I have an admin namespace which gives me the usual routes such as admin_projects and admin_project, however they are not behaving in the usual way. This is my first Rails 2.3 project so maybe related I can't find any info via Google however.
map.namespace(:admin) do |admin|
admin.resources :projects
end
The strange thing is for a given URL (eg. /admin/projects/1) I don't have to pass in an object to get URL's it somehow guesses them:
<%= admin_project_path %> # => /admin/projects/1
No worries, not really a problem just not noticed this before.
But if I try and pass an object as is usual:
<%= admin_project_path(#project) %> # => admin_project_url failed to generate from {:controller=>"admin/projects", :action=>"show", :id=>#<Project id: 1, name: "teamc...>
":id" seems to contain the entire object, so I try passing the id directly and it works:
<%= admin_project_path(#project.id) %> # => /admin/projects/1
This would not be so bad but when it comes to forms I usually use [:admin, #object], however:
<%= url_for [:admin, #project.id] %> # => undefined method `admin_fixnum_path'
So I can't pass in an id, as it needs an objects class to work out the correct route to use.
<%= url_for [:admin, #project] %> # => Unfortunately this yields the same error as passing a object to admin_project_path, which is what it is calling.
I can't spot any mistakes and this is pretty standard so I'm not sure what is going wrong...
Interesting. What happens when you define a to_param method on Project? For instance
class Project < ActiveRecord::Base
def to_param
self.id
end
end
This should be the default and this shouldnt be necessary. But what happens if you make it explicit? Try adding the above method then going back to your original approach of only passing around #project
I wish I could help you on this one. We have a large application with several namespaced sections. Our routes are defined in the exact method you have described and we are calling our path helper with objects. No where in the application are we accessing using the id.
Our application started on Rails 2.1 and has transitioned through 2.2 and 2.3 with no significant changes to the routing. Sorry I couldn't be more help.
Peer
Related
I've got routes setup like the following:
resources :projects do
resources :project_factors, as: factors
end
I like having the as: :factors so the route becomes:
project_factor_path(#project, #project_factor)
instead of
project_project_factor_path(#project, #project_factor)
but I'm having trouble getting form_for to generate the correct route.
form_for [#project, #project_factor] fails (as expected) because it tries to use project_project_factor_path, so I tried:
form_for [#project, #project_factor], as: :factor
but this fails with exactly the same error.
Is there a way to get rails to generate the correct path here without explicitly setting the correct url parameter for the create and update case?
Not ideal, but you can pass in the path separately to the objects eg something like:
form_for [#project, #project_factor], :url => project_factor_path(#project, #project_factor)
(Note: not tested)
It feels a bit redundant to me though... which is exactly what you were trying to reduce, so probably not a good solution for you :P
An alternative might be just to rename your project_factor model to factor. You can still give the database table name as project_factors (use self.table_name = 'project_factors' in the class for Rails to find it).
To me, project/project_factors feels a bit like smurf-typing... ;)
YMMV
I am just starting to wrap my head around parameters in rails. I am currently working on a project that isn't accessible to the public, so keeping params secure isn't exactly a priority in this case.
I have a link_to to a different controller action that requires an object id to fulfil the controller action.
=link_to "Barcode", print_barcode_label_admin_items_path(:item_to_print => { :article_id => article.id })
Then in the relevant controller
def print_barcode_label
if params[:item_to_print][:article_id].present?
return if force_format :pdf
..........
private
def params_document
params.require(:document).permit!
end
As I was writing the code for this controller I am certain the parameters were being passed (I am using the better-errors gem to debug along the way so I could see them being passed in the request parameters hash). But now, not sure what I have done, but i get the error
undefined method `[]' for nil:NilClass
failing at line two in my above controller action. I am sure there is something really basic I am missing. What is it? Is there a more favourable way of doing this?
Update
So I started playing with other possible solutions, and one is naming a route that specifically carries the parameter
get 'print_barcode_label/:article_id', to: 'documents#print_barcode_label', as: 'print_barcode_label'
This seems a more robust and sensible approach. Howeever, despite passing the variable in the link, like this
=link_to "Barcode", print_barcode_label_admin_items_path(article.id)
Gives a no route matches error
No route matches {:action=>"print_barcode_label", :controller=>"admin/documents"} missing required keys: [:article_id]
It is hard to answer this question without seeing more code with some context. But if you want to do rails way you should propably create custom action on document resource.
