currently working on my project.and
i'm trying to create an existing article page but i keep getting this message
undefined method `errors' for nil: Nil Class. currently working on my project
Edit existing article
<% if#article.errors.any? %>
<h>The following errors prevented the article from getting created</h>
<ul>
<%#article.errors.full_messages.each do |msg| %
#article doesn't exist. It's probably expected that your controller is setting this variable, and you haven't done that (or it's failing to get a value for some other reason).
Note that the places errors exists in your code snippet are method calls (x.y implies y is a method on the object x in Ruby). This is how to identify this problem in the future.
Related
Upon submitting a form in Sinatra, I'm coming up with the following error:
App 40327 output: 2018-06-28 02:59:17 - NoMethodError - undefined method `[]' for nil:NilClass:
App 40327 output: /Library/WebServer/Documents/blammo/routes/publish.rb:87:in `block in <class:MyApp>'
The form is a file upload form, and a single text field. Simple. The file goes through, as does the text field. They are both captured just fine.
I submit the params to a method, which is ultimately responsible for generating the error on the following line down the page:
fname = params[:s_single_file_upload][:filename]
The method in question returns fine with a boolean. I've rewritten it a couple of ways and flushed out anything that might trip something I'm
unfamiliar with.
So the params is messed up if this method mentioned above is being called. So fname can't be assigned. I expect the params to be intact
at this point in the code. Is there any destruction if the params are perused before this point? In another language, I've seen params destroyed
in one way or another for some reason, but I'm not sure about Ruby.
I'm not finding any nil:NilClass, but that's exactly what it's reporting. Here's the trigger of this method:
result = Alpha::rf_alpha_sniff(params)
And the module::method:
module Alpha
def self.rf_alpha_sniff(incoming)
qualifiers = %w(alpha bravo charlie delta echo foxtrot)
incoming.delete('captures')
incoming.delete('splat') # take out Mustermann's 'captures' and 'splat'
incoming.delete('s_single_file_upload') # non-perusal 'single_file_upload'
incoming.values.each do |item|
item = item.gsub(" ","_")
Dev::hq_log("item: #{ qualifiers.include?(item.downcase) }")
return true if qualifiers.include?(item.downcase)
end
return false
end
end
So the page progresses fine without this method. When the method is induced any way, the params seem to get screwed up, so the file is pretty much
gone.
How is this method interfering with the params so that it's unavailable later on down the script? I'm expecting it to be fully available everywhere.
Turns out, using incoming.delete was deleting items from the params hash, as it was a reference to the original, instead of using a copy.
So, I have to copy the params by using params.dup (duplicate) so they are not the same object.
Having a view of the params hash post-testing-method, showed me that objects were indeed deleted. Another one solved.
I'm using Devise (v2.1.2) with Omniauth for user verification. I'm working on a functional test for a controller that takes a JSON object as the POST body and thus using the technique from this question to set the raw POST body. This works fine for development, but when I run tests I get an exception on a method that's completely unauthenticated:
NoMethodError: undefined method `user' for nil:NilClass
Example test:
test "should be able to create an item" do
m = FactoryGirl.attributes_for(:item)
raw_post :create, {}, m.to_json
assert_response :success
end
None of my models have a user method, and nothing in this controller uses authentication, so I was pretty confused. A full stack trace shows that the error comes from the first line of this function in Devise:
def sign_out_all_scopes(lock=true)
users = Devise.mappings.keys.map { |s| warden.user(:scope => s, :run_callbacks => false) }
warden.raw_session.inspect
warden.logout
expire_devise_cached_variables!
warden.clear_strategies_cache!
warden.lock! if lock
users.any?
end
So it looks like in my functional tests (and only in my functional tests) the warden object is nil.
Why is this function being called on an unauthenticated request?
Why doesn't the warden object exist here?
What can I do to fix it?
No idea, Devise is doing its own thing.
See 1.
Include Devise::TestHelpers.
The Devise documentation says that you need to include the helpers in order to use them. It does not say that if you don't include the helpers your functional tests will fail, including those that don't use any authentication, but that's what happens.
(Note the JSON handling here, which I originally thought was the problem, ended up being just a red herring. Even with standard post or get you will have this problem.)
I've installed the filepicker-rails gem and I am able to upload files to the filepicker.io server. When I try to display the image for different users profile, I get the error:
undefined method 'avatar_url' for nil:NilClass
Under my users directory, in the show.html.erb file I have:
<%= filepicker_image_tag #user.avatar_url, w: 160, h: 160, fit: 'clip' %>
I have the following under my User.rb file:
def avatar_url(user)
user.avatar_url
end
Any ideas why this doesn't work?
Basically you'll need a column in your DB called avatar_url. Write a migration that will give you a avatar_url column as just a regular string column. Since you're using Rails, ActiveRecord will provide the avatar_url method for you.
Edit: In your controller you're likely not looking up your user correctly which is resulting in a method call on a NilClass in your view.
As a Ruby on Rails newbie, I understand that the "#" and ":" references have different meanings. I saw this post in SO, which described some of the differences.
# indicates a instance variable (e.g., #my_selection)
: indicates an alias (e.g., :my_selection)
I ran into a situation where I had a standard MVC page, similar to all of the other forms/pages in my webapp.
html.erb snippet
<%= form_for #my_selection do |f| %>
route.rb snippet
resources :my_selections
When I attempt to access this page, I get this error:
NoMethodError in selections#create
Showing C:/somedir/myapp/app/views/my_selections/index.html.erb where line #16 raised:
undefined method `my_selection_index_path' for #<#<Class:0x1197e5676>:0x25439c3b>
Line 16 is the form snippet shown above.
All of my other forms/pages in the same web app are set up in exactly the same way and are working fine. However, once I changed the erb form reference to :my_selection, this error went away and my page behaved normally.
Questions:
Is my understanding of the difference between :my_selections and #my_selections correct?
Why would switching to :my_selection resolve my original error?
Is my understanding of the difference between :my_selections and
#my_selections correct?
Nope :(
: indicates a symbol, its not an alias for anything intrinsically. It's like an immutable string, which is often used as a name to represent something.
In places where the Rails api accepts a symbol in place of an instance variable, internally it's actually doing this:
self.instance_variable_get "##{my_symbol}"
Which actually returns the value of the requested instance variable.
So the only reason that you think symbol correspond to instance variable at all, is because the code that drives the API you are using works that way. Without a framework to do that for you, there is no correlation at all.
Why would switching to :my_selection resolve my original error?
for_form(model_instance) will generate a form that submits to the create action if the model instance is unsaved, or to the update action if the model is already exiting in your DB.
No I don't know what's in #my_selection, but whatever class it is doesn't seem to be generating the routes properly.
resources :my_selections
Will generate a route you would invoke like this:
my_selections_path
How your form is generating a route for my_selection_index_path I'm not sure and it really depends on what your models are.
And when you pass a symbol instead, and there is no corresponding ivar, it uses that as the model name for route generation. Which would do the right thing by trying to invoke my_selections_path, which is directly based on the symbol you pass in.
I'm trying to do this tutorial-> http://netbeans.org/kb/docs/ruby/rapid-ruby-weblog.html
BUT
its giving me this error:
NameError in PostsController#index
uninitialized constant PostsController::Posts
I don't know whats wrong
Somewhere in the files processed for your action you have tried to use a class called Posts. Try using Post instead of Posts. There is no Posts class. You are probably looking for the Post model class.
Look for the mistake in either in the index method of posts_controller.rb or in app/views/posts/index.html.erb. The error message should help you find the offending line.