Add libretranslate support

README.md

@@ -1,5 +1,5 @@
 # translate
-A [maubot](https://github.com/maubot/maubot) to translate words using Google Translate (DeepL is planned too)
+A [maubot](https://github.com/maubot/maubot) to translate words using Google Translate, DeepL or LibreTranslate
 
 ## Usage
 
@@ -19,15 +19,11 @@ You can also use the alias `tr`:
     !tr en ru Hello world.
 
 The first parameter (source language) can be set to `auto` or omitted entirely
-to let Google Translate detect the source language. Additionally, you can reply
+to let the bot detect the source language. Additionally, you can reply
 to a message with `!tr <from> <to>` (no text) to translate the message you
 replied to.
 
 ## supported languages:
 
-- de: (german)
-- en: (english)
-- zh: (chinese)
-- ...
-
-Full list of supported languages: https://cloud.google.com/translate/docs/languages
+This depends on the translation provider you choose. For google, a list of
+supported languages can be found at https://cloud.google.com/translate/docs/languages

base-config.yaml

@@ -1,7 +1,10 @@
 # Translation provider settings
 provider:
   id: google
-  args: {}
+  args: {
+    url: 'translate.example.com',  # required if you use libretranslate, else irrelevant
+    api_key: 'loremipsumdolorsitamen1234'  # optional if you use libretranslate, else irrelevant
+  }
 auto_translate:
 - room_id: '!roomid:example.com'
   main_language: en

translate/bot.py

@@ -38,14 +38,14 @@ class TranslatorBot(Plugin):
 
     async def start(self) -> None:
         await super().start()
-        self.on_external_config_update()
+        await self.on_external_config_update()
 
-    def on_external_config_update(self) -> None:
+    async def on_external_config_update(self) -> None:
         self.translator = None
         self.config.load_and_update()
         self.auto_translate = self.config.load_auto_translate()
         try:
-            self.translator = self.config.load_translator()
+            self.translator = await self.config.load_translator()
         except TranslationProviderError:
             self.log.exception("Error loading translator")
 
@@ -84,7 +84,8 @@ def is_acceptable(lang: str) -> bool:
     async def command_handler(self, evt: MessageEvent, language: Optional[Tuple[str, str]],
                               text: str) -> None:
         if not language:
-            await evt.reply("Usage: !translate [from] <to> [text or reply to message]")
+            await evt.reply("No supported target language detected. "
+                            "Usage: !translate [from] <to> [text or reply to message]")
             return
         if not self.config["response_reply"]:
             evt.disable_reply = True
@@ -95,7 +96,7 @@ async def command_handler(self, evt: MessageEvent, language: Optional[Tuple[str,
             reply_evt = await self.client.get_event(evt.room_id, evt.content.get_reply_to())
             text = reply_evt.content.body
         if not text:
-            await evt.reply("Usage: !translate [from] <to> [text or reply to message]")
+            await evt.reply("Nothing to translate detected. Usage: !translate [from] <to> [text or reply to message]")
             return
         result = await self.translator.translate(text, to_lang=language[1], from_lang=language[0])
         await evt.reply(result.text)

translate/provider/abstract.py

@@ -23,6 +23,8 @@ class AbstractTranslationProvider(ABC):
     @abstractmethod
     def __init__(self, args: Dict) -> None:
         pass
+    async def post_init(self) -> None:
+        pass
 
     @abstractmethod
     async def translate(self, text: str, to_lang: str, from_lang: str = "auto") -> Result:

translate/provider/libretranslate.py

@@ -0,0 +1,70 @@
+# translate - A maubot plugin to translate words.
+# Copyright (C) 2022 Tammes Burghard
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+import json
+import re
+from typing import Dict
+
+from aiohttp import ClientSession, client_exceptions
+from yarl import URL
+
+from . import AbstractTranslationProvider, Result
+
+
+class LibreTranslate(AbstractTranslationProvider):
+    headers: Dict[str, str] = {"Content-Type": "application/json"}
+
+    def __init__(self, args: Dict) -> None:
+        super().__init__(args)
+        if args.get("url") is None:
+            raise ValueError("Please specify the url of your preferred libretranslate instance in provider.args.url")
+        else:
+            self._base_url = args.get("url")
+            if not re.match(r"^https?://", self._base_url):
+                self._base_url = "https://" + self._base_url
+        self.url: URL = URL(self._base_url + "/translate")
+        self.api_key = args.get("api_key")
+        self.supported_languages = None
+
+    async def post_init(self):
+        try:
+            async with ClientSession() as sess:
+                resp = await sess.get(self._base_url + "/languages")
+                self.supported_languages = {lang["code"]: lang["name"] for lang in await resp.json()}
+        except client_exceptions.ClientError:
+            raise ValueError(f"This url ({self._base_url}) does not point to a compatible libretranslate instance. "
+                             f"Please change it")
+
+    async def translate(self, text: str, to_lang: str, from_lang: str = "auto") -> Result:
+        if not from_lang:
+            from_lang = "auto"
+        async with ClientSession() as sess:
+            data=json.dumps({"q": text, "source": from_lang, "target": to_lang,
+                  "format": "text", "api_key": self.api_key})
+            resp = await sess.post(self.url, data=data, headers=self.headers)
+            if resp.status == 403:
+                raise ValueError("Request forbidden. You did probably configure an incorrect api key.")
+            data = await resp.json()
+            return Result(text=data["translatedText"],
+                          source_language=data["detectedLanguage"]["language"] if from_lang == "auto" else from_lang)
+
+    def is_supported_language(self, code: str) -> bool:
+        return code.lower() in self.supported_languages.keys()
+
+    def get_language_name(self, code: str) -> str:
+        return self.supported_languages[code]
+
+
+make_translation_provider = LibreTranslate

translate/util.py

@@ -41,15 +41,17 @@ def do_update(self, helper: ConfigUpdateHelper) -> None:
         helper.copy("auto_translate")
         helper.copy("response_reply")
 
-    def load_translator(self) -> AbstractTranslationProvider:
+    async def load_translator(self) -> AbstractTranslationProvider:
         try:
             provider = self["provider.id"]
             mod = import_module(f".{provider}", "translate.provider")
             make = mod.make_translation_provider
         except (KeyError, AttributeError, ImportError) as e:
             raise TranslationProviderError("Failed to load translation provider") from e
         try:
-            return make(self["provider.args"])
+            translation_provider = make(self["provider.args"])
+            await translation_provider.post_init()
+            return translation_provider
         except Exception as e:
             raise TranslationProviderError("Failed to initialize translation provider") from e