LibreTranslate/app/app.py

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import os
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from flask import Flask, render_template, jsonify, request, abort, send_from_directory
from flask_swagger import swagger
from flask_swagger_ui import get_swaggerui_blueprint
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from langdetect import detect_langs
from langdetect import DetectorFactory
from pkg_resources import resource_filename
from .api_keys import Database
DetectorFactory.seed = 0 # deterministic
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api_keys_db = None
def get_json_dict(request):
d = request.get_json()
if not isinstance(d, dict):
abort(400, description="Invalid JSON format")
return d
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def get_remote_address():
if request.headers.getlist("X-Forwarded-For"):
ip = request.headers.getlist("X-Forwarded-For")[0]
else:
ip = request.remote_addr or '127.0.0.1'
return ip
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def get_routes_limits(default_req_limit, api_keys_db):
if default_req_limit == -1:
# TODO: better way?
default_req_limit = 9999999999999
def limits():
req_limit = default_req_limit
if api_keys_db:
if request.is_json:
json = get_json_dict(request)
api_key = json.get('api_key')
else:
api_key = request.values.get("api_key")
if api_key:
db_req_limit = api_keys_db.lookup(api_key)
if db_req_limit is not None:
req_limit = db_req_limit
return "%s per minute" % req_limit
return [limits]
def create_app(args):
if not args.offline:
from app.init import boot
boot()
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from app.language import languages
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app = Flask(__name__)
# For faster access
language_map = {}
for l in languages:
language_map[l.code] = l.name
if args.debug:
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app.config['TEMPLATES_AUTO_RELOAD'] = True
# Map userdefined frontend languages to argos language object.
if args.frontend_language_source == "auto":
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frontend_argos_language_source = type('obj', (object,), {
'code': 'auto',
'name': 'Auto Detect'
})
else:
frontend_argos_language_source = next(iter([l for l in languages if l.code == args.frontend_language_source]), None)
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frontend_argos_language_target = next(iter([l for l in languages if l.code == args.frontend_language_target]), None)
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# Raise AttributeError to prevent app startup if user input is not valid.
if frontend_argos_language_source is None:
raise AttributeError(f"{args.frontend_language_source} as frontend source language is not supported.")
if frontend_argos_language_target is None:
raise AttributeError(f"{args.frontend_language_target} as frontend target language is not supported.")
if args.req_limit > 0 or args.api_keys:
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from flask_limiter import Limiter
limiter = Limiter(
app,
key_func=get_remote_address,
default_limits=get_routes_limits(args.req_limit, Database() if args.api_keys else None)
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)
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else:
from .no_limiter import Limiter
limiter = Limiter()
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@app.errorhandler(400)
def invalid_api(e):
return jsonify({"error": str(e.description)}), 400
@app.errorhandler(500)
def server_error(e):
return jsonify({"error": str(e.description)}), 500
@app.errorhandler(429)
def slow_down_error(e):
return jsonify({"error": "Slowdown: " + str(e.description)}), 429
@app.route("/")
@limiter.exempt
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def index():
return render_template('index.html', gaId=args.ga_id, frontendTimeout=args.frontend_timeout, offline=args.offline, api_keys=args.api_keys, web_version=os.environ.get('LT_WEB') is not None)
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@app.route("/languages", methods=['GET', 'POST'])
@limiter.exempt
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def langs():
"""
Retrieve list of supported languages
---
tags:
- translate
responses:
200:
description: List of languages
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schema:
id: languages
type: array
items:
type: object
properties:
code:
type: string
description: Language code
name:
type: string
description: Human-readable language name (in English)
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429:
description: Slow down
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schema:
id: error-slow-down
type: object
properties:
error:
type: string
description: Reason for slow down
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"""
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return jsonify([{'code': l.code, 'name': l.name} for l in languages])
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# Add cors
@app.after_request
def after_request(response):
response.headers.add('Access-Control-Allow-Origin','*')
response.headers.add('Access-Control-Allow-Headers', "Authorization, Content-Type")
response.headers.add('Access-Control-Expose-Headers', "Authorization")
response.headers.add('Access-Control-Allow-Methods', "GET, POST")
response.headers.add('Access-Control-Allow-Credentials', "true")
response.headers.add('Access-Control-Max-Age', 60 * 60 * 24 * 20)
return response
@app.route("/translate", methods=['POST'])
def translate():
"""
Translate text from a language to another
---
tags:
- translate
parameters:
- in: formData
name: q
schema:
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oneOf:
- type: string
example: Hello world!
- type: array
example: ['Hello world!']
