refactor(rest): add content-type(s) to uploads (#8290)

packages/discord.js/src/structures/MessagePayload.js

@@ -255,8 +255,8 @@ class MessagePayload {
       name = fileLike.name ?? findName(attachment);
     }
 
-    const data = await DataResolver.resolveFile(attachment);
-    return { data, name };
+    const { data, contentType } = await DataResolver.resolveFile(attachment);
+    return { data, name, contentType };
   }
 
   /**

packages/discord.js/src/util/DataResolver.js

@@ -100,32 +100,37 @@ class DataResolver extends null {
    * @see {@link https://nodejs.org/api/stream.html}
    */
 
+  /**
+   * @typedef {Object} ResolvedFile
+   * @property {Buffer} data Buffer containing the file data
+   * @property {string} [contentType] Content type of the file
+   */
+
   /**
    * Resolves a BufferResolvable to a Buffer.
    * @param {BufferResolvable|Stream} resource The buffer or stream resolvable to resolve
-   * @returns {Promise<Buffer>}
+   * @returns {Promise<ResolvedFile>}
    */
   static async resolveFile(resource) {
-    if (!resource) return null;
-    if (Buffer.isBuffer(resource)) return resource;
+    if (Buffer.isBuffer(resource)) return { data: resource };
 
     if (typeof resource[Symbol.asyncIterator] === 'function') {
       const buffers = [];
       for await (const data of resource) buffers.push(data);
-      return Buffer.concat(buffers);
+      return { data: Buffer.concat(buffers) };
     }
 
     if (typeof resource === 'string') {
       if (/^https?:\/\//.test(resource)) {
         const res = await fetch(resource);
-        return Buffer.from(await res.arrayBuffer());
+        return { data: Buffer.from(await res.arrayBuffer()), contentType: res.headers.get('content-type') };
       }
 
       const file = path.resolve(resource);
 
       const stats = await fs.stat(file);
       if (!stats.isFile()) throw new DiscordError(ErrorCodes.FileNotFound, file);
-      return fs.readFile(file);
+      return { data: await fs.readFile(file) };
     }
 
     throw new TypeError(ErrorCodes.ReqResourceType);

packages/discord.js/typings/index.d.ts

@@ -1039,11 +1039,16 @@ export class ContextMenuCommandInteraction<Cached extends CacheType = CacheType>
   private resolveContextMenuOptions(data: APIApplicationCommandInteractionData): CommandInteractionOption<Cached>[];
 }
 
+export interface ResolvedFile {
+  data: Buffer;
+  contentType?: string;
+}
+
 export class DataResolver extends null {
   private constructor();
   public static resolveBase64(data: Base64Resolvable): string;
   public static resolveCode(data: string, regex: RegExp): string;
-  public static resolveFile(resource: BufferResolvable | Stream): Promise<Buffer>;
+  public static resolveFile(resource: BufferResolvable | Stream): Promise<ResolvedFile>;
   public static resolveImage(resource: BufferResolvable | Base64Resolvable): Promise<string | null>;
   public static resolveInviteCode(data: InviteResolvable): string;
   public static resolveGuildTemplateCode(data: GuildTemplateResolvable): string;

packages/rest/package.json

@@ -55,6 +55,7 @@
 		"@sapphire/async-queue": "^1.3.2",
 		"@sapphire/snowflake": "^3.2.2",
 		"discord-api-types": "^0.36.1",
+		"file-type": "^17.1.2",
 		"tslib": "^2.4.0",
 		"undici": "^5.6.0"
 	},

packages/rest/src/lib/RequestManager.ts

@@ -9,6 +9,12 @@ import { SequentialHandler } from './handlers/SequentialHandler';
 import { DefaultRestOptions, DefaultUserAgent, RESTEvents } from './utils/constants';
 import { resolveBody } from './utils/utils';
 
+// Make this a lazy dynamic import as file-type is a pure ESM package
+const getFileType = (): Promise<typeof import('file-type')> => {
+	let cached: Promise<typeof import('file-type')>;
+	return (cached ??= import('file-type'));
+};
+
 /**
  * Represents a file to be added to the request
  */
@@ -27,6 +33,10 @@ export interface RawFile {
 	 * The actual data for the file
 	 */
 	data: string | number | boolean | Buffer;
+	/**
+	 * Content-Type of the file
+	 */
+	contentType?: string;
 }
 
 /**
@@ -401,11 +411,14 @@ export class RequestManager extends EventEmitter {
 				// FormData.append only accepts a string or Blob.
 				// https://developer.mozilla.org/en-US/docs/Web/API/Blob/Blob#parameters
 				// The Blob constructor accepts TypedArray/ArrayBuffer, strings, and Blobs.
-				if (Buffer.isBuffer(file.data) || typeof file.data === 'string') {
-					formData.append(fileKey, new Blob([file.data]), file.name);
+				if (Buffer.isBuffer(file.data)) {
+					// Try to infer the content type from the buffer if one isn't passed
+					const { fileTypeFromBuffer } = await getFileType();
+					const contentType = file.contentType ?? (await fileTypeFromBuffer(file.data))?.mime;
+					formData.append(fileKey, new Blob([file.data], { type: contentType }), file.name);
 				} else {
 					// eslint-disable-next-line @typescript-eslint/restrict-template-expressions
-					formData.append(fileKey, new Blob([`${file.data}`]), file.name);
+					formData.append(fileKey, new Blob([`${file.data}`], { type: file.contentType }), file.name);
 				}
 			}
 

