Allow to opt-out from preflight cache

[javivelasco]

Fixes #32727

With this PR we introduce a new header that can be used to respond from Middleware x-middleware-cache. When the value of this header is set to no-cache, the client will not store the effects read from a preflight response to be used in an upcoming check.

Instead of using Cache-Control we are using a custom header to not mess with browser specific caching. Accepting a specific value to opt out (no-cache) opens the future opportunity of having other caching strategies.

This feature solves the issue of having a preflight request whose parameters can change from the client affecting the effects. For example, having a cookie that would make a middleware rewrite to one pathname or another and allowing to change that cookie from the client. In that case we'd always need to revalidate the effects on navigation synchronously.

Of course when using this feature it is possible that we add some latency on navigation so the preferred mechanism will be caching by default since it covers the most common use cases.

[ijjk]

Stats from current PR

Default Build (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
buildDuration	20.3s	19.6s	-690ms
buildDurationCached	4.4s	4.4s	⚠️ +82ms
nodeModulesSize	348 MB	348 MB	⚠️ +202 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
/ failed reqs	0	0	✓
/ total time (seconds)	4.149	4.095	-0.05
/ avg req/sec	602.5	610.54	+8.04
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	2.226	2.245	⚠️ +0.02
/error-in-render avg req/sec	1123.22	1113.52	⚠️ -9.7

Client Bundles (main, webpack, commons) Overall increase ⚠️

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.2 kB	42.2 kB	✓
main-HASH.js gzip	27 kB	27.1 kB	⚠️ +15 B
webpack-HASH.js gzip	1.45 kB	1.45 kB	✓
Overall change	70.9 kB	70.9 kB	⚠️ +15 B

Legacy Client Bundles (polyfills)

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
_app-HASH.js gzip	1.37 kB	1.37 kB	✓
_error-HASH.js gzip	194 B	194 B	✓
amp-HASH.js gzip	312 B	312 B	✓
css-HASH.js gzip	326 B	326 B	✓
dynamic-HASH.js gzip	2.37 kB	2.37 kB	✓
head-HASH.js gzip	350 B	350 B	✓
hooks-HASH.js gzip	919 B	919 B	✓
image-HASH.js gzip	4.74 kB	4.74 kB	✓
index-HASH.js gzip	263 B	263 B	✓
link-HASH.js gzip	2.13 kB	2.13 kB	✓
routerDirect..HASH.js gzip	321 B	321 B	✓
script-HASH.js gzip	383 B	383 B	✓
withRouter-HASH.js gzip	318 B	318 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	14.1 kB	14.1 kB	✓

Client Build Manifests

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
_buildManifest.js gzip	459 B	459 B	✓
Overall change	459 B	459 B	✓

Rendered Page Sizes

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
index.html gzip	533 B	533 B	✓
link.html gzip	547 B	547 B	✓
withRouter.html gzip	527 B	527 B	✓
Overall change	1.61 kB	1.61 kB	✓

Diffs

Diff for main-HASH.js

@@ -6288,6 +6288,7 @@
                     throw new Error("Failed to preflight request");
                   }
                   return {
+                    cache: res.headers.get("x-middleware-cache"),
                     redirect: res.headers.get("Location"),
                     refresh: res.headers.has("x-middleware-refresh"),
                     rewrite: res.headers.get("x-middleware-rewrite"),
@@ -6295,7 +6296,7 @@
                   };
                 })
                 .then(function(data) {
-                  if (shouldCache) {
+                  if (shouldCache && data.cache !== "no-cache") {
                     _this.sde[cacheKey] = data;
                   }
                   return data;

Diff for index.html

@@ -19,7 +19,7 @@
       defer=""
     ></script>
     <script
-      src="/_next/static/chunks/main-9cee2973de78a626.js"
+      src="/_next/static/chunks/main-810ef4d365d73085.js"
       defer=""
     ></script>
     <script

Diff for link.html

@@ -19,7 +19,7 @@
       defer=""
     ></script>
     <script
-      src="/_next/static/chunks/main-9cee2973de78a626.js"
+      src="/_next/static/chunks/main-810ef4d365d73085.js"
       defer=""
     ></script>
     <script

