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1 parent 59b6ae3 commit e46c80765525817a89b784e6336a9f66250d53fc @lifo lifo committed Jan 13, 2009
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8 railties/doc/guides/html/actioncontroller_basics.html
@@ -509,14 +509,14 @@ <h2 id="_session">4. Session</h2>
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-style: italic"><span style="color: #9A1900"># Set to one of [:active_record_store, :drb_store, :mem_cache_store, :cookie_store]</span></span>
config<span style="color: #990000">.</span>action_controller<span style="color: #990000">.</span>session_store <span style="color: #990000">=</span> <span style="color: #990000">:</span>active_record_store</tt></pre></div></div>
-<h3 id="_accessing_the_session">4.1. Accessing the Session</h3>
+<h3 id="_accessing_the_session">4.1. Accessing the Session</h3>
<div class="paragraph"><p>In your controller you can access the session through the <tt>session</tt> instance method.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="./images/icons/note.png" alt="Note" />
</td>
-<td class="content">Sessions are lazily loaded. If you don&#8217;t access sessions in your action&#8217;s code, they will not be loaded. Hence you will never need to disable sessions, just not accessing them will do the job.</td>
+<td class="content">Sessions are lazily loaded. If you don&#8217;t access sessions in your action&#8217;s code, they will not be loaded. Hence you will never need to disable sessions, just not accessing them will do the job.</td>
</tr></table>
</div>
<div class="paragraph"><p>Session values are stored using key/value pairs like a hash:</p></div>
@@ -572,7 +572,7 @@ <h3 id="_accessing_the_session">4.1. Accessing the Session</h3>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
<div class="paragraph"><p>To reset the entire session, use <tt>reset_session</tt>.</p></div>
-<h3 id="_the_flash">4.2. The flash</h3>
+<h3 id="_the_flash">4.2. The flash</h3>
<div class="paragraph"><p>The flash is a special part of the session which is cleared with each request. This means that values stored there will only be available in the next request, which is useful for storing error messages etc. It is accessed in much the same way as the session, like a hash. Let&#8217;s use the act of logging out as an example. The controller can send a message which will be displayed to the user on the next request:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -622,7 +622,7 @@ <h3 id="_the_flash">4.2. The flash</h3>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<h4 id="_tt_flash_now_tt">4.2.1. <tt>flash.now</tt></h4>
+<h4 id="_tt_flash_now_tt">4.2.1. <tt>flash.now</tt></h4>
<div class="paragraph"><p>By default, adding values to the flash will make them available to the next request, but sometimes you may want to access those values in the same request. For example, if the <tt>create</tt> action fails to save a resource and you render the <tt>new</tt> template directly, that&#8217;s not going to result in a new request, but you may still want to display a message using the flash. To do this, you can use <tt>flash.now</tt> in the same way you use the normal <tt>flash</tt>:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
View
206 railties/doc/guides/html/activerecord_validations_callbacks.html
@@ -199,20 +199,19 @@ <h2 id="site_title_tagline">Sustainable productivity for web-application develop
<h2>Chapters</h2>
<ol>
<li>
- <a href="#_motivations_to_validate_your_active_record_objects">Motivations to validate your Active Record objects</a>
- </li>
- <li>
- <a href="#_how_it_works">How it works</a>
+ <a href="#_overview_of_activerecord_validation">Overview of ActiveRecord Validation</a>
<ul>
- <li><a href="#_when_does_validation_happen">When does validation happen?</a></li>
+ <li><a href="#_why_use_activerecord_validations">Why Use ActiveRecord Validations?</a></li>
+
+ <li><a href="#_when_does_validation_happen">When Does Validation Happen?</a></li>
- <li><a href="#_the_meaning_of_em_valid_em">The meaning of <em>valid</em></a></li>
+ <li><a href="#_the_meaning_of_tt_valid_tt">The Meaning of <tt>valid</tt></a></li>
</ul>
</li>
<li>
- <a href="#_the_declarative_validation_helpers">The declarative validation helpers</a>
+ <a href="#_the_declarative_validation_helpers">The Declarative Validation Helpers</a>
<ul>
<li><a href="#_the_tt_validates_acceptance_of_tt_helper">The <tt>validates_acceptance_of</tt> helper</a></li>
@@ -240,7 +239,7 @@ <h2 id="site_title_tagline">Sustainable productivity for web-application develop
</ul>
</li>
<li>
- <a href="#_common_validation_options">Common validation options</a>
+ <a href="#_common_validation_options">Common Validation Options</a>
<ul>
<li><a href="#_the_tt_allow_nil_tt_option">The <tt>:allow_nil</tt> option</a></li>
@@ -343,12 +342,12 @@ <h2 id="site_title_tagline">Sustainable productivity for web-application develop
<h1>Active Record Validations and Callbacks</h1>
<div id="preamble">
<div class="sectionbody">
-<div class="paragraph"><p>This guide teaches you how to work with the lifecycle of your Active Record objects. More precisely, you will learn how to validate the state of your objects before they go into the database and also how to teach them to perform custom operations at certain points of their lifecycles.</p></div>
+<div class="paragraph"><p>This guide teaches you how to hook into the lifecycle of your Active Record objects. More precisely, you will learn how to validate the state of your objects before they go into the database as well as how to perform custom operations at certain points in the object lifecycle.</p></div>
<div class="paragraph"><p>After reading this guide and trying out the presented concepts, we hope that you&#8217;ll be able to:</p></div>
<div class="ulist"><ul>
<li>
<p>
-Correctly use all the built-in Active Record validation helpers
+Use the built-in Active Record validation helpers
</p>
</li>
<li>
@@ -363,56 +362,55 @@ <h2 id="site_title_tagline">Sustainable productivity for web-application develop
</li>
<li>
<p>
-Register callback methods that will execute custom operations during your objects lifecycle, for example before/after they are saved.
