From 5519500f7a0c699314f29342cb6f40d3494ebe5f Mon Sep 17 00:00:00 2001
From: Uchio Kondo <udzura@udzura.jp>
Date: Thu, 20 Aug 2026 21:14:21 +0900
Subject: [PATCH 1/5] feat: configure Cloudflare HTTP request size

---
 uzumibi-on-cloudflare-spike/package.json      | 21 ++--
 .../scripts/build-wasm.mjs                    | 85 ++++++++++++++++
 uzumibi-on-cloudflare-spike/src/index.js      | 94 ++----------------
 .../src/index.vanilla.js                      | 96 ++----------------
 .../src/request-buffer.js                     | 99 +++++++++++++++++++
 .../test/request-buffer.spec.js               | 64 ++++++++++++
 uzumibi-on-cloudflare-spike/wasm-app/build.rs | 18 +++-
 .../wasm-app/src/lib.rs                       | 12 +++
 8 files changed, 303 insertions(+), 186 deletions(-)
 create mode 100644 uzumibi-on-cloudflare-spike/scripts/build-wasm.mjs
 create mode 100644 uzumibi-on-cloudflare-spike/src/request-buffer.js
 create mode 100644 uzumibi-on-cloudflare-spike/test/request-buffer.spec.js

diff --git a/uzumibi-on-cloudflare-spike/package.json b/uzumibi-on-cloudflare-spike/package.json
index 6dcb288..eba594b 100644
--- a/uzumibi-on-cloudflare-spike/package.json
+++ b/uzumibi-on-cloudflare-spike/package.json
@@ -2,15 +2,18 @@
 	"name": "uzumibi-on-cloudflare-spike",
 	"version": "0.0.0",
 	"private": true,
+	"uzumibi": {
+		"httpMaxBytes": 65536
+	},
 	"scripts": {
-		"deploy": "npm run build:wasm:asyncify && wrangler deploy",
-		"dev": "npm run build:wasm:asyncify && wrangler dev",
-		"dev:vanilla": "npm run build:wasm:vanilla && wrangler dev --config wrangler.vanilla.jsonc",
-		"build:wasm:vanilla": "cargo build --package uzumibi-on-cloudflare-spike --target wasm32-unknown-unknown --release --no-default-features && cp -v -f ../target/wasm32-unknown-unknown/release/uzumibi_on_cloudflare_spike.wasm src/",
-		"build:wasm:asyncify": "cargo build --package uzumibi-on-cloudflare-spike --target wasm32-unknown-unknown --release --features enable-external && wasm-opt --enable-bulk-memory --enable-nontrapping-float-to-int --asyncify -O2 ../target/wasm32-unknown-unknown/release/uzumibi_on_cloudflare_spike.wasm -o ./src/uzumibi_on_cloudflare_spike.wasm",
-		"build:wasm:queue": "cargo build --package uzumibi-on-cloudflare-spike --target wasm32-unknown-unknown --release --features queue && wasm-opt --enable-bulk-memory --enable-nontrapping-float-to-int --asyncify -O2 ../target/wasm32-unknown-unknown/release/uzumibi_on_cloudflare_spike.wasm -o ./src/uzumibi_on_cloudflare_spike_queue.wasm",
-		"dev:queue": "npm run build:wasm:queue && wrangler dev --config wrangler.queue.jsonc",
-		"deploy:queue": "npm run build:wasm:queue && wrangler deploy --config wrangler.queue.jsonc",
+		"deploy": "pnpm run build:wasm:asyncify && wrangler deploy",
+		"dev": "pnpm run build:wasm:asyncify && wrangler dev",
+		"dev:vanilla": "pnpm run build:wasm:vanilla && wrangler dev --config wrangler.vanilla.jsonc",
+		"build:wasm:vanilla": "node scripts/build-wasm.mjs vanilla",
+		"build:wasm:asyncify": "node scripts/build-wasm.mjs asyncify",
+		"build:wasm:queue": "node scripts/build-wasm.mjs queue",
+		"dev:queue": "pnpm run build:wasm:queue && wrangler dev --config wrangler.queue.jsonc",
+		"deploy:queue": "pnpm run build:wasm:queue && wrangler deploy --config wrangler.queue.jsonc",
 		"start": "wrangler dev",
 		"test": "vitest"
 	},
@@ -20,4 +23,4 @@
 		"vitest": "~3.2.0",
 		"wrangler": "^4.54.0"
 	}
-}
\ No newline at end of file
+}
diff --git a/uzumibi-on-cloudflare-spike/scripts/build-wasm.mjs b/uzumibi-on-cloudflare-spike/scripts/build-wasm.mjs
new file mode 100644
index 0000000..a864227
--- /dev/null
+++ b/uzumibi-on-cloudflare-spike/scripts/build-wasm.mjs
@@ -0,0 +1,85 @@
+import { copyFileSync, readFileSync } from "node:fs";
+import { spawnSync } from "node:child_process";
+import { fileURLToPath } from "node:url";
+import { dirname, join } from "node:path";
+
+const projectDir = join(dirname(fileURLToPath(import.meta.url)), "..");
+const packageJson = JSON.parse(
+    readFileSync(join(projectDir, "package.json"), "utf8"),
+);
+
+const mode = process.argv[2] ?? "asyncify";
+const supportedModes = new Set(["vanilla", "asyncify", "queue"]);
+if (!supportedModes.has(mode)) {
+    throw new Error(`Unknown build mode: ${mode}`);
+}
+
+const cliOption = process.argv.find((arg) =>
+    arg.startsWith("--http-max-bytes="),
+);
+const cliOptionIndex = process.argv.indexOf("--http-max-bytes");
+const cliValue = cliOption?.split("=", 2)[1]
+    ?? (cliOptionIndex >= 0 ? process.argv[cliOptionIndex + 1] : undefined);
+const configuredValue = cliValue
+    ?? process.env.UZUMIBI_HTTP_MAX_BYTES
+    ?? packageJson.uzumibi?.httpMaxBytes
+    ?? 65536;
+const httpMaxBytes = Number(configuredValue);
+
+if (!Number.isSafeInteger(httpMaxBytes) || httpMaxBytes <= 0 || httpMaxBytes > 0x7fffffff) {
+    throw new Error(
+        `Invalid HTTP maximum size: ${configuredValue}. `
+        + "Expected an integer between 1 and 2147483647.",
+    );
+}
+
+function run(command, args) {
+    const result = spawnSync(command, args, {
+        cwd: projectDir,
+        env: {
+            ...process.env,
+            UZUMIBI_HTTP_MAX_BYTES: String(httpMaxBytes),
+        },
+        stdio: "inherit",
+    });
+    if (result.error) throw result.error;
+    if (result.status !== 0) process.exit(result.status ?? 1);
+}
+
+const cargoArgs = [
+    "build",
+    "--package", "uzumibi-on-cloudflare-spike",
+    "--target", "wasm32-unknown-unknown",
+    "--release",
+];
+
+if (mode === "vanilla") {
+    cargoArgs.push("--no-default-features");
+} else {
+    cargoArgs.push("--features", mode === "queue" ? "queue" : "enable-external");
+}
+
+console.log(`Building ${mode} Wasm with HTTP maximum ${httpMaxBytes} bytes`);
+run("cargo", cargoArgs);
+
+const source = join(
+    projectDir,
+    "../target/wasm32-unknown-unknown/release/uzumibi_on_cloudflare_spike.wasm",
+);
+const outputName = mode === "queue"
+    ? "uzumibi_on_cloudflare_spike_queue.wasm"
+    : "uzumibi_on_cloudflare_spike.wasm";
+const output = join(projectDir, "src", outputName);
+
+if (mode === "vanilla") {
+    copyFileSync(source, output);
+} else {
+    run("wasm-opt", [
+        "--enable-bulk-memory",
+        "--enable-nontrapping-float-to-int",
+        "--asyncify",
+        "-O2",
+        source,
+        "-o", output,
+    ]);
+}
diff --git a/uzumibi-on-cloudflare-spike/src/index.js b/uzumibi-on-cloudflare-spike/src/index.js
index 388a946..53b56b2 100644
--- a/uzumibi-on-cloudflare-spike/src/index.js
+++ b/uzumibi-on-cloudflare-spike/src/index.js
@@ -1,6 +1,7 @@
 import { DurableObject } from "cloudflare:workers";
 import { instantiate } from "asyncify-wasm";
 import mod from "./uzumibi_on_cloudflare_spike.wasm";
+import { RequestTooLargeError, writeRequestToWasm } from "./request-buffer.js";
 
 const wasmModule = mod;
 
@@ -25,8 +26,6 @@ export default {
 			return new Response(null, { status: 404 });
 		}
 
-		const query = new URL(request.url).searchParams;
-
 		const kv = env.UZUMIBI_KV ?? null;
 
