[英]When working with a named pipe is there a way to do something like readlines()
總體目標:我正在嘗試從python exe讀取一些進度數據,以在另一個應用程序中更新exe的進度
我有一個要執行某些操作的python exe,我希望能夠將進度傳達給另一個程序。 基於這里的其他一些問答,我能夠使用以下代碼使正在運行的應用程序將進度數據發送到命名管道
import win32pipe
import win32file
import glob
test_files = glob.glob('J:\\someDirectory\\*.htm')
# test_files has two items a.htm and b.htm
p = win32pipe.CreateNamedPipe(r'\\.\pipe\wfsr_pipe',
win32pipe.PIPE_ACCESS_DUPLEX,
win32pipe.PIPE_TYPE_MESSAGE | win32pipe.PIPE_WAIT,
1,65536,65536,300,None)
# the following line is the server-side function for accepting a connection
# see the following SO question and answer
""" http://stackoverflow.com/questions/1749001/named-pipes-between-c-sharp-and-python
"""
win32pipe.ConnectNamedPipe(p, None)
for each in testFiles:
win32file.WriteFile(p,each + '\n')
#send final message
win32file.WriteFile(p,'Process Complete')
# close the connection
p.close()
簡而言之,示例代碼將每個文件的路徑寫入到NamedPipe中-這很有用,並且可以輕松地擴展到更多日志類型事件。 但是,問題是試圖弄清楚如何在不知道每個可能的消息大小的情況下讀取命名管道的內容。 例如,第一個文件可以命名為J:\\ someDirectory \\ a.htm,但是第二個文件可以包含300個字符。
到目前為止,我用於讀取管道內容的代碼要求我指定緩沖區大小
首先建立連接
file_handle = win32file.CreateFile("\\\\.\\pipe\\wfsr_pipe",
win32file.GENERIC_READ | win32file.GENERIC_WRITE,
0, None,
win32file.OPEN_EXISTING,
0, None)
然后我一直在玩讀文件
data = win32file.ReadFile(file_handle,128)
通常這是可行的,但我真的很想讀,直到我碰到換行符為止,在我開始閱讀和換行符之間進行內容處理,然后重復該過程,直到行中出現Process Complete為止。
在尋找換行符(\\ n)之前,我一直在努力只閱讀。 我基本上想按行讀取文件,並根據行的內容執行某些操作(顯示行或轉移應用程序焦點)。
根據@meuh提供的建議,我正在對此進行更新,因為我認為缺少示例,如何使用管道的指南
我的服務器代碼
import win32pipe
import win32file
import glob
import os
p = win32pipe.CreateNamedPipe(r'\\.\pipe\wfsr_pipe',
win32pipe.PIPE_ACCESS_DUPLEX,
win32pipe.PIPE_TYPE_MESSAGE | win32pipe.PIPE_WAIT,
1,65536,65536,300,None)
# the following line is the server-side function for accepting a connection
# see the following SO question and answer
""" http://stackoverflow.com/questions/1749001/named-pipes-between-c-sharp-and-python
"""
win32pipe.ConnectNamedPipe(p, None)
for file_id in glob.glob('J:\\level1\\level2\\level3\\*'):
for filer_id in glob.glob(file_id + os.sep + '*'):
win32file.WriteFile(p,filer_id)
#send final message
win32file.WriteFile(p,'Process Complete')
# close the connection
p.close() #still not sure if this should be here, I need more testing
# I think the client can close p
客戶端代碼
import win32pipe
import win32file
file_handle = win32file.CreateFile("\\\\.\\pipe\\wfsr_pipe",
win32file.GENERIC_READ |
win32file.GENERIC_WRITE,
0, None,win32file.OPEN_EXISTING,0, None)
# this is the key, setting readmode to MESSAGE
win32pipe.SetNamedPipeHandleState(file_handle,
win32pipe.PIPE_READMODE_MESSAGE, None, None)
# for testing purposes I am just going to write the messages to a file
out_ref = open('e:\\testpipe.txt','w')
dstring = '' # need some way to know that the messages are complete
while dstring != 'Process Complete':
# setting the blocksize at 4096 to make sure it can handle any message I
# might anticipate
data = win32file.ReadFile(file_handle,4096)
# data is a tuple, the first position seems to always be 0 but need to find
# the docs to help understand what determines the value, the second is the
# message
dstring = data[1]
out_ref.write(dstring + '\n')
out_ref.close() # got here so close my testfile
file_handle.close() # close the file_handle
我沒有Windows,但是通過api看來,您應該通過在CreateFile()之后添加調用來將客戶端轉換為消息模式:
win32pipe.SetNamedPipeHandleState(file_handle,
win32pipe.PIPE_READMODE_MESSAGE, None, None)
那么每次足夠長的讀取將返回一條消息,即另一條消息在一次寫入中所寫的內容。 創建管道時,您已經設置了PIPE_TYPE_MESSAGE。
您可以簡單地使用io.IOBase的實現來包裝NamedPipe。
class PipeIO(io.RawIOBase):
def __init__(self, handle):
self.handle = handle
def read(self, n):
if (n == 0): return ""
elif n == -1: return self.readall()
data = win32file.ReadFile(self.file_handle,n)
return data
def readinto(self, b):
data = self.read(len(b))
for i in range(len(data)):
b[i] = data[i]
return len(data)
def readall(self):
data = ""
while True:
chunk = win32file.ReadFile(self.file_handle,10240)
if (len(chunk) == 0): return data
data += chunk
注意:未經測試,但在修正最終的錯字后應該可以使用。
然后,您可以執行以下操作:
with PipeIO(file_handle) as fd:
for line in fd:
# process a line
您可以使用msvcrt
模塊並open
以將管道變成文件對象。
import win32pipe
import os
import msvcrt
from io import open
pipe = win32pipe.CreateNamedPipe(r'\\.\pipe\wfsr_pipe',
win32pipe.PIPE_ACCESS_OUTBOUND,
win32pipe.PIPE_TYPE_MESSAGE | win32pipe.PIPE_WAIT,
1,65536,65536,300,None)
# wait for another process to connect
win32pipe.ConnectNamedPipe(pipe, None)
# get a file descriptor to write to
write_fd = msvcrt.open_osfhandle(pipe, os.O_WRONLY)
with open(write_fd, "w") as writer:
# now we have a file object that we can write to in a standard way
for i in range(0, 10):
# create "a\n" in the first iteration, "bb\n" in the second and so on
text = chr(ord("a") + i) * (i + 1) + "\n"
writer.write(text)
import win32file
import os
import msvcrt
from io import open
handle = win32file.CreateFile(r"\\.\pipe\wfsr_pipe",
win32file.GENERIC_READ,
0, None,
win32file.OPEN_EXISTING,
0, None)
read_fd = msvcrt.open_osfhandle(handle, os.O_RDONLY)
with open(read_fd, "r") as reader:
# now we have a file object with the readlines and other file api methods
lines = reader.readlines()
print(lines)
一些注意事項。
os.O_RDWR
標志創建文件描述符( read_fd
和write_fd
) "r+"
模式而不是"r"
或"w"
模式創建文件對象 win32pipe.PIPE_ACCESS_DUPLEX
標志創建管道 win32file.GENERIC_READ | win32file.GENERIC_WRITE
創建文件句柄對象win32file.GENERIC_READ | win32file.GENERIC_WRITE
win32file.GENERIC_READ | win32file.GENERIC_WRITE
標志。
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