From 4776fa6abaa74e10174230fd299428d7cd4aa43b Mon Sep 17 00:00:00 2001
From: DIYgod <diy.d.god@gmail.com>
Date: Fri, 11 May 2018 17:10:10 +0800
Subject: [PATCH] middleware: filter

---
 docs/README.md       | 12 ++++++++++++
 index.js             |  6 +++++-
 middleware/cache.js  |  3 ++-
 middleware/filter.js | 20 ++++++++++++++++++++
 4 files changed, 39 insertions(+), 2 deletions(-)
 create mode 100644 middleware/filter.js

diff --git a/docs/README.md b/docs/README.md
index 63ca0d3aec..1431172611 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -13,6 +13,18 @@ RSSHub 是一个轻量、易于扩展的 RSS 生成器，可以给任何奇奇
 演示域名为 [rss.now.sh](https://rss.now.sh)，缓存时间 5 分钟，可以随意使用
 :::
 
+## 内容过滤
+
+可以使用以下 URL query 过滤出想要的内容，支持正则
+
+- filter: 过滤标题和描述
+
+- filter_title: 过滤标题
+
+- filter_description: 过滤描述
+
+举例: [https://rss.now.sh/bilibili/user/coin/2267573?filter=微小微|赤九玖|暴走大事件](https://rss.now.sh/bilibili/user/coin/2267573?filter=微小微|赤九玖|暴走大事件)
+
 ## bilibili
 
 ### 番剧
diff --git a/index.js b/index.js
index a63ed2cb66..5bd488dfb1 100644
--- a/index.js
+++ b/index.js
@@ -8,6 +8,7 @@ const header = require('./middleware/header.js');
 const utf8 = require('./middleware/utf8');
 const memoryCache = require('./middleware/cache.js');
 const redisCache = require('koa-redis-cache');
+const filter = require('./middleware/filter.js');
 
 const router = require('./router');
 
@@ -28,11 +29,14 @@ app.use(header);
 // fix incorrect `utf-8` characters
 app.use(utf8);
 
+app.use(filter);
+
 // cache
 if (config.cacheType === 'memory') {
     app.use(
         memoryCache({
-            expire: config.cacheExpire
+            expire: config.cacheExpire,
+            ignoreQuery: true,
         })
     );
 } else if (config.cacheType === 'redis') {
diff --git a/middleware/cache.js b/middleware/cache.js
index 399dbe10e6..88e9c293c2 100644
--- a/middleware/cache.js
+++ b/middleware/cache.js
@@ -13,6 +13,7 @@ module.exports = function (options = {}) {
         exclude = [],
         passParam = '',
         maxLength = Infinity,
+        ignoreQuery = false,
     } = options;
 
     const memoryCache = lru({
@@ -23,7 +24,7 @@ module.exports = function (options = {}) {
     return async function cache (ctx, next) {
         const { url, path } = ctx.request;
         const resolvedPrefix = typeof prefix === 'function' ? prefix.call(ctx, ctx) : prefix;
-        const key = resolvedPrefix + md5(url);
+        const key = resolvedPrefix + md5(ignoreQuery ? path : url);
         const tkey = key + ':type';
         let match = false;
         let routeExpire = false;
diff --git a/middleware/filter.js b/middleware/filter.js
new file mode 100644
index 0000000000..d72cf6f526
--- /dev/null
+++ b/middleware/filter.js
@@ -0,0 +1,20 @@
+const cheerio = require('cheerio');
+
+module.exports = async (ctx, next) => {
+    await next();
+
+    if (ctx.body && ctx.query && (ctx.query.filter || ctx.query.filter_title || ctx.query.filter_description)) {
+        const $ = cheerio.load(ctx.body, {
+            xmlMode: true
+        });
+        $('item').filter((index, item) => {
+            const title = $(item).find('title').text();
+            const description = $(item).find('description').text();
+            return ctx.query.filter && !title.match(ctx.query.filter) && !description.match(ctx.query.filter)
+                || ctx.query.filter_title && !title.match(ctx.query.filter_title)
+                || ctx.query.filter_description && !description.match(ctx.query.filter_description);
+        }).remove();
+
+        ctx.body = $.xml();
+    }
+};