packages/server/package.json

@@ -5,7 +5,7 @@
 	"main": "build/app.js",
 	"scripts": {
 		"compile": "swc src --out-dir dist",
-		"dev": "nodemon -r @swc-node/register --exec node app.ts",
+		"dev": "nodemon -r @swc-node/register --enable-source-maps --exec node app.ts",
 		"start": "node build/app.js"
 	},
 	"author": "",

packages/server/src/route/comic.ts

@@ -1,26 +1,33 @@
 import { type Context, DefaultContext, DefaultState, Next } from "koa";
 import Router from "koa-router";
-import { createReadableStreamFromZip, entriesByNaturalOrder, readZip, type ZipAsync } from "../util/zipwrap";
+import { createReadableStreamFromZip, entriesByNaturalOrder, readZip } from "../util/zipwrap";
 import type { ContentContext } from "./context";
 import { since_last_modified } from "./util";
+import type { ZipReader } from "@zip.js/zip.js";
+import type { FileHandle } from "node:fs/promises";
+import { Readable, Writable } from "node:stream";
 
 /**
  * zip stream cache.
  */
-
-const ZipStreamCache: { [path: string]: [ZipAsync, number] } = {};
+const ZipStreamCache: {
+	[path: string]: [{
+		reader: ZipReader<FileHandle>,
+		handle: FileHandle
+	}, number]
+} = {};
 
 async function acquireZip(path: string) {
 	if (!(path in ZipStreamCache)) {
-		const ret = await readZip(path);
-		ZipStreamCache[path] = [ret, 1];
+		const obj = await readZip(path);
+		ZipStreamCache[path] = [obj, 1];
 		// console.log(`acquire ${path} 1`);
-		return ret;
+		return obj.reader;
 	}
 	const [ret, refCount] = ZipStreamCache[path];
 	ZipStreamCache[path] = [ret, refCount + 1];
 	// console.log(`acquire ${path} ${refCount + 1}`);
-		return ret;
+	return ret.reader;
 }
 
 function releaseZip(path: string) {
@@ -29,7 +36,10 @@ function releaseZip(path: string) {
 	const [ref, refCount] = obj;
 	// console.log(`release ${path} : ${refCount}`);
 	if (refCount === 1) {
-		ref.close();
+		const { reader, handle } = ref;
+		reader.close().then(() => {
+			handle.close();
+		});
 		delete ZipStreamCache[path];
 	} else {
 		ZipStreamCache[path] = [ref, refCount - 1];
@@ -41,33 +51,35 @@ async function renderZipImage(ctx: Context, path: string, page: number) {
 	// console.log(`opened ${page}`);
 	const zip = await acquireZip(path);
 	const entries = (await entriesByNaturalOrder(zip)).filter((x) => {
-		const ext = x.name.split(".").pop();
+		const ext = x.filename.split(".").pop();
 		return ext !== undefined && image_ext.includes(ext);
 	});
 	if (0 <= page && page < entries.length) {
 		const entry = entries[page];
-		const last_modified = new Date(entry.time);
+		const last_modified = entry.lastModDate;
 		if (since_last_modified(ctx, last_modified)) {
 			return;
 		}
 		const read_stream = await createReadableStreamFromZip(zip, entry);
-		/** Exceptions (ECONNRESET, ECONNABORTED) may be thrown when processing this request
-		 * for reasons such as when the browser unexpectedly closes the connection.
-		 * Once such an exception is raised, the stream is not properly destroyed,
-		 * so there is a problem with the zlib stream being accessed even after the stream is closed.
-		 * So it waits for 100 ms and releases it.
-		 * Additionaly, there is a risk of memory leak becuase zlib stream is not properly destroyed.
-		 * @todo modify function 'stream' in 'node-stream-zip' library to prevent memory leak */
-		read_stream.once("close", () => {
+		const nodeReadableStream = new Readable();
+		nodeReadableStream._read = () => { };
+
+		read_stream.pipeTo(new WritableStream({
+			write(chunk) {
+				nodeReadableStream.push(chunk);
+			},
+			close() {
+				nodeReadableStream.push(null);
 				setTimeout(() => {
 					releaseZip(path);
 				}, 100);
-		});
+			},
+		}));
 
