多文件系统

MultiFS是由一系列其他文件系统组成的文件系统，其中每个文件系统的目录结构覆盖序列中的先前文件系统。

这种文件系统的一个用途是选择性地覆盖一组文件，满足自定义的功能。 例如，创建一个可用于Web应用程序 theme 的文件系统。 我们从以下目录开始:

`-- templates
    |-- snippets
    |   `-- panel.html
    |-- index.html
    |-- profile.html
    `-- base.html

`-- theme
    |-- snippets
    |   |-- widget.html
    |   `-- extra.html
    |-- index.html
    `-- theme.html

我们想创建一个单独的文件系统，只有在 theme/ 中没有找到时，才会从 templates/ 加载一个文件。 我们可以这样做:

from fs.osfs import OSFS
from fs.multifs import MultiFS

theme_fs = MultiFS()
theme_fs.add_fs('templates', OSFS('templates'))
theme_fs.add_fs('theme', OSFS('theme'))

现在我们有一个 theme_fs 文件系统，它提供了两个目录的单一视图:

|-- snippets
|   |-- panel.html
|   |-- widget.html
|   `-- extra.html
|-- index.html
|-- profile.html
|-- base.html
`-- theme.html
class fs.multifs.MultiFS(auto_close=True)

A filesystem that delegates to a sequence of other filesystems.

Operations on the MultiFS will try each ‘child’ filesystem in order, until it succeeds. In effect, creating a filesystem that combines the files and dirs of its children.

add_fs(name, fs, write=False, priority=0)

Adds a filesystem to the MultiFS.

参数:
  • name (str) – A unique name to refer to the filesystem being added.
  • fs (Filesystem) – The filesystem to add
  • write (bool) – If this value is True, then the fs will be used as the writeable FS.
  • priority (int) – An integer that denotes the priority of the filesystem being added. Filesystems will be searched in descending priority order and then by the reverse order they were added. So by default, the most recently added filesystem will be looked at first.
get_fs(name)

Get a filesystem from its name.

参数:name (str) – The name of a filesystem previously added.
iterate_fs()

Get iterator that returns (name, fs) in priority order.

which(path, mode='r')

Get a tuple of (name, filesystem) that the given path would map to.

参数:
  • path (str) – A path on the filesystem.
  • mode (str) – A open mode.