 		// Durable Object stub retained for Uzumibi::LegacyKV.
@@ -229,92 +228,13 @@ export default {
 		const instance = await instantiate(wasmModule, importObject);
 		const exports = instance.exports;
 
-		const reqResult = await exports.uzumibi_initialize_request(65536);
-		const reqOffset = Number(reqResult & 0xFFFFFFFFn);
-		if (reqOffset === 0) {
-			const errOffset = Number((reqResult >> 32n) & 0xFFFFFFFFn);
-			const buffer = new Uint8Array(exports.memory.buffer, errOffset);
-			let errStr = "";
-			for (let i = 0; buffer[i] !== 0; i++) {
-				errStr += String.fromCharCode(buffer[i]);
-			}
-			throw new Error(`Failed to initialize request: ${errStr}`);
-		}
-		const requestBuffer = new Uint8Array(exports.memory.buffer, reqOffset, 65536);
-
-		let pos = 0;
-		const dataView = new DataView(exports.memory.buffer, reqOffset);
-
-		const method = encoder.encode(request.method);
-		requestBuffer.fill(0, pos, pos + 6);
-		requestBuffer.set(method.slice(0, 6), pos);
-		pos += 6;
-
-		// Path size (u16 little-endian)
-		const pathBytes = encoder.encode(path);
-		dataView.setUint16(pos, pathBytes.length, true);
-		pos += 2;
-
-		// Path
-		requestBuffer.set(pathBytes, pos);
-		pos += pathBytes.length;
-
-		// Query string size (u16 little-endian)
-		const queryString = query.toString();
-		const queryBytes = encoder.encode(queryString);
-		dataView.setUint16(pos, queryBytes.length, true);
-		pos += 2;
-
-		// Query string
-		requestBuffer.set(queryBytes, pos);
-		pos += queryBytes.length;
-
-		// Headers
-		const headers = [];
-		request.headers.forEach((value, key) => {
-			if (key.toLowerCase() !== 'cf-connecting-ip' &&
-				key.toLowerCase() !== 'cf-ray' &&
-				!key.toLowerCase().startsWith('x-')) {
-				headers.push({ key, value });
+		try {
+			await writeRequestToWasm(exports, request);
+		} catch (error) {
+			if (error instanceof RequestTooLargeError) {
+				return new Response(error.message, { status: 413 });
 			}
-		});
-
-		// Headers count (u16 little-endian)
-		dataView.setUint16(pos, headers.length, true);
-		pos += 2;
-
-		// Each header
-		for (const header of headers) {
-			// Header key size (u16 little-endian)
-			const keyBytes = encoder.encode(header.key);
-			dataView.setUint16(pos, keyBytes.length, true);
-			pos += 2;
-
-			// Header key
-			requestBuffer.set(keyBytes, pos);
-			pos += keyBytes.length;
-
-			// Header value size (u16 little-endian)
-			const valueBytes = encoder.encode(header.value);
-			dataView.setUint16(pos, valueBytes.length, true);
-			pos += 2;
-
-			// Header value
-			requestBuffer.set(valueBytes, pos);
-			pos += valueBytes.length;
-		}
-
-		// Request body size (u32 little-endian)
-		const bodyBytes = request.body ? new Uint8Array(await request.arrayBuffer()) : new Uint8Array(0);
-		dataView.setUint32(pos, bodyBytes.length, true);
-		pos += 4;
-
-		// Request body
-		requestBuffer.set(bodyBytes, pos);
-		pos += bodyBytes.length;
-
-		if (pos > 65536) {
-			throw new Error("Request data exceeds allocated buffer size");
+			throw error;
 		}
 
 		const resResult = await exports.uzumibi_start_request();
diff --git a/uzumibi-on-cloudflare-spike/src/index.vanilla.js b/uzumibi-on-cloudflare-spike/src/index.vanilla.js
index e61e534..1d2a492 100644
--- a/uzumibi-on-cloudflare-spike/src/index.vanilla.js
+++ b/uzumibi-on-cloudflare-spike/src/index.vanilla.js
@@ -1,4 +1,5 @@
 import mod from "./uzumibi_on_cloudflare_spike.wasm";
+import { RequestTooLargeError, writeRequestToWasm } from "./request-buffer.js";
 
 const importObject = {
 	env: {
@@ -19,101 +20,18 @@ const exports = instance.exports;
 
 export default {
 	async fetch(request, env, ctx) {
-		const reqResult = exports.uzumibi_initialize_request(65536);
-		const reqOffset = Number(reqResult & 0xFFFFFFFFn);
-		if (reqOffset === 0) {
-			const errOffset = Number((reqResult >> 32n) & 0xFFFFFFFFn);
-			const decoder = new TextDecoder();
-			let errStr = "";
-			const buffer = new Uint8Array(exports.memory.buffer, errOffset);
-			for (let i = 0; buffer[i] !== 0; i++) {
-				errStr += String.fromCharCode(buffer[i]);
-			}
-			throw new Error(`Failed to initialize request: ${errStr}`);
-		}
-		const requestBuffer = new Uint8Array(exports.memory.buffer, reqOffset, 65536);
 		const path = new URL(request.url).pathname;
 		if (path === "/favicon.ico") {
 			return new Response(null, { status: 404 });
 		}
 
-		const query = new URL(request.url).searchParams;
-
-		let pos = 0;
-		const encoder = new TextEncoder();
-		const dataView = new DataView(exports.memory.buffer, reqOffset);
-
-		const method = encoder.encode(request.method);
-		requestBuffer.fill(0, pos, pos + 6);
-		requestBuffer.set(method.slice(0, 6), pos);
-		pos += 6;
-
-		// Path size (u16 little-endian)
-		const pathBytes = encoder.encode(path);
-		dataView.setUint16(pos, pathBytes.length, true);
-		pos += 2;
-
-		// Path
-		requestBuffer.set(pathBytes, pos);
-		pos += pathBytes.length;
-
-		// Query string size (u16 little-endian)
-		const queryString = query.toString();
-		const queryBytes = encoder.encode(queryString);
-		dataView.setUint16(pos, queryBytes.length, true);
-		pos += 2;
-
-		// Query string
-		requestBuffer.set(queryBytes, pos);
-		pos += queryBytes.length;
-
-		// Headers
-		const headers = [];
-		request.headers.forEach((value, key) => {
-			// 一般的なヘッダーのみ含める（必要に応じて調整）
-			if (key.toLowerCase() !== 'cf-connecting-ip' &&
-				key.toLowerCase() !== 'cf-ray' &&
-				!key.toLowerCase().startsWith('x-')) {
-				headers.push({ key, value });
+		try {
+			await writeRequestToWasm(exports, request);
+		} catch (error) {
+			if (error instanceof RequestTooLargeError) {
+				return new Response(error.message, { status: 413 });
 			}
-		});
-
-		// Headers count (u16 little-endian)
-		dataView.setUint16(pos, headers.length, true);
-		pos += 2;
-
-		// Each header
-		for (const header of headers) {
-			// Header key size (u16 little-endian)
-			const keyBytes = encoder.encode(header.key);
-			dataView.setUint16(pos, keyBytes.length, true);
-			pos += 2;
-
-			// Header key
-			requestBuffer.set(keyBytes, pos);
-			pos += keyBytes.length;
-
-			// Header value size (u16 little-endian)
-			const valueBytes = encoder.encode(header.value);
-			dataView.setUint16(pos, valueBytes.length, true);
-			pos += 2;
-
-			// Header value
-			requestBuffer.set(valueBytes, pos);
-			pos += valueBytes.length;
-		}
-
-		// Request body size (u32 little-endian)
-		const bodyBytes = request.body ? new Uint8Array(await request.arrayBuffer()) : new Uint8Array(0);
-		dataView.setUint32(pos, bodyBytes.length, true);
-		pos += 4;
-
-		// Request body
-		requestBuffer.set(bodyBytes, pos);
-		pos += bodyBytes.length;
-
-		if (pos > 65536) {
-			throw new Error("Request data exceeds allocated buffer size");
+			throw error;
 		}
 
