feat: CACHE_CLIENT_REDIRECT will enable a fast-path response

esroyo · Feb 22, 2024 · 1cbc475 · 1cbc475
1 parent 721a4d0
commit 1cbc475
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Showing 2 changed files with 64 additions and 7 deletions.
diff --git a/src/sjs-request-handler.ts b/src/sjs-request-handler.ts
@@ -2,8 +2,10 @@ import {
     _internals,
     cloneHeaders,
     createFinalResponse,
+    createFastPathResponse,
     denyHeaders,
     isJsResponse,
+    isRedirect,
     retrieveCache,
 } from './utils.ts';
 import { denoKv } from './services.ts';
@@ -17,6 +19,8 @@ export async function sjsRequestHandler(
     performance.mark('total');
     const BASE_PATH = Deno.env.get('BASE_PATH');
     const CACHE = Deno.env.get('CACHE') === 'true';
+    const CACHE_CLIENT_REDIRECT =
+        Number(Deno.env.get('CACHE_CLIENT_REDIRECT') as string) || 0;
     const UPSTREAM_ORIGIN = Deno.env.get('UPSTREAM_ORIGIN');
     const HOMEPAGE = Deno.env.get('HOMEPAGE');
     const OUTPUT_BANNER = Deno.env.get('OUTPUT_BANNER');
@@ -30,7 +34,7 @@ export async function sjsRequestHandler(
         performance.measure('cache-read', 'cache-read');
         if (value) {
             performance.measure('cache-hit', { start: performance.now() });
-            return createFinalResponse(
+            const response = await createFinalResponse(
                 {
                     ...value,
                     headers: new Headers(value.headers),
@@ -39,6 +43,10 @@ export async function sjsRequestHandler(
                 buildTarget,
                 false,
             );
+            if (CACHE_CLIENT_REDIRECT && isRedirect(response.status)) {
+                return createFastPathResponse(response, performance, buildTarget);
+            }
+            return response;
         }
         performance.measure('cache-miss', { start: performance.now() });
     }
@@ -94,7 +102,7 @@ export async function sjsRequestHandler(
         body = replaceOrigin(await toSystemjs(body, { banner: OUTPUT_BANNER }));
         performance.measure('build', 'build');
     }
-    return createFinalResponse(
+    const response = await createFinalResponse(
         {
             url: req.url,
             body,
@@ -110,4 +118,8 @@ export async function sjsRequestHandler(
         buildTarget,
         CACHE,
     );
+    if (CACHE && CACHE_CLIENT_REDIRECT && isRedirect(response.status)) {
+        return createFastPathResponse(response, performance, buildTarget);
+    }
+    return response;
 }
diff --git a/src/utils.ts b/src/utils.ts
@@ -146,6 +146,7 @@ export const createFinalResponse = async (
     performance: Performance,
     buildTarget: string,
     shouldCache: boolean,
+    isFastPathRedirect?: boolean,
 ): Promise<Response> => {
     const CACHE_CLIENT_REDIRECT =
         Number(Deno.env.get('CACHE_CLIENT_REDIRECT') as string) || 0;
@@ -167,17 +168,18 @@ export const createFinalResponse = async (
         await saveCache(denoKv, [url, buildTarget], responseProps);
         performance.measure('cache-write', 'cache-write');
     }
-
-    if (
-        CACHE_CLIENT_REDIRECT && isActualRedirect &&
-        !headers.has('cache-control')
-    ) {
+    const shouldSetCacheClientRedirect = CACHE_CLIENT_REDIRECT
+        && isFastPathRedirect;
+    if (shouldSetCacheClientRedirect) {
         headers.set(
             'cache-control',
             `public, max-age=${CACHE_CLIENT_REDIRECT}`,
         );
     }
 
+    if (isFastPathRedirect) {
+        performance.clearMeasures('total');
+    }
     performance.measure('total', 'total');
     headers.set('server-timing', buildDebugPerformance(performance));
 
@@ -190,6 +192,49 @@ export const createFinalResponse = async (
     return response;
 };
 
+export const createFastPathResponse = async (
+    response: Response,
+    performance: Performance,
+    buildTarget: string,
+): Promise<Response> => {
+    const redirectLocation = response.headers.get('location');
+    if (!redirectLocation) {
+        return response;
+    }
+    performance.mark('redirect-cache-read');
+    const value = await retrieveCache(denoKv, [
+        redirectLocation,
+        buildTarget,
+    ]);
+    performance.measure('redirect-cache-read', 'redirect-cache-read');
+    if (value) {
+        performance.measure('redirect-cache-hit', { start: performance.now() });
+        return createFinalResponse(
+            {
+                ...value,
+                headers: new Headers(value.headers),
+            },
+            performance,
+            buildTarget,
+            false,
+            true,
+        );
+    }
+    performance.measure('redirect-cache-miss', { start: performance.now() });
+
+    const rebuildedHeaders = cloneHeaders(response.headers);
+
+    performance.clearMeasures('total');
+    performance.measure('total', 'total');
+
+    rebuildedHeaders.set('server-timing', buildDebugPerformance(performance));
+    return new Response(response.body, {
+        headers: rebuildedHeaders,
+        status: response.status,
+        statusText: response.statusText,
+    });
+};
+
 export const _internals = {
     fetch: nodeRequest,
 };