wip

src/server/file/pour.ts

@@ -0,0 +1,93 @@
+import * as fs from 'fs';
+import * as stream from 'stream';
+import * as Koa from 'koa';
+import * as Gm from 'gm';
+
+const gm = Gm.subClass({
+	imageMagick: true
+});
+
+interface ISend {
+	contentType: string;
+	stream: stream.Readable;
+}
+
+function thumbnail(data: stream.Readable, type: string, resize: number): ISend {
+	const readable: stream.Readable = (() => {
+		// 動画であれば
+		if (/^video\/.*$/.test(type)) {
+			// TODO
+			// 使わないことになったストリームはしっかり取り壊す
+			data.destroy();
+			return fs.createReadStream(`${__dirname}/assets/thumbnail-not-available.png`);
+		// 画像であれば
+		// Note: SVGはapplication/xml
+		} else if (/^image\/.*$/.test(type) || type == 'application/xml') {
+			// 0フレーム目を送る
+			try {
+				return gm(data).selectFrame(0).stream();
+			// だめだったら
+			} catch (e) {
+				// 使わないことになったストリームはしっかり取り壊す
+				data.destroy();
+				return fs.createReadStream(`${__dirname}/assets/thumbnail-not-available.png`);
+			}
+		// 動画か画像以外
+		} else {
+			data.destroy();
+			return fs.createReadStream(`${__dirname}/assets/not-an-image.png`);
+		}
+	})();
+
+	let g = gm(readable);
+
+	if (resize) {
+		g = g.resize(resize, resize);
+	}
+
+	const stream = g
+		.compress('jpeg')
+		.quality(80)
+		.interlace('line')
+		.stream();
+
+	return {
+		contentType: 'image/jpeg',
+		stream
+	};
+}
+
+const commonReadableHandlerGenerator = (ctx: Koa.Context) => (e: Error): void => {
+	console.error(e);
+	ctx.status = 500;
+};
+
+export default function(readable: stream.Readable, type: string, ctx: Koa.Context): void {
+	readable.on('error', commonReadableHandlerGenerator(ctx));
+
+	const data = ((): ISend => {
+		if (ctx.query.thumbnail !== undefined) {
+			return thumbnail(readable, type, ctx.query.size);
+		}
+		return {
+			contentType: type,
+			stream: readable
+		};
+	})();
+
+	if (readable !== data.stream) {
+		data.stream.on('error', commonReadableHandlerGenerator(ctx));
+	}
+
+	if (ctx.query.download !== undefined) {
+		ctx.header('Content-Disposition', 'attachment');
+	}
+
+	ctx.header('Content-Type', data.contentType);
+
+	data.stream.pipe(ctx.res);
+
+	data.stream.on('end', () => {
+		ctx.res.end();
+	});
+}