-		ctx.body = read_stream;
-		ctx.response.length = entry.size;
+		ctx.body = nodeReadableStream;
+		ctx.response.length = entry.uncompressedSize;
 		// console.log(`${entry.name}'s ${page}:${entry.size}`);
-		ctx.response.type = entry.name.split(".").pop() as string;
+		ctx.response.type = entry.filename.split(".").pop() as string;
 		ctx.status = 200;
 		ctx.set("Date", new Date().toUTCString());
 		ctx.set("Last-Modified", last_modified.toUTCString());

packages/server/src/util/zipwrap.ts

@@ -1,33 +1,59 @@
-import type { ZipEntry } from "node-stream-zip";
-
-import { ReadStream } from "node:fs";
+import { type FileHandle, open } from "node:fs/promises";
 import { orderBy } from "natural-orderby";
-import StreamZip from "node-stream-zip";
+import { ZipReader, Reader, type Entry } from "@zip.js/zip.js";
 
-export type ZipAsync = InstanceType<typeof StreamZip.async>;
-export async function readZip(path: string): Promise<ZipAsync> {
-	return new StreamZip.async({
-		file: path,
-		storeEntries: true,
-	});
+class FileReader extends Reader<FileHandle> {
+	private fd: FileHandle;
+	private offset: number;
+	constructor(fd: FileHandle) {
+		super(fd);
+		this.fd = fd;
+		this.offset = 0;
+	}
+
+	async init(): Promise<void> {
+		this.offset = 0;
+		this.size = (await this.fd.stat()).size;
+	}
+	close(): void {
+		this.fd.close();
+	}
+
+	async readUint8Array(index: number, length: number): Promise<Uint8Array> {
+		const buffer = new Uint8Array(length);
+		const buf = await this.fd.read(buffer, 0, length, index);
+		if (buf.bytesRead !== length) {
+			console.error(`read error: ${buf.bytesRead} !== ${length}`);
+			throw new Error("read error");
+		}
+		return buffer;
+	}
 }
-export async function entriesByNaturalOrder(zip: ZipAsync) {
-	const entries = await zip.entries();
-	const ret = orderBy(Object.values(entries), (v) => v.name);
+
+export async function readZip(path: string): Promise<{
+	reader: ZipReader<FileHandle>
+	handle: FileHandle
+}> {
+	const fd = await open(path);
+	const reader = new ZipReader(new FileReader(fd), {
+		useCompressionStream: true,
+		preventClose: false,
+	});
+	return { reader, handle: fd };
+}
+export async function entriesByNaturalOrder(zip: ZipReader<FileHandle>) {
+	// console.log(zip);
+	const entries = await zip.getEntries();
+	// console.log(entries.map((v) => v.filename));
+	const ret = orderBy(entries, (v) => v.filename);
 	return ret;
 }
 
-export async function createReadableStreamFromZip(zip: ZipAsync, entry: ZipEntry): Promise<NodeJS.ReadableStream> {
-	return await zip.stream(entry);
-}
-export async function readAllFromZip(zip: ZipAsync, entry: ZipEntry): Promise<Buffer> {
-	const stream = await createReadableStreamFromZip(zip, entry);
-	const chunks: Uint8Array[] = [];
-	return new Promise((resolve, reject) => {
-		stream.on("data", (data) => {
-			chunks.push(data);
-		});
-		stream.on("error", (err) => reject(err));
-		stream.on("end", () => resolve(Buffer.concat(chunks)));
-	});
+export async function createReadableStreamFromZip(_zip: ZipReader<FileHandle>, entry: Entry): Promise<ReadableStream> {
+	if (entry.getData === undefined) {
+		throw new Error("entry.getData is undefined");
+	}
+	const stream = new TransformStream<Uint8Array, Uint8Array>();
+	entry.getData(stream.writable);
+	return stream.readable;
 }