Content-Dispositionでダウンロード時の名前を指定

Fix https://github.com/misskey-dev/media-proxy/issues/6

.eslintrc.cjs

@@ -1,32 +0,0 @@
-module.exports = {
-	parserOptions: {
-		tsconfigRootDir: __dirname,
-		project: ['./tsconfig.json'],
-	},
-	extends: [
-		'../shared/.eslintrc.js',
-	],
-	rules: {
-		'import/order': ['warn', {
-			'groups': ['builtin', 'external', 'internal', 'parent', 'sibling', 'index', 'object', 'type'],
-			'pathGroups': [
-				{
-					'pattern': '@/**',
-					'group': 'external',
-					'position': 'after'
-				}
-			],
-		}],
-		'no-restricted-globals': [
-			'error',
-			{
-				'name': '__dirname',
-				'message': 'Not in ESModule. Use `import.meta.url` instead.'
-			},
-			{
-				'name': '__filename',
-				'message': 'Not in ESModule. Use `import.meta.url` instead.'
-			}
-	]
-	},
-};

built/download.d.ts

@@ -19,4 +19,6 @@ export declare const defaultDownloadConfig: {
     maxSize: number;
     proxy: boolean;
 };
-export declare function downloadUrl(url: string, path: string, settings?: DownloadConfig): Promise<void>;
+export declare function downloadUrl(url: string, path: string, settings?: DownloadConfig): Promise<{
+    filename: string;
+}>;

built/download.js

@@ -6,6 +6,7 @@ import IPCIDR from 'ip-cidr';
 import PrivateIp from 'private-ip';
 import { StatusError } from './status-error.js';
 import { getAgents } from './http.js';
+import { parse } from 'content-disposition';
 const pipeline = util.promisify(stream.pipeline);
 export const defaultDownloadConfig = {
     userAgent: `MisskeyMediaProxy/0.0.0`,
@@ -19,6 +20,8 @@ export async function downloadUrl(url, path, settings = defaultDownloadConfig) {
         console.log(`Downloading ${url} to ${path} ...`);
     const timeout = 30 * 1000;
     const operationTimeout = 60 * 1000;
+    const urlObj = new URL(url);
+    let filename = urlObj.pathname.split('/').pop() ?? 'unknown';
     const req = got.stream(url, {
         headers: {
             'User-Agent': settings.userAgent,
@@ -56,6 +59,13 @@ export async function downloadUrl(url, path, settings = defaultDownloadConfig) {
                 req.destroy();
             }
         }
+        const contentDisposition = res.headers['content-disposition'];
+        if (contentDisposition != null) {
+            const parsed = parse(contentDisposition);
+            if (parsed.parameters.filename) {
+                filename = parsed.parameters.filename;
+            }
+        }
     }).on('downloadProgress', (progress) => {
         if (progress.transferred > settings.maxSize) {
             console.log(`maxSize exceeded (${progress.transferred} > ${settings.maxSize}) on downloadProgress`);
@@ -75,6 +85,10 @@ export async function downloadUrl(url, path, settings = defaultDownloadConfig) {
     }
     if (process.env.NODE_ENV !== 'production')
         console.log(`Download finished: ${url}`);
+
+    return {
+        filename,
+    };
 }
 function isPrivateIp(ip, allowedPrivateNetworks) {
     for (const net of allowedPrivateNetworks ?? []) {

