(not) displaying optional fields in rails - ruby-on-rails

(Disclaimer: I'm a bloody rookie)
My model contains some optional values. It seems that they may not exist at all (==nil) or that they may exist but are empty. In both cases, I don't want to show anything in my view. Currently, I do it like this:
<% if #score.lyricist and not #score.lyricist.empty? %>
<p>
<strong>Lyricist:</strong>
<%= #score.lyricist %>
</p>
<% end %>
This seems awkward and repetitive. Is there a better way?

blank? method will check both nil and empty values
<% unless #score.lyricist.blank? %>
<p>
<strong>Lyricist:</strong>
<%= #score.lyricist %>
</p>
<% end %>
Documentation here

present? method is the opposite of blank? method.
<% if #score.lyricist.present? %>
<p>
<strong>Lyricist:</strong>
<%= #score.lyricist %>
</p>
<% end %>

Related

How to specify syntax error in Ruby on Rails

My controller is like this
def show
#receipt = Receipt.find(params[:id])
#hospitalizations=#receipt.hospitalizations
#outpatients=#receipt.outpatients
#surgeries=#receipt.surgeries
end
my show.html.erb is like this.
<h1>details of receiptid: <%= #receipt.id %></h1>
<% #hospitalizations.each do |hospitalization| %>
<p>hospitalization_id:<%= hospitalization.id %>hospitalization_start :<%= hospitalization.hospitalization_start %> hospitalization_end:<%= hospitalization.hospitalization_end %> </p>
<% #surgeries.each do |surgery| %>
<p>surgeryid:<%= surgery.id %> surgery_day :<%= surgery.surgery_day %> </p>
<% #outpatients.each do |outpatient| %>
<p>outpatientid:<%= outpatient.id %>outpatient_day :<%= outpatient.outpatient_day %> </p>
<% end %>
When I access it's page,some error like below was incurred. I tried to specify error location,but didn't work well.
It seems syntax error,where should end insert?
If someone has experienced same issues,please let me know.
Each of your each loop requires an <% end %> clause, you can't find the specific line since the error says it reached the end when it expected "end". Close all your loops like this:
<% #hospitalizations.each do |hospitalization| %>
<p>hospitalization_id:<%= hospitalization.id %>hospitalization_start :<%= hospitalization.hospitalization_start %> hospitalization_end:<%= hospitalization.hospitalization_end %> </p>
<% end %>

Ruby on Rails how to get last query?

I'm having trouble trying to figure out when I reached the end of my query. So what I want to do is list all the records in my database that begin with the letter A which I got however I want to output a message if the query turns out blank. When I try I get a bunch of my custom messages even the query didn't turn out blank. Is there any way to tell if I've reached EOF in ruby on rails?
Sample
<div id = "content-A">
<p>A</p>
<% #animes.each do |anime| %>
<% if anime.aname.starts_with?('A') %>
<%= link_to anime.aname, {:action => 'list'} %>
<% else %>
<p>No anime listed in this Category :( </p>
<%end%>
<%end %>
</div>
I believe you want sth like:
<% animes_group = #animes.group_by {|anime| anime.aname.to_s[0].upcase}
('A'..'Z').each do |letter| %>
<div id="content-<%= letter %>">
<p><%= letter %></p>
<% if animes = animes_group[letter] %>
<% animes.each do |anime| %>
<%= link_to anime.aname, {:action => 'list'} %>
<% end %>
<% else %>
<p>No anime listed in this Category :( </p>
<%end%>
<% end %>
You should consider moving some of the logic to the controller here, however what is to be moved depends on many factors like whether #animes are being used anywhere else etc.

