Fix SVG detection (#4401)

* Fix SVG detection

* remove unnecessary import

src/misc/check-svg.ts

+import * as fs from 'fs';
+import * as isSvg from 'is-svg';
+
+export default function(path: string) {
+	try {
+		const size = fs.statSync(path).size;
+		if (size > 1 * 1024 * 1024) return false;
+		return isSvg(fs.readFileSync(path));
+	} catch {
+		return false;
+	}
+}

src/server/proxy/proxy-media.ts

@@ -4,10 +4,10 @@ import * as tmp from 'tmp';
 import * as Koa from 'koa';
 import * as request from 'request';
 import * as fileType from 'file-type';
-import * as isSvg from 'is-svg';
 import { serverLogger } from '..';
 import config from '../../config';
 import { IImage, ConvertToPng } from '../../services/drive/image-processor';
+import checkSvg from '../../misc/check-svg';
 
 export async function proxyMedia(ctx: Koa.BaseContext) {
 	const url = 'url' in ctx.query ? ctx.query.url : 'https://' + ctx.params.url;
@@ -102,7 +102,7 @@ async function detectMine(path: string) {
 				const type = fileType(buffer);
 				if (type) {
 					res([type.mime, type.ext]);
-				} else if (isSvg(buffer)) {
+				} else if (checkSvg(path)) {
 					res(['image/svg+xml', 'svg']);
 				} else {
 					// 種類が同定できなかったら application/octet-stream にする

src/services/drive/add-file.ts

@@ -7,7 +7,6 @@ import * as Minio from 'minio';
 import * as uuid from 'uuid';
 import * as sharp from 'sharp';
 import * as fileType from 'file-type';
-import * as isSvg from 'is-svg';
 
 import DriveFile, { IMetadata, getDriveFileBucket, IDriveFile } from '../../models/drive-file';
 import DriveFolder from '../../models/drive-folder';
@@ -26,6 +25,7 @@ import { GenerateVideoThumbnail } from './generate-video-thumbnail';
 import { driveLogger } from './logger';
 import { IImage, ConvertToJpeg, ConvertToWebp, ConvertToPng } from './image-processor';
 import Instance from '../../models/instance';
+import checkSvg from '../../misc/check-svg';
 
 const logger = driveLogger.createSubLogger('register', 'yellow');
 
@@ -311,7 +311,7 @@ export default async function(
 				const type = fileType(buffer);
 				if (type) {
 					res([type.mime, type.ext]);
-				} else if (isSvg(buffer)) {
+				} else if (checkSvg(path)) {
 					res(['image/svg+xml', 'svg']);
 				} else {
 					// 種類が同定できなかったら application/octet-stream にする