[Devise] redundant use of method: :delete while using destroy_user_session_path

While using devise I have to use
%li= link_to “Sign up”, destroy_user_session_path, method: :delete
now that destroy_user_session_path should automatically default to
delete
method because that’s how it is defined in routes. Why is it generate
links
to get method for default for given path?

On Saturday, March 8, 2014 9:32:04 AM UTC-5, Arun kant sharma wrote:

While using devise I have to use
%li= link_to “Sign up”, destroy_user_session_path, method: :delete
now that destroy_user_session_path should automatically default to delete
method because that’s how it is defined in routes. Why is it generate links
to get method for default for given path?

Before I answer your question, something looks a little off.
destroy_user_session_path would normally be used to Log Off, not for
Sign
Up.

However, to answer your question, there are two independent actions
here.
The first is the use of the link_to method to generate a html anchor
tag.
In your case, this would look something like:

Sign
Up

This gets passed to the browser as part of the html for the page.

Now, let’s assume the user clicks on this link. This is generates a
completely separate action from the one above.

The browser now processes the anchor link. However, in HTML, anchor
links
(the <a … >) only support GET method requests and no matter what you
put
in there, the request generated will be a GET. Rails has written
javascript to intervene, detect the “data-method” and generate a request
with the appropriate method (in this case, delete). If javascript is
disabled or there’s an error, it will get sent as a GET request.

Therefore, the following information gets passed to the routing table:

URL: /users/sign_out
METHOD: Delete

It looks for a route matching both of those parameters and routes
accordingly. Please note the routing table does not define methods for a
request, it uses the method passed in a request in combination with the
URL
to determine the appropriate route for the request (or reject it if no
rule
is defined). You might want to read (or re-read) the following:

http://edgeguides.rubyonrails.org/routing.html

My question is that why link_to method does not default to DELETE method
when passed link is destroy_user_session_path as we know from routes
what
it should use. I don’t have problem passing method: :delete but it feels
redundant.
Also my bad. “Sign Up” should be “Sign out”.

On Tuesday, March 11, 2014 10:27:36 AM UTC, Arun kant sharma wrote:

My question is that why link_to method does not default to DELETE method
when passed link is destroy_user_session_path as we know from routes what
it should use. I don’t have problem passing method: :delete but it feels
redundant.
Also my bad. “Sign Up” should be “Sign out”.

I think that would turn link_to from a very simple help which is just
generating some markup for you into a much more complicated ones that
interrogates routes in order find out what methods are acceptable.

Fred

On Tuesday, March 11, 2014 7:39:52 AM UTC-4, Frederick C. wrote:

I think that would turn link_to from a very simple help which is just
generating some markup for you into a much more complicated ones that
interrogates routes in order find out what methods are acceptable.

Fred

I agree with Fred and adding overhead to view helpers is generally not
good. There is also another problem with doing that. The example you
chose happens to have only one method mapped to the URI pattern. This
frequently isn’t the case. For example, suppose you have the following
in
your routes.db file:

resources :products

That’s going to generate four routes for product_path, all having the
url
‘/products/:id(.:format)’. product_path/method:GET maps to one action.
product_path/method:PATCH maps to a different action, and so on (the
other
two are PUT and DELETE).

If you do as you suggest and have the following statement:

<%= link_to “my example”, product_path(1) %>

There would be no way the program could assign a method from the
routes.db
file since it would have four to choose from.

mike

On 11 March 2014 10:27, Arun kant sharma [email protected] wrote:

My question is that why link_to method does not default to DELETE method
when passed link is destroy_user_session_path as we know from routes what it
should use. I don’t have problem passing method: :delete but it feels
redundant.

You are missing what the purpose of routes.rb is. It is to tell the
system what to do when a request is received (how to route it in
fact). It is nothing to do with generating the code in the views.

Colin

On 12 March 2014 02:04, Walter Lee D. [email protected] wrote:

system what to do when a request is received (how to route it in
in the routes.rb, right?
I don’t believe so, no, though someone may correct me. Easy to find
out. Have a look at the html generated by widgets_path in the view,
delete resources :widgets in routes.rb, restart the server and view
the page again. Compare the html, which I believe will show no
difference. If you click the link you should get a route not found
error.

Colin

On Mar 12, 2014, at 10:25 AM, Colin L. wrote:

You are missing what the purpose of routes.rb is. It is to tell the

in the routes.rb, right?

I don’t believe so, no, though someone may correct me. Easy to find
out. Have a look at the html generated by widgets_path in the view,
delete resources :widgets in routes.rb, restart the server and view
the page again. Compare the html, which I believe will show no
difference. If you click the link you should get a route not found
error.

Wow, tested this just now by removing the index method from routes with
except: :index, and sure enough, the helper still works. This directly
contradicts what I heard from Obie F. a number of years ago at
the Philly ETE conference. Probably used to be true, and didn’t survive
the many changes to Rails over the years. I tried removing the index
method from my widgets_controller too, just to see if that was the
source, and I can’t make this helper give up. Very odd.

Walter

On Mar 11, 2014, at 4:59 PM, Colin L. wrote:

On 11 March 2014 10:27, Arun kant sharma [email protected] wrote:

My question is that why link_to method does not default to DELETE method
when passed link is destroy_user_session_path as we know from routes what it
should use. I don’t have problem passing method: :delete but it feels
redundant.

You are missing what the purpose of routes.rb is. It is to tell the
system what to do when a request is received (how to route it in
fact). It is nothing to do with generating the code in the views.

True, the routes file doesn’t generate the views directly, but doesn’t
the routes file generate or seed the url helpers? When I type in

<%= widgets_path %>

in a view, that’s coming (somewhat) directly from the line

resources :widgets

in the routes.rb, right?

Walter

On Wednesday, March 12, 2014 11:05:44 AM UTC-4, Walter Lee D. wrote:

wrote:

Philly ETE conference. Probably used to be true, and didn’t survive the

You received this message because you are subscribed to the Google

I think there might be a bug here. Otherwise, I’m stumped. Dynamic
URI’s
are created using the routes.rb file and made available for any ruby
code
(views, controllers, etc.). I did a little testing as recommended
above.
I created a base application using a REST class Products. I then
created
a page with a link to products_path (as a GET) which should invoke the
index method. The link looks as follows:

<%= link_to “testing product link”, products_path %>

In the first test case, I had the following in my routes file:

resources :products
root ‘pages#home’

Note, the root entry is just to define a default. The home page is
where I
had my link. This works as you would expect.

Next, I changed this to:

resources :products, except: [:index]
root ‘pages#home’

In this case, when I run rake routes, the route for products_path,
method:GET is gone. Also, if I type ‘localhost:3000/products’, I get a
routing error. However, the home page still comes up and the link still
translates to the following:

This is unexpected.

Next, I eliminated the resources route and defined the following route:

get ‘/getproducts’ => ‘pages#about’, as: :products

pages#about is just a static page i built for this example. I did this
because the only way the link_to function could get this right would be
to
read the routes file. It did. The link produced was:

Finally, I deleted all routes except the root ‘pages#home’. Now, the
home
page gives me an error on the link_to function because of an invalid
route.

Therefore, the link_to function does use dynamic paths that are
generated
from the routes file, although this is not a specific part of view
rendering, it’s available anywhere you have ruby code, such as
controllers.
However, in the one case where REST routes are defined, it’s ignoring
the
except parameter (or, at least, that’s what it appears to be doing).

On 13 March 2014 15:08, mike2r [email protected] wrote:


Finally, I deleted all routes except the root ‘pages#home’. Now, the home
page gives me an error on the link_to function because of an invalid route.

Therefore, the link_to function does use dynamic paths that are generated
from the routes file, although this is not a specific part of view
rendering, it’s available anywhere you have ruby code, such as controllers.
However, in the one case where REST routes are defined, it’s ignoring the
except parameter (or, at least, that’s what it appears to be doing).

I see you are correct, those paths are generated from the routes. I
was completely wrong.

Colin

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