I use the following code to group locations depending on the first letter.
mobile_controller:
def index
#locations = Location.all.group_by{|l| l.name[0].capitalize.match(/[A-Z]/) ? l.name[0].capitalize : "#"}
end
view:
<% #locations.keys.sort.each do |starting_letter| %>
<%= starting_letter %>
<% #locations[starting_letter].each do |location| %>
<%= location.name %>
<% end %>
<% end %>
Everything works fine on my local machine, but heroku doesn't like it and keeps showing me this error:
NoMethodError (undefined method `capitalize' for 66:Fixnum):
app/controllers/mobile_controller.rb:13:in `search'
app/controllers/mobile_controller.rb:13:in `search'
How can I fix this?
Thanks in advance
Solution:
Updated my Heroku Stack to Ruby 1.9.
Your local machine is probably on Ruby 1.9, and your Heroku app is running on 1.8.
In Ruby 1.8, calling String#[] will give you the character code (a number), whereas Ruby 1.9 will give you a string with the first character.
# Ruby 1.8
"test"[0]
# => 116
# Ruby 1.9
"test"[0]
# => "t"
You can use l.name[0..0] to get around this, or switch to a Ruby 1.9 stack on Heroku.
Under Ruby 1.8, String#[] returns the ASCII code of the referenced character rather than the character itself. Try l.name[0,1].capitalize in your controller.
Related
I frequently use Sinatra for smallish projects. It's pretty good for what I need but I miss the ability to mark strings as HTML safe, and then ERB knowing when to escape or not escape accordingly.
I'd really like it if I could rip out the patches that Rails makes to Erubi (around here) and then apply those patches to Erubi myself so that tilt can just use the monkey-patched Erubi and everyone lives happily ever after. However, after digging around in the source, it's not clear to me how I could actually accomplish that.
I also tried to find some way to get an interface into ActionView like the render method, but I couldn't even find where that was defined.
How can I use ActionView outside of Rails, ideally by using ActionView's monkey-patches to Erubi, or if that won't work, how else can I use ActionView to go from template string to rendered string outside Rails?
Specifically, I'd like to be able to do the following:
def some_wrapper_func(unescaped_html)
"<div>#{h unescaped_html}</div>".html_safe
end
# test1.erb
hello world <%= "<script>alert('hi');</script>" %> <%= some_wrapper_func("<span>foobar</span>") %>
#=> hello world <script>alert('hi');</script> <div><span>foobar</span></div>
What you need here is ActiveSupport. I'm not sure if it is overkill or not, but you can do this:
#app.rb:
require 'sinatra'
require 'active_support/all'
get '/' do
erb :index
end
And in a view:
#views/index.erb
Hello, world!
<%= "<script>alert('Hello!')</script>".html_safe %>
Mind that requre 'active_support' will load nothing and requre 'active_support' will load all modules. You can specify what modules do need as described
in Active Support Core Extensions.
If the only goal is to enable auto-escaping, there is no need for ActionView at all. It can be done like this (mind the <%== %> tag):
#app.rb
require 'sinatra'
require 'erubis'
set :erb, :escape_html => true
get '/' do
erb :index
end
#View
<%= "<script>alert('Hello, and it will not produce alert!')</script>" %>
<%== "<script>alert('Hello and it will!')</script>" %>
We will try to get ActionView up and running with Sinatra (or any Ruby program):
require 'sinatra'
require 'action_view'
get '/' do
av_render :index
end
def av_render view
paths = ActionView::PathSet.new(["views"])
lookup_context = ActionView::LookupContext.new(paths)
renderer = ActionView::Renderer.new(lookup_context)
view_context = ActionView::Base.new(renderer)
renderer.render(view_context, template: view)
end
And in the view we use html_safe:
<%= "<script>alert('Hello, and it will not produce alert!')</script>" %>
<%= "<script>alert('Hello and it will!')</script>".html_safe %>
Wrapper functions also work with this approach. The only problem here is a custom-render method, but it can be avoided.
If you'd like to avoid ActionView entirely and just use Tilt+Erubi, you can actually create for yourself a SafeString class and have Erubi use it for compilation.
Erubi takes some important options, specifically:
- escape: If this is true, then <%= %> will escape by default, otherwise only <%== %> will escape by default
- bufval: Internally, erubi uses what is basically an accumulator to build up your template. This is the value that it will initialize that accumulator to. It is important that it has a <<(str) method to concat new pieces on, and a to_s method to get the return value out.