In your routes.rb:
namespace :admin do
resources :documents
get :print_barcode_label, :on => :member
end
end
And then you can create link to this action:
= link_to 'Barcode', print_barcode_label_admin_document_path(article)
i'v been trying to resolve this error for the past 5 hours and I'm gonna burn my computer if I can't solve this.
undefined method `pushes_path' for #<#:0x007f859d605250> this is the error code I'm getting but i don't understand why.
this is my index.html.erb file inside of the interaction
<%= simple_form_for #push do |f| %>
<%= f.input :payload, as: :text %>
<%= f.input :segment, as: :radio_buttons %>
<%= submit_tag "start the campaign" %>
<% end %>
and this is my interaction controller
class InteractionController < ApplicationController
def index
#push =Push.new
end
end
Push is my table in the database and i'll get the inputs and write them in the database to use them for later one.
and this is my routes file
devise_for :partners
get 'home/index'
get 'segmentation/index'
get 'interaction/index'
root to: "home#index"
i really don't know why its looking for pushes_path, what am i doing wrong?
form_for
The problem you have is that your form_for method is going to try and generate a route based off your #path object. And as such, if you don't have a path created for it, you'll receive the error you're getting:
:url- The URL the form is to be submitted to. This may be represented
in the same way as values passed to url_for or link_to. So for example
you may use a named route directly. When the model is represented by a
string or symbol, as in the example above, if the :url option is not
specified, by default the form will be sent back to the current url
(We will describe below an alternative resource-oriented usage of
form_for in which the URL does not need to be specified explicitly).
The bottom line is that as Rails is object orientated, its built around the assumption that you'll have routes set up to handle the creation of individual objects.
Every time you use form_for, Rails will attempt to construct your routes from your object -- so if you're trying to do the following, it will treat the routes as photo_path etc:
#app/views/pushes/new.html.erb
<%= form_for #push do |f| %>
...
<% end %>
--
Fixes
As #mandeep suggested, there are several fixes you can employ to get this to work:
Firstly, you can just create a route for your push objects:
#config/routes.rb
resources :pushes
Secondly, as you're using a different controller, you'll want to do the following:
#config/routes.rb
resources :interactions
#app/views/pushes/new.html.erb
<%= form_for #push, url: interaction_path do |f| %>
...
<% end %>
This will route your form submission to the interactions controller, rather than the pushes controller that you'll get by default!
Objects
Something to consider when creating Rails-based backends is the object-orientated nature of the framework.
By virtue of being built on Ruby, Rails is centered on objects - a term for a variable, which basically encompasses much more than just a piece of data. Objects, in the case of Rails, are designed to give the application:
Once you understand this, the entire spectrum of Rails functionality becomes apparent. The trick is to realize that everything you do in Rails should be tied to an object. This goes for the controllers too:
--
Ever wondered why you call resources directive in your routes, for a controller? It's because you're creating a set of resourceful routes based for it:
Do you see how it's all object orientated?
This gives you the ability to define the routes for specific controllers etc. The most important thing to note is how this will give you the ability to determine which routes / controller actions your requests should go
--
There's nothing wrong in using the controller setup as you have - the most important thing is to ensure you're able to define the custom URL argument, as to accommodate the non-object based structure
In your index action you have
def index
#push =Push.new
end
and your form has
<%= simple_form_for #push do |f| %>
so your form is looking for /pushes with post verb or pushes_path and you don't have that route in your routes.rb file so to fix this you need to add this in routes.rb:
resources :pushes
Update:
when you add resources :push rails basically creates seven different routes for you. One of which is
POST /pushes pushes#create create a new push
and if you look at the html generated by your form it would be something like:
<form action="/pushes" class="new_push" id="new_push" method="post">
// your fields
</form>
notice the action and verb so when you submit your form your routes are checked for them and since you didn't define them in your routes you were getting this error
And how will i be able to use the params i m getting from this form with this new resource addition?
Your form will take you to pushes_controller create action so first of all you'll have to define them. You can access them simply by params[:pushes] in your controller action but since you want to create a new record so you'll have to permit those attributes, checkout strong parameters
If you are using rails >= 4 then you can do
class PushesController < ApplicationController
def create
#push =Push.new(push_params)
if #push.save
redirect_to #push
else
render 'interaction/index'
end
end
private
def push_params
params.require(:push).permit(:attributes)
end
end
If you are using rails < 4 then instead of permitting these attributes(because strong parameters feature came from rails 4) you'll have to tell rails that these attributes are accessible by writing this in your pushes.rb
attr_accessible :attribute_name
Why it is assuming that its pushes controller?Because of the Push.new creation?
That's because if you look at your index action #push = Push.new so #push contains a push object with nil values(as you have just initialized it) so this is where rails magic comes, rails automatically tries to figure out url of your form and since your #push is only an initialized variable so rails takes you to create action for it. For details you should checkout rails polymorphic urls If you want your form to go to interaction_controller or some other url then you'll have to specify the url option for it
<%= form_for #push, url: "your_url_for_custom_method" %>
// other fields
<% end %>
And in the end you should really read docs
As my understanding on nested resources, on edge Rails, should not
link_to 'User posts', #user.posts
point to
/users/:id/posts
?