Diff for withRouter.html

@@ -19,7 +19,7 @@
       defer=""
     ></script>
     <script
-      src="/_next/static/chunks/main-9cee2973de78a626.js"
+      src="/_next/static/chunks/main-810ef4d365d73085.js"
       defer=""
     ></script>
     <script

---

Default Build with SWC (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
buildDuration	21.9s	21.3s	-585ms
buildDurationCached	4.4s	4.2s	-242ms
nodeModulesSize	348 MB	348 MB	⚠️ +202 B

Page Load Tests Overall increase ✓

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
/ failed reqs	0	0	✓
/ total time (seconds)	4.072	4.081	⚠️ +0.01
/ avg req/sec	613.89	612.56	⚠️ -1.33
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	2.299	2.207	-0.09
/error-in-render avg req/sec	1087.35	1132.77	+45.42

Client Bundles (main, webpack, commons) Overall increase ⚠️

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.3 kB	42.3 kB	✓
main-HASH.js gzip	27.2 kB	27.2 kB	⚠️ +17 B
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	71.1 kB	71.1 kB	⚠️ +17 B

Legacy Client Bundles (polyfills)

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
_app-HASH.js gzip	1.35 kB	1.35 kB	✓
_error-HASH.js gzip	180 B	180 B	✓
amp-HASH.js gzip	305 B	305 B	✓
css-HASH.js gzip	321 B	321 B	✓
dynamic-HASH.js gzip	2.36 kB	2.36 kB	✓
head-HASH.js gzip	342 B	342 B	✓
hooks-HASH.js gzip	906 B	906 B	✓
image-HASH.js gzip	4.76 kB	4.76 kB	✓
index-HASH.js gzip	256 B	256 B	✓
link-HASH.js gzip	2.19 kB	2.19 kB	✓
routerDirect..HASH.js gzip	314 B	314 B	✓
script-HASH.js gzip	375 B	375 B	✓
withRouter-HASH.js gzip	309 B	309 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	14.1 kB	14.1 kB	✓

Client Build Manifests

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
_buildManifest.js gzip	459 B	459 B	✓
Overall change	459 B	459 B	✓

Rendered Page Sizes

	vercel/next.js canary	javivelasco/next.js add/prelight-cache-opt-out	Change
index.html gzip	531 B	531 B	✓
link.html gzip	545 B	545 B	✓
withRouter.html gzip	526 B	526 B	✓
Overall change	1.6 kB	1.6 kB	✓

Diffs

Diff for main-HASH.js

@@ -6288,6 +6288,7 @@
                     throw new Error("Failed to preflight request");
                   }
                   return {
+                    cache: res.headers.get("x-middleware-cache"),
                     redirect: res.headers.get("Location"),
                     refresh: res.headers.has("x-middleware-refresh"),
                     rewrite: res.headers.get("x-middleware-rewrite"),
@@ -6295,7 +6296,7 @@
                   };
                 })
                 .then(function(data) {
-                  if (shouldCache) {
+                  if (shouldCache && data.cache !== "no-cache") {
                     _this.sde[cacheKey] = data;
                   }
                   return data;

Diff for index.html

@@ -19,7 +19,7 @@
       defer=""
     ></script>
     <script
-      src="/_next/static/chunks/main-9cee2973de78a626.js"
+      src="/_next/static/chunks/main-810ef4d365d73085.js"
       defer=""
     ></script>
     <script

Diff for link.html

@@ -19,7 +19,7 @@
       defer=""
     ></script>
     <script
-      src="/_next/static/chunks/main-9cee2973de78a626.js"
+      src="/_next/static/chunks/main-810ef4d365d73085.js"
       defer=""
     ></script>
     <script

Diff for withRouter.html

@@ -19,7 +19,7 @@
       defer=""
     ></script>
     <script
-      src="/_next/static/chunks/main-9cee2973de78a626.js"
+      src="/_next/static/chunks/main-810ef4d365d73085.js"
       defer=""
     ></script>
     <script

Commit: 29caf7a