tcp - Python socket sendall 随机失败

Question

我有一个简单的脚本，可以将图像文件从一台机器传输到另一台机器，进行图像处理并将结果返回为“骰子计数”。问题是随机收到的图像是部分灰色的。似乎没有关于传输何时未完成的原因，我在代码中看不到其他问题。客户端没有给出任何错误或任何表明 sendall 失败或不完整的指示。谢谢大家。

服务器代码:

def reciveImage():
    #create local buffer file 
    fo = open("C:/foo.jpg", "wb")
    print "inside reciveImage"
    while True:
        print "inside loop"
        data = client.recv(4096)
        print "data length: ", len(data)
        fo.write(data)
        print "data written"
        if (len(data) < 4096):
            break
            print "break"       
    fo.close()
    print "Image received"

和(简化的)客户端代码:

data = open("/home/nao/recordings/cameras/image1.jpg", "rb")    
        # prepare to send data
        binary_data = data.read()
        data.close()

        sock.sendall(binary_data)

正常的服务器输出:

Client Command: findBlob. Requesting image...
inside reciveImage
inside loop
data length:  4096
data written
#... This happens a bunch of times....
inside loop
data length:  4096
data written
inside loop
data length:  1861
data written
Image received
dice count:  0
Waiting for a connection

但随机它只会循环几次或更少，例如:

Client Command: findBlob. Requesting image...
inside reciveImage
inside loop
data length:  1448
data written
Image received
dice count:  0
Waiting for a connection

Answer 1

recv 在接收到所有数据之前不会阻塞，它只会阻塞直到接收到一些数据并返回它们。例如。如果客户端先发送 512 个字节，然后再发送另一个 512 字节，即使您请求 4096，您的 recv 也会返回前 512 个字节。因此，您应该只在 recv 返回时中断，因为没有更多数据可用(连接已关闭) .