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PaddleSpeech/paddlespeech/server/ws/asr_api.py

135 lines
5.9 KiB

# Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import json
from fastapi import APIRouter
from fastapi import WebSocket
from fastapi import WebSocketDisconnect
from starlette.websockets import WebSocketState as WebSocketState
from paddlespeech.cli.log import logger
from paddlespeech.server.engine.engine_pool import get_engine_pool
router = APIRouter()
@router.websocket('/paddlespeech/asr/streaming')
async def websocket_endpoint(websocket: WebSocket):
"""PaddleSpeech Online ASR Server api
Args:
websocket (WebSocket): the websocket instance
"""
#1. the interface wait to accept the websocket protocal header
# and only we receive the header, it establish the connection with specific thread
await websocket.accept()
#2. if we accept the websocket headers, we will get the online asr engine instance
engine_pool = get_engine_pool()
asr_model = engine_pool['asr']
#3. each websocket connection, we will create an PaddleASRConnectionHanddler to process such audio
# and each connection has its own connection instance to process the request
# and only if client send the start signal, we create the PaddleASRConnectionHanddler instance
connection_handler = None
try:
#4. we do a loop to process the audio package by package according the protocal
# and only if the client send finished signal, we will break the loop
while True:
# careful here, changed the source code from starlette.websockets
# 4.1 we wait for the client signal for the specific action
assert websocket.application_state == WebSocketState.CONNECTED
message = await websocket.receive()
websocket._raise_on_disconnect(message)
#4.2 text for the action command and bytes for pcm data
if "text" in message:
# we first parse the specific command
message = json.loads(message["text"])
if 'signal' not in message:
resp = {"status": "ok", "message": "no valid json data"}
await websocket.send_json(resp)
# start command, we create the PaddleASRConnectionHanddler instance to process the audio data
# end command, we process the all the last audio pcm and return the final result
# and we break the loop
if message['signal'] == 'start':
resp = {"status": "ok", "signal": "server_ready"}
# do something at beginning here
# create the instance to process the audio
#connection_handler = PaddleASRConnectionHanddler(asr_model)
connection_handler = asr_model.new_handler()
await websocket.send_json(resp)
elif message['signal'] == 'end':
# reset single engine for an new connection
# and we will destroy the connection
connection_handler.decode(is_finished=True)
connection_handler.rescoring()
asr_results = connection_handler.get_result()
word_time_stamp = connection_handler.get_word_time_stamp()
connection_handler.reset()
resp = {
"status": "ok",
"signal": "finished",
'result': asr_results,
'times': word_time_stamp
}
await websocket.send_json(resp)
break
else:
resp = {"status": "ok", "message": "no valid json data"}
await websocket.send_json(resp)
elif "bytes" in message:
# bytes for the pcm data
message = message["bytes"]
# we extract the remained audio pcm
# and decode for the result in this package data
connection_handler.extract_feat(message)
connection_handler.decode(is_finished=False)
if connection_handler.endpoint_state:
logger.info("endpoint: detected and rescoring.")
connection_handler.rescoring()
word_time_stamp = connection_handler.get_word_time_stamp()
asr_results = connection_handler.get_result()
if connection_handler.endpoint_state:
if connection_handler.continuous_decoding:
logger.info("endpoint: continue decoding")
connection_handler.reset_continuous_decoding()
else:
logger.info("endpoint: exit decoding")
# ending by endpoint
resp = {
"status": "ok",
"signal": "finished",
'result': asr_results,
'times': word_time_stamp
}
await websocket.send_json(resp)
break
# return the current partial result
# if the engine create the vad instance, this connection will have many partial results
resp = {'result': asr_results}
await websocket.send_json(resp)
except WebSocketDisconnect as e:
logger.error(e)