Duplicate slashes are removed from path parameters. #11049
Description
When processing the requested path, Nextcloud cleans up subsequent slashes paths, such that e.g. /apps//test will become /apps/test. While usually not an issue, it becomes problematic when you want to keep those double slashes, most commonly when expecting a url as a parameter in apps for redirection, proxying, or archiving.
Reproduce
For example, an app could try to use the following URL syntax:
/apps/redirectme/to/https://example.org
And therefore define a route like this:
[
'name' => 'page#redirect',
'url' => '/to/{target}',
'requirements' => array('target' => '.+')
]
Expected behaviour
Parameter $target will be https://example.org.
Actual behaviour
Parameter $target is https:/example.org (note the single slash).
Even when using a function such as IRequest->getRawPathInfo(), you will obtain the 'cleaned'/corrupted value.
Cause
This one line seems to be the culprit:
$requestUri = preg_replace('%/{2,}%', '/', $requestUri);
Workaround
You can work around this by reading the parameter manually; somewhat hacky, but something like this seems to work: (cleaner solutions welcome!)
$path = $_SERVER['REQUEST_URI'];
$routePath = 'apps/redirectme/to/'; // (presumably nobody has this string in their web root)
$target = substr($path, strpos($path, $routePath) + strlen($routePath));
Prior discussion
This issue has been traced by and discussed with @nickvergessen and @LukasReschke. The thought thus far was that there was no particularly strong reason for the implemented behaviour, but that changing this behaviour might be problematic due to existing apps that may rely on it.
Reporting the issue nevertheless to have it documented, and perhaps the thoughts on this may change, or it may be worth providing an extra method somewhere to get the parameters without the slash-cleaning step.