 		const resResult = exports.uzumibi_start_request();
diff --git a/uzumibi-on-cloudflare-spike/src/request-buffer.js b/uzumibi-on-cloudflare-spike/src/request-buffer.js
new file mode 100644
index 0000000..a17d2b8
--- /dev/null
+++ b/uzumibi-on-cloudflare-spike/src/request-buffer.js
@@ -0,0 +1,99 @@
+export class RequestTooLargeError extends Error {
+    constructor(actualBytes, maxBytes) {
+        super(`Encoded request size ${actualBytes} exceeds the configured maximum of ${maxBytes} bytes`);
+        this.name = "RequestTooLargeError";
+        this.actualBytes = actualBytes;
+        this.maxBytes = maxBytes;
+    }
+}
+
+function readError(exports, result, operation) {
+    const errorOffset = Number((result >> 32n) & 0xFFFFFFFFn);
+    const buffer = new Uint8Array(exports.memory.buffer, errorOffset);
+    let message = "";
+    for (let i = 0; buffer[i] !== 0; i++) {
+        message += String.fromCharCode(buffer[i]);
+    }
+    return new Error(`Failed to ${operation}: ${message}`);
+}
+
+export async function writeRequestToWasm(exports, request) {
+    const encoder = new TextEncoder();
+    const url = new URL(request.url);
+    const methodBytes = encoder.encode(request.method);
+    const pathBytes = encoder.encode(url.pathname);
+    const queryBytes = encoder.encode(url.searchParams.toString());
+    const bodyBytes = request.body
+        ? new Uint8Array(await request.arrayBuffer())
+        : new Uint8Array(0);
+
+    const headers = [];
+    request.headers.forEach((value, key) => {
+        if (key.toLowerCase() !== "cf-connecting-ip"
+            && key.toLowerCase() !== "cf-ray"
+            && !key.toLowerCase().startsWith("x-")) {
+            headers.push({
+                key: encoder.encode(key),
+                value: encoder.encode(value),
+            });
+        }
+    });
+
+    const headersSize = headers.reduce(
+        (size, header) => size + 2 + header.key.length + 2 + header.value.length,
+        0,
+    );
+    const requiredSize = 6
+        + 2 + pathBytes.length
+        + 2 + queryBytes.length
+        + 2 + headersSize
+        + 4 + bodyBytes.length;
+    const maxBytes = Number(await exports.uzumibi_http_max_bytes());
+
+    if (requiredSize > maxBytes) {
+        throw new RequestTooLargeError(requiredSize, maxBytes);
+    }
+
+    const result = await exports.uzumibi_initialize_request(requiredSize);
+    const offset = Number(result & 0xFFFFFFFFn);
+    if (offset === 0) {
+        throw readError(exports, result, "initialize request");
+    }
+
+    const requestBuffer = new Uint8Array(exports.memory.buffer, offset, requiredSize);
+    const dataView = new DataView(exports.memory.buffer, offset, requiredSize);
+    let pos = 0;
+
+    requestBuffer.fill(0, pos, pos + 6);
+    requestBuffer.set(methodBytes.slice(0, 6), pos);
+    pos += 6;
+
+    dataView.setUint16(pos, pathBytes.length, true);
+    pos += 2;
+    requestBuffer.set(pathBytes, pos);
+    pos += pathBytes.length;
+
+    dataView.setUint16(pos, queryBytes.length, true);
+    pos += 2;
+    requestBuffer.set(queryBytes, pos);
+    pos += queryBytes.length;
+
+    dataView.setUint16(pos, headers.length, true);
+    pos += 2;
+    for (const header of headers) {
+        dataView.setUint16(pos, header.key.length, true);
+        pos += 2;
+        requestBuffer.set(header.key, pos);
+        pos += header.key.length;
+        dataView.setUint16(pos, header.value.length, true);
+        pos += 2;
+        requestBuffer.set(header.value, pos);
+        pos += header.value.length;
+    }
+
+    dataView.setUint32(pos, bodyBytes.length, true);
+    pos += 4;
+    requestBuffer.set(bodyBytes, pos);
+
+    return requiredSize;
+}
diff --git a/uzumibi-on-cloudflare-spike/test/request-buffer.spec.js b/uzumibi-on-cloudflare-spike/test/request-buffer.spec.js
new file mode 100644
index 0000000..b9fd12a
--- /dev/null
+++ b/uzumibi-on-cloudflare-spike/test/request-buffer.spec.js
@@ -0,0 +1,64 @@
+import { describe, expect, it } from "vitest";
+import {
+    RequestTooLargeError,
+    writeRequestToWasm,
+} from "../src/request-buffer.js";
+
+function createExports(maxBytes) {
+    const memory = new WebAssembly.Memory({ initial: 4 });
+    let allocatedSize = 0;
+
+    return {
+        exports: {
+            memory,
+            uzumibi_http_max_bytes: () => maxBytes,
+            uzumibi_initialize_request: (size) => {
+                allocatedSize = size;
+                return 1024n;
+            },
+        },
+        allocatedSize: () => allocatedSize,
+    };
+}
+
+describe("Cloudflare request buffer", () => {
+    it("allocates the encoded request size instead of the configured maximum", async () => {
+        const wasm = createExports(131072);
+        const request = new Request("https://example.com/items?q=uzumibi", {
+            method: "POST",
+            headers: { "content-type": "text/plain" },
+            body: "hello",
+        });
+
+        const encodedSize = await writeRequestToWasm(wasm.exports, request);
+
+        expect(wasm.allocatedSize()).toBe(encodedSize);
+        expect(encodedSize).toBeLessThan(131072);
+    });
+
+    it("accepts a request larger than the old 64 KiB limit", async () => {
+        const wasm = createExports(131072);
+        const request = new Request("https://example.com/upload", {
+            method: "POST",
+            body: new Uint8Array(70000),
+        });
+
+        const encodedSize = await writeRequestToWasm(wasm.exports, request);
+
+        expect(encodedSize).toBeGreaterThan(65536);
+        expect(wasm.allocatedSize()).toBe(encodedSize);
+    });
+
+    it("rejects a request that exceeds the configured maximum", async () => {
+        const wasm = createExports(65536);
+        const request = new Request("https://example.com/upload", {
+            method: "POST",
+            body: new Uint8Array(70000),
+        });
+
+        await expect(writeRequestToWasm(wasm.exports, request)).rejects.toBeInstanceOf(
+            RequestTooLargeError,
+        );
+        expect(wasm.allocatedSize()).toBe(0);
+    });
+});
diff --git a/uzumibi-on-cloudflare-spike/wasm-app/build.rs b/uzumibi-on-cloudflare-spike/wasm-app/build.rs
index f94e82f..2176067 100644
--- a/uzumibi-on-cloudflare-spike/wasm-app/build.rs
+++ b/uzumibi-on-cloudflare-spike/wasm-app/build.rs
@@ -1,9 +1,25 @@
-use std::path::Path;
+use std::{fs, path::Path};
 
 extern crate mruby_compiler2_sys;
 
 fn main() {
     let out_dir = std::env::var("OUT_DIR").unwrap();
+    let http_max_bytes = std::env::var("UZUMIBI_HTTP_MAX_BYTES")
+        .unwrap_or_else(|_| "65536".to_string())
+        .parse::<u32>()
+        .expect("UZUMIBI_HTTP_MAX_BYTES must be a positive 32-bit integer");
+    assert!(
+        http_max_bytes > 0 && http_max_bytes <= i32::MAX as u32,
+        "UZUMIBI_HTTP_MAX_BYTES must be between 1 and {}",
+        i32::MAX
+    );
+    fs::write(
+        Path::new(&out_dir).join("uzumibi_config.rs"),
+        format!("pub const HTTP_MAX_BYTES: u32 = {http_max_bytes};\n"),
+    )
+    .expect("failed to write Uzumibi build configuration");
+    println!("cargo:rerun-if-env-changed=UZUMIBI_HTTP_MAX_BYTES");
+
     let mrb_path = Path::new(&out_dir).join("app.mrb");
     let code = include_str!("../lib/app.rb");
     println!("cargo:rerun-if-changed=../lib/app.rb");
diff --git a/uzumibi-on-cloudflare-spike/wasm-app/src/lib.rs b/uzumibi-on-cloudflare-spike/wasm-app/src/lib.rs
index 0317321..b9f9305 100644
--- a/uzumibi-on-cloudflare-spike/wasm-app/src/lib.rs
+++ b/uzumibi-on-cloudflare-spike/wasm-app/src/lib.rs
@@ -14,6 +14,8 @@ use mrubyedge::{
     },
 };
 
+include!(concat!(env!("OUT_DIR"), "/uzumibi_config.rs"));
+
 #[cfg(not(feature = "queue"))]
 static MRB: &[u8] = include_bytes!(concat!(env!("OUT_DIR"), "/app.mrb"));
 #[cfg(feature = "queue")]
@@ -61,6 +63,11 @@ fn assume_init_vm() -> Result<&'static mut VM, mrubyedge::Error> {
 }
 
 fn do_uzumibi_initialize_request(size: i32) -> Result<*mut u8, mrubyedge::Error> {
+    if size <= 0 || size as u32 > HTTP_MAX_BYTES {
+        return Err(mrubyedge::Error::RuntimeError(format!(
+            "Request size {size} exceeds the configured maximum of {HTTP_MAX_BYTES} bytes"
+        )));
+    }
     let vm = assume_init_vm()?;
     let size = RObject::integer(size as i64).to_refcount_assigned();
     let app = vm
@@ -71,6 +78,11 @@ fn do_uzumibi_initialize_request(size: i32) -> Result<*mut u8, mrubyedge::Error>
     ret.as_ref().try_into()
 }
 
