socket.io python big file Transmission problem. help me,please.

• Z时代
• 2024-02-12
• 分类：IT

问题描述

我使用socket.io向客户端发送文件数据,启动一个发送线程后,emit()对应的接收事件只会接收一次，但发送还是正常的。
I send big file data to the client using socket.io, and response(event named "file_content" ) of emit() only once after in a send thread that I defined it myself .

相关代码 The relevant code

@sio.on("file_content")
def send_fileContent(sid, temp):
    #我将sio和session都传给新的线程
    #I passed the variables sio and session to the new thread
    threading.Thread(
        target=send_fileContent_thread, args=(sio, handle_dir, session,)).start() 

线程的Run方法
The Run method of a thread

def send_fileContent_thread(sio_re, handle_dir, session):
    """
    发送文件内容的线程
    """
    with open(handle_dir, "r", encoding='utf-8') as f:
        # if the code is  `for i in range(10):`it has the same result.
        # 如果for i in range(10):也是只接收一次，发送都没问提
        while True:
            line = f.read(10)
            print(line)
            if not line:
                break
            sio_re.emit('file_content', line)
            print("test 发送了数据")
            time.sleep(3)

但这样客户端file_content事件只接收到了一次.
However, the client event named file_content is only received once.
但以下这样就可以接收到多次
But the following can be received multiple times

def send_fileContent_thread(sio_re, handle_dir, session):
    """
    发送文件内容的线程
    The thread that sends the contents of the file
    """
    for i in range(10):
        sio_re.emit('file_content', i)

客户端代码如下:
The client code is as follows:
q是一个队列，q = queue.Queue(),用于缓存数据
q is a queue, q = queue.queue (), used to cache data

@sio.on('file_content')
def file_content(data):
    """
    接收文件内容
    Receive file contents
    """
    print("test", data)
    q.put(data)

这是我本地运行的结果
This is the result of my local computer

回答：

我补了解socket.io，但从你的代码看来，问题很可能出在time.sleep上
参照下sio的文档：https://python-socketio.readt...
不知道你是不是用background方式跑起来的，也许你该试试sio.sleep

回答：

is there anyone help me?

找到原因了。

原因是因为底层的eventlet是使用的协程

协程即这里的greenthread。
而我如果使用time.sleep()相当于休息整个python thread。
比如我greenthread1向客户端发送data1(但还未完全发送),我此时调用time.sleep(),整个python thread进入休息。休息完成后greenthread2开始发送data2(但还未完全发送)，又休息，直到time.sleep()运行完后，所有greenthread进行后半部分的发送。
如下代码：

Server.py

import eventlet
import time
sockets = {}
client_f = ""
def handle():
    while True:
        if not client_f:
            continue
        for i in range(10):
            sockets[client_f].send(bytes(str(i), encoding='utf-8'))
server = eventlet.listen(('127.0.0.1', 9999))
pool = eventlet.GreenPool()
while True:
    try:
        client_sock, client_addr = server.accept()
        sockets[client_addr] = client_sock
        client_f = client_addr
        print("accepted", client_addr)
        pool.spawn_n(handle)
        for i in range(3):
            #这种休眠方式会一直阻塞整个pythonthread,从而什么也发不出去
            time.sleep(2)
            #这种瞬间就发出去了。
            # eventlet.sleep(2)
            print(time.strftime('%H: %M: %S',
                                time.localtime(time.time())), "I'm sleeping")
    except (SystemExit, KeyboardInterrupt):
        break

Client.py

import eventlet
import time
socket = eventlet.connect(('127.0.0.1', 9999))
for i in range(5):
    t = socket.recv(1000).decode()
    if t:
        print(time.strftime('%H: %M: %S',
                            time.localtime(time.time())), t)

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