Python错误:"socket.error:[Errno 11]资源暂时不可用"发送图像时 [英] Python error: "socket.error: [Errno 11] Resource temporarily unavailable" when sending image

问题描述

我想制作一个程序，用于从文件访问图像，对图像进行编码，然后将其发送到服务器. 比服务器应该对图像进行解码，然后将其保存到文件中. 我测试了图像编码本身，并且可以正常工作，所以问题出在服务器和客户端连接上.

I want to make a program that accesses images from files, encodes them, and sends them to an server. Than the server is supposed to decode the image, and save it to file. I tested the image encoding itself, and it worked, so the problem lies in the server and client connection.

这是服务器:

import socket
import errno
import base64

from PIL import Image
import StringIO

def connect(c):
    try:
        image = c.recv(8192)
        return image
    except IOError as e:
        if e.errno == errno.EWOULDBLOCK:
            connect(c)


def Main():
    host = '138.106.180.21'
    port = 12345

    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM, socket.IPPROTO_TCP)
    s.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
    s.bind((host, port))
    s.listen(1)


    while True:

        c, addr = s.accept()
        c.setblocking(0)

        print "Connection from: " + str(addr)

        image = c.recv(8192)#connect(c)

        imgname = 'test.png'

        fh = open(imgname, "wb")
        if image == 'cusdom_image':
            with open('images.png', "rb") as imageFile:
                image = ''
                image = base64.b64encode(imageFile.read())
                print image
        fh.write(image.decode('base64'))
        fh.close()


if __name__ == '__main__':
    Main()

这是客户:

import socket
import base64

from PIL import Image
import StringIO
import os, sys

ip = '138.106.180.21'
port = 12345
print 'Add event executed'
s = socket.socket()
s.connect((ip, port))

image_path = '/home/gilgamesch/Bilder/Bildschirmfoto.png'

print os.getcwd()
olddir = os.getcwd()
os.chdir('/')
print os.getcwd()

if image_path != '':
    with open(image_path, "rb") as imageFile:
        image_data = base64.b64encode(imageFile.read())
        print 'open worked'
else:
    image_data = 'cusdom_image'

os.chdir(olddir)

s.send(image_data)


s.close()

错误消息是:

Traceback (most recent call last):
  File "imgserv.py", line 49, in <module>
    Main()
  File "imgserv.py", line 34, in Main
    image = c.recv(8192)#connect(c)
socket.error: [Errno 11] Resource temporarily unavailable

推荐答案

在服务器中，您正在将远程套接字(由accept()返回的套接字)设置为非阻塞模式，这意味着该套接字上的I/O将如果没有要读取的数据，则异常立即终止.

In the server you are setting the remote socket (that returned by accept()) to non-blocking mode, which means that I/O on that socket will terminate immediately by an exception if there is no data to read.

与服务器建立连接与客户端发送图像数据之间通常会有一段时间.一旦连接被接受，服务器就会尝试立即从客户端读取数据，但是，可能尚无任何数据可以读取，因此c.recv()会引发socket.error: [Errno 11] Resource temporarily unavailable异常. Errno 11对应于EWOULDBLOCK，因此recv()中止，因为没有可供读取的数据.

There will usually be a period of time between establishing the connection with the server and the image data being sent by the client. The server attempts to immediately read data from the client once the connection is accepted, however, there might not be any data to read yet, so c.recv() raises a socket.error: [Errno 11] Resource temporarily unavailable exception. Errno 11 corresponds to EWOULDBLOCK, so recv() aborted because there was no data ready to read.

您的代码似乎不需要非阻塞套接字，因为while循环的顶部有一个accept()，因此一次只能处理一个连接.您只需删除对c.setblocking(0)的呼叫，该问题就会消失.

Your code does not seem to require non-blocking sockets because there is an accept() at the top of the while loop, and so only one connection can be handled at a time. You can just remove the call to c.setblocking(0) and this problem should go away.

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