Two ways:

    class Notifications &lt; ActionMailer::Base
      default :from     =&gt; &#39;your_app@your_domain.com&#39;,
              :reply_to =&gt; &#39;some_other_address@your_domain.com&#39;
    end

Or:

    class Contacts &lt; ActionMailer::Base
      def new_contact
        mail( :to       =&gt; &#39;somebody@some_domain.com&#39;,
              :from     =&gt; &#39;your_app@your_domain.com&#39;,
              :reply_to =&gt; &#39;someone_else@some_other_domain.com&#39;)
      end
    end

Or you can mix the two approaches. I&#39;m sure there are even more ways to do this.

Solution for Rails 5.2 and possibly older/newer versions:

Amend the file:
```
config/environments/development.rb
```

With content:

```
Rails.application.configure do
  config.action_mailer.default_options = {
      reply_to:             &#39;test@example.com&#39;
  }
end
```

The reference:

https://guides.rubyonrails.org/action_mailer_basics.html#action-mailer-configuration

Can someone explain to me the difference between `AlarmManager.RTC_WAKEUP` and `AlarmManager.ELAPSED_REALTIME_WAKEUP`? I have read the documentation but still don&#39;t really understand the implication of using one over the other.

Example code:

        alarmManager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, 
                         scheduledAlarmTime, 
                         pendingIntent);

        alarmManager.set(AlarmManager.RTC_WAKEUP, 
                         scheduledAlarmTime, 
                         pendingIntent);
    

How different will the two lines of code execute? When will those two lines of code execute relative to each other?

I appreciate your help.

Android AlarmManager - RTC_WAKEUP vs ELAPSED_REALTIME_WAKEUP

The below fails to compile:

    typedef int arr[10];
    int main(void) {
    	return sizeof arr;
    }

    sizeof.c:3: error: expected expression before ‘arr’
but if I change it to

    sizeof(arr);
everything is fine. Why?

Why (and when) do I need to use parentheses after sizeof?

How can I define a reply-to address different than the `:from` one? Is that even possible?

How to define a reply-to address?

<p>How can I define a reply-to address different than the <code>:from</code> one? Is that even possible?</p>


Very simple question here - if migrations can get slow and cumbersome as an app gets more complex and if we have the much cleaner `rake db:schema:load` to call instead, why do migrations exist at all?

If the answer to the above is that migrations are used for version control (a stepwise record of changes to the database), then as an app gets more complex and `rake db:schema:load` is used more instead, do they continue to maintain their primary function?

---

### Caution:

From the answers to this question: `rake db:schema:load` &lt;b&gt;will delete data&lt;/b&gt; on a production server so be careful when using it.

rake db:schema:load vs. migrations

After significant troubleshooting, I figured out that I needed to run `rake spec` once (I can abort with control-c) before I can run rspec directly (e.g. on a subset of our specs). We are running Rails 3.0.7 and RSpec 2.5.0.

Clearly, rake is running some important database setup tasks / code (we have custom code in the root level rails Rakefile and possibly other places).

**How can I run the rake test database setup tasks / code without running `rake spec`?**

In addition to being able to run rspec on a subset of files, I am using [specjour][1] to spread our specs across multiple cores (haven&#39;t had success with spreading them across the LAN yet), but I see the same behavior as for running rspec directly: I need to run `rake spec` on each test database (assuming two cores) before specjour works:

    rake spec TEST_ENV_NUMBER=1
    control-c (after tests start)
    rake spec TEST_ENV_NUMBER=2
    control-c (after tests start)
    specjour

Note: my config/database.yml has this entry for test (as is common for the parallel testing gems):

    test:
      adapter: postgresql
      encoding: unicode
      database: test&lt;%=ENV[&#39;TEST_ENV_NUMBER&#39;]%&gt;
      username: user
      password:

[parallel_tests][2] seems to set up its databases correctly, but many of our specs fail.

I should also mention that running `specjour prepare` causes Postgres to log errors that it can&#39;t find the databases, but it creates them (without tables). On a subsequent run, no errors are logged, but also no tables are created. It is possible that my whole issue is simply a bug in `prepare`, so I reported it on github.

I think that I can run arbitrary code on each specjour test database by setting `Specjour::Configuration.prepare` in .specjour/hooks.rb, so if there&#39;s any rake tasks or other code that I need to run, it may work there.

  [1]: https://github.com/sandro/specjour
  [2]: https://github.com/grosser/parallel_tests

How do I prepare test database(s) for Rails rspec tests without running rake spec?

I have the name of a class and I want to create an instance of that class so that I can loop through each rails attribute that is present in the schema of that class.

How would I go about doing that?

1. I have the name as a string of the class I want to check
2. I guess I need to instantiate a class instance so that I can
3. Loop through it&#39;s attributes and print them.



