Routing with an optional parameter

Question

I added in the route file:

map.show_book "/show_book/:name/year/:year", :controller => "book", :action => "show_version"

I also added:

map.show_book "/show_book/:name", :controller => "book", :action => "show_version"

to show the latest book without specifying the year.

But it doesn't work, it cannot find the route in "show_book/NAME" if I don't pass the year.

Do you have some ideas why it doesn't work ?

THANKS !

PS. I know that I can use year as parameter with "?year=XXXX", but I want to use the year as a part of the URL

Solution

Put the optional parts between parenthesis:

map.show_book "/show_book/:name(/year/:year)", :controller => "book", :action => "show_version"

and remove the second route.

Update

The above answer is only for rails 3 and above. Inverting the two routes definitions fixed the problem (see Alessandro's comment below).

Comments

[Alessandro De Simone]

Wow, this it is very simple, but I think it is only for Rails3. I forgot to specify that the project is in rails 2.3. But I have find out that it's enough to use both routes, but in a correct order (I wrote it in a wrong order). Thanks

[AlexQueue]

"Only" is no longer true, since this is valid in Rails 4, and likely future versions as well.

[Eric Walsh]

Is there a way to have multiple optional parts in the same route with an unspecified order? Soa long the lines of... map.show_book "/show_book/:name((/year/:year)(/day/:day))"

[Benoit Garret]

@EricWalsh you should ask that as a question, you're much more likely to get an answer (haven't touched rails for a long time, I won't be of much use)

[Eric Walsh]

Thanks @BenoitGarret, I opened up a question (stackoverflow.com/questions/29501364/…) just wanted to see if anyone in the thread would be able to shed some light!

[W.M.]

How to make attachments :id optional in a route like this: PATCH /pages/:page_id/attachments/:id(.:format) attachments#update defined by resources :pages do resources :attachments, only: [:create, :destroy, :update] end

[Joshua Pinter]

Damn, been using Rails for over a decade and this is the first time I've seen this. F'ing magical.