Email tag and image problem

[ricklach]

How do you show an email image with an address attached to it. I have tried numerous mail_to and image_tag variations but just can't seem to figure it out. Does anyone have the solution to this problem?

Rick

[ivanv]

link_to image_tag(parameters...), 'mailto:someone@somewhere.com'

[ricklach]

Ivan,
Thanks for that, so simple yet so difficult at the same time. Syntax is the big problem here and getting used to it.

Rick

[ivanv]

I feel your pain But rest assured you'll get up to speed fast enough, and then there's no turning back.

<%= link_to image_tag("emailButton"), "mailto:#{list_stripes.email}" %>

See the difference? Let me try to explain:

image_tag("emailButton") translates to this: <img src="emailButton.png" />

The first parameter to link_to, would be what goes between <a href...> and </a>, and the second parameter is the actual href. So, it outputs this (obviosly with the correct values):

<a href="mailto:whatever is the value of list_stripes.email">here goes the output of the image_tag function (a helper actually)</a>

Also, if you don't know what #{..} is for inside a double quoted string ("..."), it works by replacing that brackets along with anything inside them with the value of the ruby expression inside, in this case, the value of list_stripes.email

I hope this helps you better understand how it all works.

Ivan V.

[Fenrir2]

If you are a PHP programmer, #{var} is the same as $var in PHP in a string:

$var = "a string";
$one = "this is $var";
$two = 'this is $var';

Now, $one is "this is a string", and $two is "this is $var" because the variable substitution doesn't exist in single-quoted strings.

This is the same in Ruby:

var = "a string"
one = "this is #{var}"
two = 'this is #{var}'

But you can put "real" code in it too:

three = "two is #{two.kind_of?(String) ? 'a string' : 'not a string'}"

three will be: "two is a string".

I hope this is not confusing you :P.

[ricklach]

Let me thank you both for those excellent examples and descriptions. I am awaiting the book but in the meantime I am trying to forge on. I have one more relatively simple question. Let's say a returned field is null or blank. Is there an easy way to test for that condition. I am using

<% if list_stripes.email != '' %>

as an example and I have tried

<% if list_stripes.email.nil? %>

with mixed success. Which method do you recommend.

Rick

[ivanv]

You can use both:

<% if list_stripes.email.nil? || list_stripes.email.empty? %>

[Fenrir2]

No, just use object.blank?

>> [].blank?
=> true
>> [1, 2, 3].blank?
=> false
>> "".blank?
=> true
>> 0.blank?
=> false
>> nil.blank?
=> true

Works for many things, but keep in mind that you have to use 0.zero? to test whether a number is zero or not.

[ivanv]

Nice, I didn't know about those two.

[ricklach]

Thanks for that info. Where is it documented in the API docs?

Rick

[Luke Redpath]

No, just use object.blank?

>> [].blank?
=> true
>> [1, 2, 3].blank?
=> false
>> "".blank?
=> true
>> 0.blank?
=> false
>> nil.blank?
=> true

Works for many things, but keep in mind that you have to use 0.zero? to test whether a number is zero or not.

What version of Ruby is that? I can't find it in the online API docs or the Rails docs if its an extension.

[Fenrir2]

It's not in the Ruby documentation, it works only if you use Rails.

They've nodoc'd the method:

class Object #:nodoc:
  # "", "   ", nil, [], and {} are blank
  def blank?
    if respond_to?(:empty?) && respond_to?(:strip)
      empty? or strip.empty?
    elsif respond_to?(:empty?)
      empty?
    else
      !self
    end
  end
end

class NilClass #:nodoc:
  def blank?
    true
  end
end

class FalseClass #:nodoc:
  def blank?
    true
  end
end

class TrueClass #:nodoc:
  def blank?
    false
  end
end

class Array #:nodoc:
  alias_method :blank?, :empty?
end

class Hash #:nodoc:
  alias_method :blank?, :empty?
end

class String #:nodoc:
  def blank?
    empty? || strip.empty?
  end
end

class Numeric #:nodoc:
  def blank?
    false
  end
end

It's in rails/activesupport/lib/active_support/core_ext/blank.rb.

Maybe it's intended for internal use only? I don't remember how I learned that this method exists...