Question

我目前正在尝试创建一个客户端服务器应用程序，其中客户端可以使用TCP协议将多个文件发送到服务器。服务器最终将创建一个哈希算法并将其发送回客户端，但是我遇到了从客户端向服务器发送多个文件的问题。按照当前格式，第一个文件可以正确发送，但是遇到错误后将信息合并在一起，因此文件正确发送。 IE的文件大小被列为第二个文件的名称。我是一名JavaScript专家，并且是python的新手，因此非常感谢您提供有关如何实现此目标的解释。我相信线程是答案，但是由于我对python的了解有限，所以我不知道该如何做。目前，我一次只能发送一个文件，并且服务器保持打开状态。但是，我想从当前目录输入几个文件名并进行处理。我最终会将整个客户端转换为C，但是我正在努力使服务器在python中正常工作。任何建议将不胜感激！

Server.py

import socket
import hashlib
import threading
import struct

HOST = '127.0.0.1'
PORT = 2345

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(10)
print("Waiting for a connection.....")

conn, addr = s.accept()
print("Got a connection from ", addr)

while True:

hash_type = conn.recv(1024)
print('hash type: ', hash_type)
if not hash_type:
    break

file_name = conn.recv(1024)
print('file name: ', file_name)

file_size = conn.recv(1024)
file_size = int(file_size, 2)
print('file size: ', file_size )

f = open(file_name, 'wb')
chunk_size = 4096
while file_size > 0:
    if file_size < chunk_size:
        chuk_size = file_size
    data = conn.recv(chunk_size)
f.write(data)

file_size -= len(data)
f.close()
print('File received successfully')
s.close()

Client.py

import socket
import threading
import os

HOST = '127.0.0.1'
PORT = 2345

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))

hash_type = input('Enter hash type: ')

files = input('Enter file(s) to send: ')
files_to_send = files.split()

for file_name in files_to_send:
s.send(hash_type.encode())

print(file_name)
s.send(file_name.encode())

file_size = os.path.getsize(file_name)
file_size = bin(file_size)
print(file_size)
s.send(file_size.encode())

f = open(file_name, 'rb')
l = f.read()
while(l):
    s.send(l)
    l = f.read()
f.close()
print('File Sent')

s.close()

Answer 1

1。 file_size = conn.recv(1024) 在服务器代码中，您读取的1024字节为file_size，file_size只有4或8个字节长

2。 file_name = conn.recv(1024)您的服务器不知道文件名/哈希类型有多长时间。

->将long用作两个大小，并仅从流中读取sizeof（long）个字节。

您可以使用https://docs.python.org/2/library/struct.html打包/编码这些数字

->或者只是简单的方法，并使用https://docs.python.org/3/library/pickle.html进行序列化

Answer 2

处理您正在做的事情的一种方法是缓冲套接字数据。下面是一个类，用于缓冲数据，并且知道如何发送和接收以null终止，UTF-8编码的字符串以及原始字节块：

buffer.py：

class Buffer:
    def __init__(self,s):
        '''Buffer a pre-created socket.
        '''
        self.sock = s
        self.buffer = b''

    def get_bytes(self,n):
        '''Read exactly n bytes from the buffered socket.
           Return remaining buffer if <n bytes remain and socket closes.
        '''
        while len(self.buffer) < n:
            data = self.sock.recv(1024)
            if not data:
                data = self.buffer
                self.buffer = b''
                return data
            self.buffer += data
        # split off the message bytes from the buffer.
        data,self.buffer = self.buffer[:n],self.buffer[n:]
        return data

    def put_bytes(self,data):
        self.sock.sendall(data)

    def get_utf8(self):
        '''Read a null-terminated UTF8 data string and decode it.
           Return an empty string if the socket closes before receiving a null.
        '''
        while b'\x00' not in self.buffer:
            data = self.sock.recv(1024)
            if not data:
                return ''
            self.buffer += data
        # split off the string from the buffer.
        data,_,self.buffer = self.buffer.partition(b'\x00')
        return data.decode()

    def put_utf8(self,s):
        if '\x00' in s:
            raise ValueError('string contains delimiter(null)')
        self.sock.sendall(s.encode() + b'\x00')

使用此类，您的客户端和服务器将变为：

client.py：

import socket
import threading
import os

import buffer

HOST = '127.0.0.1'
PORT = 2345

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))

with s:
    sbuf = buffer.Buffer(s)

    hash_type = input('Enter hash type: ')

    files = input('Enter file(s) to send: ')
    files_to_send = files.split()

    for file_name in files_to_send:
        print(file_name)
        sbuf.put_utf8(hash_type)
        sbuf.put_utf8(file_name)

        file_size = os.path.getsize(file_name)
        sbuf.put_utf8(str(file_size))

        with open(file_name, 'rb') as f:
            sbuf.put_bytes(f.read())
        print('File Sent')

server.py：

import socket
import os

import buffer

HOST = ''
PORT = 2345

# If server and client run in same local directory,
# need a separate place to store the uploads.
try:
    os.mkdir('uploads')
except FileExistsError:
    pass

s = socket.socket()
s.bind((HOST, PORT))
s.listen(10)
print("Waiting for a connection.....")

while True:
    conn, addr = s.accept()
    print("Got a connection from ", addr)
    connbuf = buffer.Buffer(conn)

    while True:
        hash_type = connbuf.get_utf8()
        if not hash_type:
            break
        print('hash type: ', hash_type)

        file_name = connbuf.get_utf8()
        if not file_name:
            break
        file_name = os.path.join('uploads',file_name)
        print('file name: ', file_name)

        file_size = int(connbuf.get_utf8())
        print('file size: ', file_size )

        with open(file_name, 'wb') as f:
            remaining = file_size
            while remaining:
                chunk_size = 4096 if remaining >= 4096 else remaining
                chunk = connbuf.get_bytes(chunk_size)
                if not chunk: break
                f.write(chunk)
                remaining -= len(chunk)
            if remaining:
                print('File incomplete.  Missing',remaining,'bytes.')
            else:
                print('File received successfully.')
    print('Connection closed.')
    conn.close()

演示

客户端：

Enter hash type: abc
Enter file(s) to send: demo1.dat demo2.dat
demo1.dat
File Sent
demo2.dat
File Sent

服务器：

Waiting for a connection.....
Got a connection from  ('127.0.0.1', 22126)
hash type:  abc
file name:  uploads\demo1.dat
file size:  488892
File received successfully.
hash type:  abc
file name:  uploads\demo2.dat
file size:  212992
File received successfully.
Connection closed.

使用套接字发送多个文件Python

2 个答案: