* fileserver: Support virtual file systems (close#3720)
This change replaces the hard-coded use of os.Open() and os.Stat() with
the use of the new (Go 1.16) io/fs APIs, enabling virtual file systems.
It introduces a new module namespace, caddy.fs, for such file systems.
Also improve documentation for the file server. I realized it was one of
the first modules written for Caddy 2, and the docs hadn't really been
updated since!
* Virtualize FS for file matcher; minor tweaks
* Fix tests and rename dirFS -> osFS
(Since we do not use a root directory, it is dynamic.)
* fastcgi: Set PATH_INFO to file matcher remainder as fallback
* fastcgi: Avoid changing scriptName when not necessary
* Stylistic tweaks
Co-authored-by: Matthew Holt <mholt@users.noreply.github.com>
* fileserver: Fix try_files for directories, windows fix
* fileserver: Add new file type placeholder, refactoring, tests
* fileserver: Review cleanup
* fileserver: Flip the return args order
* fileserver: First attempt to fix failing test on Linux
I think I updated the wrong test case before
* Make new test function
I guess what we really are trying to test is the case insensitivity of
firstSplit. So a new test function is better for that.
We can't use a positional index on an original string that we got from
its lower-cased equivalent. Implement our own IndexFold() function b/c
the std lib does not have one.
* matcher: Add `split_path` option to file matcher; used in php_fastcgi
* matcher: Skip try_files split if not the final part of the filename
* matcher: Add MatchFile tests
* matcher: Clarify SplitPath godoc