The routes.rb file contains
map.resources :users, :has_many => :posts
If this is not the default behavior, can it be accomplished doing something else?
Along the same lines as Rishav:
link_to "User Posts", [#user, :posts]
Here's an explanation from my blog.
Really early on in Rails, you would write routes like this:
redirect_to :controller => "posts", :action => "show", :id => #post.id
What this would do is dutifully redirect to the show action inside the PostsController and pass along the id parameter with a
value of whatever #post.id returns. Typical 302 response.
Then Rails 1.2 came along and allowed you to use routing helpers, like this:
redirect_to post_path(#post)
And the people rejoiced.
This would do effectively the same thing. post_path here would build a route using the #post object that would look something
like /posts/1 and then redirect_to would send back a 302 response to that route and the browser would follow it.
Then later versions (I can't remember which one), allowed syntax like this:
redirect_to #post
And the people rejoiced a second time.
Magic, but not really
Any sufficiently advanced technology is indistinguishable from magic.
While this seems like magic, it's not. What this is doing is actually very, very neat. The redirect_to method, much like its cousins link_to and form_for all use a common method to build URLs, called url_for. The url_for method takes many different
varieties of objects, such as strings, hashes or even instances of models, like in the example above.
What it does with these objects then, is quite neat. In the case of the redirect_to #post call above, it inspects the #post
object, sees that it is an object of the Post class (we assume, anyway) and checks to see if that object has been persisted in a
database somewhere by calling persisted? on it.
By "persisted", I mean that a Ruby object has a matching record in the database somewhere. The persisted? method in Active Record is implemented like this:
def persisted?
!(new_record? || destroyed?)
end
If the object wasn't created through a call such as Model.new then it won't be a new record, and if it hasn't had the destroy method called on it won't be
destroyed either. If both of these cases are true, then that makes the object has most likely been persisted to the database in the form of a record.
If it has been persisted, then url_for knows that this object can be found
somewhere, and that the place it can be found is most likely under a method called post_path. So it calls this method, and passes
in the to_param value of this object which is usually the id.
In short, it's effectively doing this:
#{#post.class.downcase}_path(#post.to_param)
Which comes out to being this:
post_path(1)
And when that method is called you would get this little string:
"/posts/1"
Lovely!
This is called polymorphic routing. You can pass an object to methods like redirect_to, link_to and form_for and it will
attempt to work out the correct URL of what to use.
The form of form_for
Now, when you're coding Rails you may have used form_for like this a very long time ago:
<% form_for #post, :url => { :controller => "posts", :action => "create" } do |f| %>
Of course, with advancements in Rails you could simplify it to this:
<% form_for #post, :url => posts_path do |f| %>
Because the form is going to default to having a POST HTTP method and therefore a request to posts_path is going to go to the
create action of PostsController, rather than the index action, which is what would result if it were a GET request.
But why stop there? Why not just write this?
<%= form_for #post do |f| %>
Personally, I see no reason not to... if it's something as simple as this. The form_for method uses url_for underneath, just like
redirect_to to work out where the form should go. It knows that the #post object is of the Post class (again, we assume) and it
checks to see if the object is persisted. If it is, then it will use post_path(#post). If it's not, then posts_path.
The form_for method itself checks to see if the object passed in is persisted also, and if it is then it'll default to a PUT HTTP
method, otherwise a POST.
So this is how form_for can be flexible enough to have an identical syntax on both a new and edit view. It's becoming more and
more common these days for people to even put their whole form_for tags into a single partial and include it in both the new and
edit pages.
A more complex form
So form_for is fairly simple for when you pass a normal object, but what happens if you pass an array of objects? Like this, for
instance:
<%= form_for [#post, #comment] do |f| %>
Well, both url_for and form_for have you covered there too.
The url_for method detects that this is an array and separates out each part and inspects them individually. First, what is this
#post thing? Well, in this case let's assume it's a Post instance that is persisted and has the id of 1. Second, what is this
#comment object? It's a Comment instance that has not yet been persisted to the database.
What url_for will do here is build up the URL helper method piece by piece by placing each part in an array, joining it into a routing method and then calling that routing method with the necessary arguments.
First, it knows that the #post object is of the Post class and is persisted, therefore the URL helper will begin with post. Second, it knows that the #comment object is of the Comment class and is not persisted, and therefore comments will follow post in the URL helper build. The parts that url_for now knows about are [:post, :comments].