- escapefunc: The function that Erubi will use for escaping. It's important to override this, because we'll want to escape anything that isn't a SafeString but let SafeStrings pass through unchanged.
So, first let's define this SafeString class:
# main.rb
require 'tilt'
require 'erubi'
class SafeString
def initialize(str = '')
#str = str
end
def <<(str)
if str.is_a? String
return (#str << str)
elsif str.is_a? SafeString
#str = #str << str
return self
else
throw "Can't concat"
end
end
def to_s
#str
end
def self.escape(val)
if val.is_a? SafeString
return val.to_s
else
return Erubi.h(val.to_s)
end
end
module Helpers
def raw(content)
SafeString.new(content)
end
end
end
Then, we'll need to include the raw helper we defined and to test it on an ERB file:
include SafeString::Helpers
puts Tilt::ErubiTemplate.new("somefile.erb", bufval: 'SafeString.new', escapefunc: 'SafeString.escape', escape: true).render
# somefile.erb
<%= "<script>alert('Hello, and it will not produce alert!')</script>" %>
<%= raw("<script>alert('Hello and it will!')</script>") %>
And this will give us the output we desire!
# stdout
<script>alert('Hello, and it will not produce alert!')</script>
<script>alert('Hello and it will!')</script>
To improve this, instead of this minimal SafeString class, you could use ActiveSupport::SafeBuffer.
I'd like to make some modifications on variable in erb templates:
e.g. decode base64 and split string
It tried
<%= Base64.decode64(#my_variable).rpartition(':').last %>
and
<%= Base64.decode64(<%= #my_variable %>).rpartition(':').last %>
and via scope
<%= Base64.decode64(scope['my_class::my_variable']).rpartition(':').last %>
but it is nil.
Filepath: /usr/lib/ruby/1.9.1/base64.rb
Line: 58
Detail: undefined method `unpack' for nil:NilClass
puppet version 3.8.2
The first example that you tried is the correct ERB notation.
That error would be occurring because you passed the nil object to Base64.decode64():
[1] pry(main)> require 'base64'
=> true
[2] pry(main)> Base64.decode64(nil).rpartition(':').last
NoMethodError: undefined method `unpack' for nil:NilClass
from /Users/alexharvey/.rvm/rubies/ruby-2.1.4/lib/ruby/2.1.0/base64.rb:58:in `decode64'
(Admittedly, I don't have your Ruby 1.9.1 and I wasn't able to easily install it, but it's unlikely this changed.)
That means that #my_variable is set to nil, and that would happen if you failed to actually set the Puppet variable $my_variable in your manifest.
So you would need to call the template with a block something like this:
$my_variable = 'foo'
file { '/tmp/foo':
ensure => file,
content => template('test/mytemplate.erb')
}
I don't have much experience with Ruby all I wan't to do is render a value that I declare in an .rb file in an .erb file.
In my .rb file I have this:
def abc()
begin
"aaaaa"
end
end
In my .erb file I have this:
Hello <% abc %>
When I run the app I only see:
Hello
But I expect to see:
Hello aaaa
Anybody can give me a hand, I don't really know ruby at all. Also I have no idea if this is ruby or ruby on rails so sorry if the tag below is wrong.
In Sinatra, register your method as a helper in .rb file:
helpers do
def abc
"aaaaa"
end
end
Omit parentheses if your methods don't need arguments. Also, begin/end block isn't necessary here.
You can call your helper in .erb template:
<%= abc %>
Don't forget = in the opening tag.
http://sinatrarb.com/intro.html section 'Helpers'.
It's unclear what you want to achieve. But If you just want some text in your erb you can do something like this:
erb :myerb, locals: {text: "aaaaa", saved: false}
myerb.erb
<% if saved %>
Hello <%= text %>
<% endif %>
This would also work for functions.
First of all, you need to be aware that a defined method inherently includes the functionality of a begin/end block so you don´t need to put them again. Assuming you are using sinatra, here is what I think you need:
my.rb
require 'sinatra'
def abc
"aaaa"
end
get '/' do
erb :my, locals: {variable: abc}
end
my.erb
<html>
<body>
<p>
Hello <%= variable %>
</p>
</body>
</html>
Run ruby my.rb and then open http://localhost:4567/
Ruby newbie here who just started using Ruby with .erb templates and I'm having a problem with the code. I have a hangman game that's passing variables from the .rb file to the .erb file and everything was working fine until I tried to check it on initial load (no variables present) and it threw errors. So I figured I'd use defined? with an if statement to check if the variable exists and then execute the code if it does and ignore if doesn't. It works fine when I use:
<% if defined?bad_guesses %>
<%= bad_guesses %>
<% end %>
But the information I need is an array and when I try to use an .each or .times statement like this:
<% if defined?bad_guesses %>
<% bad_guesses.each do |i| %>
<%= i %>
<% end %>
<% end %>
I get:
NoMethodError at /
undefined method `each' for nil:NilClass
C:/Projects/hangman/views/index.erb in block in singleton class
<% bad_guesses.each do |i| %> hangman.rb in block in
erb :index, :locals => {:game_status => game_status, :bad_guesses => bad_guesses, :good_guesses => good_guesses, :word => word}
Any suggestions appreciated.
