It is not immediately obvious how to avoid the error handler making a
different 404 response when the application code returns an explicit 404
page. Since we were already replying "Resource not found" in all cases
except one where we reply "File not found" not much is lost by relying
on the error handler behavior.
This PR solves the issue of there being both "<url>/" and "<url>" paths, that in the builder-web context shouldn't mean different things.
The slashes are now removed using a `Dream` middleware, and the request is redirected using a permanent redirect (that doesn't change the method used): https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Location
Notable changes:
* Trailing slashes from the hardcoded link urls were removed, as unneccesary redirects are then avoided.
* All links in `Views` were rewritten to be absolute instead of relative.
* As `Dream` deprecated `path` - `Utils.Path` was created containing some helpers for manipulating paths. *Note that `String.split_on_char` has a different semantics.*
* A blacklist `routeprefix_blacklist_when_removing_trailing_slash` was added, containing `Dream` route-prefixes to ignore.
* Only `GET` and `HEAD` requests are redirected.
* `redirect_parent` helper was rewritten using new `Utils.Path` functions to avoid brittle string manipulation + fixed the edgecase of redirecting to `/`.
* Added `Uri` dependency to make URL manipulation safer.
Co-authored-by: rand00 <oth.rand@gmail.com>
Co-authored-by: Reynir Björnsson <reynir@reynir.dk>
Reviewed-on: https://git.robur.io/robur/builder-web/pulls/80
Co-authored-by: rand <rand@r7p5.earth>
Co-committed-by: rand <rand@r7p5.earth>
.. there are too many common names in this modules scope, and code gets easier to understand
.. also I don't think global open is a good idea in general for this kind of module, so better
to fix this style now than be sorry later
