在python中发送/接收文件UDP
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/13993514/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
sending/receiving file UDP in python
提问by Hamoudaq
I've made this sending / receiving scripts but i corrupted file ! i have no idea why I'm getting this issue !
我已经制作了这个发送/接收脚本，但我损坏了文件！我不知道为什么我会遇到这个问题！
sender.py
发件人.py
#!/usr/bin/env python
from socket import *
import sys
s = socket(AF_INET,SOCK_DGRAM)
host =sys.argv[1]
port = 9999
buf =1024
addr = (host,port)
file_name=sys.argv[2]
f=open(file_name,"rb")
data = f.read(buf)
s.sendto(file_name,addr)
s.sendto(data,addr)
while (data):
if(s.sendto(data,addr)):
print "sending ..."
data = f.read(buf)
s.close()
f.close()
receiver.py
接收器.py
#!/usr/bin/env python
from socket import *
import sys
import select
host="0.0.0.0"
port = 9999
s = socket(AF_INET,SOCK_DGRAM)
s.bind((host,port))
addr = (host,port)
buf=1024
data,addr = s.recvfrom(buf)
print "Received File:",data.strip()
f = open(data.strip(),'wb')
data,addr = s.recvfrom(buf)
try:
while(data):
f.write(data)
s.settimeout(2)
data,addr = s.recvfrom(buf)
except timeout:
f.close()
s.close()
print "File Downloaded"
and this the original receiver that I've modify it (works fine 100%)
这是我修改过的原始接收器（工作正常 100%）
#!/usr/bin/env python
from socket import *
import sys
import select
host="0.0.0.0"
port = 9999
s = socket(AF_INET,SOCK_DGRAM)
s.bind((host,port))
addr = (host,port)
buf=1024
f = open("file.pdf",'wb')
data,addr = s.recvfrom(buf)
try:
while(data):
f.write(data)
s.settimeout(2)
data,addr = s.recvfrom(buf)
except timeout:
f.close()
s.close()
print "File Donwloaded"
as you notice it's making file at the beginning.
正如您注意到的那样，它在开始时正在制作文件。
exacted: client => send file (name.ext) => server:save it (name.ext)
精确：客户端=> 发送文件（名称.ext）=> 服务器：保存（名称.ext）
my output : corrupted file for pdf and empty for txt
我的输出：pdf 文件损坏，txt 文件为空
回答by Thomas Orozco
There are two problems here:
这里有两个问题：
Syntax errors:
语法错误：
You're using a from socket import *. It's not an error on its own, but it becomes one when you do except socket.timeout.
你正在使用一个from socket import *. 这本身不是一个错误，但当你这样做时它就会变成一个错误except socket.timeout。
Using UDP:
使用UDP：
Using UDP, corruption shouldn't be a surprise. You probably don't want to be using UDP here, you should switch to TCP.
使用 UDP，损坏不应该是一个意外。您可能不想在这里使用 UDP，您应该切换到 TCP。
Here's why UDP is not appropriate here:
这就是 UDP 在这里不合适的原因：
- Packets may be lost but others could still reach their destination.
- Packets may be duplicated
- Packets may arrive in the wrong order
- 数据包可能会丢失，但其他数据包仍可到达目的地。
- 数据包可能重复
- 数据包可能以错误的顺序到达
Note that switching to TCP will involve some refactoring of your code (it's a bit more complicated that just replacing SOCK_DGRAMwith SOCK_STREAM), but in your case, you have to do it.
请注意，切换到 TCP 将涉及对您的代码进行一些重构（仅替换SOCK_DGRAM为 会更复杂一些SOCK_STREAM），但在您的情况下，您必须这样做。
I'm not saying UDP is bad, but it's not appropriate in your case.
我并不是说 UDP 不好，但它不适合您的情况。
回答by ATOzTOA
The problem with your code:
您的代码的问题：
- When data is send through sockets, normally the lower layers will merge the data from multiple sendTo calls and send them together to reduce network load.
- You are sending the first 1024 bytes of the file twice.
- 当数据通过套接字发送时，通常低层会将来自多个 sendTo 调用的数据合并在一起发送，以减少网络负载。
- 您要发送文件的前 1024 个字节两次。
What you should do:
你应该做什么：
Use some kind of a delimiter string having couple of characters (like "**_$$") so that it won't exist in the actual file binary representation. Then append this delimiter to the end of the filename.
使用某种具有几个字符的分隔符字符串（如“**_$$”），这样它就不会存在于实际的文件二进制表示中。然后将此分隔符附加到文件名的末尾。
Read from file again before starting the while loop.
在开始 while 循环之前再次从文件中读取。
At receiver end, receive everything into a single stream and then split using the delimiter. You will have the filename and the file data.
在接收器端，将所有内容接收到单个流中，然后使用分隔符进行拆分。您将拥有文件名和文件数据。
Update:
更新：
Working Code (Ubuntu / Windows XP)
工作代码 (Ubuntu / Windows XP)
# ----- sender.py ------
#!/usr/bin/env python
from socket import *
import sys
s = socket(AF_INET,SOCK_DGRAM)
host =sys.argv[1]
port = 9999
buf =1024
addr = (host,port)
file_name=sys.argv[2]
s.sendto(file_name,addr)
f=open(file_name,"rb")
data = f.read(buf)
while (data):
if(s.sendto(data,addr)):
print "sending ..."
data = f.read(buf)
s.close()
f.close()
# ----- receiver.py -----
#!/usr/bin/env python
from socket import *
import sys
import select
host="0.0.0.0"
port = 9999
s = socket(AF_INET,SOCK_DGRAM)
s.bind((host,port))
addr = (host,port)
buf=1024
data,addr = s.recvfrom(buf)
print "Received File:",data.strip()
f = open(data.strip(),'wb')
data,addr = s.recvfrom(buf)
try:
while(data):
f.write(data)
s.settimeout(2)
data,addr = s.recvfrom(buf)
except timeout:
f.close()
s.close()
print "File Downloaded"
Usage
用法
>> python recevier.py
>> python sender.py localhost filename.txt
