python通过TCP套接字发送/接收十六进制数据 [英] python send/receive hex data via TCP socket

问题描述

我有一个以太网访问控制设备，据说可以通过TCP进行通信。


我如何通过输入十六进制数据来发送补丁，因为这是我从其手册中获得的信息（发送和接收的通信数据包的标准格式）在每个命令之后）

您能否显示一些示例代码或链接以开始使用...。

I have a ethenet access control device that is said to be able to communicate via TCP.
How can i send a pachet by entering the HEX data, since this is what i have from their manual (a standard format for the communication packets sent and received after each command)
Can you please show some example code or links to get started....

standard return packet from the terminal
                               Size (bytes) 
BS (0x08) : ASCII Character         1
STX (0x02) : ASCII Character        1 
LENGTH : length from BS to ETX      4 
TID : system unique I.D.            1 
RESULT                              1 
DATA : returned parameter           N 
CHECKSUM : byte sum from BS to DATA 1 
ETX (0x03) : ASCII Character        1 

Standard command packet to the terminal  
                               Size (bytes) 
ACK (0x06) : ASCII Character         1 
STX (0x02) : ASCII Character         1 
LENGTH : length from ACK to ETX      4 
TID : system unique I.D. (ex: 1)     1 
COMMAND                              1 
Access Key(Optional)                 6 
DATA : command parameter             N 
CHECKSUM : byte sum from ACK to DATA 1 
ETX (0x03) : ASCII Character         1 

This packet starts from ACK. 
In this packet, multiple byte value must be started from MSB. 
For example, if length was 10, LENGTH is 0x00 0x00 0x00 0x0a. 

推荐答案

我会使用 struct.pack 即可从要发送的数据中准备要发送的字节字符串。请确保以> 开头打包格式，以表示您想要大端顺序和标准尺寸，因为它们清楚地记录了这些内容！

I'd use struct.pack to prepare the string of bytes to send, from the data you want to send. Be sure to start the packing format with > to mean you want big-endian ordering and standard sizes, since they document that so clearly!

所以（我不知道访问密钥的可选是什么意思，如果没有访问密钥，我认为这意味着该字段可以是全零字节），如果数据已经是一个字节字符串，命令是一个小的无符号整数，例如...：

So (I don't know what the "optional" means for the access key, I'll assume it means that the field can be all-zero bytes if you have no access key), if "data" is already a string of bytes and "command" a small unsigned integer for example, something like...:

def stringfor(command, data, accesskey='\0'*6, tid=1):
  length = 16 + len(data)
  prefix = struct.pack('>BBIBB6s', 6, 2, length, tid, command, accesskey)
  checksum = sum(ord(c) for c in prefix) &0xFF
  return prefix + chr(checksum) + chr(3)

这篇关于python通过TCP套接字发送/接收十六进制数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！