backend: Add LibreTranslate support

packages/backend/migration/1668661888188-add-libretranslate.js

@@ -0,0 +1,19 @@
+export class addLibretranslate1668661888188 {
+    name = 'addLibretranslate1668661888188'
+
+    async up(queryRunner) {
+        await queryRunner.query(`CREATE TYPE "public"."meta_translationservice_enum" AS ENUM('deepl', 'libretranslate')`);
+        await queryRunner.query(`ALTER TABLE "meta" ADD "translationService" "public"."meta_translationservice_enum"`);
+        await queryRunner.query(`ALTER TABLE "meta" ADD "libreTranslateAuthKey" character varying(128)`);
+        await queryRunner.query(`ALTER TABLE "meta" ADD "libreTranslateEndpoint" character varying(2048)`);
+				// Set translationService to 'deepl' if auth key is already set
+				await queryRunner.query(`UPDATE "meta" SET "translationService"='deepl' WHERE "deeplAuthKey" IS NOT NULL`);
+    }
+
+    async down(queryRunner) {
+        await queryRunner.query(`ALTER TABLE "meta" DROP COLUMN "libreTranslateEndpoint"`);
+        await queryRunner.query(`ALTER TABLE "meta" DROP COLUMN "libreTranslateAuthKey"`);
+        await queryRunner.query(`ALTER TABLE "meta" DROP COLUMN "translationService"`);
+        await queryRunner.query(`DROP TYPE "public"."meta_translationservice_enum"`);
+    }
+}

packages/backend/src/models/entities/meta.ts

@@ -3,6 +3,11 @@ import { id } from '../id.js';
 import { User } from './user.js';
 import { Clip } from './clip.js';
 
+export enum TranslationService {
+	DeepL = 'deepl',
+	LibreTranslate = 'libretranslate',
+}
+
 @Entity()
 export class Meta {
 	@PrimaryColumn({
@@ -299,6 +304,12 @@ export class Meta {
 	})
 	public discordClientSecret: string | null;
 
+	@Column('enum', {
+		enum: TranslationService,
+		nullable: true,
+	})
+	public translationService: TranslationService | null;
+
 	@Column('varchar', {
 		length: 128,
 		nullable: true,
@@ -310,6 +321,18 @@ export class Meta {
 	})
 	public deeplIsPro: boolean;
 
+	@Column('varchar', {
+		length: 128,
+		nullable: true,
+	})
+	public libreTranslateAuthKey: string | null;
+
+	@Column('varchar', {
+		length: 2048,
+		nullable: true,
+	})
+	public libreTranslateEndpoint: string | null;
+
 	@Column('varchar', {
 		length: 512,
 		nullable: true,

packages/backend/src/server/api/common/translator.ts

@@ -0,0 +1,12 @@
+import { Meta, TranslationService } from '@/models/entities/meta.js';
+
+export function translatorAvailable(instance: Meta): boolean {
+	switch (instance.translationService) {
+		case TranslationService.DeepL:
+			return instance.deeplAuthKey != null;
+		case TranslationService.LibreTranslate:
+			return instance.libreTranslateEndpoint != null;
+		default:
+			return false;
+	}
+}

packages/backend/src/server/api/endpoints/admin/meta.ts

@@ -1,5 +1,6 @@
 import config from '@/config/index.js';
 import { fetchMeta } from '@/misc/fetch-meta.js';
+import { translatorAvailable } from '../../common/translator.js';
 import define from '../../define.js';
 
 export const meta = {
@@ -317,7 +318,7 @@ export default define(meta, paramDef, async (ps, me) => {
 		enableGithubIntegration: instance.enableGithubIntegration,
 		enableDiscordIntegration: instance.enableDiscordIntegration,
 		enableServiceWorker: instance.enableServiceWorker,
-		translatorAvailable: instance.deeplAuthKey != null,
+		translatorAvailable: translatorAvailable(instance),
 		pinnedPages: instance.pinnedPages,
 		pinnedClipId: instance.pinnedClipId,
 		cacheRemoteFiles: instance.cacheRemoteFiles,

