增加：知乎-问题回答 (#927)

因为在写 jsbox ~~吸猫~~脚本刚好用到了，干脆顺手推上来了（光速逃

docs/README.md

@@ -404,6 +404,8 @@ RSSHub 提供下列 API 接口:
 
 <route name="知乎想法热榜" author="xyqfer" example="/zhihu/pin/hotlist" path="/zhihu/pin/hotlist"/>
 
+<route name="问题" author="xyqfer" example="/zhihu/question/59895982" path="/zhihu/question/:questionId" :paramsDesc="['问题 id']"/>
+
 ### pixiv
 
 <route name="用户收藏" author="EYHN" example="/pixiv/user/bookmarks/15288095" path="/pixiv/user/bookmarks/:id" :paramsDesc="['用户 id, 可在用户主页 URL 中找到']"/>

router.js

@@ -163,6 +163,7 @@ router.get('/zhihu/zhuanlan/:id', require('./routes/zhihu/zhuanlan'));
 router.get('/zhihu/daily', require('./routes/zhihu/daily'));
 router.get('/zhihu/hotlist', require('./routes/zhihu/hotlist'));
 router.get('/zhihu/pin/hotlist', require('./routes/zhihu/pin/hotlist'));
+router.get('/zhihu/question/:questionId', require('./routes/zhihu/question'));
 
 // 妹子图
 router.get('/mzitu', require('./routes/mzitu/category'));

routes/zhihu/question.js

@@ -0,0 +1,38 @@
+const axios = require('../../utils/axios');
+const utils = require('./utils');
+
+module.exports = async (ctx) => {
+    const { questionId } = ctx.params;
+    const sort = 'created';
+    const limit = 20;
+    const include = `data[*].content.excerpt&limit=${limit}&offset=0`;
+    const url = `https://www.zhihu.com/api/v4/questions/${questionId}/answers?include=${include}&sort_by=${sort}`;
+    const response = await axios({
+        method: 'get',
+        url,
+        headers: {
+            ...utils.header,
+            Referer: `https://www.zhihu.com/question/${questionId}`,
+            Authorization: 'oauth c3cef7c66a1843f8b3a9e6a1e3160e20', // hard-coded in js
+        },
+    });
+    const listRes = response.data.data;
+
+    ctx.state.data = {
+        title: `知乎-${listRes[0].question.title}`,
+        link: `https://www.zhihu.com/question/${questionId}`,
+        item: listRes.map((item) => {
+            const title = `${item.author.name}的回答：${item.excerpt}`;
+            const description = `${item.author.name}的回答<br/><br/>${utils.ProcessImage(item.content)}`;
+
+            return {
+                title,
+                description,
+                author: item.author.name,
+                pubDate: new Date(item.updated_time * 1000).toUTCString(),
+                guid: item.id.toString(),
+                link: `https://www.zhihu.com/question/${questionId}/answer/${item.id}`,
+            };
+        }),
+    };
+};