From 36b075cbbf5a5e6414ee3c307d1c1b955bb7d20d Mon Sep 17 00:00:00 2001 From: Hanno Hecker Date: Tue, 15 Dec 2015 18:18:10 +0100 Subject: [PATCH] show how filtering is used --- README.md | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/README.md b/README.md index 19545cd..61bc984 100644 --- a/README.md +++ b/README.md @@ -31,6 +31,8 @@ filesystem for full interoperability. * A set of interfaces to encourage and enforce interoperability between backends * An atomic cross platform memory backed file system * Support for compositional file systems by joining various different file systems (see httpFs) +* Filtering of calls to intercept opening / modifying files, several filters +may be stacked. * A set of utility functions ported from io, ioutil & hugo to be afero aware @@ -273,6 +275,28 @@ implement: * Mem buffering to disk/network * BasePath (where all paths are relative to a fixed basepath) +# Filters + +You can add "filtering" to an Fs by adding a FilterFs to an existing Afero Fs +like +```go + ROFs := afero.NewFilter(AppFs) + ROFs.AddFilter(afero.NewReadonlyFilter()) +``` +The ROFs behaves like a normal afero.Fs now, with the only exception, that it +provides a readonly view of the underlying Fs. + +The FilterFs is run before the source Fs, any non nil error is returned +to the caller without going to the source Fs. If every filter in the +chain returns a nil error, the call is sent to the source Fs. + +The `AddFilter` adds a new filter before any existing filters. + +## Available filters + +* NewReadonlyFilter() - provide a read only view of the source Fs + + # About the project ## What's in the name