+#[unsafe(export_name = "uzumibi_http_max_bytes")]
+extern "C" fn uzumibi_http_max_bytes() -> u32 {
+    HTTP_MAX_BYTES
+}
+
 fn do_uzumibi_start_request() -> Result<*mut u8, mrubyedge::Error> {
     uzumibi_cloudflare_ext::debug_console_log_internal("uzumibi_start_request called");
     let vm = assume_init_vm()?;

From c1aef911dc1e2e5256e9e438055a78e2fe0264c0 Mon Sep 17 00:00:00 2001
From: Uchio Kondo <udzura@udzura.jp>
Date: Thu, 20 Aug 2026 21:28:08 +0900
Subject: [PATCH 2/5] feat: configure Cloudflare template request size

---
 .../__features__/enable-external/package.json | 11 ++-
 .../__features__/enable-external/src/index.js | 94 ++----------------
 .../enable-external/wasm-app/src/lib.rs       | 12 +++
 .../__features__/queue/package.json           | 11 ++-
 .../__features__/queue/wasm-app/build.rs      | 18 +++-
 .../__features__/queue/wasm-app/src/lib.rs    | 12 +++
 uzumibi-cli/templates/cloudflare/package.json | 10 +-
 .../cloudflare/scripts/build-wasm.mjs         | 85 ++++++++++++++++
 uzumibi-cli/templates/cloudflare/src/index.js | 96 ++----------------
 .../cloudflare/src/request-buffer.js          | 99 +++++++++++++++++++
 .../cloudflare/test/request-buffer.spec.js    | 64 ++++++++++++
 .../templates/cloudflare/wasm-app/build.rs    | 18 +++-
 .../templates/cloudflare/wasm-app/src/lib.rs  | 12 +++
 uzumibi-cli/tests/runn/new_cloudflare.yml     |  6 ++
 14 files changed, 359 insertions(+), 189 deletions(-)
 create mode 100644 uzumibi-cli/templates/cloudflare/scripts/build-wasm.mjs
 create mode 100644 uzumibi-cli/templates/cloudflare/src/request-buffer.js
 create mode 100644 uzumibi-cli/templates/cloudflare/test/request-buffer.spec.js

diff --git a/uzumibi-cli/templates/cloudflare/__features__/enable-external/package.json b/uzumibi-cli/templates/cloudflare/__features__/enable-external/package.json
index c04421a..3e09d6d 100644
--- a/uzumibi-cli/templates/cloudflare/__features__/enable-external/package.json
+++ b/uzumibi-cli/templates/cloudflare/__features__/enable-external/package.json
@@ -2,10 +2,13 @@
     "name": "$$PROJECT_NAME$$",
     "version": "0.0.0",
     "private": true,
+    "uzumibi": {
+        "httpMaxBytes": 65536
+    },
     "scripts": {
-        "deploy": "npm run build:wasm:asyncify && wrangler deploy",
-        "dev": "npm run build:wasm:asyncify && wrangler dev",
-        "build:wasm:asyncify": "cargo build --package $$PROJECT_NAME$$ --target wasm32-unknown-unknown --release --features enable-external && wasm-opt --enable-bulk-memory --enable-nontrapping-float-to-int --asyncify -O2 target/wasm32-unknown-unknown/release/$$PROJECT_NAME_UNDERSCORE$$.wasm -o ./src/$$PROJECT_NAME_UNDERSCORE$$.wasm",
+        "deploy": "pnpm run build:wasm:asyncify && wrangler deploy",
+        "dev": "pnpm run build:wasm:asyncify && wrangler dev",
+        "build:wasm:asyncify": "node scripts/build-wasm.mjs asyncify",
         "start": "wrangler dev",
         "test": "vitest"
     },
@@ -15,4 +18,4 @@
         "vitest": "~3.2.0",
         "wrangler": "^4.54.0"
     }
-}
\ No newline at end of file
+}
diff --git a/uzumibi-cli/templates/cloudflare/__features__/enable-external/src/index.js b/uzumibi-cli/templates/cloudflare/__features__/enable-external/src/index.js
index 537c981..87096a4 100644
--- a/uzumibi-cli/templates/cloudflare/__features__/enable-external/src/index.js
+++ b/uzumibi-cli/templates/cloudflare/__features__/enable-external/src/index.js
@@ -1,6 +1,7 @@
 import { DurableObject } from "cloudflare:workers";
 import { instantiate } from "asyncify-wasm";
 import mod from "./$$PROJECT_NAME_UNDERSCORE$$.wasm";
+import { RequestTooLargeError, writeRequestToWasm } from "./request-buffer.js";
 
 const wasmModule = mod;
 
@@ -25,8 +26,6 @@ export default {
             return new Response(null, { status: 404 });
         }
 
-        const query = new URL(request.url).searchParams;
-
         const kv = env.UZUMIBI_KV ?? null;
 
         // Durable Object stub retained for Uzumibi::LegacyKV.
@@ -229,92 +228,13 @@ export default {
         const instance = await instantiate(wasmModule, importObject);
         const exports = instance.exports;
 
-        const reqResult = await exports.uzumibi_initialize_request(65536);
-        const reqOffset = Number(reqResult & 0xFFFFFFFFn);
-        if (reqOffset === 0) {
-            const errOffset = Number((reqResult >> 32n) & 0xFFFFFFFFn);
-            const buffer = new Uint8Array(exports.memory.buffer, errOffset);
-            let errStr = "";
-            for (let i = 0; buffer[i] !== 0; i++) {
-                errStr += String.fromCharCode(buffer[i]);
-            }
-            throw new Error(`Failed to initialize request: ${errStr}`);
-        }
-        const requestBuffer = new Uint8Array(exports.memory.buffer, reqOffset, 65536);
-
-        let pos = 0;
-        const dataView = new DataView(exports.memory.buffer, reqOffset);
-
-        const method = encoder.encode(request.method);
-        requestBuffer.fill(0, pos, pos + 6);
-        requestBuffer.set(method.slice(0, 6), pos);
-        pos += 6;
-
-        // Path size (u16 little-endian)
-        const pathBytes = encoder.encode(path);
-        dataView.setUint16(pos, pathBytes.length, true);
-        pos += 2;
-
-        // Path
-        requestBuffer.set(pathBytes, pos);
-        pos += pathBytes.length;
-
-        // Query string size (u16 little-endian)
-        const queryString = query.toString();
-        const queryBytes = encoder.encode(queryString);
-        dataView.setUint16(pos, queryBytes.length, true);
-        pos += 2;
-
-        // Query string
-        requestBuffer.set(queryBytes, pos);
-        pos += queryBytes.length;
-
-        // Headers
-        const headers = [];
-        request.headers.forEach((value, key) => {
-            if (key.toLowerCase() !== 'cf-connecting-ip' &&
-                key.toLowerCase() !== 'cf-ray' &&
-                !key.toLowerCase().startsWith('x-')) {
-                headers.push({ key, value });
+        try {
+            await writeRequestToWasm(exports, request);
+        } catch (error) {
+            if (error instanceof RequestTooLargeError) {
+                return new Response(error.message, { status: 413 });
             }
-        });
-
-        // Headers count (u16 little-endian)
-        dataView.setUint16(pos, headers.length, true);
-        pos += 2;
-
-        // Each header
-        for (const header of headers) {
-            // Header key size (u16 little-endian)
-            const keyBytes = encoder.encode(header.key);
-            dataView.setUint16(pos, keyBytes.length, true);
-            pos += 2;
-
-            // Header key
-            requestBuffer.set(keyBytes, pos);
-            pos += keyBytes.length;
-
-            // Header value size (u16 little-endian)
-            const valueBytes = encoder.encode(header.value);
-            dataView.setUint16(pos, valueBytes.length, true);
-            pos += 2;
-
-            // Header value
-            requestBuffer.set(valueBytes, pos);
-            pos += valueBytes.length;
-        }
-
-        // Request body size (u32 little-endian)
-        const bodyBytes = request.body ? new Uint8Array(await request.arrayBuffer()) : new Uint8Array(0);
-        dataView.setUint32(pos, bodyBytes.length, true);
-        pos += 4;
-
-        // Request body
-        requestBuffer.set(bodyBytes, pos);
-        pos += bodyBytes.length;
-
-        if (pos > 65536) {
-            throw new Error("Request data exceeds allocated buffer size");
+            throw error;
         }
 
         const resResult = await exports.uzumibi_start_request();
diff --git a/uzumibi-cli/templates/cloudflare/__features__/enable-external/wasm-app/src/lib.rs b/uzumibi-cli/templates/cloudflare/__features__/enable-external/wasm-app/src/lib.rs
index 9a667f1..ce85618 100644
--- a/uzumibi-cli/templates/cloudflare/__features__/enable-external/wasm-app/src/lib.rs
+++ b/uzumibi-cli/templates/cloudflare/__features__/enable-external/wasm-app/src/lib.rs
@@ -14,6 +14,8 @@ use mrubyedge::{
     },
 };
 
