From 20c4926e13de4cbeef47c73f402bbcd08ab89f58 Mon Sep 17 00:00:00 2001
From: Michael Jackson <michael@jackson.us>
Date: Mon, 28 Jan 2019 12:15:05 -0800
Subject: [PATCH] Lengthen cache ttl on 404s

---
 modules/middleware/findFile.js | 40 +++++++++++++++++++---------------
 1 file changed, 23 insertions(+), 17 deletions(-)

diff --git a/modules/middleware/findFile.js b/modules/middleware/findFile.js
index 860c974..15dcc67 100644
--- a/modules/middleware/findFile.js
+++ b/modules/middleware/findFile.js
@@ -94,26 +94,24 @@ function searchEntries(tarballStream, entryName, wantsIndex) {
 
         const chunks = [];
 
-        stream
-          .on('data', chunk => chunks.push(chunk))
-          .on('end', () => {
-            const content = Buffer.concat(chunks);
+        stream.on('data', chunk => chunks.push(chunk)).on('end', () => {
+          const content = Buffer.concat(chunks);
 
-            // Set some extra properties for files that we will
-            // need to serve them and for ?meta listings.
-            entry.contentType = getContentType(entry.name);
-            entry.integrity = getIntegrity(content);
-            entry.lastModified = header.mtime.toUTCString();
-            entry.size = content.length;
+          // Set some extra properties for files that we will
+          // need to serve them and for ?meta listings.
+          entry.contentType = getContentType(entry.name);
+          entry.integrity = getIntegrity(content);
+          entry.lastModified = header.mtime.toUTCString();
+          entry.size = content.length;
 
-            // Set the content only for the foundEntry and
-            // discard the buffer for all others.
-            if (entry === foundEntry) {
-              entry.content = content;
-            }
+          // Set the content only for the foundEntry and
+          // discard the buffer for all others.
+          if (entry === foundEntry) {
+            entry.content = content;
+          }
 
-            next();
-          });
+          next();
+        });
       });
   });
 }
@@ -139,6 +137,10 @@ export default function findFile(req, res, next) {
         if (!foundEntry) {
           return res
             .status(404)
+            .set({
+              'Cache-Control': 'public, max-age=31536000', // 1 year
+              'Cache-Tag': 'missing, missing-entry'
+            })
             .type('text')
             .send(`Cannot find "${req.filename}" in ${req.packageSpec}`);
         }
@@ -158,6 +160,10 @@ export default function findFile(req, res, next) {
           } else {
             return res
               .status(404)
+              .set({
+                'Cache-Control': 'public, max-age=31536000', // 1 year
+                'Cache-Tag': 'missing, missing-index'
+              })
               .type('text')
               .send(
                 `Cannot find an index in "${req.filename}" in ${