packages/backend/src/server/api/endpoints/admin/update-meta.ts

@@ -1,5 +1,6 @@
 import { insertModerationLog } from '@/services/insert-moderation-log.js';
 import { fetchMeta, setMeta } from '@/misc/fetch-meta.js';
+import { TranslationService } from '@/models/entities/meta.js';
 import define from '../../define.js';
 
 export const meta = {
@@ -55,8 +56,11 @@ export const paramDef = {
 			type: 'string',
 		} },
 		summalyProxy: { type: 'string', nullable: true },
+		translationService: { type: 'string', nullable: true, enum: [null, ...Object.values(TranslationService)] },
 		deeplAuthKey: { type: 'string', nullable: true },
 		deeplIsPro: { type: 'boolean' },
+		libreTranslateAuthKey: { type: 'string', nullable: true },
+		libreTranslateEndpoint: { type: 'string', nullable: true },
 		enableTwitterIntegration: { type: 'boolean' },
 		twitterConsumerKey: { type: 'string', nullable: true },
 		twitterConsumerSecret: { type: 'string', nullable: true },
@@ -362,6 +366,10 @@ export default define(meta, paramDef, async (ps, me) => {
 		set.objectStorageS3ForcePathStyle = ps.objectStorageS3ForcePathStyle;
 	}
 
+	if (ps.translationService !== undefined) {
+		set.translationService = ps.translationService;
+	}
+
 	if (ps.deeplAuthKey !== undefined) {
 		if (ps.deeplAuthKey === '') {
 			set.deeplAuthKey = null;
@@ -374,6 +382,22 @@ export default define(meta, paramDef, async (ps, me) => {
 		set.deeplIsPro = ps.deeplIsPro;
 	}
 
+	if (ps.libreTranslateEndpoint !== undefined) {
+		if (ps.libreTranslateEndpoint === '') {
+			set.libreTranslateEndpoint = null;
+		} else {
+			set.libreTranslateEndpoint = ps.libreTranslateEndpoint;
+		}
+	}
+
+	if (ps.libreTranslateAuthKey !== undefined) {
+		if (ps.libreTranslateAuthKey === '') {
+			set.libreTranslateAuthKey = null;
+		} else {
+			set.libreTranslateAuthKey = ps.libreTranslateAuthKey;
+		}
+	}
+
 	const meta = await fetchMeta();
 	await setMeta({
 		...meta,

packages/backend/src/server/api/endpoints/meta.ts

@@ -3,6 +3,7 @@ import config from '@/config/index.js';
 import { fetchMeta } from '@/misc/fetch-meta.js';
 import { Emojis, Users } from '@/models/index.js';
 import define from '../define.js';
+import { translatorAvailable } from '../common/translator.js';
 
 export const meta = {
 	tags: ['meta'],
@@ -322,7 +323,7 @@ export default define(meta, paramDef, async (ps, me) => {
 
 		enableServiceWorker: instance.enableServiceWorker,
 
-		translatorAvailable: instance.deeplAuthKey != null,
+		translatorAvailable: translatorAvailable(instance),
 
 		pinnedPages: instance.pinnedPages,
 		pinnedClipId: instance.pinnedClipId,

packages/backend/src/server/api/endpoints/notes/translate.ts

@@ -4,6 +4,7 @@ import config from '@/config/index.js';
 import { getAgentByUrl } from '@/misc/fetch.js';
 import { fetchMeta } from '@/misc/fetch-meta.js';
 import { Notes } from '@/models/index.js';
+import { TranslationService } from '@/models/entities/meta.js';
 import { ApiError } from '../../error.js';
 import { getNote } from '../../common/getters.js';
 import define from '../../define.js';
@@ -113,50 +114,101 @@ export default define(meta, paramDef, async (ps, user) => {
 		if (err.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError('NO_SUCH_NOTE');
 		throw err;
 	});
+	const instance = await fetchMeta();
 
-	if (note.text == null) {
+	if (instance.translationService == null) {
 		return 204;
 	}
 
