非阻塞文件读取(Non-blocking file read)

 如何以非阻塞模式读取二进制文件或文本文件的内容？ 
 
 对于二进制文件：当我open(filename, mode='rb') ，我得到一个io.BufferedReader的实例。 io.BufferedReader.read文档说 ： 
 
 
 
 读取和返回大小字节，或者如果未给出大小或为负，则直到EOF或读取调用将在非阻塞模式下阻塞。 
 
 
 显然是一个简单的open(filename, 'rb').read()处于阻塞模式。 令我惊讶的是，我无法在io文档中的任何地方找到有关如何选择非阻塞模式的解释。 
 
 对于文本文件：当我open(filename, mode='rt') ，我得到io.TextIOWrapper 。 我假设相关文档是在其基类中read文档， io.TextIOBase ; 根据这些文档 ，根本没有办法进行非阻塞读取： 
 
 
 
 从流中读取并返回最多大小字符作为单个str。 如果大小为负或无，则读取直至EOF。 
 

How can I read the contents of a binary or a text file in a non-blocking mode?
 
For binary files: when I open(filename, mode='rb'), I get an instance of io.BufferedReader. The documentation fort io.BufferedReader.read says:
 
 
 
Read and return size bytes, or if size is not given or negative, until EOF or if the read call would block in non-blocking mode.
 
 
Obviously a straightforward open(filename, 'rb').read() is in a blocking mode. To my surprise, I could not find an explanation anywhere in the io docs of how to choose the non-blocking mode.
 
For text files: when I open(filename, mode='rt'), I get io.TextIOWrapper. I assume the relevant docs are those for read in its base class, io.TextIOBase; and according to those docs, there seems no way to do non-blocking read at all:
 
 
 
Read and return at most size characters from the stream as a single str. If size is negative or None, reads until EOF.
 

原文：https://stackoverflow.com/questions/39948588