The url_for method combines these individual parts with an underscore, so that it becomes post_comments and then appends _path
to the end of that, resulting in post_comments_path. Then it passes in just the persisted objects to the call to that method, resulting in a call like this:
post_comments_path(#post)
Calling that method results in this:
"/posts/1/comments"
Best part? form_for will still know to use POST if the #comment object is not a persisted object, and PUT if it is. A good
thing to remember is that the form_for is always for the last object specified in the array. The objects prior to it are just its
nesting, nothing more.
The more objects that are added, the more times url_for will do the hard yards and build the path out... although I recommend that
you keep it to just two parts.
A symbolic form
Now that we've covered using an array containing objects for form_for, let's take a look at another common use. An array containing
at least one Symbol object, like this:
<%= form_for [:admin, #post, #comment] do |f| %>
What the url_for method does here is very simple. It sees that there's a Symbol and takes it as it is. The first part of the
url will simply be the same as the symbol: admin. The URL that url_for knows of at this point is just [:admin].
Then url_for goes through the remaining parts of the array. In this case, let's assume both #post and #comment are persisted
and that they have the ids of 1 and 2 respectively. Same classes as before. url_for then adds post to the URL that it's building,
and comment too, resulting in [:admin, :post, :comment].
Then the joining happens, resulting in a method of admin_post_comment_path, and because both #post and #comment are persisted here,
they're passed in, resulting in this method call:
admin_post_comment_path(#post, #comment)
Which (usually) turns into this path:
/admin/posts/1/comments/2
You can use the array form of polymorphic routing with the redirect_to, link_to and form_for methods. There's probably other
methods that I'm not remembering right now that can do it too... it's generally anything in Rails that would normally take a URL.
There's no need to build your URLs in any Rails version greater-than 2 using hashes; that's pretty old school.
Instead, experiment with your new knowledge of polymorphic routing and use it to the best of your advantage.
This should work:
link_to "User Posts", user_posts_path(#user)
for more details visit:
http://guides.rubyonrails.org/routing.html
link_to uses url_for which uses polymorphic_url.
polymorphic_url:
builds the helper method, using the class name of active record objects
calls the helper with the active record objects as arguments
Therefore, as others said, you should use:
link_to 'User Posts', [#user, :posts]
for which the path is:
user_posts_path(#user)
^^^^ ^^^^^ ^^^^^
1 2 3
class of #user because it is an active record
convert to string because symbol
add as call argument because active record
That builds the good helper method.
This is how to link to a nested resource in the latest Rails:
link_to 'Destroy Comment', post_comment_path(comment.post, comment)
Note: This is in a partial so there isn't a #.
I'm having a little issue...I setup a rails application that is to serve a german website. To make use of Rails' internal pluralization features, I kept all my models in english (e.g. the model "JobDescription").
Now, if I call "http://mysite.com/job_descriptions/", I get all my job_descriptions....so far, so good. Because I didn't want the english term "job_descriptions" in my url, I put the following into my routes.rb
map.german_term '/german_term', :controller => 'job_descriptions', :action => 'index'
map.german_term '/german_term/:id', :controller => 'job_descriptions', :action => 'show'
If I call "http://mysite.com/german_term/" or "http://mysite.com/german_term/283" I get all my job_descriptions, which is fine.
However, to make the URL more SEO friendly, I'd like to exchange the id for a more userfriendly slug in the URL. Thus, I put the following in my job_description.rb:
def to_param
"#{id}-#{name.gsub(/[^a-z0-9]+/i, '-')}"
end
which, whenever I use "job_description_path" in any link_to method, renders my URLs out to something like "http://mysite/job_descriptions/13-my-job-description-title".
However, and this is where I'm stuck, I'd like to get "http://mysite/german_term/13-my-job-description-title". I already tried to exchange the "job_description_path" with "german_term_path" in the link_to code, but that only generates "http://mysite/german_term/13". Obviously, to_param isn't called.
One workaround I found is to build the link with:
<%= link_to job_description.name, german_term_path(job_description.to_param) %>
But that's rather tedious to change all the link_to calls in my code. What I want is to replace "job_description" by "german_term" whenever it occurs in a URL.
Any thoughts?!?
Regards,
Sebastian
I think you're going to need to use the restful route helpers to get what you want.
In that case, it wouldn't take much re-factoring (assuming you've mapped JobDescriptions as a resource). Leave your to_param as is and change your JobDescriptions route to something like the following:
map.resources :job_descriptions, :as => 'german_term'
Hope this helps!
Rails only utilizes the
def to_params
end
URL builder when you are using a restful route/link helper. The only way I am aware of is to do it similar to how you did, unless you are willing to just scrap your english language links and do it all in German. In that case, just get rid of the named route lines and change the to_params to use the correct name field from the database. At that point, the REST routes should behave correctly.