-	const instance = await fetchMeta();
+	type Translation = {
+		sourceLang: string;
+		text: string;
+	};
 
-	if (instance.deeplAuthKey == null) {
-		return 204; // TODO: 良い感じのエラー返す
+	async function translateDeepL(): Promise<Translation | number> {
+		if (note.text == null || instance.deeplAuthKey == null) {
+			return 204; // TODO: Return a better error
+		}
+
+		const sourceLang = ps.sourceLang;
+		const targetLang = ps.targetLang;
+
+		const params = new URLSearchParams();
+		params.append('auth_key', instance.deeplAuthKey);
+		params.append('text', note.text);
+		params.append('target_lang', targetLang);
+		if (sourceLang) params.append('source_lang', sourceLang);
+
+		const endpoint = instance.deeplIsPro ? 'https://api.deepl.com/v2/translate' : 'https://api-free.deepl.com/v2/translate';
+
+		const res = await fetch(endpoint, {
+			method: 'POST',
+			headers: {
+				'Content-Type': 'application/x-www-form-urlencoded',
+				'User-Agent': config.userAgent,
+				Accept: 'application/json, */*',
+			},
+			body: params,
+			// TODO
+			//timeout: 10000,
+			agent: getAgentByUrl,
+		});
+
+		const json = (await res.json()) as {
+			translations: {
+				detected_source_language: string;
+				text: string;
+			}[];
+		};
+
+		return {
+			sourceLang: json.translations[0].detected_source_language,
+			text: json.translations[0].text,
+		};
 	}
 	
-	const sourceLang = ps.sourceLang;
-	const targetLang = ps.targetLang;
+	async function translateLibreTranslate(): Promise<Translation | number> {
+		if (note.text == null || instance.libreTranslateEndpoint == null) {
+			return 204;
+		}
 
-	const params = new URLSearchParams();
-	params.append('auth_key', instance.deeplAuthKey);
-	params.append('text', note.text);
-	params.append('target_lang', targetLang);
-	if (sourceLang) params.append('source_lang', sourceLang);
+		// LibteTranslate only understands 2-letter codes
+		const source = ps.sourceLang?.toLowerCase().split('-', 1)[0] ?? 'auto';
+		const target = ps.targetLang.toLowerCase().split('-', 1)[0];
+		const api_key = instance.libreTranslateAuthKey ?? undefined;
+		const endpoint = instance.libreTranslateEndpoint;
 
-	const endpoint = instance.deeplIsPro ? 'https://api.deepl.com/v2/translate' : 'https://api-free.deepl.com/v2/translate';
+		const params = {
+			q: note.text,
+			source,
+			target,
+			api_key,
+		};
 
-	const res = await fetch(endpoint, {
-		method: 'POST',
-		headers: {
-			'Content-Type': 'application/x-www-form-urlencoded',
-			'User-Agent': config.userAgent,
-			Accept: 'application/json, */*',
-		},
-		body: params,
-		// TODO
-		//timeout: 10000,
-		agent: getAgentByUrl,
-	});
+		const res = await fetch(endpoint, {
+			method: 'POST',
+			body: JSON.stringify(params),
+			headers: { 'Content-Type': 'application/json' },
+		});
 
-	const json = (await res.json()) as {
-		translations: {
-			detected_source_language: string;
-			text: string;
-		}[];
-	};
+		const json = (await res.json()) as {
+			detectedLanguage?: {
+				confidence: number;
+				language: string;
+			};
+			translatedText: string;
+		};
 
-	return {
-		sourceLang: json.translations[0].detected_source_language,
-		text: json.translations[0].text,
-	};
+		return {
+			sourceLang: (json.detectedLanguage?.language ?? source).toUpperCase(),
+			text: json.translatedText,
+		};
+	}
+
+	switch (instance.translationService) {
+		case TranslationService.DeepL:
+			return await translateDeepL();
+		case TranslationService.LibreTranslate:
+			return await translateLibreTranslate();
+	}
 });