Python通过套接字发送和接收对象

Question

我在网上搜索了很多，但是没有找到通过套接字发送对象并按原样接收的解决方案。我知道它需要酸洗，我已经做过了。将其转换为字节，然后从另一方面接收。但如何将这些字节转换为该类型的对象。

        process_time_data = (current_process_start_time, current_process_end_time)
        prepared_process_data = self.prepare_data_to_send(process_time_data)
        data_string = io.StringIO(prepared_process_data)
        data_string =  pack('>I' ,len(data_string)) + data_string
        self.send_to_server(data_string)            

这是在客户端将对象转换为StringIO并发送到服务器的代码。在服务器端，我得到字节。现在我正在搜索要再次转换为StringIO的字节，以便获得对象值。

在代码中，对象被包装在StringIO中，并通过套接字发送。任何更好的方法都将受到高度赞赏。

服务器端代码如下。

server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
#server.setblocking(0)
server.bind(('127.0.0.1',50000))
server.listen(5)
inputs = [server]
outputs = []
message_queues = {}

while inputs:
    readable, writeable, exceptional = select.select(inputs, outputs, inputs)
    for s in readable:
        if s is server:
            connection, client_address = s.accept()
            print(client_address)
            connection.setblocking(0)
            inputs.append(connection)
            message_queues[connection] = queue.Queue()
            print('server started...')
        else:
            print('Getting data step 1')
            raw_msglen = s.recv(4)
            msglen = unpack('>I',raw_msglen)[0]
            final_data = b''
            while len(final_data) < msglen:
                data = s.recv(msglen - len(final_data))
                if data:
                    #print(data)
                    final_data += data
                    message_queues[s].put(data)
                    if s not in outputs:
                        outputs.append(s)
                    else:
                        if s in outputs:
                            outputs.remove(s)
                else:
                    break
            inputs.remove(connection)
#            s.close()
            del message_queues[s]

            process_data = ProcessData()
            process_screen = ProcessScreen()

            if final_data is not None:
                try:
                    deserialized_data = final_data.decode("utf-8")
                    print(deserialized_data)
                except (EOFError):
                    break
            else:
                print('final data is empty.')

            print(process_data.project_id)
            print(process_data.start_time)
            print(process_data.end_time)
            print(process_data.process_id)

两个助手函数如下

def receive_all(server, message_length, message_queues, inputs, outputs):
    # Helper function to recv message_length bytes or return None if EOF is hit
    data = b''
    while len(data) < message_length:
        packet = server.recv(message_length - len(data))
        if not packet:
            return None
        data += packet
        message_queues[server].put(data)
        if server not in outputs:
            outputs.append(server)
        else:
            if server in outputs:
                outputs.remove(server)
    inputs.remove(server)
    del message_queues[server]
    return data


def receive_message(server, message_queues, inputs, outputs):
    # Read message length and unpack it into an integer
    raw_msglen = receive_all(server, 4, message_queues, inputs, outputs)
    if not raw_msglen:
        return None
    message_length = unpack('>I', raw_msglen)[0]

    return receive_all(server, message_length, message_queues, inputs, outputs)

其中两个模型类如下所示

class ProcessData:
    process_id = 0
    project_id = 0
    task_id = 0
    start_time = 0
    end_time = 0
    user_id = 0
    weekend_id = 0

# Model class to send image data to the server
class ProcessScreen:
    process_id = 0
    image_data = bytearray()

Answer 1

Pickle对于网络通信并不特别安全，因为它可以用来注入可执行代码。我建议您试试json。

伪代码：

import json
to_send  = json.dumps(object)
s.sendall (to_send)

Answer 2

一个选项是使用JSON序列化。但是Python对象是不可序列化的，因此您必须首先使用函数vars（首选）或内置的\udict\udict将类对象映射到Dict。

改编Sudheesh Singanamalla的答案，并基于此答案：

import socket, json

class ProcessData:
    process_id = 0
    project_id = 0
    task_id = 0
    start_time = 0
    end_time = 0
    user_id = 0
    weekend_id = 0


HOST = 'localhost'
PORT = 50007
# Create a socket connection.
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))

# Create an instance of ProcessData() to send to server.
variable = ProcessData()

# Map your object into dict 
data_as_dict = vars(variable)

# Serialize your dict object
data_string = json.dumps(data_as_dict)

# Send this encoded object
s.send(data_string.encode(encoding="utf-8"))

s.close()
print 'Data Sent to Server'

import socket, json

class ProcessData:
    process_id = 0
    project_id = 0
    task_id = 0
    start_time = 0
    end_time = 0
    user_id = 0
    weekend_id = 0


HOST = 'localhost'
PORT = 50007
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(1)
conn, addr = s.accept()
print 'Connected by', addr

data_encoded = conn.recv(4096)
data_string = data_encoded.decode(encoding="utf-8")

data_variable = json.loads(data_string)
# data_variable is a dict representing your sent object

conn.close()
print 'Data received from client'

重要的一点是，对象实例的dict映射不映射类变量，只映射实例变量。有关更多信息，请参阅此anwser。例子：

class ProcessData:
    # class variables
    process_id = 0 
    project_id = 1

    def __init__(self):
        # instance variables
        self.task_id = 2
        self.start_time = 3

obj = ProcessData()
dict_obj = vars(obj)

print(dict_obj)
# outputs: {'task_id': 2, 'start_time': 3}

# To access class variables:
dict_class_variables = vars(ProcessData)

print(dict_class_variables['process_id'])
# outputs: 0

Answer 3

这里要查找的是pickle和加载和转储操作。套接字基本上是字节流。让我们考虑一下你的情况。

class ProcessData:
    process_id = 0
    project_id = 0
    task_id = 0
    start_time = 0
    end_time = 0
    user_id = 0
    weekend_id = 0

需要通过执行data\u string=pickle将此类的实例pickle到数据字符串中。转储（ProcessData（））并通过执行data\u variable=pickle取消勾选。加载（数据）其中数据是接收的内容。

因此，让我们考虑这样一种情况：客户端创建了ProcessData的对象并将其发送到服务器。这是客户的样子。这里有一个最小的例子。

import socket, pickle

class ProcessData:
    process_id = 0
    project_id = 0
    task_id = 0
    start_time = 0
    end_time = 0
    user_id = 0
    weekend_id = 0


HOST = 'localhost'
PORT = 50007
# Create a socket connection.
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))

# Create an instance of ProcessData() to send to server.
variable = ProcessData()
# Pickle the object and send it to the server
data_string = pickle.dumps(variable)
s.send(data_string)

s.close()
print 'Data Sent to Server'

现在，您接收此数据的服务器如下所示

import socket, pickle

class ProcessData:
    process_id = 0
    project_id = 0
    task_id = 0
    start_time = 0
    end_time = 0
    user_id = 0
    weekend_id = 0


HOST = 'localhost'
PORT = 50007
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(1)
conn, addr = s.accept()
print 'Connected by', addr

data = conn.recv(4096)
data_variable = pickle.loads(data)
conn.close()
print data_variable
# Access the information by doing data_variable.process_id or data_variable.task_id etc..,
print 'Data received from client'

运行服务器首先在端口上创建一个绑定，然后运行客户端通过套接字进行数据搬迁。你也可以看看这个答案