built/index.js

@@ -10,6 +10,7 @@ import sharp from 'sharp';
 import { StatusError } from './status-error.js';
 import { defaultDownloadConfig, downloadUrl } from './download.js';
 import { getAgents } from './http.js';
+import _contentDisposition from 'content-disposition';
 const _filename = fileURLToPath(import.meta.url);
 const _dirname = dirname(_filename);
 const assets = `${_dirname}/../assets/`;
@@ -182,6 +183,7 @@ async function proxyHandler(request, reply) {
         }
         reply.header('Content-Type', image.type);
         reply.header('Cache-Control', 'max-age=31536000, immutable');
+        reply.header('Content-Disposition', contentDisposition('inline', file.filename));
         return reply.send(image.data);
     }
     catch (e) {
@@ -193,12 +195,13 @@ async function proxyHandler(request, reply) {
 async function downloadAndDetectTypeFromUrl(url) {
     const [path, cleanup] = await createTemp();
     try {
-        await downloadUrl(url, path, config);
+        const { filename } = await downloadUrl(url, path, config);
         const { mime, ext } = await detectType(path);
         return {
             state: 'remote',
             mime, ext,
             path, cleanup,
+            filename: correctFilename(filename, ext),
         };
     }
     catch (e) {
@@ -206,3 +209,19 @@ async function downloadAndDetectTypeFromUrl(url) {
         throw e;
     }
 }
+function correctFilename(filename, ext) {
+    if (!ext)
+        return filename;
+    const dotExt = `.${ext}`;
+    if (filename.endsWith(dotExt)) {
+        return filename;
+    }
+    if (ext === 'jpg' && filename.endsWith('.jpeg')) {
+        return filename;
+    }
+    return `${filename}${dotExt}`;
+}
+function contentDisposition(type, filename) {
+    const fallback = filename.replace(/[^\w.-]/g, '_');
+    return _contentDisposition(filename, { type, fallback });
+}

package.json

@@ -28,6 +28,7 @@
   "devDependencies": {
     "@swc/cli": "^0.1.61",
     "@swc/core": "^1.3.32",
+    "@types/content-disposition": "^0.5.5",
     "@types/node": "^18.11.19",
     "@types/sharp": "^0.31.1",
     "@types/tmp": "^0.2.3",
@@ -36,6 +37,7 @@
   "dependencies": {
     "@fastify/static": "^6.8.0",
     "cacheable-lookup": "^7.0.0",
+    "content-disposition": "^0.5.4",
     "fastify": "^4.12.0",
     "fastify-cli": "^5.7.1",
     "file-type": "^18.2.0",

pnpm-lock.yaml

@@ -4,10 +4,12 @@ specifiers:
   '@fastify/static': ^6.8.0
   '@swc/cli': ^0.1.61
   '@swc/core': ^1.3.32
+  '@types/content-disposition': ^0.5.5
   '@types/node': ^18.11.19
   '@types/sharp': ^0.31.1
   '@types/tmp': ^0.2.3
   cacheable-lookup: ^7.0.0
+  content-disposition: ^0.5.4
   fastify: ^4.12.0
   fastify-cli: ^5.7.1
   file-type: ^18.2.0
@@ -23,6 +25,7 @@ specifiers:
 dependencies:
   '@fastify/static': 6.8.0
   cacheable-lookup: 7.0.0
+  content-disposition: 0.5.4
   fastify: 4.12.0
   fastify-cli: 5.7.1
   file-type: 18.2.0
@@ -37,6 +40,7 @@ dependencies:
 devDependencies:
   '@swc/cli': 0.1.61_@swc+core@1.3.32
   '@swc/core': 1.3.32
+  '@types/content-disposition': 0.5.5
   '@types/node': 18.11.19
   '@types/sharp': 0.31.1
   '@types/tmp': 0.2.3
@@ -300,6 +304,10 @@ packages:
       '@types/responselike': 1.0.0
     dev: true
 
+  /@types/content-disposition/0.5.5:
+    resolution: {integrity: sha512-v6LCdKfK6BwcqMo+wYW05rLS12S0ZO0Fl4w1h4aaZMD7bqT3gVUns6FvLJKGZHQmYn3SX55JWGpziwJRwVgutA==}
+    dev: true
+
   /@types/http-cache-semantics/4.0.1:
     resolution: {integrity: sha512-SZs7ekbP8CN0txVG2xVRH6EgKmEm31BOxA07vkFaETzZz1xh+cbt8BcI0slpymvwhx5dlFnQG2rTlPVQn+iRPQ==}
 

src/download.ts

@@ -8,6 +8,7 @@ import IPCIDR from 'ip-cidr';
 import PrivateIp from 'private-ip';
 import { StatusError } from './status-error.js';
 import { getAgents } from './http.js';
+import { parse } from 'content-disposition';
 
 const pipeline = util.promisify(stream.pipeline);
 