+include!(concat!(env!("OUT_DIR"), "/uzumibi_config.rs"));
+
 static MRB: &[u8] = include_bytes!(concat!(env!("OUT_DIR"), "/app.mrb"));
 
 static mut MRUBY_VM: MaybeUninit<VM> = MaybeUninit::uninit();
@@ -58,6 +60,11 @@ fn assume_init_vm() -> Result<&'static mut VM, mrubyedge::Error> {
 }
 
 fn do_uzumibi_initialize_request(size: i32) -> Result<*mut u8, mrubyedge::Error> {
+    if size <= 0 || size as u32 > HTTP_MAX_BYTES {
+        return Err(mrubyedge::Error::RuntimeError(format!(
+            "Request size {size} exceeds the configured maximum of {HTTP_MAX_BYTES} bytes"
+        )));
+    }
     let vm = assume_init_vm()?;
     let size = RObject::integer(size as i64).to_refcount_assigned();
     let app = vm
@@ -68,6 +75,11 @@ fn do_uzumibi_initialize_request(size: i32) -> Result<*mut u8, mrubyedge::Error>
     ret.as_ref().try_into()
 }
 
+#[unsafe(export_name = "uzumibi_http_max_bytes")]
+extern "C" fn uzumibi_http_max_bytes() -> u32 {
+    HTTP_MAX_BYTES
+}
+
 fn do_uzumibi_start_request() -> Result<*mut u8, mrubyedge::Error> {
     uzumibi_cloudflare_ext::debug_console_log_internal("uzumibi_start_request called");
     let vm = assume_init_vm()?;
diff --git a/uzumibi-cli/templates/cloudflare/__features__/queue/package.json b/uzumibi-cli/templates/cloudflare/__features__/queue/package.json
index 3304c76..f7a66e9 100644
--- a/uzumibi-cli/templates/cloudflare/__features__/queue/package.json
+++ b/uzumibi-cli/templates/cloudflare/__features__/queue/package.json
@@ -2,10 +2,13 @@
     "name": "$$PROJECT_NAME$$",
     "version": "0.0.0",
     "private": true,
+    "uzumibi": {
+        "httpMaxBytes": 65536
+    },
     "scripts": {
-        "deploy": "npm run build:wasm:asyncify && wrangler deploy",
-        "dev": "npm run build:wasm:asyncify && wrangler dev",
-        "build:wasm:asyncify": "cargo build --package $$PROJECT_NAME$$ --target wasm32-unknown-unknown --release --features queue && wasm-opt --enable-bulk-memory --enable-nontrapping-float-to-int --asyncify -O2 target/wasm32-unknown-unknown/release/$$PROJECT_NAME_UNDERSCORE$$.wasm -o ./src/$$PROJECT_NAME_UNDERSCORE$$_queue.wasm",
+        "deploy": "pnpm run build:wasm:queue && wrangler deploy",
+        "dev": "pnpm run build:wasm:queue && wrangler dev",
+        "build:wasm:queue": "node scripts/build-wasm.mjs queue",
         "start": "wrangler dev",
         "test": "vitest"
     },
@@ -15,4 +18,4 @@
         "vitest": "~3.2.0",
         "wrangler": "^4.54.0"
     }
-}
\ No newline at end of file
+}
diff --git a/uzumibi-cli/templates/cloudflare/__features__/queue/wasm-app/build.rs b/uzumibi-cli/templates/cloudflare/__features__/queue/wasm-app/build.rs
index 47fbb9b..5f5ffbe 100644
--- a/uzumibi-cli/templates/cloudflare/__features__/queue/wasm-app/build.rs
+++ b/uzumibi-cli/templates/cloudflare/__features__/queue/wasm-app/build.rs
@@ -1,9 +1,25 @@
-use std::path::Path;
+use std::{fs, path::Path};
 
 extern crate mruby_compiler2_sys;
 
 fn main() {
     let out_dir = std::env::var("OUT_DIR").unwrap();
+    let http_max_bytes = std::env::var("UZUMIBI_HTTP_MAX_BYTES")
+        .unwrap_or_else(|_| "65536".to_string())
+        .parse::<u32>()
+        .expect("UZUMIBI_HTTP_MAX_BYTES must be a positive 32-bit integer");
+    assert!(
+        http_max_bytes > 0 && http_max_bytes <= i32::MAX as u32,
+        "UZUMIBI_HTTP_MAX_BYTES must be between 1 and {}",
+        i32::MAX
+    );
+    fs::write(
+        Path::new(&out_dir).join("uzumibi_config.rs"),
+        format!("pub const HTTP_MAX_BYTES: u32 = {http_max_bytes};\n"),
+    )
+    .expect("failed to write Uzumibi build configuration");
+    println!("cargo:rerun-if-env-changed=UZUMIBI_HTTP_MAX_BYTES");
+
     let mrb_path = Path::new(&out_dir).join("consumer.mrb");
     let code = include_str!("../lib/consumer.rb");
     println!("cargo:rerun-if-changed=../lib/consumer.rb");
diff --git a/uzumibi-cli/templates/cloudflare/__features__/queue/wasm-app/src/lib.rs b/uzumibi-cli/templates/cloudflare/__features__/queue/wasm-app/src/lib.rs
index 0317321..b9f9305 100644
--- a/uzumibi-cli/templates/cloudflare/__features__/queue/wasm-app/src/lib.rs
+++ b/uzumibi-cli/templates/cloudflare/__features__/queue/wasm-app/src/lib.rs
@@ -14,6 +14,8 @@ use mrubyedge::{
     },
 };
 
+include!(concat!(env!("OUT_DIR"), "/uzumibi_config.rs"));
+
 #[cfg(not(feature = "queue"))]
 static MRB: &[u8] = include_bytes!(concat!(env!("OUT_DIR"), "/app.mrb"));
 #[cfg(feature = "queue")]
@@ -61,6 +63,11 @@ fn assume_init_vm() -> Result<&'static mut VM, mrubyedge::Error> {
 }
 
 fn do_uzumibi_initialize_request(size: i32) -> Result<*mut u8, mrubyedge::Error> {
+    if size <= 0 || size as u32 > HTTP_MAX_BYTES {
+        return Err(mrubyedge::Error::RuntimeError(format!(
+            "Request size {size} exceeds the configured maximum of {HTTP_MAX_BYTES} bytes"
+        )));
+    }
     let vm = assume_init_vm()?;
     let size = RObject::integer(size as i64).to_refcount_assigned();
     let app = vm
@@ -71,6 +78,11 @@ fn do_uzumibi_initialize_request(size: i32) -> Result<*mut u8, mrubyedge::Error>
     ret.as_ref().try_into()
 }
 