How do I create a class instance from a string name in ruby?

I have a rails model which has 7 numeric attributes filled in by the user via a form.

I need to validate the presence of each of these attributes which is obviously easy using

    validates :attribute1, :presence =&gt; true
    validates :attribute2, :presence =&gt; true
    # and so on through the attributes


However I also need to run a custom validator which takes a number of the attributes and does some calculations with them. If the result of these calculations is not within a certain range then the model should be declared invalid.

On it&#39;s own, this too is easy

    validate :calculations_ok?
    
    def calculations_ok?
      errors[:base] &lt;&lt; &quot;Not within required range&quot; unless within_required_range?
    end
    
    def within_required_range?
      # check the calculations and return true or false here
    end

However the problem is that the method &quot;validate&quot; always gets run before the method &quot;validates&quot;. This means that if the user leaves one of the required fields blank, rails throws an error when it tries to do a calculation with a blank attribute.

So how can I check the presence of all the required attributes first?

Controlling the order of rails validations

How do you upgrade from Rails 3 to Rails 3.1 beta?

Upgrading from Rails 3 to Rails 3.1

I&#39;m trying to send multiple emails based on a boolean value in my database. The app is a simple scheduling app and user can mark their shift as &quot;replacement_needed&quot; and this should send out emails to all the users who&#39;ve requested to receive these emails. Trouble is, it only every seems to send to one email. Here&#39;s my current code:


     def request_replacement(shift)
          @shift = shift
          @user = shift.user
          @recipients = User.where(:replacement_emails =&gt; true).all
          @url  = root_url
          @recipients.each do |r|
            @name = r.fname
            mail(:to =&gt; r.email,
               :subject =&gt; &quot;A replacement clerk has been requested&quot;)
          end
      end



Send to multiple recipients in Rails with ActionMailer

Is there a tutorial out there that explains how to set up Devise&#39;s signup confirmation email from scratch (in both development and production), i.e. if you don&#39;t have Action Mailer set up? 

Google searching has just turned up a bunch of separate pieces related to this. No one piece explains enough, and I&#39;m not sure how they fit together. Is there a step-by-step explanation out there, or even something that explains the initial steps? 

---
Finally got it working. Followed all the steps in the accepted answer below, then added the following to my environment.rb file:

    ActionMailer::Base.delivery_method = :smtp
    ActionMailer::Base.smtp_settings = {
       :tls =&gt; true,
       :address =&gt; &quot;smtp.gmail.com&quot;,
       :port =&gt; 587,
       :domain =&gt; &quot;gmail.com&quot;,
       :authentication =&gt; :login,
       :user_name =&gt; &quot;[username]&quot;,
       :password =&gt; &quot;[password]&quot;
     }



How do I set up email confirmation with Devise?

trying to upgrade to Rails 4.2, using delayed_job_active_record. I&#39;ve not set the delayed_job backend for test environment as thought that way jobs would execute straight away. 

I&#39;m trying to test the new &#39;deliver_later&#39; method with RSpec, but I&#39;m not sure how.

Old controller code:

    ServiceMailer.delay.new_user(@user)

New controller code:

    ServiceMailer.new_user(@user).deliver_later

I USED to test it like so:

    expect(ServiceMailer).to receive(:new_user).with(@user).and_return(double(&quot;mailer&quot;, :deliver =&gt; true))

Now I get errors using that. (Double &quot;mailer&quot; received unexpected message :deliver_later with (no args))

Just

    expect(ServiceMailer).to receive(:new_user)

fails too with &#39;undefined method `deliver_later&#39; for nil:NilClass&#39;

I&#39;ve tried some examples that allow you to see if jobs are enqueued using test_helper in ActiveJob but I haven&#39;t managed to test that the correct job is queued.

    expect(enqueued_jobs.size).to eq(1)

This passes if the test_helper is included, but it doesn&#39;t allow me to check it is the correct email that is being sent.

What I want to do is:

 - test that the correct email is queued (or executed straight away in test env)
 - with the correct parameters (@user)

Any ideas??
thanks

Content Type	Original Author	Original Content on Stackoverflow
Question	empz	View Question on Stackoverflow
Solution 1 - Ruby on-Rails-3	dogenpunk	View Answer on Stackoverflow
Solution 2 - Ruby on-Rails-3	laimison	View Answer on Stackoverflow

How to define a reply-to address?

Ruby on-Rails-3 Problem Overview

Ruby on-Rails-3 Solutions

Solution 1 - Ruby on-Rails-3

Solution 2 - Ruby on-Rails-3

Why (and when) do I need to use parentheses after sizeof?

Android AlarmManager - RTC_WAKEUP vs ELAPSED_REALTIME_WAKEUP

Attributions