Tracking issue of implementing a Webdav Compatibility Layer for Oay

[Young-Flash]

Hi OpenDAL Community, this issue tracks the development of Webdav Compatibility Layer for Oay. It will update when we make progress, or for discussion, feel free to join together.

The basic idea is as follows:

• Add a frontends-webdav feature for Oay.
• Introduce the dav-server-rs dependency (Apache License, Version 2.0) and hide it within the frontends-webdav feature.
• Make a struct named WebDAVFs that implements traits like fs::DavDirEntry, fs::DavFile, fs::DavFileSystem, fs::DavMetaData from dav-server-rs. Utilize various data operation operators (such as read, write, create_dir, stat) from the OpenDAL operator to implement the interfaces of these traits.
• Setup integration tests.

[Xuanwo]

The idea seems interesting, but it may not be effective for tracking issues. Have we considered how to divide the work into multiple pull requests?

I think we need following steps:

• Add basic layout (setup feature, deps, traits, leave todo!() for needed functions)
• Implement read support (so users can use oay to read data from webdav)
• Implement write support (so users can write data into oay webdav)
• Setup integration tests (Is there webdav test suites? Maybe we can running opendal webdav tests?)

[Xuanwo]

Most work is done, let's close.