- Email translation moves from LibreTranslate to our own translator
service (translator/): Mozilla's Firefox Translations models on the
Bergamot engine, fastText language detection (176 languages). Polish,
English, German, French, Spanish and Italian on first start (~350 MB
instead of ~10 GB); Admin panel > Email translation installs and
removes languages. Built and pushed as the `translator` image.
- Every message is translated paragraph by paragraph as plain text;
names travel with their sentence and are kept only where the model
changed them; a sentence start the model copied ("Enclosed") is tried
again in lower case; list markers are not sent
- The Translate button shows only for installed languages
- New logo: favicon, app/maskable/iPhone icons, notification badge,
email logo and calendar copy regenerated; BIMI logo rebuilt in SVG
Tiny PS with its gradients; masks render in browsers
- Launch screen background is the app's dark grey
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
424 lines
17 KiB
Python
424 lines
17 KiB
Python
"""Email translation, on this server: the translator service (translator/:
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Mozilla's Firefox Translations models and fastText language identification)
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in its own container, reached only by the API. A message's text never leaves
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the server.
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- A message's language is detected the first time it is shown (from its own
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text: quoted replies and signatures left out) and kept on the message, so the
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reading pane can offer "Translate" when it differs from the interface language.
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- A translation is of the message HTML the user sees (already sanitized; the
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result is sanitized again), cached per message, target language and whether
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remote images were shown. It is made paragraph by paragraph, as plain text
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(translation_prep.split_pieces), each paragraph from its own language.
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- The languages on offer are those installed on the service (admin panel).
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Off when ``TRANSLATOR_URL`` is empty.
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"""
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from __future__ import annotations
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import html as html_lib
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import logging
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import re
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import time
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from collections.abc import Iterable
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from dataclasses import dataclass
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import httpx
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from app import translation_prep as prep
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from app.completion import own_text
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from app.config import get_settings
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logger = logging.getLogger(__name__)
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DETECT_CHARS = 1500 # of the message's own text: plenty to tell the language
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MIN_CONFIDENCE = 50.0 # below this, the detector is guessing
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MAX_HTML_CHARS = 150_000 # a translation request bigger than this is refused
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_TIMEOUT = httpx.Timeout(120.0, connect=5.0) # long messages take a while on a CPU
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_LANG_CACHE_S = 60
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class TranslationError(Exception):
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"""Translation is off, the service is unreachable, or it refused the text."""
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@dataclass(frozen=True)
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class Language:
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code: str
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name: str
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def enabled() -> bool:
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return bool(get_settings().translator_url.strip())
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def _url(path: str) -> str:
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return get_settings().translator_url.rstrip("/") + path
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async def _call(method: str, path: str, payload: dict[str, object] | None = None) -> object:
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if not enabled():
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raise TranslationError("translation is not set up on this server")
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try:
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async with httpx.AsyncClient(timeout=_TIMEOUT) as client:
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resp = await client.request(method, _url(path), json=payload)
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except httpx.HTTPError as exc:
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raise TranslationError(f"the translation service is unreachable: {exc}") from exc
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if resp.status_code not in (200, 202):
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detail = resp.text[:200]
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raise TranslationError(f"the translation service refused: {resp.status_code} {detail}")
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return resp.json()
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async def _post(path: str, payload: dict[str, object]) -> object:
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return await _call("POST", path, payload)
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_languages: tuple[float, list[Language]] = (0.0, [])
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async def languages() -> list[Language]:
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"""The installed languages, English among them (cached for a minute). The
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browser names them in the interface language; ``name`` is the code."""
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global _languages
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if not enabled():
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return []
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stamp, cached = _languages
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if cached and time.monotonic() - stamp < _LANG_CACHE_S:
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return cached
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try:
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async with httpx.AsyncClient(timeout=httpx.Timeout(10.0, connect=3.0)) as client:
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resp = await client.get(_url("/languages"))
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resp.raise_for_status()
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codes = resp.json()["installed"]
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except (httpx.HTTPError, ValueError, KeyError, TypeError) as exc:
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logger.info("translation languages unavailable: %s", exc)
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return []
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found = [Language(code=str(c), name=str(c)) for c in codes]
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_languages = (time.monotonic(), found)
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return found
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def forget_languages() -> None:
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"""After an install or removal: ask the service again."""
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global _languages
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_languages = (0.0, [])
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async def status() -> dict[str, object]:
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"""The service's own account (admin panel): installed, installing (bytes
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done of total), available from Mozilla, and why an install failed."""