+Create callback methods to respond to events in the object lifecycle.
</p>
</li>
<li>
<p>
-Create special classes that encapsulate common behaviour for your callbacks
+Create special classes that encapsulate common behavior for your callbacks
</p>
</li>
<li>
<p>
-Create Observers - classes with callback methods specific for each of your models, keeping the callback code outside your models' declarations.
+Create Rails Observers
</p>
</li>
</ul></div>
</div>
</div>
-<h2 id="_motivations_to_validate_your_active_record_objects">1. Motivations to validate your Active Record objects</h2>
+<h2 id="_overview_of_activerecord_validation">1. Overview of ActiveRecord Validation</h2>
<div class="sectionbody">
+<div class="paragraph"><p>Before you dive into the detail of validations in Rails, you should understand a bit about how validations fit into the big picture. Why should you use validations? When do these validations take place?</p></div>
+<h3 id="_why_use_activerecord_validations">1.1. Why Use ActiveRecord Validations?</h3>
<div class="paragraph"><p>The main reason for validating your objects before they get into the database is to ensure that only valid data is recorded. It&#8217;s important to be sure that an email address column only contains valid email addresses, or that the customer&#8217;s name column will never be empty. Constraints like that keep your database organized and helps your application to work properly.</p></div>
-<div class="paragraph"><p>There are several ways to validate the data that goes to the database, like using database native constraints, implementing validations only at the client side or implementing them directly into your models. Each one has pros and cons:</p></div>
+<div class="paragraph"><p>There are several ways that you could validate the data that goes to the database, including native database constraints, client-side validations, and model-level validations. Each of these has pros and cons:</p></div>
<div class="ulist"><ul>
<li>
<p>
-Using database constraints and/or stored procedures makes the validation mechanisms database-dependent and may turn your application into a hard to test and mantain beast. However, if your database is used by other applications, it may be a good idea to use some constraints also at the database level.
+Using database constraints and/or stored procedures makes the validation mechanisms database-dependent and may turn your application into a hard to test and maintain beast. However, if your database is used by other applications, it may be a good idea to use some constraints also at the database level. Additionally, database-level validations can safely handle some things (such as uniqueness in heavily-used tables) that are problematic to implement from the application level.
</p>
</li>
<li>
<p>
-Implementing validations only at the client side can be problematic, specially with web-based applications. Usually this kind of validation is done using javascript, which may be turned off in the user&#8217;s browser, leading to invalid data getting inside your database. However, if combined with server side validation, client side validation may be useful, since the user can have a faster feedback from the application when trying to save invalid data.
+Implementing validations only at the client side can be difficult in web-based applications. Usually this kind of validation is done using javascript, which may be turned off in the user&#8217;s browser, leading to invalid data getting inside your database. However, if combined with server side validation, client side validation may be useful, since the user can have a faster feedback from the application when trying to save invalid data.
</p>
</li>
<li>
<p>
-Using validation directly into your Active Record classes ensures that only valid data gets recorded, while still keeping the validation code in the right place, avoiding breaking the MVC pattern. Since the validation happens on the server side, the user cannot disable it, so it&#8217;s also safer. It may be a hard and tedious work to implement some of the logic involved in your models' validations, but fear not: Active Record gives you the hability to easily create validations, using several built-in helpers while still allowing you to create your own validation methods.
