Im trying to display all the images from active storage on an index page. Note: The image will display in the show page
Heres what i have on the index page:
<% #imagelists.each do |il| %>
<%= image_tag(#il.image) &>
<% end %>
I can do the following which shows the active storage data
<% #imagelists.each do |il| %>
<%= #il.image &>
<% end %>
When you do this:
<% #imagelists.each do |il| %>
You are defining a variable il which is available within that each block.
However, in your code you are referencing #il - an instance variable which doesn't exist. Unlike a normal variable, when you reference an instance variable which isn't defined, you just get nil, not a NoMethodError.
So, just use il instead of #il and you'll be fine.
Related
I'm using Sinatra and I'd like to include another erb file in one of my views but using a variable for the file name.
I was thinking something like this may work but I get an error saying no such file could be found.
<%= erb :'layout/nav/#{device_type}' %>
Currently I'm using the below switch statement to achieve the desired results but the above would be cleaner and less code.
<% case device_type
when 'mobile'%>
<%= erb :'layout/nav/mobile' %>
<% when 'tablet' %>
<%= erb :'layout/nav/tablet' %>
<% else %>
<%= erb :'layout/nav/desktop' %>
<% end %>
Thanks
Giles
I think that could work, you just need to use double quotes to interpolate strings.
Try
<%= erb :"layout/nav/#{device_type}" %>
To learn Rails, I am writing a simple guestbook app that does not use a database.
Anyway, this is what my view looks like:
views/guest_book_pages/home.html.erb
<h1>Guest Book</h1>
<%= #userinput %>
<%= form_for(:guestbook) do |f| %>
<%= f.label :input %>
<%= f.text_field :input %>
<%= f.submit "Sign" %>
<% end %>
And the controller looks like this:
controllers/guest_book_pages_controller.rb
class StaticPagesController < ApplicationController
def home
#userinput = params[:guestbook]["input"]
end
end
Whenever I change the "input" to a symbol :input, the application breaks and gives me a warning that says: undefined method `[]' for nil:NilClass
What is the reason for this? Why can't I use a symbol?
update: Now it won't even work with the string. What is going on?
update#2: It works with both symbols and string. The only problem is that it will not load the first time. If I can get the page to load, then either will work. How can I get the page to load?
Action use to be handle something, and render view.
when you inter home, the home action has be called, and no param posted now.
for your code, home action should just be empty, it just to render the home_page.
your handle code should move to some action like sign_in, whitch handle the form post and you can get the params.
The first time you load the page the params var is not set. It is only when you submit your form back that there are params
Try
#userinput = params[:guestbook]["input"] || ''
which will initialize the #userinput to an empty string if the params is not found
edit:
This will check if the params has the key guestbook first, then will either set the instance var userinput to an empty string or the value of [guestbook][input] if it exsists.
If all else fails, the instance var is initialized to an empty string to prevent an error in your view.
if params.has_key?(:guestbook)
#userinput = params[:guestbook]["input"] || ''
else
#userinput = ''
end
I'm trying to write some puppet .erb, I'd like to handle this "environment" variable if it's:
undefined
a string with newlines
an array.
I've got as far as this:
<% Array(environment).join("\n").split(%r{\n}).each do |f| %>
one line: <%= f %>
<% end %>
But haven't gotten around the undefined case yet. I've tried this
<% if (defined?(environment)).nil? %?
<% Array(environment).join("\n").split(%r{\n}).each do |f| %>
one line: <%= f %>
<% end %>
<% end %>
but am still getting "(erb):11: undefined local variable or method `environment' for main:Object (NameError)" when trying to test it like this:
ruby -rerb -e "environmentUNDEFINEME= [ 'cronvar=cronval', 'var2=val2' ];
puts ERB.new(File.read('templates/job.erb')).result"
Sorry this is so basic, but somebody's got to ask the easy questions. Any help?
I would do this:
<% if defined?(environment) %>
<% Array(environment).each do |f| %>
one line: <%= f %>
<% end %>
<% end %>
I didn't understand why you joining on new lines and then splitting on them again, so I removed it from the example.
I have a _form which renders another form with simple_fields_for. Everything works fine except I can't figure out the symbol that holds the different URLs, I particularly want the thumb URL.
For example, picture.image_uploader_url — but I don't have the actual object, just the :pictures symbol which is being iterated on. So far :image_uploader_url.to_s doesn't give anything useful and I realized this is because that will always just give the symbol name.
Super form:
<%= simple_form_for(#project) do |f| %>
[...]
<%= f.simple_fields_for :pictures do |builder| %>
<%= render "pictures/form", f: builder %>
[...]
Sub form (pictures/_form):
<% unless [:image_uploader_url].nil? or [:image_uploader_url].empty? %>
<%= image_tag(:thumb_url.to_s) %>
<% end %>
<%= f.input :name %>
<%= f.input :description %>
<%= f.input :image_uploader, as: :file %>
<%= f.hidden_field :image_uploader_cache %>
How do I know in general what symbols I will have access to and how do I use them? maybe I dont have them?
EDIT: I don't have 'picture' to work with, only ':pictures' which I'm struggling to find what all I can get from this (i.e. picture has an image_uploader which I can get image_uploader_url(:thumb) but I can't do this with symbols, nor do I know how to get the picture that is the current iteration).
To get the thumb url for picture, just do this: picture.thumb.url. To get the original url, picture.url would do fine.
As far as I could figure out there is no way to get to the individual pictures that are related to the :pictures symbol. I ended up just scrapping the symbol and passing local variables (I was trying to avoid having the controller from making more information directly available).
I still don't have a satisfactory answer but this is the best I could come up with.
I have the following .erb view in a Sinatra app:
<% sessions.each do |session| %>
<%= session.balance_beginning %>
<%= session.balance_ending %>
<% end %>
It works as expected, displaying the beginning and ending balances recorded for each session. I would like to calculate the net balances from within the .erb file, but I can't figure out how to do it. I have tried variations of this:
<% sessions.each do |session| %>
<%= session.balance_ending - session.balance_beginning %>
<% end %>
That doesn't work. I receive the following error in Sinatra:
undefined method `-' for nil:NilClass
How do I do what I'm trying to do?
Right #Zabba, in this case I think you would add a method to your Session model so you could call session.net_balance.
Then in your balance_ending and balance_beginning methods you would want to handle nil, either raise an error or return zero if that is valid.