将多个文件从一台主机传输到另一台主机

解决问题的简单方法是为每个文件创建一个新连接。下面的代码就是这样做的。

发件人

from __future__ import print_function
import socket

HOST = 'localhost'
PORT = 12345
BUFSIZE = 4096

def send_file(fname):
    with open(fname, 'rb') as f:
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        try:
            sock.connect((HOST, PORT))
        except socket.error as err:
            print(err, HOST, PORT)
            sock.close()
            return

        while True:
            data = f.read(BUFSIZE)
            if not data:
                break
            while data:
                sent = sock.send(data)
                data = data[sent:]

    sock.close()

fnames = [
    'test0.jpg',
    'test1.jpg',
    'test2.jpg',
    'test3.jpg',
]

def main():
    for fname in fnames:
        send_file(fname)

if __name__ == '__main__':
    main()

接收者

from __future__ import print_function
import socket

HOST = 'localhost'
PORT = 12345
BUFSIZE = 4096

class Receiver:
    ''' Buffer binary data from socket conn '''
    def __init__(self, conn):
        self.conn = conn
        self.buff = bytearray()

    def get(self, size):
        ''' Get size bytes from the buffer, reading
            from conn when necessary 
        '''
        while len(self.buff) < size:
            data = self.conn.recv(BUFSIZE)
            if not data:
                break
            self.buff.extend(data)
        # Extract the desired bytes
        result = self.buff[:size]
        # and remove them from the buffer
        del self.buff[:size]
        return bytes(result)

    def save(self, fname):
        ''' Save the remaining bytes to file fname '''
        with open(fname, 'wb') as f:
            if self.buff:
                f.write(bytes(self.buff))
            while True:
                data = self.conn.recv(BUFSIZE)
                if not data:
                    break
                f.write(data)

def main():
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    try:
        sock.bind((HOST, PORT))
    except socket.error as err:
        print('Bind failed', err)
        return

    sock.listen(1)
    print('Socket now listening at', HOST, PORT)
    file_number = 0
    try:
        while True:
            conn, addr = sock.accept()
            print('Connected with', *addr)

            fname = 'image%d.jpg' % file_number
            with open(fname, 'wb') as f:
                while True:
                    data = conn.recv(BUFSIZE)
                    if not data:
                        break
                    f.write(data)
            conn.close()
            print(fname, 'saved\n')
            file_number += 1

    # Hit Break / Ctrl-C to exit
    except KeyboardInterrupt:
        print('\nClosing')

    sock.close()

if __name__ == '__main__':
    main()

您需要点击CtrlC或Break（取决于您的操作系统）退出接收器。

但是在接收器上使用这些数字文件名并不是很令人满意，所以我决定让它更复杂一些。:) 在以下版本中，我们在文件数据之前发送文件名。这有点棘手，因为接收器需要将文件名与实际文件数据分开。如果每个socket.recv调用对应一个socket.send调用，这很容易，但不能保证一定会发生：接收的字节可能与发送的方式不同。接收器需要缓冲字节，以便正确分解它们。有关详细信息，请参阅套接字编程 HOWTO。

为了让接收者知道文件名的结尾，我们首先发送一个对文件名长度进行编码的字节。一个字节可以容纳 0 到 255 之间的数字，因此此代码无法处理超过此长度的文件名。在长度字节之后，我们发送使用 UTF-8 编码的文件名本身。然后我们发送实际的文件内容。

接收器使用名为 Receiver 的类来处理缓冲。这个类有一个.get方法，我们可以用它来获取指定数量的字节。我们使用该方法来获取文件名长度和文件名。然后我们使用Receiver的.save方法将接收到的文件内容保存到一个新文件中。

这段代码有点乱，因为它旨在以任意组合在 Python 2 和 Python 3 上运行。如果仅用于 Python 3，它会更整洁一些。我将“localhost”硬编码为主机名，因为我只有一台计算机，所以我无法通过网络对其进行测试，但我相信它可以在网络上正常工作。

这是发件人：

from __future__ import print_function
import socket
from struct import pack

HOST = 'localhost'
PORT = 12345
BUFSIZE = 4096

def send(sock, data):
    while data:
        sent = sock.send(data)
        data = data[sent:]

def send_file(fname):
    with open(fname, 'rb') as f:
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        try:
            sock.connect((HOST, PORT))
        except socket.error as err:
            print(err, HOST, PORT)
            sock.close()
            return

        # Send the file name length & the filename itself in one packet          
        send(sock, pack('B', len(fname)) + fname.encode())
        while True:
            data = f.read(BUFSIZE)
            if not data:
                break
            send(sock, data)

    sock.close()

fnames = [
    'test1.gif',
    'test2.jpg',
    'test3.png',
    'test4.pdf',
]

def main():
    for fname in fnames:
        send_file(fname)

if __name__ == '__main__':
    main()

这是接收器：

from __future__ import print_function
import socket
from struct import unpack

HOST = 'localhost'
PORT = 12345
BUFSIZE = 4096

class Receiver:
    ''' Buffer binary data from socket conn '''
    def __init__(self, conn):
        self.conn = conn
        self.buff = bytearray()

    def get(self, size):
        ''' Get size bytes from the buffer, reading
            from conn when necessary 
        '''
        while len(self.buff) < size:
            data = self.conn.recv(BUFSIZE)
            if not data:
                break
            self.buff.extend(data)
        # Extract the desired bytes
        result = self.buff[:size]
        # and remove them from the buffer
        del self.buff[:size]
        return bytes(result)

    def save(self, fname):
        ''' Save the remaining bytes to file fname '''
        with open(fname, 'wb') as f:
            if self.buff:
                f.write(bytes(self.buff))
            while True:
                data = self.conn.recv(BUFSIZE)
                if not data:
                    break
                f.write(data)

def main():
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    try:
        sock.bind((HOST, PORT))
    except socket.error as err:
        print('Bind failed', err)
        return

    sock.listen(1)
    print('Socket now listening at', HOST, PORT)
    try:
        while True:
            conn, addr = sock.accept()
            print('Connected with', *addr)
            # Create a buffer for this connection
            receiver = Receiver(conn)
            # Get the length of the file name
            name_size = unpack('B', receiver.get(1))[0] 
            # Get the file name itself
            name = receiver.get(name_size).decode()
            print('name', name)
            # Save the file
            receiver.save(name)
            conn.close()
            print('saved\n')
    # Hit Break / Ctrl-C to exit
    except KeyboardInterrupt:
        print('\nClosing')

    sock.close()

if __name__ == '__main__':
    main()