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async with httpx.AsyncClient(timeout=httpx.Timeout(20.0, connect=3.0)) as client:
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try:
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resp = await client.get(_url("/languages"))
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resp.raise_for_status()
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data = resp.json()
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except (httpx.HTTPError, ValueError) as exc:
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raise TranslationError(f"the translation service is unreachable: {exc}") from exc
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return data if isinstance(data, dict) else {}
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async def install(code: str) -> None:
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await _call("POST", f"/languages/{code}")
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forget_languages()
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async def remove(code: str) -> None:
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await _call("DELETE", f"/languages/{code}")
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forget_languages()
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_CJK = re.compile(r"[\u3040-\u30ff\u3400-\u9fff\uac00-\ud7af\uf900-\ufaff]")
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MIN_LETTERS = 25 # fewer, and the detector guesses ("Jacqueline Lian" → Esperanto)
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MAX_DETECT = 60 # pieces of one message asked about
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MIN_SHARE = 0.15 # of a message's letters, for its language to count
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async def _detect_many(texts: list[str]) -> list[str]:
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"""The language of each of ``texts`` ('' where unsure), in one request."""
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if not texts:
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return []
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result = await _post("/detect", {"q": [t[:DETECT_CHARS] for t in texts]})
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if not isinstance(result, list) or len(result) != len(texts):
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return [""] * len(texts)
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return [
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str(r.get("language", ""))
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if isinstance(r, dict) and float(r.get("confidence", 0)) >= MIN_CONFIDENCE
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else ""
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for r in result
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]
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async def _detect_one(text: str) -> str:
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return (await _detect_many([text]))[0]
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def _weight(text: str) -> int:
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"""How much text this is: letters, a Chinese/Japanese/Korean sign as a word."""
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return sum(3 if _CJK.match(c) else 1 for c in text if c.isalpha())
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async def languages_of(parts: list[str]) -> list[str]:
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"""The language of each of ``parts`` (paragraphs, in order). Parts too
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short to tell take the language of the next part that could be told (a
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greeting goes with what follows it), the last ones that of the one before;
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parts without letters get ''."""
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# Addresses say nothing about a language ("E-mail: lianshaojuan.lsj@…" → Estonian).
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parts = [_ADDRESS.sub(" ", part) for part in parts]
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told: list[str] = [""] * len(parts)
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asked = [
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i
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for i, part in enumerate(parts)
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if _CJK.search(part) or sum(c.isalpha() for c in part) >= MIN_LETTERS
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][:MAX_DETECT]
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for i, language in zip(asked, await _detect_many([parts[i] for i in asked]), strict=True):
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told[i] = language
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out = list(told)
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following = ""
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for i in reversed(range(len(parts))):
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if told[i]:
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following = told[i]
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elif any(c.isalpha() for c in parts[i]):
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out[i] = following
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previous = ""
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for i, part in enumerate(parts):
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if told[i]:
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previous = told[i]
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elif not out[i] and any(c.isalpha() for c in part):
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out[i] = previous
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return out
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async def detect(text: str) -> str:
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"""The languages of ``text`` (a message's plain text), most of it first,
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comma-separated ("zh-Hans,pl,en"); '' if unsure. A message can be in
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several: each language that makes up a good part of it counts."""
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own = own_text(text)
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if len(" ".join(own.split())) < 20:
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return "" # a line or two says too little
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lines: list[str] = []
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total = 0
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for line in (x.strip() for x in own.splitlines()):
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if line and total < DETECT_CHARS * 4:
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lines.append(line)
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total += len(line)
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found = await languages_of(lines)
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weight: dict[str, int] = {}
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for line, language in zip(lines, found, strict=True):
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if language:
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weight[language] = weight.get(language, 0) + _weight(_ADDRESS.sub(" ", line))
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if not weight:
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return await _detect_one(" ".join(own.split()))
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all_of_it = sum(weight.values())
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ranked = sorted(weight, key=lambda k: weight[k], reverse=True)
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return ",".join(k for k in ranked if weight[k] / all_of_it >= MIN_SHARE)
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def _base(code: str) -> str:
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return code.lower().split("-")[0]
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async def _texts(texts: list[str], source: str, target: str) -> list[str]:
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"""``texts`` translated, in batches."""