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required: true
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description: Text(s) to translate
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- in: formData
name: source
schema:
type: string
example: en
required: true
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description: Source language code
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- in: formData
name: target
schema:
type: string
example: es
required: true
description: Target language code
- in: formData
name: api_key
schema:
type: string
example: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
required: false
description: API key
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responses:
200:
description: Translated text
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schema:
id: translate
type: object
properties:
translatedText:
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oneOf:
- type: string
- type: array
description: Translated text(s)
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400:
description: Invalid request
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schema:
id: error-response
type: object
properties:
error:
type: string
description: Error message
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500:
description: Translation error
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schema:
id: error-response
type: object
properties:
error:
type: string
description: Error message
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429:
description: Slow down
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schema:
id: error-slow-down
type: object
properties:
error:
type: string
description: Reason for slow down
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"""
if request.is_json:
json = get_json_dict(request)
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q = json.get('q')
source_lang = json.get('source')
target_lang = json.get('target')
else:
q = request.values.get("q")
source_lang = request.values.get("source")
target_lang = request.values.get("target")
if not q:
abort(400, description="Invalid request: missing q parameter")
if not source_lang:
abort(400, description="Invalid request: missing source parameter")
if not target_lang:
abort(400, description="Invalid request: missing target parameter")
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batch = isinstance(q, list)
if batch and args.batch_limit != -1:
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batch_size = len(q)
if args.batch_limit < batch_size:
abort(400, description="Invalid request: Request (%d) exceeds text limit (%d)" % (batch_size, args.batch_limit))
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if args.char_limit != -1:
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if batch:
chars = sum([len(text) for text in q])
else:
chars = len(q)
if args.char_limit < chars:
abort(400, description="Invalid request: Request (%d) exceeds character limit (%d)" % (chars, args.char_limit))
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if source_lang == 'auto':
candidate_langs = list(filter(lambda l: l.lang in language_map, detect_langs(q)))
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if len(candidate_langs) > 0:
candidate_langs.sort(key=lambda l: l.prob, reverse=True)
if args.debug:
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print(candidate_langs)
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source_lang = next(iter([l.code for l in languages if l.code == candidate_langs[0].lang]), None)
if not source_lang:
source_lang = 'en'
else:
source_lang = 'en'
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if args.debug:
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print("Auto detected: %s" % source_lang)
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src_lang = next(iter([l for l in languages if l.code == source_lang]), None)
tgt_lang = next(iter([l for l in languages if l.code == target_lang]), None)
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if src_lang is None:
abort(400, description="%s is not supported" % source_lang)
if tgt_lang is None:
abort(400, description="%s is not supported" % target_lang)
translator = src_lang.get_translation(tgt_lang)
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try:
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if batch:
return jsonify({"translatedText": [translator.translate(text) for text in q] })
else:
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return jsonify({"translatedText": translator.translate(q) })
except Exception as e:
abort(500, description="Cannot translate text: %s" % str(e))
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@app.route("/detect", methods=['POST'])
def detect():
"""
Detect the language of a single text
---
tags:
- translate
parameters:
- in: formData
name: q
schema:
type: string
example: Hello world!
required: true
description: Text to detect
- in: formData
name: api_key
schema:
type: string
example: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
required: false
description: API key
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responses:
200:
description: Detections
schema:
id: detections
type: array
items:
type: object
properties:
confidence:
type: number
format: float
minimum: 0
maximum: 1
description: Confidence value
example: 0.6
language:
type: string
description: Language code
example: en
400:
description: Invalid request
schema:
id: error-response
type: object
properties:
error:
type: string
description: Error message
500:
description: Detection error
schema:
id: error-response
type: object
properties:
error:
type: string
description: Error message
429:
description: Slow down
schema:
id: error-slow-down
type: object
properties:
error:
type: string
description: Reason for slow down
"""
if request.is_json:
json = get_json_dict(request)
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q = json.get('q')
else:
q = request.values.get("q")
if not q:
abort(400, description="Invalid request: missing q parameter")
candidate_langs = list(filter(lambda l: l.lang in language_map, detect_langs(q)))
candidate_langs.sort(key=lambda l: l.prob, reverse=True)
return jsonify([{
'confidence': l.prob,
'language': l.lang
} for l in candidate_langs])
@app.route("/frontend/settings")
@limiter.exempt
def frontend_settings():
"""
Retrieve frontend specific settings
---
tags:
- frontend
responses:
200:
description: frontend settings
schema:
id: frontend-settings
type: object
properties:
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charLimit:
type: integer
description: Character input limit for this language (-1 indicates no limit)
frontendTimeout:
type: integer
description: Frontend translation timeout
language:
type: object
properties:
source:
type: object
properties:
code:
type: string
description: Language code
name:
type: string
description: Human-readable language name (in English)
target:
type: object
properties:
code:
type: string
description: Language code
name:
type: string
description: Human-readable language name (in English)
"""
return jsonify({'charLimit': args.char_limit,
'frontendTimeout': args.frontend_timeout,
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'language': {
'source': {'code': frontend_argos_language_source.code, 'name': frontend_argos_language_source.name},
'target': {'code': frontend_argos_language_target.code, 'name': frontend_argos_language_target.name}}
})
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swag = swagger(app)
swag['info']['version'] = "1.2"
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swag['info']['title'] = "LibreTranslate"
@app.route("/spec")
@limiter.exempt
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def spec():
return jsonify(swag)
SWAGGER_URL = '/docs' # URL for exposing Swagger UI (without trailing '/')
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API_URL = '/spec'
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# Call factory function to create our blueprint
swaggerui_blueprint = get_swaggerui_blueprint(
SWAGGER_URL,
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API_URL
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)
app.register_blueprint(swaggerui_blueprint)
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return app