我写了我认为相当简单的脚本,可以使用Python套接字通过网络下载文件,但是服务器卡在服务器端的socket.sendall上。我可以获得一次我想要的文件,但是随后对senddata的调用导致崩溃。
在进一步研究之后,我相当确定这与打包 header 数据有关,这意味着它很可能是一个低级问题,超出了我的范围。
对于上下文:“主”代码在x86计算机上运行,而“从”代码在Raspberry Pi Zero(ARM)上运行。
header 已在代码中定义,但这是一个概述:
我对为什么这不起作用感到困惑,因为这看起来像是例行代码。
从站(服务器)
#takes filename and sends the data to the connected socket
def senddata(filename,socket):
try:
filehandle = open(filename,'rb')
except IOError:
socket.sendall('ABORT')
print 'File ' +filename+ ' not found; not sending...'
else:
#writes 8 byte header consisting of:
#length of file (including filename) in kb (4b)
#length of filename (4b)
numbytes = struct.pack("<I",math.ceil((os.stat(filename).st_size + len(filename)) / 1024))
#amount of KB (1024) to receive, written to 4-byte integer
filenamebytes = struct.pack("<I",len(filename))
print 'Sending '+filename+'...'
socket.sendall(numbytes + filenamebytes)
data = filename + filehandle.read(1024 - len(filename))
while True:
socket.sendall(data)
data = filehandle.read(1024)
if not data:
break
filehandle.close()
print 'Send complete.'
硕士(客户)
def ReceiveDownload(socket):
#gets header
data = socket.recv(8)
if data != 'ABORT':
filekb = struct.unpack("<I",data[:4])[0]#endianness may be affecting data transfer
filenamebytes = struct.unpack("<I",data[4:])[0]
data = socket.recv(1024)
filename = data[:filenamebytes]
curkb = 1
print 'Getting '+filename+"..."
writeto = open('./footage/'+filename,'wb')
while curkb <= filekb:
print '\r' + str(curkb) + "/" + str(filekb),
sys.stdout.flush()
writeto.write(data)
data = socket.recv(1024)
curkb += 1
writeto.close()
print 'Download of '+filename+' successful.'
else:
print 'Download failed.'
最佳答案
我自己根据jasonharper的建议解决了这个问题。
通过使用以字节为单位的更普通的代码切换出以kb为单位的代码,总是读取套接字中的所有数据。我不确定此故障的最初原因是否是浮点问题或其他原因,但它确实有效。如果我需要更多容量,我将改用Longs。
为了便于阅读代码并减少舍入错误的可能性,我还停止了将文件名和数据集中在一起的情况,将其合并到一个传输块中。
当更简单的代码可以解决问题时,原始代码将被过度设计。
修改后的代码:
客户
def ReceiveDownload(socket):
#gets header
data = socket.recv(8)
if data != 'ABORT':
fileb = struct.unpack("<I",data[:4])[0]#endianness may be affecting data transfer
filenamebytes = struct.unpack("<I",data[4:])[0]
data = socket.recv(filenamebytes)
filename = data
curb = 0
print 'Getting '+filename+"..."
writeto = open('./footage/'+filename,'wb')
while curb < fileb:
sys.stdout.flush()
data = socket.recv(1024)
writeto.write(data)
curb += len(data)
print '\r' + str(curb) + "/" + str(fileb),
writeto.close()
print 'Download of '+filename+' successful.'
else:
print 'Download failed.'
服务器
def senddata(filename,socket):
try:
filehandle = open(filename,'rb')
except IOError:
socket.sendall('ABORT')
print 'File ' +filename+ ' not found; not sending...'
else:
#writes 8 byte header consisting of:
#length of file in kb (4b)
#length of filename (4b)
numbytes = struct.pack("<I",math.ceil(os.stat(filename).st_size))
#amount of KB (1024) to receive, written to 4-byte integer
filenamebytes = struct.pack("<I",len(filename))
print 'Sending '+filename+'...'
socket.sendall(numbytes + filenamebytes)
data = filename
socket.sendall(data)
while True:
data = filehandle.read(1024)
socket.sendall(data)
if not data:
break
filehandle.close()
print 'Send complete.'
关于python - 通过Python套接字发送文件-卡在socket.sendall,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/45680693/