+Using validation directly in your Active Record classes ensures that only valid data gets recorded, while still keeping the validation code in the right place, avoiding breaking the MVC pattern. Since the validation happens on the server side, the user cannot disable it, so it&#8217;s also safer. It may be a hard and tedious work to implement some of the logic involved in your models' validations, but fear not: Active Record gives you the ability to easily create validations, providing built-in helpers for common validations while still allowing you to create your own validation methods.
</p>
</li>
</ul></div>
-</div>
-<h2 id="_how_it_works">2. How it works</h2>
-<div class="sectionbody">
-<h3 id="_when_does_validation_happen">2.1. When does validation happen?</h3>
-<div class="paragraph"><p>There are two kinds of Active Record objects: those that correspond to a row inside your database and those who do not. When you create a fresh object, using the <tt>new</tt> method, that object does not belong to the database yet. Once you call <tt>save</tt> upon that object it&#8217;ll be recorded to it&#8217;s table. Active Record uses the <tt>new_record?</tt> instance method to discover if an object is already in the database or not. Consider the following simple and very creative Active Record class:</p></div>
+<h3 id="_when_does_validation_happen">1.2. When Does Validation Happen?</h3>
+<div class="paragraph"><p>There are two kinds of Active Record objects: those that correspond to a row inside your database and those that do not. When you create a fresh object, using the <tt>new</tt> method, that object does not belong to the database yet. Once you call <tt>save</tt> upon that object it will be saved into the appropriate database table. Active Record uses the <tt>new_record?</tt> instance method to determine whether an object is already in the database or not. Consider the following simple Active Record class:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> Person <span style="color: #990000">&lt;</span> ActiveRecord<span style="color: #990000">::</span>Base
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<div class="paragraph"><p>We can see how it works by looking at the following script/console output:</p></div>
+<div class="paragraph"><p>We can see how it works by looking at some script/console output:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>&gt;&gt; p = Person.new(:name =&gt; "John Doe", :birthdate =&gt; Date.parse("09/03/1979"))
@@ -424,25 +422,25 @@ <h3 id="_when_does_validation_happen">2.1. When does validation happen?</h3>
&gt;&gt; p.new_record?
=&gt; false</tt></pre>
</div></div>
-<div class="paragraph"><p>Saving new records means sending an SQL insert operation to the database, while saving existing records (by calling either <tt>save</tt> or <tt>update_attributes</tt>) will result in a SQL update operation. Active Record will use these facts to perform validations upon your objects, avoiding then to be recorded to the database if their inner state is invalid in some way. You can specify validations that will be beformed every time a object is saved, just when you&#8217;re creating a new record or when you&#8217;re updating an existing one.</p></div>
+<div class="paragraph"><p>Saving new records means sending an SQL <tt>INSERT</tt> operation to the database, while saving existing records (by calling either <tt>save</tt> or <tt>update_attributes</tt>) will result in a SQL <tt>UPDATE</tt> operation. Active Record will use these facts to perform validations upon your objects, keeping them out of the database if their inner state is invalid in some way. You can specify validations that will be beformed every time a object is saved, just when you&#8217;re creating a new record or when you&#8217;re updating an existing one.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="./images/icons/caution.png" alt="Caution" />
</td>
-<td class="content">There are four methods that when called will trigger validation: <tt>save</tt>, <tt>save!</tt>, <tt>update_attributes</tt> and <tt>update_attributes!</tt>. There is one method left, which is <tt>update_attribute</tt>. This method will update the value of an attribute without triggering any validation, so be careful when using <tt>update_attribute</tt>, since it can let you save your objects in an invalid state.</td>
+<td class="content">There are four methods that when called will trigger validation: <tt>save</tt>, <tt>save!</tt>, <tt>update_attributes</tt> and <tt>update_attributes!</tt>. There is one update method for Active Record objects left, which is <tt>update_attribute</tt>. This method will update the value of an attribute <em>without</em> triggering any validation. Be careful when using <tt>update_attribute</tt>, because it can let you save your objects in an invalid state.</td>
</tr></table>
</div>
-<h3 id="_the_meaning_of_em_valid_em">2.2. The meaning of <em>valid</em></h3>
-<div class="paragraph"><p>For verifying if an object is valid, Active Record uses the <tt>valid?</tt> method, which basically looks inside the object to see if it has any validation errors. These errors live in a collection that can be accessed through the <tt>errors</tt> instance method. The proccess is really simple: If the <tt>errors</tt> method returns an empty collection, the object is valid and can be saved. Each time a validation fails, an error message is added to the <tt>errors</tt> collection.</p></div>
