Erlang Virtual Filesystem
Switch branches/tags
Nothing to show
Pull request Compare This branch is 18 commits behind yrashk:master.
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.

evfs: Erlang Virtual Filesystem

This application allows to create virtual filesystems on top of standard file API. Imagine if you can do this:

> {ok, Bin} = file:read_file("").

Or this:

> {ok, Bin} = file:read_file("config://host").

Looks interesting, right? Now, basically, because of the way evfs operates, you can feed unsuspecting Erlang code file names that are served off your VFSes. That's where the fun begins.

Also, the way evfs is organized, you are not limited to this "scheme" way of overriding the filesystem. You can override particular files, for example, or whole directories -- or do that basing on some external state. So, for example, if some application expects a file at a hard coded location, just override it with your VFS.

You can register any number of virtual FS handlers using evfs:register/2 function. Also, by default, you get the handler that redirects file:// and plain filename requests to the original file server, but you can unregiser it with evfs:unregister/1 if you need.

Please bear in mind that this is a very early prototype. I still haven't implemented a behaviour for file I/O (file_request and io_request). Not that it blocks you from creating your VFS. It just will make it simpler. Right now you have to look into file_io_server.erl from OTP in order to figure out how to do this.

For an example on how to build a VFS, look into test/evfs_test_fs.erl. Hopefully it will help.