fix(cloudflare-pages): exclude assets from function call (#965)

Co-authored-by: Pooya Parsa <pooya@pi0.io>

.gitignore

@@ -66,4 +66,6 @@ Temporary Items
 .netlify
 .vercel
 staticwebapp.config.json
-.eslintcache
+.eslintcache
+
+test/fixture/functions

src/presets/cloudflare.ts

@@ -1,5 +1,7 @@
-import { resolve } from "pathe";
+import { join, resolve } from "pathe";
 import fse from "fs-extra";
+import { joinURL, withLeadingSlash, withoutLeadingSlash } from "ufo";
+import { globby } from "globby";
 import { writeFile } from "../utils";
 import { defineNitroPreset } from "../preset";
 import type { Nitro } from "../types";
@@ -25,6 +27,15 @@ export const cloudflare = defineNitroPreset({
   },
 });
 
+/**
+ * https://developers.cloudflare.com/pages/platform/functions/routing/#functions-invocation-routes
+ */
+interface CloudflarePagesRoutes {
+  version: 1;
+  include: string[];
+  exclude: string[];
+}
+
 export const cloudflarePages = defineNitroPreset({
   extends: "cloudflare",
   entry: "#internal/nitro/entries/cloudflare-pages",
@@ -56,6 +67,51 @@ export const cloudflarePages = defineNitroPreset({
         resolve(nitro.options.output.serverDir, "path.js.map"),
         resolve(nitro.options.output.serverDir, "[[path]].js.map")
       );
+
+      const routes: CloudflarePagesRoutes = {
+        version: 1,
+        include: ["/*"],
+        exclude: [],
+      };
+
+      // Exclude public assets from hitting the worker
+      const explicitPublicAssets = nitro.options.publicAssets.filter(
+        (i) => !i.fallthrough
+      );
+
+      // Explicit prefixes
+      routes.exclude.push(
+        ...explicitPublicAssets
+          .map((dir) => joinURL(dir.baseURL, "*"))
+          .sort(comparePaths)
+      );
+
+      // Unprefixed assets
+      const publicAssetFiles = await globby("**", {
+        cwd: nitro.options.output.publicDir,
+        absolute: false,
+        dot: true,
+        ignore: [
+          ...explicitPublicAssets.map((dir) =>
+            withoutLeadingSlash(joinURL(dir.baseURL, "**"))
+          ),
+        ],
+      });
+      routes.exclude.push(
+        ...publicAssetFiles.map((i) => withLeadingSlash(i)).sort(comparePaths)
+      );
+
+      // Only allow 100 routes
+      routes.exclude.splice(100);
+
+      await fse.writeFile(
+        resolve(nitro.options.output.publicDir, "_routes.json"),
+        JSON.stringify(routes, undefined, 2)
+      );
     },
   },
 });
+
+function comparePaths(a: string, b: string) {
+  return a.split("/").length - b.split("/").length || a.localeCompare(b);
+}

test/presets/cloudflare.test.ts

@@ -1,6 +1,7 @@
+import { promises as fsp } from "node:fs";
 import { resolve } from "pathe";
 import { Miniflare } from "miniflare";
-import { describe } from "vitest";
+import { describe, it, expect } from "vitest";
 
 import { setupTest, testNitro } from "../tests";
 
@@ -20,3 +21,35 @@ describe("nitro:preset:cloudflare", async () => {
     };
   });
 });
+
+describe("nitro:preset:cloudflare-pages", async () => {
+  const ctx = await setupTest("cloudflare-pages");
+
+  it("should generate a _routes.json", async () => {
+    const config = await fsp
+      .readFile(resolve(ctx.outDir, "public/_routes.json"), "utf8")
+      .then((r) => JSON.parse(r));
+    expect(config).toMatchInlineSnapshot(`
+      {
+        "exclude": [
+          "/build/*",
+          "/favicon.ico",
+          "/icon.png",
+          "/api/hello",
+          "/prerender/index.html",
+          "/prerender/index.html.br",
+          "/prerender/index.html.gz",
+          "/api/hey/index.html",
+          "/api/param/foo.json/index.html",
+          "/api/param/prerender1/index.html",
+          "/api/param/prerender3/index.html",
+          "/api/param/prerender4/index.html",
+        ],
+        "include": [
+          "/*",
+        ],
+        "version": 1,
+      }
+    `);
+  });
+});

test/tests.ts

@@ -39,8 +39,17 @@ export async function setupTest(preset: string) {
     dev: ctx.isDev,
     rootDir: ctx.rootDir,
     serveStatic:
-      preset !== "cloudflare" && preset !== "vercel-edge" && !ctx.isDev,
-    output: { dir: ctx.outDir },
+      preset !== "cloudflare" &&
+      preset !== "cloudflare-pages" &&
+      preset !== "vercel-edge" &&
+      !ctx.isDev,
+    output: {
+      dir: ctx.outDir,
+      serverDir:
+        preset === "cloudflare-pages"
+          ? "{{ output.dir }}/functions"
+          : undefined,
+    },
     routeRules: {
       "/rules/headers": { headers: { "cache-control": "s-maxage=60" } },
       "/rules/cors": {