yarn.lock

@@ -3003,6 +3003,7 @@ __metadata:
     c8: ^7.11.3
     discord-api-types: ^0.36.1
     eslint: ^8.19.0
+    file-type: ^17.1.2
     prettier: ^2.7.1
     tslib: ^2.4.0
     tsup: ^6.1.3
@@ -4188,6 +4189,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@tokenizer/token@npm:^0.3.0":
+  version: 0.3.0
+  resolution: "@tokenizer/token@npm:0.3.0"
+  checksum: 1d575d02d2a9f0c5a4ca5180635ebd2ad59e0f18b42a65f3d04844148b49b3db35cf00b6012a1af2d59c2ab3caca59451c5689f747ba8667ee586ad717ee58e1
+  languageName: node
+  linkType: hard
+
 "@tootallnate/once@npm:1":
   version: 1.1.2
   resolution: "@tootallnate/once@npm:1.1.2"
@@ -9702,6 +9710,17 @@ dts-critic@latest:
   languageName: node
   linkType: hard
 
+"file-type@npm:^17.1.2":
+  version: 17.1.2
+  resolution: "file-type@npm:17.1.2"
+  dependencies:
+    readable-web-to-node-stream: ^3.0.2
+    strtok3: ^7.0.0-alpha.7
+    token-types: ^5.0.0-alpha.2
+  checksum: 22103084b47d1fdc82e84b979512a2e9e488643f975b04cfd39acb2a9ab212438274a4f06039061631ca01be030f174c387c4a3ab9fe3417a1a199cb59079cb8
+  languageName: node
+  linkType: hard
+
 "file-uri-to-path@npm:1.0.0":
   version: 1.0.0
   resolution: "file-uri-to-path@npm:1.0.0"
@@ -10997,7 +11016,7 @@ dts-critic@latest:
   languageName: node
   linkType: hard
 
-"ieee754@npm:^1.1.13":
+"ieee754@npm:^1.1.13, ieee754@npm:^1.2.1":
   version: 1.2.1
   resolution: "ieee754@npm:1.2.1"
   checksum: 5144c0c9815e54ada181d80a0b810221a253562422e7c6c3a60b1901154184f49326ec239d618c416c1c5945a2e197107aee8d986a3dd836b53dffefd99b5e7e
@@ -15009,6 +15028,13 @@ dts-critic@latest:
   languageName: node
   linkType: hard
 
+"peek-readable@npm:^5.0.0-alpha.5":
+  version: 5.0.0-alpha.5
+  resolution: "peek-readable@npm:5.0.0-alpha.5"
+  checksum: cab949ed457dac95ae191dd412c6a0ba05e8db4842fd51704ccf2c8c16d6f3ceeefc997e8caea584a0395f229e468c0203a38a8d0ec68cfef8bacc157a006dcb
+  languageName: node
+  linkType: hard
+
 "peek-stream@npm:^1.1.0":
   version: 1.1.3
   resolution: "peek-stream@npm:1.1.3"
@@ -15671,6 +15697,15 @@ dts-critic@latest:
   languageName: node
   linkType: hard
 
+"readable-web-to-node-stream@npm:^3.0.2":
+  version: 3.0.2
+  resolution: "readable-web-to-node-stream@npm:3.0.2"
+  dependencies:
+    readable-stream: ^3.6.0
+  checksum: 8c56cc62c68513425ddfa721954875b382768f83fa20e6b31e365ee00cbe7a3d6296f66f7f1107b16cd3416d33aa9f1680475376400d62a081a88f81f0ea7f9c
+  languageName: node
+  linkType: hard
+
 "readdirp@npm:~3.6.0":
   version: 3.6.0
   resolution: "readdirp@npm:3.6.0"
@@ -17239,6 +17274,16 @@ dts-critic@latest:
   languageName: node
   linkType: hard
 
+"strtok3@npm:^7.0.0-alpha.7":
+  version: 7.0.0-alpha.8
+  resolution: "strtok3@npm:7.0.0-alpha.8"
+  dependencies:
+    "@tokenizer/token": ^0.3.0
+    peek-readable: ^5.0.0-alpha.5
+  checksum: 00e5c9ed0c5de537839cf443d5628f0ae88d2956ca1fdcbd45cd97372045d7179a40ec99f6d06b02c59ec2141e362142ad0a87c59506d401dbd3bd1ee242abaa
+  languageName: node
+  linkType: hard
+
 "style-to-object@npm:^0.3.0":
   version: 0.3.0
   resolution: "style-to-object@npm:0.3.0"
@@ -17737,6 +17782,16 @@ dts-critic@latest:
   languageName: node
   linkType: hard
 
+"token-types@npm:^5.0.0-alpha.2":
+  version: 5.0.0-alpha.2
+  resolution: "token-types@npm:5.0.0-alpha.2"
+  dependencies:
+    "@tokenizer/token": ^0.3.0
+    ieee754: ^1.2.1
+  checksum: ee23eeed6f383b1072d99781d62fc7840f1296a96d47e636e36fca757debd7eb4274d31fcd2d56997606eede00b12b1e61a64610fe0ed7807d6b1c4dcf5ccc6b
+  languageName: node
+  linkType: hard
+
 "toml@npm:^3.0.0":
   version: 3.0.0
   resolution: "toml@npm:3.0.0"