Question

我有一段代码在Python 2.7.5中运行良好，但不适用于Python 3.

主要问题是tee.write，无法写入文件。

这段代码假设在文件a和/tmp/tee-test-1中写入20个字母/tmp/tee-test-2，但它没有，这两个文件是空的......

有人可以给我一些建议吗？

import sys
import os
import subprocess
#from  netsa.util.shell import *
from string import Template

__author__ = 'Brandon Sandrowicz <brandon@sandrowicz.org>'
__version__ = '0.1'

valid_modes = ['a','w']

def create_tee(files, mode, buffer_size=128):


        if mode not in valid_modes:
            raise IOError("Only valid modes to create_tee() are: %s" % ', '.join(valid_modes))

        tee_list = []
        for file in files:
            if type(file) == str:
                fp = open(file, mode)
                tee_list.append(fp)
            else:
                tee_list.append(file)

        pipe_read, pipe_write = os.pipe()
        pid = os.fork()
        if pid == 0:
            # Child -- Read bytes from the pipe and write them to the specified
            # files.
            try:
                # Close parent's end of the pipe
                os.close(pipe_write)

                bytes = os.read(pipe_read, buffer_size)
                print (bytes)
                while(bytes):
                    for file in tee_list:
                        file.write(bytes)
                        file.flush()
                        # TODO maybe add in fsync() here if the fileno() method
                        # exists on file

                    bytes = os.read(pipe_read, buffer_size)
            except:
                pass
            finally:
                os._exit(255)
        else:
            # Parent -- Return a file object wrapper around the pipe to the
            # child.
            return os.fdopen(pipe_write,'w')



if __name__ == '__main__':

    files = [ '/tmp/tee-test-1', '/tmp/tee-test-2' ]
    num_chars = 100000

    print("Writing %d chars to files (using create_tee):" % num_chars)
    for file in files:
        print(" %s" % file)
    print()

    tee = create_tee(files,mode='a')
    #print("a" * num_chars, end=' ', file=tee)
    tee.write("a" * 20)
    tee.close()
    os.wait()

    for filename in files:
        with open(filename, 'r') as fh:
            chars = len(fh.read())
            print("File '%s' has %d chars" % (filename, chars))

Answer 1

好吧，我发现这个问题很有趣，也很有挑战性，最后发现了什么是错的，它在that document中说过：

一个常见问题是文件以错误的模式打开。确保使用't'标志和带有'b'标志的二进制文件打开文本文件，并解决了许多问题。

因此，当您将数据写为b""数据类型时，我尝试了以下内容：

    for file in files:
        if type(file) == str:
            fp = open(file, mode+'b')
            tee_list.append(fp)
        else:
            tee_list.append(file)

并且效果很好：

File '/tmp/tee-test-1' has 20 chars
File '/tmp/tee-test-2' has 20 chars

pytee无法在python3中生成正确的输出

1 个答案: