Adding a prefix makes a subtle, non-intuitive change in routing

[kenneth-olwing]

Hi, as a beginner with Dancer2 I caught the below - no idea if it's a bug or a expected feature, but for me it was non-intuitive given 'principle of least surprise'...

Consider this simple helloworld.pl:

use Dancer2;
prefix undef;
get '/' => sub { 'hello' };
get '/foo' => sub { 'world' };
dance;

Starting this makes browsing to http://localhost:3000 perfectly fine (renders 'hello') as well as http://localhost:3000/foo (renders 'world'). So far so good.

Now consider that I want to use a prefix:

use Dancer2;
prefix '/myprefix';
get '/' => sub { 'hello' };
get '/foo' => sub { 'world' };
dance;

My expectation here was that the only change needed when browsing is adding the prefix to the URL. However, browsing to http://localhost:3000/myprefix now gives me 404 - I need to explicitly add the trailing '/' to make it work again, e.g. http://localhost:3000/myprefix/. However, http://localhost:3000/myprefix/foo works as before.

So it's a subtle and fairly minor change in behavior. I haven't checked the code but assume it's an artifact of basically just smooshing the prefix and the route together - would it be relevant to add special case handling for the top-level '/' route when a prefix is involved?

Thanks,

ken1

[simbabque]

The paths /myprefix and /myprefix/ are not the same. The first, without the slash, usually means a file. The second, with the slash, means a directory.

There are a lot of discussions on whether those should point to the same thing in the SEO world. Take a look at https://webmasters.googleblog.com/2010/04/to-slash-or-not-to-slash.html, for example. (By no means am I an authority, that was the first credible source that came up when googling).

Funny enough, there is a https://metacpan.org/pod/Plack::Middleware::TrailingSlashKiller, which removes all the trailing slashes on the way in.

But then there is #593, where @xsawyerx explains why the two are different. So it seems it's by-design and a feature.

[kenneth-olwing]

Thanks for the insight! Now I understand the issue.

[xsawyerx]

Closed as a non-issue.