I type rake routes and I get a bunch of urls like this - /articles/:id(.:format)
My question is - what does the .:format
mean? It is not clear from the Rails Guides Routing article and there are no other helpful matches for .:format
on StackOverflow or google. There is a similar format which is /:controller(/:action(/:id(.:format)))
which I also don't understand.
Thanks
EDIT follow up question -
If I wanted to only route HTML pages. Would it be best practice to specify something like .:html in the route or to use .:format and just write a respond_to block for format.html? Would all other formats be ignored in that latter case?
This is the simple option. When you use namespace , it will prefix the URL path for the specified resources, and try to locate the controller under a module named in the same manner as the namespace.
Rails routes are matched in the order they are specified, so if you have a resources :photos above a get 'photos/poll' the show action's route for the resources line will be matched before the get line. To fix this, move the get line above the resources line so that it is matched first.
It's a way to redirect incoming requests to controllers and actions. It replaces the mod_rewrite rules. Best of all, Rails' Routing works with any web server. Routes are defined in app/config/routes.
TIP: If you ever want to list all the routes of your application you can use rails routes on your terminal and if you want to list routes of a specific resource, you can use rails routes | grep hotel . This will list all the routes of Hotel.
That's the format of the file being requested. For instance, if you want an image, you'd probably have a file extension in the request - for instance, example.com/example_image.png
would give you the format as png
. This is then included in the request so you can vary response type based of of the format requested, need be.
For a usage example, you may want to allow a resource to be represented as a pdf, as a plain html page and as json - you'd probably write something like this:
respond_to do |format| format.html { ... } format.pdf { ... } format.json { ... } end
Then have separate render calls under the respective formats.
EDIT:
Explanation of GET /:controller(/:action(/:id(.:format))) :controller#:action
-
First, a bit about formatting. The parentheses mean that a given piece of data is optional. The colon means that whatever string it finds in the corresponding URL should be passed to the controller within the params hash.
This is essentially a wildcard matcher will will attempt to match a very broad number of requests to a controller. For instance, lets say this is your only route, and someone tries to get '/users'. This will map users
to the UsersController
, and by default call/render index
within it. If someone gets users/new
, the new
action within the controller will be called. If id
and format
are called, they too will be passed along to the controller.
.:format matches a mime type.
For instance if you send a request looking for index.html the format catches 'html' as :format.
Then in your controller it will get processed by something like
respond_to do |format| format.html { #do something like redirect in here } end
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