Python code to implement client-side and server-side image transmission

The content of this article is about the code for python to realize client and server-side image transmission. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

Problem: Use windows as the client and linux as the server to transfer the graph

Program:

'''
Fuction：客户端发送图片和数据
Date：2018.9.8
Author：snowking
'''
###客户端client.py
import socket
import os
import sys
import struct

def sock_client_image():
    while True:
        try:
            s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            s.connect(('服务器的ip', 6666))  #服务器和客户端在不同的系统或不同的主机下时使用的ip和端口，首先要查看服务器所在的系统网卡的ip
            # s.connect(('127.0.0.1', 6666))  #服务器和客户端都在一个系统下时使用的ip和端口
        except socket.error as msg:
            print(msg)
            print(sys.exit(1))
        filepath = input('input the file: ')   #输入当前目录下的图片名 xxx.jpg
        fhead = struct.pack(b'128sq', bytes(os.path.basename(filepath), encoding='utf-8'), os.stat(filepath).st_size)  #将xxx.jpg以128sq的格式打包
        s.send(fhead)

        fp = open(filepath, 'rb')  #打开要传输的图片
        while True:
            data = fp.read(1024) #读入图片数据
            if not data:
                print('{0} send over...'.format(filepath))
                break
            s.send(data)  #以二进制格式发送图片数据
        s.close()
        # break    #循环发送
   
if __name__ == '__main__':
    sock_client_image()

---

###服务器端server.py
import socket
import os
import sys
import struct

def socket_service_image():
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        # s.bind(('127.0.0.1', 6666))
        s.bind(('服务器的ip', 6666))
        s.listen(10)
    except socket.error as msg:
        print(msg)
        sys.exit(1)

    print("Wait for Connection.....................")

    while True:
        sock, addr = s.accept()  #addr是一个元组(ip,port)
        deal_image(sock, addr)
def deal_image(sock, addr):
    print("Accept connection from {0}".format(addr))  #查看发送端的ip和端口

    while True:
        fileinfo_size = struct.calcsize('128sq')
        buf = sock.recv(fileinfo_size)   #接收图片名
        if buf:
            filename, filesize = struct.unpack('128sq', buf)
            fn = filename.decode().strip('\x00')
            new_filename = os.path.join('./', 'new_' + fn)  #在服务器端新建图片名（可以不用新建的，直接用原来的也行，只要客户端和服务器不是同一个系统或接收到的图片和原图片不在一个文件夹下）

            recvd_size = 0
            fp = open(new_filename, 'wb')

            while not recvd_size == filesize:
                if filesize - recvd_size > 1024:
                    data = sock.recv(1024)
                    recvd_size += len(data)
                else:
                    data = sock.recv(1024)
                    recvd_size = filesize
                fp.write(data)  #写入图片数据
            fp.close()
        sock.close()
        break
        
if __name__ == '__main__':
    socket_service_image()

---

Running results:
Server side:

Client side:

Additional instructions:
1. First run server.py (python server.py) under the linux system, then run client.py under the windows python terminal, and enter the name of the image to be transferred in the current directory in the terminal, which is heat .jpg, you can see that the new_heat.jpg image file appears in the server path, proving that the file transfer is successful.
2. At first, various errors occurred when referring to the code on the Internet. During debugging, the received image data kept being lost and the image could not be opened. After understanding the compression format of struct.pack, I found that the reason was The problem with parameter setting was originally 128sl, where l is a long integer. If it exceeds the range, the received picture data will be lost. Therefore, after changing to q, the range becomes larger and pictures can be received normally. The following figure is the compression format and data range correspondence table of struct.pack:

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