使用Python的套接字编程发送图像

Question

我正在尝试用Python的socket编程发送一个图片文件。我可以发送文本文件，但我一直在尝试发送图片文件。我是这样做的：先打开图片文件，把它的内容读成一个字符串，然后把这个字符串发送出去，客户端再接收这个字符串，然后把它写入一个不同目录下同名的文件。但是我发现我无法打开这个文件。此外，我在下面贴出了我的代码，注释部分表示我已经尝试过的做法。我还遇到了一些问题，就是在发送整数size时，另一边收到的是一些随机字符串。

这是服务器端的脚本

import socket
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.bind(("", 5000))
server_socket.listen(5)
import os


client_socket, address = server_socket.accept()
print "Conencted to - ",address,"\n"
while (1):
    choice = client_socket.recv(1024)
    choice = int(choice)
    if(choice == 1):
        data = client_socket.recv(1024)
        print "The following data was received - ",data
        print "Opening file - ",data
        fp = open(data,'r')
        strng = fp.read()
        size = os.path.getsize(data)
        size = str(size)
        client_socket.send(size)
        client_socket.send (strng)
        #client_socket.close()

    if (choice == 2):
        data = client_socket.recv(1024)
        print "The following data was received - ",data
        print "Opening file - ",data
        fp = open(data,'r')
        strng = fp.read()
        #strng = str(fp)
        size = os.path.getsize(data)
        print size
        size = str(size)
        print size
        client_socket.send(size)
        client_socket.send (strng)
        #client_socket.close()

这是客户端的脚本 -

#!/usr/bin/python
# TCP client example
import socket,os
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client_socket.connect(("", 5000))
k = ' '
size = 1024

while(1):
    print "Do you want to transfer a \n1.Text File\n2.Image\n3.Video\n"
    k = raw_input()
    client_socket.send(k)
    k = int (k)
    if(k == 1):
        print "Enter file name\n"
        strng = raw_input()
        client_socket.send(strng)
        size = client_socket.recv(1024)
        size = int(size)
        print "The file size is - ",size," bytes"
        size = size*2
        strng = client_socket.recv(size)
        print "\nThe contents of that file - "
        print strng

    if (k==2):
        print "Enter file name of the image with extentsion (example: filename.jpg,filename.png) - "
        fname = raw_input()
        client_socket.send(fname)
        size = client_socket.recv(1)
        print size
        #size = int(size)
        print "The file size is - ",size
        size = size*2
        strng = client_socket.recv(256456)
        print "\nThe file will be saved and opened- "
        fname = 'downloads/'+fname
        nf = open(fname,'w')
        nf.write(strng)
        nf.close()
        fname = 'viewnior '+ fname
        print fname
        os.system(fname)

我在Crunchbang Linux上编程，这是一个基于Debian的非官方发行版，viewnior是我用来查看图片的工具。

Answer 1

我在自己的系统上（Ubuntu 11.10）运行了相同的代码，发现发送大小作为字符串时出现了问题。当我添加了处理这部分的逻辑后，程序就顺利运行了。我也能打开文件了。以下是我解决你问题的方法：

第一个改动是在客户端代码（client.py）中，处理接收大小和发送确认的部分：

size = ' '
while(1):
   tmpsize = client_socket.recv(1)
   if tmpsize.isdigit() == True:
      print "Here : ",tmpsize
      size += tmpsize
   else:
      break

client_socket.send("received")

第二个改动是在服务器端代码（server.py）中，处理接收确认的部分：

client_socket.send(size)
ack = client_socket.recv(1024)
if ack == "received":
   client_socket.send (strng)

希望这能帮助你解决问题。

Answer 2

谢谢你，Sanket。:D 我之前在发送大量数据时遇到了问题，所以我把数据分成了512字节的小块，现在即使是视频也能完美发送了。:D 现在只需要添加一个pygtk界面，用来确认接收和发送文件就好了。:D

#!/usr/bin/python
# TCP client example
import socket,os
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client_socket.connect(("", 5005))
k = ' '
size = 1024

while(1):
    print "Do you want to transfer a \n1.Text File\n2.Image\n3.Video\n"
    k = raw_input()
    client_socket.send(k)
    k = int (k)
    if(k == 1):
        print "Enter file name\n"
        strng = raw_input()
        client_socket.send(strng)
        size = client_socket.recv(1024)
        size = int(size)
        print "The file size is - ",size," bytes"
        size = size*2
        strng = client_socket.recv(size)
        print "\nThe contents of that file - "
        print strng

    if (k==2 or k==3):
        print "Enter file name of the image with extentsion (example: filename.jpg,filename.png or if a video file then filename.mpg etc) - "
        fname = raw_input()
        client_socket.send(fname)
        fname = 'documents/'+fname
        fp = open(fname,'w')
        while True:
            strng = client_socket.recv(512)
            if not strng:
                break
            fp.write(strng)
        fp.close()
        print "Data Received successfully"
        exit()
        #data = 'viewnior '+fname
        #os.system(data)

这是服务器的代码

import socket
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.bind(("", 5005))
server_socket.listen(5)
import os


client_socket, address = server_socket.accept()
print "Conencted to - ",address,"\n"
while (1):
    choice = client_socket.recv(1024)
    choice = int(choice)
    if(choice == 1):
        data = client_socket.recv(1024)
        print "The following data was received - ",data
        print "Opening file - ",data
        fp = open(data,'r')
        strng = fp.read()
        size = os.path.getsize(data)
        size = str(size)
        client_socket.send(size)
        client_socket.send (strng)
        #client_socket.close()

    if (choice == 2 or choice == 3):
        data = client_socket.recv(1024)
        print "The following data was received - ",data
        print "Opening file - ",data
        img = open(data,'r')
        while True:
            strng = img.readline(512)
            if not strng:
                break
            client_socket.send(strng)
        img.close()
        print "Data sent successfully"
        exit()
        #data = 'viewnior '+data
        #os.system(data)