+#[unsafe(export_name = "uzumibi_http_max_bytes")]
+extern "C" fn uzumibi_http_max_bytes() -> u32 {
+    HTTP_MAX_BYTES
+}
+
 fn do_uzumibi_start_request() -> Result<*mut u8, mrubyedge::Error> {
     uzumibi_cloudflare_ext::debug_console_log_internal("uzumibi_start_request called");
     let vm = assume_init_vm()?;
diff --git a/uzumibi-cli/templates/cloudflare/package.json b/uzumibi-cli/templates/cloudflare/package.json
index 08e5fdd..bea0376 100644
--- a/uzumibi-cli/templates/cloudflare/package.json
+++ b/uzumibi-cli/templates/cloudflare/package.json
@@ -2,9 +2,13 @@
 	"name": "$$PROJECT_NAME$$",
 	"version": "0.0.0",
 	"private": true,
+	"uzumibi": {
+		"httpMaxBytes": 65536
+	},
 	"scripts": {
-		"deploy": "wrangler deploy",
-		"dev": "cargo build --package $$PROJECT_NAME$$ --target wasm32-unknown-unknown --release && cp -v -f target/wasm32-unknown-unknown/release/$$PROJECT_NAME_UNDERSCORE$$.wasm src/ && wrangler dev",
+		"deploy": "pnpm run build:wasm:vanilla && wrangler deploy",
+		"dev": "pnpm run build:wasm:vanilla && wrangler dev",
+		"build:wasm:vanilla": "node scripts/build-wasm.mjs vanilla",
 		"start": "wrangler dev",
 		"test": "vitest"
 	},
@@ -13,4 +17,4 @@
 		"vitest": "~3.2.0",
 		"wrangler": "^4.54.0"
 	}
-}
\ No newline at end of file
+}
diff --git a/uzumibi-cli/templates/cloudflare/scripts/build-wasm.mjs b/uzumibi-cli/templates/cloudflare/scripts/build-wasm.mjs
new file mode 100644
index 0000000..423d57e
--- /dev/null
+++ b/uzumibi-cli/templates/cloudflare/scripts/build-wasm.mjs
@@ -0,0 +1,85 @@
+import { copyFileSync, readFileSync } from "node:fs";
+import { spawnSync } from "node:child_process";
+import { fileURLToPath } from "node:url";
+import { dirname, join } from "node:path";
+
+const projectDir = join(dirname(fileURLToPath(import.meta.url)), "..");
+const packageJson = JSON.parse(
+    readFileSync(join(projectDir, "package.json"), "utf8"),
+);
+
+const mode = process.argv[2] ?? "asyncify";
+const supportedModes = new Set(["vanilla", "asyncify", "queue"]);
+if (!supportedModes.has(mode)) {
+    throw new Error(`Unknown build mode: ${mode}`);
+}
+
+const cliOption = process.argv.find((arg) =>
+    arg.startsWith("--http-max-bytes="),
+);
+const cliOptionIndex = process.argv.indexOf("--http-max-bytes");
+const cliValue = cliOption?.split("=", 2)[1]
+    ?? (cliOptionIndex >= 0 ? process.argv[cliOptionIndex + 1] : undefined);
+const configuredValue = cliValue
+    ?? process.env.UZUMIBI_HTTP_MAX_BYTES
+    ?? packageJson.uzumibi?.httpMaxBytes
+    ?? 65536;
+const httpMaxBytes = Number(configuredValue);
+
+if (!Number.isSafeInteger(httpMaxBytes) || httpMaxBytes <= 0 || httpMaxBytes > 0x7fffffff) {
+    throw new Error(
+        `Invalid HTTP maximum size: ${configuredValue}. `
+        + "Expected an integer between 1 and 2147483647.",
+    );
+}
+
+function run(command, args) {
+    const result = spawnSync(command, args, {
+        cwd: projectDir,
+        env: {
+            ...process.env,
+            UZUMIBI_HTTP_MAX_BYTES: String(httpMaxBytes),
+        },
+        stdio: "inherit",
+    });
+    if (result.error) throw result.error;
+    if (result.status !== 0) process.exit(result.status ?? 1);
+}
+
+const cargoArgs = [
+    "build",
+    "--package", "$$PROJECT_NAME$$",
+    "--target", "wasm32-unknown-unknown",
+    "--release",
+];
+
+if (mode === "vanilla") {
+    cargoArgs.push("--no-default-features");
+} else {
+    cargoArgs.push("--features", mode === "queue" ? "queue" : "enable-external");
+}
+
+console.log(`Building ${mode} Wasm with HTTP maximum ${httpMaxBytes} bytes`);
+run("cargo", cargoArgs);
+
+const source = join(
+    projectDir,
+    "target/wasm32-unknown-unknown/release/$$PROJECT_NAME_UNDERSCORE$$.wasm",
+);
+const outputName = mode === "queue"
+    ? "$$PROJECT_NAME_UNDERSCORE$$_queue.wasm"
+    : "$$PROJECT_NAME_UNDERSCORE$$.wasm";
+const output = join(projectDir, "src", outputName);
+
+if (mode === "vanilla") {
+    copyFileSync(source, output);
+} else {
+    run("wasm-opt", [
+        "--enable-bulk-memory",
+        "--enable-nontrapping-float-to-int",
+        "--asyncify",
+        "-O2",
+        source,
+        "-o", output,
+    ]);
+}
diff --git a/uzumibi-cli/templates/cloudflare/src/index.js b/uzumibi-cli/templates/cloudflare/src/index.js
index 943618f..0c9457b 100644
--- a/uzumibi-cli/templates/cloudflare/src/index.js
+++ b/uzumibi-cli/templates/cloudflare/src/index.js
@@ -1,4 +1,5 @@
 import mod from "./$$PROJECT_NAME_UNDERSCORE$$.wasm";
+import { RequestTooLargeError, writeRequestToWasm } from "./request-buffer.js";
 
 const importObject = {
 	env: {
@@ -19,101 +20,18 @@ const exports = instance.exports;
 
 export default {
 	async fetch(request, env, ctx) {
-		const reqResult = exports.uzumibi_initialize_request(65536);
-		const reqOffset = Number(reqResult & 0xFFFFFFFFn);
-		if (reqOffset === 0) {
-			const errOffset = Number((reqResult >> 32n) & 0xFFFFFFFFn);
-			const decoder = new TextDecoder();
-			let errStr = "";
-			const buffer = new Uint8Array(exports.memory.buffer, errOffset);
-			for (let i = 0; buffer[i] !== 0; i++) {
-				errStr += String.fromCharCode(buffer[i]);
-			}
-			throw new Error(`Failed to initialize request: ${errStr}`);
-		}
-		const requestBuffer = new Uint8Array(exports.memory.buffer, reqOffset, 65536);
 		const path = new URL(request.url).pathname;
 		if (path === "/favicon.ico") {
 			return new Response(null, { status: 404 });
 		}
 
-		const query = new URL(request.url).searchParams;
-
-		let pos = 0;
-		const encoder = new TextEncoder();
-		const dataView = new DataView(exports.memory.buffer, reqOffset);
-
-		const method = encoder.encode(request.method);
-		requestBuffer.fill(0, pos, pos + 6);
-		requestBuffer.set(method.slice(0, 6), pos);
-		pos += 6;
-
-		// Path size (u16 little-endian)
-		const pathBytes = encoder.encode(path);
-		dataView.setUint16(pos, pathBytes.length, true);
-		pos += 2;
-
-		// Path
-		requestBuffer.set(pathBytes, pos);
-		pos += pathBytes.length;
-
-		// Query string size (u16 little-endian)
-		const queryString = query.toString();
-		const queryBytes = encoder.encode(queryString);
-		dataView.setUint16(pos, queryBytes.length, true);
-		pos += 2;
-
-		// Query string
-		requestBuffer.set(queryBytes, pos);
-		pos += queryBytes.length;
-
-		// Headers
-		const headers = [];
-		request.headers.forEach((value, key) => {
-			// 一般的なヘッダーのみ含める（必要に応じて調整）
-			if (key.toLowerCase() !== 'cf-connecting-ip' &&
-				key.toLowerCase() !== 'cf-ray' &&
-				!key.toLowerCase().startsWith('x-')) {
-				headers.push({ key, value });
+		try {
+			await writeRequestToWasm(exports, request);
+		} catch (error) {
+			if (error instanceof RequestTooLargeError) {
+				return new Response(error.message, { status: 413 });
 			}
-		});
-
-		// Headers count (u16 little-endian)
-		dataView.setUint16(pos, headers.length, true);
-		pos += 2;
-
-		// Each header
-		for (const header of headers) {
-			// Header key size (u16 little-endian)
-			const keyBytes = encoder.encode(header.key);
-			dataView.setUint16(pos, keyBytes.length, true);
-			pos += 2;
-
-			// Header key
-			requestBuffer.set(keyBytes, pos);
-			pos += keyBytes.length;
-
-			// Header value size (u16 little-endian)
-			const valueBytes = encoder.encode(header.value);
-			dataView.setUint16(pos, valueBytes.length, true);
-			pos += 2;
-
-			// Header value
-			requestBuffer.set(valueBytes, pos);
-			pos += valueBytes.length;
-		}
-
-		// Request body size (u32 little-endian)
-		const bodyBytes = request.body ? new Uint8Array(await request.arrayBuffer()) : new Uint8Array(0);
-		dataView.setUint32(pos, bodyBytes.length, true);
-		pos += 4;
-
-		// Request body
-		requestBuffer.set(bodyBytes, pos);
-		pos += bodyBytes.length;
-
-		if (pos > 65536) {
-			throw new Error("Request data exceeds allocated buffer size");
+			throw error;
 		}
 
