如何使用io将内存中的数据流生成为类似文件的对象?

@迪尔马蒂和@ShadowRanger提到了这一点 io.BytesIO()

我通过创建一个简单的类来克服这个问题,该类实现了一个读指针并记住了写入的字节数。当读取的字节数等于写入的字节数时,文件将收缩以节省内存。

#!/usr/local/bin/python3
# encoding: utf-8

import io

class memoryStreamIO(io.BytesIO):
    """
    memoryStreamIO

    a in memory file like stream object 
    """

    def __init__(self):
        super().__init__()
        self._wIndex = 0
        self._rIndex = 0
        self._mutex = threading.Lock()

    def write(self, d : bytearray):
        self._mutex.acquire()
        r = super().write(d)
        self._wIndex += len(d)
        self._mutex.release()
        return r

    def read(self, n : int):
        self._mutex.acquire()
        super().seek(self._rIndex)
        r = super().read(n)
        self._rIndex += len(r)
        # now we are checking if we can
        if self._rIndex == self._wIndex:
            super().truncate(0)
            super().seek(0)
            self._rIndex = 0
            self._wIndex = 0
        self._mutex.release()
        return r

    def seek(self, n):
        self._mutex.acquire()
        self._rIndex = n
        r = super().seek(n)
        self._mutex.release()
        return r


if __name__ == '__main__':
    a = streamIO()

    a.write("hello".encode())
    txt = (a.read(100)).decode()
    print(txt)

    a.write("abc".encode())
    txt = (a.read(100)).decode()
    print(txt)

实际上,它是书面的,但阅读是个问题。你应该指的是 class io.BytesIO . 您可以使用 getvalue() . 比如,

import io

a = io.BytesIO()
a.write("hello".encode())
txt = a.getvalue()
txt = txt.decode("utf-8")
print(txt)