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