Also, is this even the proper way to do this? When you make an .erb template that uses variables passed in from a class in your .rb file, how do you ignore it until it exists to the template?
Passing variables using:
get '/' do
if params['make'] != nil
make = params['make'].to_i
game_status, bad_guesses, good_guesses, word = Hangman.get_word(make)
elsif params['guess'] != nil
guess = params['guess'].to_s
game_status, bad_guesses, good_guesses, word = Hangman.check_guess(guess)
end
erb :index, :locals => {:game_status => game_status, :bad_guesses => bad_guesses, :good_guesses => good_guesses, :word => word}
end
Looking at this:
<% if defined?bad_guesses %>
<% bad_guesses.each do |i| %>
<%= i %>
<% end %>
<% end %>
a few points:
defined?a is bad style; use defined?(bad_guesses) or defined? bad_guesses instead.
defined? checks if it's defined, so if you say foo = nil; defined? foo it will be true.
You could alternatively use this:
defined?(bad_guesses) && bad_guesses
On the other hand, undefined instance variables are nil by default:
# it shows undefined
defined? #non_existing_var
# but you can still check if it's truthy:
puts "found" if #non_existing_var
# it won't print anything
Similar to instance variables in this regard are hashes. The default value of an unknown key is nil.
The problem with instance variables is they are not scoped to the partial. Instead, I recommend sending your local variables as a nested hash:
locals: { data: { foo: "bar" } }
Then you can safely check for values which may not exist:
if data[:foo]
# this runs
elsif data[:non_existent]
# this doesnt run
end
For my purposes, the following syntax worked:
<% if some_var %>
<%= some_var %>
<% end %>
This block is rendered if some_var is not nil.
I'm working on a Sinatra app and want to write my own form helpers. In my erb file I want to use the rails 2.3 style syntax and pass a block to a form_helper method:
<% form_helper 'action' do |f| %>
<%= f.label 'name' %>
<%= f.field 'name' %>
<%= f.button 'name' %>
<% end %>
Then in my simplified form helper I can create a FormBuilder class and yield the methods to the erb block like so:
module ViewHelpers
class FormBuilder
def label(name)
name
end
def field(name)
name
end
def button(name)
name
end
end
def form_helper(action)
form = FormBuilder.new
yield(form)
end
end
What I don't understand is how to output the surrounding <form></form> tags. Is there a way to append text on only the first and last <%= f.___ %> tags?
Rails has had to use some tricks in order to get block helpers to work as wanted, and they changed moving from Rails 2 to Rails 3 (see the blogposts Simplifying Rails Block Helpers and Block Helpers in Rails 3 for more info).
The form_for helper in Rails 2.3 works by directly writing to the output buffer from the method, using the Rails concat method. In order to do something similar in Sinatra, you’ll need to find a way of writing to the output from your helper in the same way.
Erb works by creating Ruby code that builds up the output in a variable. It also allows you to set the name of this variable, by default it is _erbout (or _buf in Erubis). If you change this to be an instance variable rather than a local variable (i.e. provide a variable name that starts with #) you can access it from helpers. (Rails uses the name #output_buffer).
Sinatra uses Tilt for rendering templates, and Tilt provides an :outvar option for setting the variable name in Erb or Erubis templates.
Here’s an example of how this would work:
# set the name of the output variable
set :erb, :outvar => '#output_buffer'
helpers do
def form_helper
# use the new name to write directly to the output buffer
#output_buffer << "<form>\n"
# yield to the block (this is a simplified example, you'll want
# to yield your FormBuilder object here)
yield
# after the block has returned, write any closing text
#output_buffer << "</form>\n"
end
end
With this (fairly simple) example, an Erb template like this:
<% form_helper do %>
... call other methods here
<% end %>
results in the generated HTML:
<form>
... call other methods here
</form>