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out: list[str] = []
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for start in range(0, len(texts), 100):
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batch = texts[start : start + 100]
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result = await _post("/translate", {"q": batch, "source": source, "target": target})
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got = result.get("translatedText") if isinstance(result, dict) else None
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if not isinstance(got, list) or len(got) != len(batch):
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raise TranslationError("the translation service sent no translation")
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out += [str(x) for x in got]
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return out
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def _kept(name: str, translated: str) -> bool:
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"""Whether ``name`` came through a translation: each of its words still
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there, give or take an ending ("Lukas" → "Lukasie": yes; "Milan" →
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"Mediolan": no)."""
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return all(
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word[: max(3, len(word) - 2)] in translated for word in name.split() if len(word) >= 2
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)
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# A capitalised word that starts a sentence ("Enclosed is a summary…").
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_SENTENCE_START = re.compile(r"(?:^|(?<=[.!?…]\s))(?P<word>[^\W\d_][^\W\d_'’-]{2,})\b")
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def _copied_starts(core: str, text: str, names: list[str]) -> list[str]:
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"""Words that start a sentence of ``core`` and came through ``text``
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untranslated, and are no known name: the models take a capitalised
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sentence start for a name ("Enclosed is…" → "Enclosed jest…")."""
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found: list[str] = []
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for m in _SENTENCE_START.finditer(core):
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word = m.group("word")
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if not word[0].isupper() or word.isupper() or any(word in n for n in names):
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continue
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if re.search(rf"(?<!\w){re.escape(word)}(?!\w)", text):
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found.append(word)
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return found
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def _lowered(core: str, words: list[str]) -> str:
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"""``core`` with ``words`` lower-cased where they start a sentence."""
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return _SENTENCE_START.sub(
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lambda m: m.group(0).lower() if m.group("word") in words else m.group(0), core
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)
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def _capitalised(text: str) -> str:
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"""Sentence starts capitalised again (after ``_lowered``): the first
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letter, and one after a sentence's end — a full stop after a word of four
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letters or more, so not after "r.", "np.", "tzw." (abbreviations)."""
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text = re.sub(r"^(\W*)([^\W\d_])", lambda m: m.group(1) + m.group(2).upper(), text)
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return re.sub(
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r"((?:[^\W\d_]{4,}[.…]|[!?])\s+)([^\W\d_])",
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lambda m: m.group(1) + m.group(2).upper(),
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text,
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)
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def _as_before(text: str, first: str) -> str:
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"""A word after a comma capitalised in ``text`` but not in ``first`` (the
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first try) is lower-cased: lower-cased input makes the models capitalise
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elsewhere ("…2026, od 13 lipca" → "…2026 r., Od 13 lipca")."""
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def repl(m: re.Match[str]) -> str:
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word = m.group(2)
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lower = word[0].lower() + word[1:]
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return m.group(1) + (lower if f", {lower}" in first else word)
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return re.sub(r"(,\s+)([^\W\d_][\w'’-]*)", repl, text)
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async def _with_names_kept(core: str, names: list[str], source: str, target: str) -> str:
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"""``core`` translated around ``names``, which are left as they are."""
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pattern = re.compile("(" + "|".join(re.escape(n) for n in names) + ")")
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parts = pattern.split(core)
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todo = [
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(i, m.groups())
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for i, part in enumerate(parts)
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if i % 2 == 0 and (m := _EDGE_SPACE.match(part)) and any(c.isalnum() for c in part)
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]
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done = await _texts([groups[1] for _, groups in todo], source, target)
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for (i, (lead, _, trail)), text in zip(todo, done, strict=True):
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parts[i] = f"{lead}{text}{trail}"
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return "".join(parts)
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async def _translate_paragraphs(
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html: str, target: str, sources: list[str], names: Iterable[str] = ()
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) -> str:
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"""``html`` in ``target``, as plain text paragraph by paragraph: from the
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one language in ``sources``, or (several, or none known) each paragraph
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from its own. Paragraphs already in ``target``, or in a language that is
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not installed, are left as they are.
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``names`` go along with their sentence, which then translates as a whole
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(kept apart, "I came across <Imaginary Pixels>" lost its verb: "Przyszedłem
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Imaginary Pixels"). Only a piece where one came out changed ("Milan" →
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"Mediolan") is translated again with it left as it is."""
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watch = sorted({n.strip() for n in names if len(n.strip()) >= 2}, key=len, reverse=True)
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pieces, paragraphs = prep.split_pieces(html)
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if len(sources) == 1:
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found = [sources[0]] * len(paragraphs)
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else:
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found = await languages_of([p.text for p in paragraphs])
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installed = {x.code for x in await languages()}
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# Chinese and Japanese go without spaces: two pieces of one sentence
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# ("…奎琳,</span>我从…") need one between them once translated.
