Destination webdav header missing slash

[mnutt]

I'm running into an issue when using the Destination header to move a file. I might send something like this in the request header:

Destination: http://ui-dedd82ceddacee6aafced10c1fbe0c7b.local.sandstorm.io:6090/dav/asdfafsd/shuttle.jpg

However, when I log the destination header inside of the grain server I get: http://ui-dedd82ceddacee6aafced10c1fbe0c7b.local.sandstorm.io:6090dav/asdfafsd/shuttle.jpg (note the missing slash after the port)

It looks like it is due to this line:

sandstorm/src/sandstorm/web-session-bridge.c++

Lines 463 to 464 in 9e77d99

	// Remove leading '/'.
	return kj::str(dest.slice(1));

...which seems very deliberate, so I didn't want to go ahead and make a PR without understanding why we might be removing the leading slash here? Constructing the header is just joining [basePath, destination] and the basePath has no trailing slash.

This is not an urgent issue, as for the time being I can just subtract the x-sandstorm-base-path to get the destination pathname, and add the leading slash if necessary.

[zenhack]

Looks like this was originally introduced in 5834c50 (which started handling , and there is a (still present) comment in web-session.capnp that seems relevant:

sandstorm/src/sandstorm/web-session.capnp

Lines 98 to 99 in 0811bcd

	# "destination" is a *path*, but *not* a URI -- the origin is stripped, and there is no leading
	# '/', just like with the `path` parameter.

It looks like web-session-bridge strips out the bit of the url before the path, and it gets added back in sandstorm-http-bridge, in makeDestinationHeader -- presumably that would be the correct place to add the slash? (cc: @kentonv)