+<h3 id="_the_meaning_of_tt_valid_tt">1.3. The Meaning of <tt>valid</tt></h3>
+<div class="paragraph"><p>To verify whether an object is valid, Active Record uses the <tt>valid?</tt> method, which basically looks inside the object to see if it has any validation errors. These errors live in a collection that can be accessed through the <tt>errors</tt> instance method. The process is really simple: If the <tt>errors</tt> method returns an empty collection, the object is valid and can be saved. Each time a validation fails, an error message is added to the <tt>errors</tt> collection.</p></div>
</div>
-<h2 id="_the_declarative_validation_helpers">3. The declarative validation helpers</h2>
+<h2 id="_the_declarative_validation_helpers">2. The Declarative Validation Helpers</h2>
<div class="sectionbody">
-<div class="paragraph"><p>Active Record offers many pre-defined validation helpers that you can use directly inside your class definitions. These helpers create validations rules that are commonly used in most of the applications that you&#8217;ll write, so you don&#8217;t need to recreate it everytime, avoiding code duplication, keeping everything organized and boosting your productivity. Everytime a validation fails, an error message is added to the object&#8217;s <tt>errors</tt> collection, this message being associated with the field being validated.</p></div>
-<div class="paragraph"><p>Each helper accepts an arbitrary number of attributes, received as symbols, so with a single line of code you can add the same kind of validation to several attributes.</p></div>
-<div class="paragraph"><p>All these helpers accept the <tt>:on</tt> and <tt>:message</tt> options, which define when the validation should be applied and what message should be added to the <tt>errors</tt> collection when it fails, respectively. The <tt>:on</tt> option takes one of the values <tt>:save</tt> (it&#8217;s the default), <tt>:create</tt> or <tt>:update</tt>. There is a default error message for each one of the validation helpers. These messages are used when the <tt>:message</tt> option isn&#8217;t used. Let&#8217;s take a look at each one of the available helpers, listed in alphabetic order.</p></div>
-<h3 id="_the_tt_validates_acceptance_of_tt_helper">3.1. The <tt>validates_acceptance_of</tt> helper</h3>
-<div class="paragraph"><p>Validates that a checkbox has been checked for agreement purposes. It&#8217;s normally used when the user needs to agree with your application&#8217;s terms of service, confirm reading some clauses or any similar concept. This validation is very specific to web applications and actually this <em>acceptance</em> does not need to be recorded anywhere in your database (if you don&#8217;t have a field for it, the helper will just create a virtual attribute).</p></div>
+<div class="paragraph"><p>Active Record offers many pre-defined validation helpers that you can use directly inside your class definitions. These helpers create validation rules that are commonly used. Every time a validation fails, an error message is added to the object&#8217;s <tt>errors</tt> collection, and this message is associated with the field being validated.</p></div>
+<div class="paragraph"><p>Each helper accepts an arbitrary number of attributes identified by symbols, so with a single line of code you can add the same kind of validation to several attributes.</p></div>
+<div class="paragraph"><p>All these helpers accept the <tt>:on</tt> and <tt>:message</tt> options, which define when the validation should be applied and what message should be added to the <tt>errors</tt> collection when it fails, respectively. The <tt>:on</tt> option takes one of the values <tt>:save</tt> (the default), <tt>:create</tt> or <tt>:update</tt>. There is a default error message for each one of the validation helpers. These messages are used when the <tt>:message</tt> option isn&#8217;t used. Let&#8217;s take a look at each one of the available helpers.</p></div>
+<h3 id="_the_tt_validates_acceptance_of_tt_helper">2.1. The <tt>validates_acceptance_of</tt> helper</h3>
+<div class="paragraph"><p>Validates that a checkbox on the user interface was checked when a form was submitted. This is normally used when the user needs to agree to your application&#8217;s terms of service, confirm reading some text, or any similar concept. This validation is very specific to web applications and actually this <em>acceptance</em> does not need to be recorded anywhere in your database (if you don&#8217;t have a field for it, the helper will just create a virtual attribute).</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -452,7 +450,7 @@ <h3 id="_the_tt_validates_acceptance_of_tt_helper">3.1. The <tt>validates_accept
validates_acceptance_of <span style="color: #990000">:</span>terms_of_service
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
<div class="paragraph"><p>The default error message for <tt>validates_acceptance_of</tt> is "<em>must be accepted</em>"</p></div>