Conditional line spacing in ERb partials

This is the code for an address partial I just wrote. People might put single line addresses in either street line, company name is optional, etc... It works exactly how I want it to, but I know that checking each variable twice is ugly and terrible.
<%= "#{a.name}" unless a.name.blank? %>
<% unless a.name.blank? %> <br> <% end %>
<%= "#{a.company_name}" unless a.company_name.blank? %>
<% unless a.company_name.blank? %> <br> <% end %>
<%= "#{a.street_1}" unless a.street_1.blank? %>
<% unless a.street_1.blank? %> <br> <% end %>
<%= "#{a.street_2}" unless a.street_2.blank? %>
<% unless a.street_2.blank? %> <br> <% end %>
<%= "#{a.city}, #{a.state} #{a.zip}" %>
So, my gratuitous use of unless aside, how should I be putting in a conditional line break?
Update:
As discussed below, it is dangerous to use .html_safe on user input. If you do use a helper method as suggested below, you must also sanitize all user input on the way into the database. I've rewritten the code above as:
<% unless a.name.blank? %>
<%= a.name %>
<br>
<% end %>
<% unless a.company_name.blank? %>
<%= a.company_name %>
<br>
<% end %>
<% unless a.street_1.blank? %>
<%= a.street_1 %>
<br>
<% end %>
<% unless a.street_2.blank? %>
<%= a.street_2 %>
<br>
<% end %>
<%= "#{a.city}, #{a.state}" %> <%= a.zip %>
The redundant checking was just me overcomplicating things. I'd strongly recommend against using .html_safe in a situation like this, since you create new problems for yourself: sanitizing the input, and remembering which fields are safe. Better to not override the sensible protection Rails provides.
There are many, many ways to go about cleaning it up, but a helper would be appropriate here:
module ApplicationHelper
def format_address(a)
top = [a.name, a.company_name, a.street_1, a.street_2]
top.reject! {|s| s.blank?} # remove null and empty values
"#{top.join('<br/>')}#{a.city}, #{a.state} #{a.zip}".html_safe
end
end
Then in your view:
<%= format_address(a) %>

How to add a line break with conditional operators

OK, stupid newbie question: how do you make a line break only when it's needed?
I'm creating a basic address listing and only want to include a line of an address if it isn't blank. How do I keep the blank line from printing? I've tried including the break and new line tags, and tried using puts and quotation marks of both varieties and escaping the slashes but can't seem to display the address correctly.
Is there a way to have each line of the address to print on its own line or simply omit the line if there is no info to put on it?
Here's the current version of the code:
<p><strong>Main Address</strong></p>
<p><%= if #vendor.address1 || null
#vendor.address1 #need a break here
end %>
<%= if #vendor.address2 || null
#vendor.address2 #need a break here
end %>
<%= #vendor.city %>, <%= #vendor.state %> <%= #vendor.zip %></p>
This is how I would do it:
<p>
<strong>Main Address</strong>
</p>
<p>
<% unless #vendor.address1.blank? %>
<%= #vendor.address1 %><br>
<% end %>
<% unless #vendor.address2.blank? %>
<%= #vendor.address2 %><br>
<% end %>
<%= #vendor.city %>, <%= #vendor.state %> <%= #vendor.zip %>
</p>
By the way: the || null in your code is not valid Ruby. null does not exist, it should be nil. But even if you had used nil, your code does not do what you expect it to do. For these kind of things, you'd better use blank?.
<p><strong>Main Address</strong></p>
<p><%= #vendor.address1%><%= <br/> if #vendor.address1.blank? %>
<%= #vendor.address2%><%= <br/> if #vendor.address2.blank? %>
<%= #vendor.city %>, <%= #vendor.state %> <%= #vendor.zip %></p>

Whats wrong with my simple If Else?

Im new to RoR/Ruby and i cant seem to get the simplest thing to work. (trust me, ive search google and reread docs, i dont know what wrong)
So in my main view, I added the following:
<%= if 1>2 %>
<%= print "helllloooo" %>
<%= else %>
<%= print "nada" %>
<%= end %>
And nothing is outputted..
**UPDATE**
Ok heres my new CORRECTED code and its STILL NOT WORKING
<th>
<% if 1 > 2 %>
<%= print "helllloooo" %>
<% else %>
<%= print "nada" %>
<% end %>
</th>
Your statements are not intended to be displayed so instead of
<%= if 1>2 %>
write
<% if 1 > 2 %>
Same thing for else and end
EDIT
<% if 1 > 2 %>
<%= "helllloooo" %> #option 1 to display dynamic data
<% else %>
nada #option 2 to display static data
<% end %>
You don't need to use print, or even ERB for the text. Also, your if, else, and end statements should be <%, not <%=:
<% if 1 > 2 %>
helllloooo
<% else %>
nada
<% end %>
<%= already means "print to the HTML response" in ERB (Ruby's own templating language).
So <%= print '...' means "print the return type of print '...'" which is nothing.
The right code would look like:
<% if 1>2 %>
<%= "helllloooo" %>
<% else %>
<%= "nada" %>
<% end %>
In fact you can even omit the <%= because you're just printing strings (not arbitrary objects):
<% if 1>2 %>
helllloooo
<% else %>
nada
<% end %>
The = is the problem. Use <% instead. <%= is for printing something, while <% is for instructions.
for dynamic content use: <%= %>

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