 		const resResult = exports.uzumibi_start_request();
diff --git a/uzumibi-cli/templates/cloudflare/src/request-buffer.js b/uzumibi-cli/templates/cloudflare/src/request-buffer.js
new file mode 100644
index 0000000..a17d2b8
--- /dev/null
+++ b/uzumibi-cli/templates/cloudflare/src/request-buffer.js
@@ -0,0 +1,99 @@
+export class RequestTooLargeError extends Error {
+    constructor(actualBytes, maxBytes) {
+        super(`Encoded request size ${actualBytes} exceeds the configured maximum of ${maxBytes} bytes`);
+        this.name = "RequestTooLargeError";
+        this.actualBytes = actualBytes;
+        this.maxBytes = maxBytes;
+    }
+}
+
+function readError(exports, result, operation) {
+    const errorOffset = Number((result >> 32n) & 0xFFFFFFFFn);
+    const buffer = new Uint8Array(exports.memory.buffer, errorOffset);
+    let message = "";
+    for (let i = 0; buffer[i] !== 0; i++) {
+        message += String.fromCharCode(buffer[i]);
+    }
+    return new Error(`Failed to ${operation}: ${message}`);
+}
+
+export async function writeRequestToWasm(exports, request) {
+    const encoder = new TextEncoder();
+    const url = new URL(request.url);
+    const methodBytes = encoder.encode(request.method);
+    const pathBytes = encoder.encode(url.pathname);
+    const queryBytes = encoder.encode(url.searchParams.toString());
+    const bodyBytes = request.body
+        ? new Uint8Array(await request.arrayBuffer())
+        : new Uint8Array(0);
+
+    const headers = [];
+    request.headers.forEach((value, key) => {
+        if (key.toLowerCase() !== "cf-connecting-ip"
+            && key.toLowerCase() !== "cf-ray"
+            && !key.toLowerCase().startsWith("x-")) {
+            headers.push({
+                key: encoder.encode(key),
+                value: encoder.encode(value),
+            });
+        }
+    });
+
+    const headersSize = headers.reduce(
+        (size, header) => size + 2 + header.key.length + 2 + header.value.length,
+        0,
+    );
+    const requiredSize = 6
+        + 2 + pathBytes.length
+        + 2 + queryBytes.length
+        + 2 + headersSize
+        + 4 + bodyBytes.length;
+    const maxBytes = Number(await exports.uzumibi_http_max_bytes());
+
+    if (requiredSize > maxBytes) {
+        throw new RequestTooLargeError(requiredSize, maxBytes);
+    }
+
+    const result = await exports.uzumibi_initialize_request(requiredSize);
+    const offset = Number(result & 0xFFFFFFFFn);
+    if (offset === 0) {
+        throw readError(exports, result, "initialize request");
+    }
+
+    const requestBuffer = new Uint8Array(exports.memory.buffer, offset, requiredSize);
+    const dataView = new DataView(exports.memory.buffer, offset, requiredSize);
+    let pos = 0;
+
+    requestBuffer.fill(0, pos, pos + 6);
+    requestBuffer.set(methodBytes.slice(0, 6), pos);
+    pos += 6;
+
+    dataView.setUint16(pos, pathBytes.length, true);
+    pos += 2;
+    requestBuffer.set(pathBytes, pos);
+    pos += pathBytes.length;
+
+    dataView.setUint16(pos, queryBytes.length, true);
+    pos += 2;
+    requestBuffer.set(queryBytes, pos);
+    pos += queryBytes.length;
+
+    dataView.setUint16(pos, headers.length, true);
+    pos += 2;
+    for (const header of headers) {
+        dataView.setUint16(pos, header.key.length, true);
+        pos += 2;
+        requestBuffer.set(header.key, pos);
+        pos += header.key.length;
+        dataView.setUint16(pos, header.value.length, true);
+        pos += 2;
+        requestBuffer.set(header.value, pos);
+        pos += header.value.length;
+    }
+
+    dataView.setUint32(pos, bodyBytes.length, true);
+    pos += 4;
+    requestBuffer.set(bodyBytes, pos);
+
+    return requiredSize;
+}
diff --git a/uzumibi-cli/templates/cloudflare/test/request-buffer.spec.js b/uzumibi-cli/templates/cloudflare/test/request-buffer.spec.js
new file mode 100644
index 0000000..b9fd12a
--- /dev/null
+++ b/uzumibi-cli/templates/cloudflare/test/request-buffer.spec.js
@@ -0,0 +1,64 @@
+import { describe, expect, it } from "vitest";
+import {
+    RequestTooLargeError,
+    writeRequestToWasm,
+} from "../src/request-buffer.js";
+
+function createExports(maxBytes) {
+    const memory = new WebAssembly.Memory({ initial: 4 });
+    let allocatedSize = 0;
+
+    return {
+        exports: {
+            memory,
+            uzumibi_http_max_bytes: () => maxBytes,
+            uzumibi_initialize_request: (size) => {
+                allocatedSize = size;
+                return 1024n;
+            },
+        },
+        allocatedSize: () => allocatedSize,
+    };
+}
+
+describe("Cloudflare request buffer", () => {
+    it("allocates the encoded request size instead of the configured maximum", async () => {
+        const wasm = createExports(131072);
+        const request = new Request("https://example.com/items?q=uzumibi", {
+            method: "POST",
+            headers: { "content-type": "text/plain" },
+            body: "hello",
+        });
+
+        const encodedSize = await writeRequestToWasm(wasm.exports, request);
+
+        expect(wasm.allocatedSize()).toBe(encodedSize);
+        expect(encodedSize).toBeLessThan(131072);
+    });
+
+    it("accepts a request larger than the old 64 KiB limit", async () => {
+        const wasm = createExports(131072);
+        const request = new Request("https://example.com/upload", {
+            method: "POST",
+            body: new Uint8Array(70000),
+        });
+
+        const encodedSize = await writeRequestToWasm(wasm.exports, request);
+
+        expect(encodedSize).toBeGreaterThan(65536);
+        expect(wasm.allocatedSize()).toBe(encodedSize);
+    });
+
+    it("rejects a request that exceeds the configured maximum", async () => {
+        const wasm = createExports(65536);
+        const request = new Request("https://example.com/upload", {
+            method: "POST",
+            body: new Uint8Array(70000),
+        });
+
+        await expect(writeRequestToWasm(wasm.exports, request)).rejects.toBeInstanceOf(
+            RequestTooLargeError,
+        );
+        expect(wasm.allocatedSize()).toBe(0);
+    });
+});
diff --git a/uzumibi-cli/templates/cloudflare/wasm-app/build.rs b/uzumibi-cli/templates/cloudflare/wasm-app/build.rs
index a35f9a7..3ce57eb 100644
--- a/uzumibi-cli/templates/cloudflare/wasm-app/build.rs
+++ b/uzumibi-cli/templates/cloudflare/wasm-app/build.rs
@@ -1,9 +1,25 @@
-use std::path::Path;
+use std::{fs, path::Path};
 
 extern crate mruby_compiler2_sys;
 
 fn main() {
     let out_dir = std::env::var("OUT_DIR").unwrap();
+    let http_max_bytes = std::env::var("UZUMIBI_HTTP_MAX_BYTES")
+        .unwrap_or_else(|_| "65536".to_string())
+        .parse::<u32>()
+        .expect("UZUMIBI_HTTP_MAX_BYTES must be a positive 32-bit integer");
+    assert!(
+        http_max_bytes > 0 && http_max_bytes <= i32::MAX as u32,
+        "UZUMIBI_HTTP_MAX_BYTES must be between 1 and {}",
+        i32::MAX
+    );
+    fs::write(
+        Path::new(&out_dir).join("uzumibi_config.rs"),
+        format!("pub const HTTP_MAX_BYTES: u32 = {http_max_bytes};\n"),
+    )
+    .expect("failed to write Uzumibi build configuration");
+    println!("cargo:rerun-if-env-changed=UZUMIBI_HTTP_MAX_BYTES");
+
     let mrb_path = Path::new(&out_dir).join("app.mrb");
     let code = include_str!("../lib/app.rb");
     println!("cargo:rerun-if-changed=../lib/app.rb");
diff --git a/uzumibi-cli/templates/cloudflare/wasm-app/src/lib.rs b/uzumibi-cli/templates/cloudflare/wasm-app/src/lib.rs
index 9a667f1..ce85618 100644
--- a/uzumibi-cli/templates/cloudflare/wasm-app/src/lib.rs
+++ b/uzumibi-cli/templates/cloudflare/wasm-app/src/lib.rs
@@ -14,6 +14,8 @@ use mrubyedge::{
     },
 };
 
+include!(concat!(env!("OUT_DIR"), "/uzumibi_config.rs"));
+
 static MRB: &[u8] = include_bytes!(concat!(env!("OUT_DIR"), "/app.mrb"));
 
 static mut MRUBY_VM: MaybeUninit<VM> = MaybeUninit::uninit();
@@ -58,6 +60,11 @@ fn assume_init_vm() -> Result<&'static mut VM, mrubyedge::Error> {
 }
 
 fn do_uzumibi_initialize_request(size: i32) -> Result<*mut u8, mrubyedge::Error> {
+    if size <= 0 || size as u32 > HTTP_MAX_BYTES {
+        return Err(mrubyedge::Error::RuntimeError(format!(
+            "Request size {size} exceeds the configured maximum of {HTTP_MAX_BYTES} bytes"
+        )));
+    }
     let vm = assume_init_vm()?;
     let size = RObject::integer(size as i64).to_refcount_assigned();
     let app = vm
@@ -68,6 +75,11 @@ fn do_uzumibi_initialize_request(size: i32) -> Result<*mut u8, mrubyedge::Error>
     ret.as_ref().try_into()
 }
 
