While refactoring I though it'll b great to convert
%p.user-greatings #{gravatar_for #project.user} #{link_to #project.user.name, #project.user}
to helper method in order to follow DRY convention.
My raw helper method:
def assigned_user
gravatar_for yield link_to yield.name, yield
end
And my view:
%p.user-greatings #{assigned_user{#project.user}}
But my "assigned_user" displays only one part:
gravatar_for yield
How to change my method to display both parts in my view?
Calling methods while not adding braces can be confusing. Actually you are calling:
def assigned_user
gravatar_for(yield(link_to(yield.name, yield)))
end
Since your block ignores the parameters passed to it, you get something equivalent to
gravatar_for yield
I'm not sure what you tried to do, and why did you opt to bass a block rather than a simple value:
def assigned_user(user)
"#{gravatar_for user} #{link_to user.name, user}"
end
%p.user-greatings #{assigned_user(#project.user)}
Related
When I did this in ERB, it works as expected, giving me an a tag that wraps around an image and some text
<%= link_to(...) do %>
<img src="..." />
text
<% end %>
But when I tried to put this in a method, the a tag only wraps the last argument, which in this case, is the text.
def build_link
link_to(...) do
image_tag(...)
text
end
end
Looking at the docs, they only gave an example of using link_to in ERB, so is it smart to assume that using it in a method doesn't work as well and can't accept two parameters?
Following up to my comment:
The reason is behavior happens is because of how Ruby handles blocks, and how Rails handles the output for ActionController.
The trick here is to use handy-dandy concat.
def build_link
link_to("#") do
concat image_tag("http://placehold.it/300x300")
concat "hello world"
end
end
Pretend the block you pass to link_to is just another method, and it gets returned some object/value. In this case, your text object gets returned.
But because you want to output both image_tag and text, you need to pass that together to the output.
I asked a similar question recently, though that was aimed at having multiple blocks as arguments. This problem is a little more immediate.
The problem I have is, I have a helper method which I want to be able to pass content as a block to render. However, if I add more than one partial only the last one in the block is rendered. The methods are below.
def bootrap_panel(title, klass = 'primary', &block)
content_tag(:div, panel_heading(title) + panel_body(&block), class: 'panel panel-' + klass)
end
def panel_body(&block)
content_tag(:div, yield, class: 'panel-body') if block_given?
end
And an example of an issue I am having is here, where only the last partial is being displayed on the page.
=bootrap_panel 'Panels', 'primary' do
- render "dynamic_panels/partials/new"
- render "dynamic_panels/partials/dynamic_panels", dynamic_panels: dynamic_page.dynamic_panels
My first thought is, well I should be yielding the partials to an array or something first, then display that (I am not sure I am able to do that). Secondly, i am using the '-' operator instead of the '=' operator for displaying ruby content in haml. Why?
Pass the block itsef instead of its return value to content_tag:
content_tag(:div, class: 'panel-body', &block)
Other method:
content_tag(:div, capture(&block), class: 'panel-body')
I am reading the book Agile web developpment with rails 4.
there is a part where the products' cart is showing only if it is not empty, my question is the function in the view send to the helper only 2 attributes while in the implementation there are 3 parameters.
in the view I have the bellow code, which render to _cart where I have the cart show
<%= hidden_div_if(#cart.line_items.empty?, id: 'cart') do %>
<%= render #cart %>
<% end %>
the helper has:
module ApplicationHelper
def hidden_div_if(condition, attributes = {}, &block)
if condition
attributes["style"] = "display: none"
end
content_tag("div", attributes, &block) end
end
My question is the &block in this case receives id: 'cart' but is it a optional attibute? that why it comes with &. but what about attributes = {}?
I am really not sure how that is happening, could someone explain me a bit?
Thanks!!
The code between and including do and end is the block, and this is the third argument for hidden_div_if, which is simply passed on to content_tag. The & in the definition of hidden_div_if captures the block in your view, whereas the & in the call to content_tag expands it again to pass it along.
The answer here explains this idea nicely with a few examples. I recommend testing everything out yourself in irb to get a feel for it.
I want to show a post author's name; <% #post.author.name %> works unless author is nil. So I either use unless #post.author.nil? or add a author_name method that checks for nil as in <% #post.author_name %>. The latter I try to avoid.
The problem is that I may need to add/remove words depending on whether there is a value or not. For instance, "Posted on 1/2/3 by " would be the content if I simply display nil. I need to remove the " by " if author is nil.
Null object pattern is one way to avoid this. In your class:
def author
super || build_author
end
This way you will get an empty author no matter what. However, since you don't actually want to have an empty object sometimes when you do expect nil, you can use presenter of some kind.
class PostPresenter
def initialize(post)
#post = post
end
def post_author
(#post.author && #post.author.name) || 'Anonymous'
end
end
Another way is using try, as in #post.author.try(:name), if you can get used to that.
You can use try:
<%= #post.author.try(:name) %>
It will attempt to call the name method on #post.author if it is non-nil. Otherwise it will return nil, and no exception will be raised.
Answer to your second question: In principle there is nothing wrong with the following:
<% if #post.author %>
written by <%= #post.author.name %>
<% end %>
or
<%= "written by #{#post.author.name}" if #post.author %>
But if this is a recurring pattern, you might want to write a helper method for it.
# app/helpers/authors_helper.rb or app/helpers/people_helper.rb
class AuthorsHelper
def written_by(author)
"written by #{author.name}" if author
end
end
# in your views
<%= written_by(#post.author) %>
Write a method which accepts any variable and checks to see if it is nuil first, and if it is not displays it. Then you only have to write one method.
I found your question interesting as I have often come across similar situations, so I thought I'd try out making my first Rails plugin.
I'm afraid I haven't put in any tests yet but you can try it out http://github.com/reubenmallaby/acts_as_nothing (I'm using Ruby 1.9.1 so let me know if you get any problems in the comments or on Github!)
I have this code
<% if approved %>
<td>Flow Number</td>
<% end %>
and I'd like to shorten it using statement modifiers. Of course I can use
<%="<td>Flow Number</td>" if approved -%>
but is there a shorter way? I'd also like to get the markup out of quotes.
You could use "content_tag", which isn't actually shorter, but may be more appealing, keeping HTML out of your ruby blocks:
<%= content_tag :td, "Flow Number" if approved %>
Otherwise, you could consider writing a helper - which may be appealing if you need to reuse similar logic throughout the page (or over several pages).
Maybe HAML?
That'd be:
- if approved?
%td Flow Number
Not exactly what you're after I know.
Yeah, I think a helper method using content_tag internally would be the best short way.
Using a helper method, you could also yield to the desired output like this:
# in view helper
def show_if(condition, wrapper_tag)
condition ? content_tag(wrapper_tag, yield) : ''
end
# in view
<%= show_if(approved, :td) {'Flow Number'} %>
or
# in view helper
def show_if(condition)
condition ? yield : ''
end
# in view
<% show_if(approved) do %>
<td>Flow Number</td>
<% end %>
I like this last method for a nice generic way to show or hide whole blocks based on a condition. Hope that helps!