我在使用Python套接字接收和发送数据方面遇到了麻烦。在我的脚本中，我需要监听套接字中的传入数据并读取FIFO文件以获得响应，并在找到\ n时使用套接字发送它。我创建了单独的线程来读取FIFO并且它可以工作，但有时它真的很慢。是否可以在主线程中执行这两项操作？我的代码：
#!/usr/bin/python
from __future__ import absolute_import, print_function, unicode_literals
from optparse import OptionParser, make_option
import os
import errno
import sys
import socket
import uuid
import dbus
import dbus.service
import dbus.mainloop.glib
import time
from threading import Thread
try:
from gi.repository import GObject
except ImportError:
import gobject as GObject
class ArduinoFifo:
fifofile = -1
OUT_PIPE_FILE = '/tmp/ble_pipe_out'
def removeFile(self, filename):
try:
os.remove(filename)
except OSError as e: # this would be "except OSError, e:" before Python 2.6
if e.errno != errno.ENOENT: # errno.ENOENT = no such file or directory
print(e)
raise # re-raise exception if a different error occured
def createFifo(self):
print('removing pipe file\n')
self.removeFile(self.OUT_PIPE_FILE)
print('making pipe\n')
try:
os.mkfifo(self.OUT_PIPE_FILE, 0777)
except OSError as err:
print (err)
raise
def openFifo(self):
print('waiting to open pipe\n')
try:
self.fifofile = os.open(self.OUT_PIPE_FILE, os.O_WRONLY) # | os.O_NONBLOCK)
except OSError as err:
print (err)
def writeFifo(self, data):
try:
if (self.fifofile == -1):
openFifo(self)
os.write(self.fifofile, data)
except OSError as err:
print (err)
class FIFOReader(Thread):
def __init__(self, server_sock):
super(FIFOReader, self).__init__()
self.server_sock = server_sock
self.daemon = True
self.received_msg = ""
self.cancelled = False
print('remove in fifo')
try:
os.remove("/tmp/ble_pipe_in")
except OSError as e: # this would be "except OSError, e:" before Python 2.6
if e.errno != errno.ENOENT: # errno.ENOENT = no such file or directory
print(e)
raise
print('create in fifo')
try:
os.mkfifo("/tmp/ble_pipe_in", 0777)
except OSError as err:
print (err)
raise
print('open in fifo')
try:
self.fifofile = os.open("/tmp/ble_pipe_in", os.O_RDWR)
except OSError as err:
print (err)
print('fifo in opened')
def run(self):
while not self.cancelled:
print("READING")
self.received_msg += os.read(self.fifofile, 1)
print("read: %s\n" % self.received_msg)
if "\n" in self.received_msg :
print("Sending Message...")
self.server_sock.send(self.received_msg)
self.received_msg = ""
def cancel(self):
self.cancelled = True
myfifo = ArduinoFifo()
class Profile(dbus.service.Object):
fd = -1
@dbus.service.method("org.bluez.Profile1",
in_signature="", out_signature="")
def Release(self):
print("Release")
mainloop.quit()
@dbus.service.method("org.bluez.Profile1",
in_signature="", out_signature="")
def Cancel(self):
print("Cancel")
@dbus.service.method("org.bluez.Profile1",
in_signature="oha{sv}", out_signature="")
def NewConnection(self, path, fd, properties):
global received_msg
self.fd = fd.take()
print("NewConnection(%s, %d)" % (path, self.fd))
server_sock = socket.fromfd(self.fd, socket.AF_UNIX, socket.SOCK_STREAM)
server_sock.setblocking(1)
myfifo.openFifo()
infifo = FIFOReader(server_sock)
infifo.start()
print('enter recv loop\n')
try:
while True:
data = server_sock.recv(1024)
#print("received: %s" % data)
if data:
myfifo.writeFifo(data)
#if data == "h":
#server_sock.send("Hello!\n")
except IOError as err:
print (err)
pass
server_sock.close()
print("all done")
os.kill(os.getpid(), 9)
@dbus.service.method("org.bluez.Profile1",
in_signature="o", out_signature="")
def RequestDisconnection(self, path):
print("RequestDisconnection(%s)" % (path))
if (self.fd > 0):
os.close(self.fd)
self.fd = -1
if __name__ == '__main__':
dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
bus = dbus.SystemBus()
manager = dbus.Interface(bus.get_object("org.bluez",
"/org/bluez"), "org.bluez.ProfileManager1")
option_list = [
make_option("-C", "--channel", action="store",
type="int", dest="channel",
default=None),
]
parser = OptionParser(option_list=option_list)
(options, args) = parser.parse_args()
options.uuid = "1101"
options.psm = "3"
options.role = "server"
options.name = "Edison SPP Loopback"
options.service = "spp char loopback"
options.path = "/foo/bar/profile"
options.auto_connect = False
options.record = ""
profile = Profile(bus, options.path)
mainloop = GObject.MainLoop()
opts = {
"AutoConnect" : options.auto_connect,
}
if (options.name):
opts["Name"] = options.name
if (options.role):
opts["Role"] = options.role
if (options.psm is not None):
opts["PSM"] = dbus.UInt16(options.psm)
if (options.channel is not None):
opts["Channel"] = dbus.UInt16(options.channel)
if (options.record):
opts["ServiceRecord"] = options.record
if (options.service):
opts["Service"] = options.service
if not options.uuid:
options.uuid = str(uuid.uuid4())
manager.RegisterProfile(options.path, options.uuid, opts)
myfifo.createFifo()
mainloop.run()
EIDT2：我用它来立即接收消息并一个接一个地发送响应
答案 0 :(得分：0)
我怀疑这个问题与单独的线程有关。 Python中的“线程”不一定是操作系统级线程，但可能只是异步操作主操作系统级线程进程。 In cPython, which most people use, this is how they work.但我确实看到了几个可能的问题：
我不熟悉其中一些库，但os.read(self.fifofile, 1)脱颖而出。如果你使用内置open()（不是os中的那个）或BufferedReader，那么这将被缓冲，因此可以。但是os.open是一个低级调用，不会缓冲读取或写入，所以你实际上是从文件句柄一次读取1个字节，这不是一个好主意，因为它可能导致因各种难以追查的原因而放缓。您应该为此使用更高级别的库，或者自己进行缓冲。
其次，如果您的Python解释器每次都在内部创建一个新字符串，那么您对消息字符串的读取输入的+=重复将会很慢。所以你可能会看到O（N ^ 2），其中N是消息大小时间复杂度，应该是O（N）。这取决于你的翻译，所以为了便于携带，你应该改为列表。
不相关，但如果您不知道您的FIFO文件是否为文本，则不应在文本模式下打开它，否则您将遇到错误。字符串只允许有效的文本字节，UTF-8（如果它是Py3）和我认为ASCII（如果它是Py2），如果收到，则会收到错误，比如0x00。
希望这有帮助。