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followed = {i for p in paragraphs for i in p.pieces[:-1]}
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by_language: dict[str, list[int]] = {}
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for paragraph, language in zip(paragraphs, found, strict=True):
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if language in installed and _base(language) != _base(target):
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by_language.setdefault(language, []).extend(paragraph.pieces)
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for language, where in by_language.items():
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todo: list[tuple[int, str, str, str]] = []
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for i in where:
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m = _EDGE_SPACE.match(html_lib.unescape(pieces[i]))
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lead, core, trail = m.groups() if m else ("", "", "")
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# A list marker stays out: the models repeat it ("1. Thursday" →
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# "1. 1. Czwartek").
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marker = _LIST_MARKER.match(core)
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if marker:
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lead, core = lead + marker.group(0), core[marker.end() :]
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if not trail and i in followed and _base(language) in _NO_SPACES:
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trail = " "
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if any(c.isalnum() for c in core):
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todo.append((i, lead, core, trail))
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done = await _texts([core for _, _, core, _ in todo], language, target)
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# Sentence starts that came through untranslated: once more, lower-case.
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again = [
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(k, words)
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for k, ((_, _, core, _), text) in enumerate(zip(todo, done, strict=True))
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if (words := _copied_starts(core, text, watch))
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]
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if again:
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retried = await _texts(
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[_lowered(todo[k][2], words) for k, words in again], language, target
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)
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for (k, words), text in zip(again, retried, strict=True):
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# Still there: a name after all, and the first try stands.
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if len(_copied_starts(todo[k][2], text, watch)) < len(words):
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done[k] = _as_before(_capitalised(text), done[k])
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for (i, lead, core, trail), text in zip(todo, done, strict=True):
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lost = [n for n in watch if n in core and not _kept(n, text)]
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if lost:
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text = await _with_names_kept(core, lost, language, target)
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pieces[i] = html_lib.escape(f"{lead}{text}{trail}", quote=False)
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return "".join(pieces)
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_NO_SPACES = {"zh", "ja", "th"}
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_LIST_MARKER = re.compile(r"(?:\d{1,3}[.)]|[a-zA-Z][.)]|[-•*–])\s+(?=\S)")
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_EDGE_SPACE = re.compile(r"^(\s*)(.*?)(\s*)$", re.DOTALL)
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# Web and mail addresses in the text: the models break them up ("https: / /
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# vimeo.com"), so they are marked translate="no" and not sent.
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_ADDRESS = re.compile(r"(?:https?://|www\.)[^\s<>\"']+|[\w.+-]+@[\w-]+(?:\.[\w-]+)+", re.IGNORECASE)
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_TAG = re.compile(r"(<[^>]*>)")
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def protect_addresses(html: str) -> str:
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"""Mark the addresses in ``html``'s text as not to be translated (style
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blocks and tag attributes are left alone)."""
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out: list[str] = []
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in_style = False
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for piece in _TAG.split(html):
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if piece.startswith("<"):
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lowered = piece.lower()
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if lowered.startswith("<style"):
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in_style = True
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elif lowered.startswith("</style"):
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in_style = False
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out.append(piece)
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elif in_style or not piece:
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out.append(piece)
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else:
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out.append(_ADDRESS.sub(lambda m: f'<span translate="no">{m.group(0)}</span>', piece))
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return "".join(out)
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# Bumped when what goes to the service, or what is done with the result,
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# changes: translations kept from before are made again.
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PIPELINE_VERSION = 8
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async def translate_html(
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html: str, source: str, target: str, keep: Iterable[str] = (), names: Iterable[str] = ()
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) -> str:
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"""``html`` (a sanitized message body) in ``target``; source "auto", a code,
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or several ("zh-Hans,pl,en": then each paragraph from its own language).
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``keep``: words always left as they are; ``names``: left as they are if
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the model would change them (translation_prep)."""
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if len(html) > MAX_HTML_CHARS:
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raise TranslationError("this message is too long to translate")
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sources = [x for x in (source or "").split(",") if x and x != "auto"]
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prepared = prep.join_wrapped_lines(html)
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for language in sources:
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prepared = prep.translate_phrases(prepared, language, target)
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candidates = {*names, *prep.find_names(prepared, sources[0] if sources else "")}
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prepared = prep.keep_symbols(protect_addresses(prep.keep_terms(prepared, keep)))
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||
return prep.tidy(await _translate_paragraphs(prepared, target, sources, candidates))
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