在Python中通過sockets收發對象

Question

我在 Inte.net 上搜索了很多，但一直無法找到通過套接字發送 object 並按原樣接收的解決方案。 我知道它需要我已經做過的酸洗。 然后將其轉換為字節並在另一方面接收。 但是如何將這些字節轉換為 object 的類型呢？

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)

這是在客戶端將 object 轉換為 StringIO 並發送到服務器的代碼。 在服務器端，我正在獲取字節。 現在我正在搜索要再次轉換為 StringIO 的字節，以便我可以獲得 object 值。

在代碼中，Object 包裝在 StringIO 中並通過套接字發送。 有更好的方法嗎？

服務器端代碼如下。

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)

兩個輔助函數如下：

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)

而model類中的兩個類如下：

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

您在這里尋找的是pickle以及loads和dumps操作。 套接字基本上是字節流。 讓我們考慮一下您的情況。

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

此類的一個實例需要通過執行data_string = pickle.dumps(ProcessData())來腌制為數據字符串，並通過執行data_variable = pickle.loads(data)來data_variable = pickle.loads(data) ，其中data是接收到的內容。

因此，讓我們考慮一個客戶端創建ProcessData對象並將其發送到服務器的情況。 這是客戶端的樣子。 這是一個最小的例子。

客戶

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'

現在您接收此數據的服務器如下所示

服務器

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'

運行服務器首先在端口上創建一個bind ，然后運行client通過套接字進行數據傳輸。 你也可以看看這個答案

Answer 2

Pickle 對於網絡通信並不是特別安全，因為它可用於注入可執行代碼。 我建議你試試 json 。

偽代碼：

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

Answer 3

一種選擇是使用 JSON 序列化。 但是 Python 對象不可序列化，因此您必須首先使用函數vars （首選）或內置__dict__將類對象映射到Dict 。

改編來自Sudheesh Singanamalla的答案並基於此答案：

客戶

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'

服務器

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'

警告

重要的一點是對象實例的字典映射不映射class variable ，只映射instance variable 。 有關更多信息，請參閱此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 4

無恥地插在這里，但我和一個朋友最近發布了tlspyo ，這是一個開源庫，其目的是幫助您輕松安全地通過網絡傳輸 python 個對象。

通過 Inte.net sockets 傳輸 pickled 對象而不使用 tlspyo 之類的東西基本上是為黑客敞開的大門，所以不要這樣做。

使用 tlspyo，您的代碼如下所示：

服務器：

from tlspyo import Relay

if __name__ == "__main__":
    my_server = Relay(port=3000,password="<same strong password>")

    # (...)

客戶 1：

from tlspyo import Endpoint

if __name__ == "__main__":
    client_1 = Endpoint(
        ip_server='<ip of your server>'
        port=3000,
        password="<same strong password>",
        groups="client 1")

    # send an object to client 2:
    my_object = "my object"  # doesn't have to be a string, of course
    client_1.broadcast(my_object, "client 2")

    # (...)

客戶 2：

from tlspyo import Endpoint

if __name__ == "__main__":
    client_2 = Endpoint(
        ip_server='<ip of my Relay>'
        port=3000,
        password="<same strong password>",
        groups="client 2")

    # receive the object sent by client 1:
    my_object = client_2.receive_all(blocking=True)[0]


    # (...)

（您需要設置 TLS 才能使此代碼正常工作，請查看文檔- 或者您可以使用 security=None 禁用 TLS，但如果您通過 Inte.net 進行傳輸，則不想這樣做。）