@@ -29,12 +30,17 @@ export const defaultDownloadConfig = {
     ...getAgents()
 }
 
-export async function downloadUrl(url: string, path: string, settings:DownloadConfig = defaultDownloadConfig): Promise<void> {
+export async function downloadUrl(url: string, path: string, settings:DownloadConfig = defaultDownloadConfig): Promise<{
+    filename: string;
+}> {
     if (process.env.NODE_ENV !== 'production') console.log(`Downloading ${url} to ${path} ...`);
 
     const timeout = 30 * 1000;
     const operationTimeout = 60 * 1000;
 
+    const urlObj = new URL(url);
+    let filename = urlObj.pathname.split('/').pop() ?? 'unknown';
+
     const req = got.stream(url, {
         headers: {
             'User-Agent': settings.userAgent,
@@ -73,6 +79,14 @@ export async function downloadUrl(url: string, path: string, settings:DownloadCo
                 req.destroy();
             }
         }
+
+        const contentDisposition = res.headers['content-disposition'];
+        if (contentDisposition != null) {
+            const parsed = parse(contentDisposition);
+            if (parsed.parameters.filename) {
+                filename = parsed.parameters.filename;
+            }
+        }
     }).on('downloadProgress', (progress: Got.Progress) => {
         if (progress.transferred > settings.maxSize) {
             console.log(`maxSize exceeded (${progress.transferred} > ${settings.maxSize}) on downloadProgress`);
@@ -91,6 +105,10 @@ export async function downloadUrl(url: string, path: string, settings:DownloadCo
     }
 
     if (process.env.NODE_ENV !== 'production') console.log(`Download finished: ${url}`);
+
+    return {
+        filename,
+    }
 }
 
 function isPrivateIp(ip: string, allowedPrivateNetworks: string[]): boolean {

src/index.ts

@@ -13,6 +13,7 @@ import sharp from 'sharp';
 import { StatusError } from './status-error.js';
 import { DownloadConfig, defaultDownloadConfig, downloadUrl } from './download.js';
 import { getAgents } from './http.js';
+import _contentDisposition from 'content-disposition';
 
 const _filename = fileURLToPath(import.meta.url);
 const _dirname = dirname(_filename);
@@ -230,6 +231,7 @@ async function proxyHandler(request: FastifyRequest<{ Params: { url: string; };
 
         reply.header('Content-Type', image.type);
         reply.header('Cache-Control', 'max-age=31536000, immutable');
+        reply.header('Content-Disposition', contentDisposition('inline', file.filename));
         return reply.send(image.data);
     } catch (e) {
         if ('cleanup' in file) file.cleanup();
@@ -238,11 +240,11 @@ async function proxyHandler(request: FastifyRequest<{ Params: { url: string; };
 }
 
 async function downloadAndDetectTypeFromUrl(url: string): Promise<
-    { state: 'remote'; mime: string; ext: string | null; path: string; cleanup: () => void; }
+    { state: 'remote'; mime: string; ext: string | null; path: string; cleanup: () => void; filename: string; }
 > {
     const [path, cleanup] = await createTemp();
     try {
-        await downloadUrl(url, path, config);
+        const { filename } = await downloadUrl(url, path, config);
 
         const { mime, ext } = await detectType(path);
 
@@ -250,9 +252,28 @@ async function downloadAndDetectTypeFromUrl(url: string): Promise<
             state: 'remote',
             mime, ext,
             path, cleanup,
+            filename: correctFilename(filename, ext),
         }
     } catch (e) {
         cleanup();
         throw e;
     }
 }
+
+function correctFilename(filename: string, ext: string | null) {
+    if (!ext) return filename;
+
+    const dotExt = `.${ext}`;
+    if (filename.endsWith(dotExt)) {
+        return filename;
+    }
+    if (ext === 'jpg' && filename.endsWith('.jpeg')) {
+        return filename;
+    }
+    return `${filename}${dotExt}`;
+}
+
+function contentDisposition(type: 'inline' | 'attachment', filename: string): string {
+	const fallback = filename.replace(/[^\w.-]/g, '_');
+	return _contentDisposition(filename, { type, fallback });
+}