
+        url: newBookUrl,
+        headers: {
+            Referer: link,
+        },
+    });
+
+    // 这个有个重定向，需要获取到真实地址后添加排序参数后再请求一次
+    const realUrl = `${newBookLandingPage.request.res.responseUrl}?sort=time&sub_type=`;
+    const newBookPage = await axios({
+        method: 'get',
+        url: realUrl,
+        headers: {
+            Referer: link,
+        },
+    });
+
+    $ = cheerio.load(newBookPage.data);
+    const resultItem = $('.doulist-item')
+        .map(function(_, item) {
+            const $item = $(item);
+
+            return {
+                title: $item.find('.title > a').text(),
+                link: $item.find('.title > a').attr('href'),
+                description: `<img src="${$item.find('.post img').attr('src')}" referrerpolicy="no-referrer" /><br>${$item.find('.abstract').html()}`,
+                pubDate: new Date($item.find('.time > span').attr('title')).toUTCString(),
+            };
+        })
+        .get();
+
+    ctx.state.data = {
+        title: `商务印书馆-${title}`,
+        link,
+        item: resultItem,
+    };
+};