+#[unsafe(export_name = "uzumibi_http_max_bytes")]
+extern "C" fn uzumibi_http_max_bytes() -> u32 {
+    HTTP_MAX_BYTES
+}
+
 fn do_uzumibi_start_request() -> Result<*mut u8, mrubyedge::Error> {
     uzumibi_cloudflare_ext::debug_console_log_internal("uzumibi_start_request called");
     let vm = assume_init_vm()?;
diff --git a/uzumibi-cli/tests/runn/new_cloudflare.yml b/uzumibi-cli/tests/runn/new_cloudflare.yml
index faa354b..49552cb 100644
--- a/uzumibi-cli/tests/runn/new_cloudflare.yml
+++ b/uzumibi-cli/tests/runn/new_cloudflare.yml
@@ -54,6 +54,12 @@ steps:
       command: test -f {{ vars.tmpdir }}/{{ vars.project_name }}/wrangler.jsonc
     test: current.exit_code == 0
 
+  check_http_max_bytes:
+    desc: Check configurable HTTP request size files
+    exec:
+      command: cd {{ vars.tmpdir }}/{{ vars.project_name }} && node -e 'const p = require("./package.json"); if (p.uzumibi.httpMaxBytes !== 65536) process.exit(1)' && test -f scripts/build-wasm.mjs && test -f src/request-buffer.js
+    test: current.exit_code == 0
+
   check_assets_index_html:
     desc: Check public/assets/index.html exists and contains expected content
     exec:

From 72cf1741b3477491563e75d1503a478d15fb5764 Mon Sep 17 00:00:00 2001
From: Uchio Kondo <udzura@udzura.jp>
Date: Thu, 20 Aug 2026 21:33:26 +0900
Subject: [PATCH 3/5] test: add Cloudflare Queue smoke scenario

---
 .../tests/runn/new_cloudflare_queue.yml       | 86 +++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 uzumibi-cli/tests/runn/new_cloudflare_queue.yml

diff --git a/uzumibi-cli/tests/runn/new_cloudflare_queue.yml b/uzumibi-cli/tests/runn/new_cloudflare_queue.yml
new file mode 100644
index 0000000..32a7781
--- /dev/null
+++ b/uzumibi-cli/tests/runn/new_cloudflare_queue.yml
@@ -0,0 +1,86 @@
+desc: Test uzumibi new command with Cloudflare Queue template
+runners:
+  req: http://127.0.0.1:8787
+vars:
+  binary: ${UZUMIBI_TEST_BINARY:-../target/release/uzumibi}
+  tmpdir: ${UZUMIBI_TEST_TMPDIR:-../tmp}
+  project_name: ${UZUMIBI_PROJECT_NAME:-test-cloudflare-queue-project}
+steps:
+  build:
+    desc: Build release binary
+    exec:
+      command: cargo build --release --quiet
+    test: current.exit_code == 0
+
+  setup_tmpdir:
+    desc: Setup temp directory
+    exec:
+      command: mkdir -p {{ vars.tmpdir }}
+    test: current.exit_code == 0
+
+  cleanup_before:
+    desc: Clean up existing test directory
+    exec:
+      command: rm -rf {{ vars.tmpdir }}/{{ vars.project_name }}
+    test: current.exit_code == 0
+
+  create_project:
+    desc: Create new Cloudflare Queue project
+    exec:
+      command: cd {{ vars.tmpdir }} && {{ vars.binary }} new -t cloudflare --features queue {{ vars.project_name }}
+    test: |
+      current.exit_code == 0 &&
+      current.stdout contains 'Successfully created project'
+
+  check_queue_files:
+    desc: Check Queue-specific files and configuration
+    exec:
+      command: cd {{ vars.tmpdir }}/{{ vars.project_name }} && test -f lib/consumer.rb && grep -q '"consumers"' wrangler.jsonc && node -e 'const p = require("./package.json"); if (p.uzumibi.httpMaxBytes !== 65536 || !p.scripts["build:wasm:queue"]) process.exit(1)'
+    test: current.exit_code == 0
+
+  pnpm_install:
+    desc: Install Node.js dependencies
+    exec:
+      command: cd {{ vars.tmpdir }}/{{ vars.project_name }} && pnpm install
+    test: current.exit_code == 0
+
+  build_queue_wasm:
+    desc: Build and asyncify the Queue WASM app
+    exec:
+      command: cd {{ vars.tmpdir }}/{{ vars.project_name }} && pnpm run build:wasm:queue
+    test: current.exit_code == 0
+
+  start_server:
+    desc: Start Queue Worker dev server in background
+    exec:
+      command: cd {{ vars.tmpdir }}/{{ vars.project_name }} && pnpm start
+      background: true
+
+  wait_for_server:
+    desc: Wait for Queue Worker to start
+    exec:
+      command: for i in $(seq 1 300); do curl -s -o /dev/null http://127.0.0.1:8787 && exit 0; sleep 0.1; done; exit 1
+    test: current.exit_code == 0
+
+  test_http_endpoint:
+    desc: Confirm Queue Worker rejects ordinary HTTP requests
+    req:
+      "/":
+        get:
+          body: null
+    test: |
+      current.res.status == 400 &&
+      current.res.rawBody contains 'queue processing'
+
+  kill_server:
+    desc: Kill dev server
+    exec:
+      command: kill -INT $(ps -ef | grep 'wrangler.js de[v]' | awk '{print $2}') || true
+    test: current.exit_code == 0
+
+  cleanup_after:
+    desc: Clean up test directory
+    exec:
+      command: rm -rf {{ vars.tmpdir }}/{{ vars.project_name }}
+    dump: steps
+    test: current.exit_code == 0

From e40e6be9ee675af4fad6caea99fd827b7bb91ae9 Mon Sep 17 00:00:00 2001
From: Uchio Kondo <udzura@udzura.jp>
Date: Thu, 20 Aug 2026 21:40:02 +0900
Subject: [PATCH 4/5] Bump uzumibi-cli to 0.8.1

---
 Cargo.lock             | 2 +-
 uzumibi-cli/Cargo.toml | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 016f457..0ec1726 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2896,7 +2896,7 @@ dependencies = [
 
 [[package]]
 name = "uzumibi-cli"
-version = "0.8.0"
+version = "0.8.1"
 dependencies = [
  "clap",
  "dialoguer",
diff --git a/uzumibi-cli/Cargo.toml b/uzumibi-cli/Cargo.toml
index 07a4f8c..09ddf0e 100644
--- a/uzumibi-cli/Cargo.toml
+++ b/uzumibi-cli/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "uzumibi-cli"
-version = "0.8.0"
+version = "0.8.1"
 edition = "2024"
 authors = ["Uchio Kondo <udzura@udzura.jp>"]
 description = "Uzumibi CLI tool to generate serverless mruby/edge apps"

From 53dafcf399409317036642f096db1159c92b74a4 Mon Sep 17 00:00:00 2001
From: Uchio Kondo <udzura@udzura.jp>
Date: Thu, 20 Aug 2026 21:43:24 +0900
Subject: [PATCH 5/5] Add Cloudflare Queue CI smoke test

---
 .github/workflows/runn-cli-tests.yml | 48 ++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/.github/workflows/runn-cli-tests.yml b/.github/workflows/runn-cli-tests.yml
index 250a60c..53252be 100644
--- a/.github/workflows/runn-cli-tests.yml
+++ b/.github/workflows/runn-cli-tests.yml
@@ -148,6 +148,54 @@ jobs:
           UZUMIBI_PROJECT_NAME: test-cloudflare-project-${{ github.run_id }}
         run: runn run new_cloudflare.yml --verbose
 
+  cloudflare-queue-test:
+    name: Cloudflare Queue template test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Install wasm32 target
+        run: rustup target add wasm32-unknown-unknown
+
+      - name: Cache cargo registry and build
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-cloudflare-queue-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-cargo-cloudflare-queue-
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 10
+
+      - name: Install wasm-opt
+        run: |
+          curl -L https://github.com/WebAssembly/binaryen/releases/download/version_120/binaryen-version_120-x86_64-linux.tar.gz | tar xz
+          sudo cp binaryen-version_120/bin/wasm-opt /usr/local/bin/
+
+      - name: Install runn
+        uses: k1LoW/gh-setup@v1
+        with:
+          repo: k1LoW/runn
+          bin-match: runn
+
+      - name: Run Cloudflare Queue smoke test
+        working-directory: uzumibi-cli/tests/runn
+        env:
+          RUNN_SCOPES: "read:parent,run:exec"
+          UZUMIBI_TEST_BINARY: ${{ github.workspace }}/target/release/uzumibi
+          UZUMIBI_TEST_TMPDIR: ${{ runner.temp }}
+          UZUMIBI_PROJECT_NAME: test-cloudflare-queue-project-${{ github.run_id }}
+        run: runn run new_cloudflare_queue.yml --verbose
+
   cloudrun-test:
     name: Cloud Run template test
     runs-on: ubuntu-latest