From 6ec230f58f74c13e8c40af005cdef5455806bbfd Mon Sep 17 00:00:00 2001
From: DIYgod <diy.d.god@gmail.com>
Date: Tue, 29 Sep 2020 18:53:24 +0800
Subject: [PATCH] feat: support etag

---
 lib/app.js               |  9 +++++----
 lib/middleware/debug.js  |  4 ++++
 lib/middleware/header.js | 24 +++++++++++++-----------
 lib/routes/index.js      |  8 ++++++--
 4 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/lib/app.js b/lib/app.js
index 904adf3001..61ad7129e6 100644
--- a/lib/app.js
+++ b/lib/app.js
@@ -39,15 +39,13 @@ app.use(favicon(__dirname + '/favicon.png'));
 // global error handing
 app.use(onerror);
 
-// 1 set header
-app.use(header);
-
 app.use(accessControl);
 
-// 6 debug
+// 7 debug
 app.context.debug = {
     hitCache: 0,
     request: 0,
+    etag: 0,
     paths: [],
     routes: [],
     ips: [],
@@ -56,6 +54,9 @@ app.context.debug = {
 };
 app.use(debug);
 
+// 6 set header
+app.use(header);
+
 // 5 fix incorrect `utf-8` characters
 app.use(utf8);
 
diff --git a/lib/middleware/debug.js b/lib/middleware/debug.js
index e30854fe8f..d3c41ae9dc 100644
--- a/lib/middleware/debug.js
+++ b/lib/middleware/debug.js
@@ -23,4 +23,8 @@ module.exports = async (ctx, next) => {
     }
 
     ctx.state.debuged = true;
+
+    if (ctx.status === 304) {
+        ctx.debug.etag++;
+    }
 };
diff --git a/lib/middleware/header.js b/lib/middleware/header.js
index e1118af539..ff4272cbf4 100644
--- a/lib/middleware/header.js
+++ b/lib/middleware/header.js
@@ -19,8 +19,7 @@ module.exports = async (ctx, next) => {
 
     await next();
 
-    let body = ctx.body;
-    if (!body || typeof body !== 'string' || ctx.response.get('ETag')) {
+    if (!ctx.body || typeof ctx.body !== 'string' || ctx.response.get('ETag')) {
         return;
     }
 
@@ -29,14 +28,17 @@ module.exports = async (ctx, next) => {
         return;
     }
 
-    const match = body.match(/<lastBuildDate>(.*)<\/lastBuildDate>/);
-    if (match) {
-        ctx.set({
-            'Last-Modified': body.match(/<lastBuildDate>(.*)<\/lastBuildDate>/)[1],
-        });
+    ctx.set('ETag', etagCalculate(ctx.body.replace(/<lastBuildDate>(.*)<\/lastBuildDate>/, '').replace(/<atom:link(.*)\/>/, '')));
+
+    if (ctx.fresh) {
+        ctx.status = 304;
+        ctx.body = null;
+    } else {
+        const match = ctx.body.match(/<lastBuildDate>(.*)<\/lastBuildDate>/);
+        if (match) {
+            ctx.set({
+                'Last-Modified': match[1],
+            });
+        }
     }
-
-    body = body.replace(/<lastBuildDate>(.*)<\/lastBuildDate>/, '');
-
-    ctx.response.etag = etagCalculate(body);
 };
diff --git a/lib/routes/index.js b/lib/routes/index.js
index 3688cbb719..b8cccbd846 100644
--- a/lib/routes/index.js
+++ b/lib/routes/index.js
@@ -85,12 +85,16 @@ module.exports = async (ctx) => {
             },
             {
                 name: 'request frequency',
-                value: ((ctx.debug.request / (stats.elapsed / 1000)) * 60).toFixed(3) + ' 次/分钟',
+                value: ((ctx.debug.request / (stats.elapsed / 1000)) * 60).toFixed(3) + ' times/minute',
             },
             {
                 name: 'cache hit ratio',
                 value: ctx.debug.request ? (ctx.debug.hitCache / ctx.debug.request).toFixed(3) : 0,
             },
+            {
+                name: 'ETag Matched',
+                value: ctx.debug.etag,
+            },
             {
                 name: 'memory usage',
                 value: stats.memory / 1000000 + ' MB',
@@ -101,7 +105,7 @@ module.exports = async (ctx) => {
             },
             {
                 name: 'run time',
-                value: (stats.elapsed / 3600000).toFixed(2) + ' 小时',
+                value: (stats.elapsed / 3600000).toFixed(2) + ' hour(s)',
             },
             {
                 name: 'hot routes',