-<div class="paragraph"><p><tt>validates_acceptance_of</tt> can receive an <tt>:accept</tt> option, which determines the value that will be considered acceptance. It defaults to "1", but you can change it.</p></div>
+<div class="paragraph"><p><tt>validates_acceptance_of</tt> can receive an <tt>:accept</tt> option, which determines the value that will be considered acceptance. It defaults to "1", but you can change this.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -461,7 +459,7 @@ <h3 id="_the_tt_validates_acceptance_of_tt_helper">3.1. The <tt>validates_accept
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> Person <span style="color: #990000">&lt;</span> ActiveRecord<span style="color: #990000">::</span>Base
validates_acceptance_of <span style="color: #990000">:</span>terms_of_service<span style="color: #990000">,</span> <span style="color: #990000">:</span>accept <span style="color: #990000">=&gt;</span> <span style="color: #FF0000">'yes'</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<h3 id="_the_tt_validates_associated_tt_helper">3.2. The <tt>validates_associated</tt> helper</h3>
+<h3 id="_the_tt_validates_associated_tt_helper">2.2. The <tt>validates_associated</tt> helper</h3>
<div class="paragraph"><p>You should use this helper when your model has associations with other models and they also need to be validated. When you try to save your object, <tt>valid?</tt> will be called upon each one of the associated objects.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -478,12 +476,12 @@ <h3 id="_the_tt_validates_associated_tt_helper">3.2. The <tt>validates_associate
<td class="icon">
<img src="./images/icons/caution.png" alt="Caution" />
</td>
-<td class="content">Pay attention not to use <tt>validates_associated</tt> on both ends of your associations, because this will lead to several recursive calls and blow up the method calls' stack.</td>
+<td class="content">Don&#8217;t use <tt>validates_associated</tt> on both ends of your associations, because this will lead to several recursive calls and blow up the method calls' stack.</td>
</tr></table>
</div>
-<div class="paragraph"><p>The default error message for <tt>validates_associated</tt> is "<em>is invalid</em>". Note that the errors for each failed validation in the associated objects will be set there and not in this model.</p></div>
-<h3 id="_the_tt_validates_confirmation_of_tt_helper">3.3. The <tt>validates_confirmation_of</tt> helper</h3>
-<div class="paragraph"><p>You should use this helper when you have two text fields that should receive exactly the same content, like when you want to confirm an email address or password. This validation creates a virtual attribute, using the name of the field that has to be confirmed with <em>_confirmation</em> appended.</p></div>
+<div class="paragraph"><p>The default error message for <tt>validates_associated</tt> is "<em>is invalid</em>". Note that each associated object will contain its own <tt>errors</tt> collection; errors do not bubble up to the calling model.</p></div>
+<h3 id="_the_tt_validates_confirmation_of_tt_helper">2.3. The <tt>validates_confirmation_of</tt> helper</h3>
+<div class="paragraph"><p>You should use this helper when you have two text fields that should receive exactly the same content. For example, you may want to confirm an email address or a password. This validation creates a virtual attribute, using the name of the field that has to be confirmed with <em>_confirmation</em> appended.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -494,10 +492,12 @@ <h3 id="_the_tt_validates_confirmation_of_tt_helper">3.3. The <tt>validates_conf
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
<div class="paragraph"><p>In your view template you could use something like</p></div>
<div class="listingblock">
-<div class="content">
+<div class="content"><!-- Generator: GNU source-highlight 2.9
+by Lorenzo Bettini
+http://www.lorenzobettini.it
+http://www.gnu.org/software/src-highlite -->
<pre><tt>&lt;%= text_field :person, :email %&gt;
-&lt;%= text_field :person, :email_confirmation %&gt;</tt></pre>
-</div></div>
+&lt;%= text_field :person, :email_confirmation %&gt;</tt></pre></div></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
@@ -516,7 +516,7 @@ <h3 id="_the_tt_validates_confirmation_of_tt_helper">3.3. The <tt>validates_conf
validates_presence_of <span style="color: #990000">:</span>email_confirmation
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
<div class="paragraph"><p>The default error message for <tt>validates_confirmation_of</tt> is "<em>doesn&#8217;t match confirmation</em>"</p></div>
-<h3 id="_the_tt_validates_exclusion_of_tt_helper">3.4. The <tt>validates_exclusion_of</tt> helper</h3>
+<h3 id="_the_tt_validates_exclusion_of_tt_helper">2.4. The <tt>validates_exclusion_of</tt> helper</h3>
<div class="paragraph"><p>This helper validates that the attributes' values are not included in a given set. In fact, this set can be any enumerable object.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -527,10 +527,10 @@ <h3 id="_the_tt_validates_exclusion_of_tt_helper">3.4. The <tt>validates_exclusi
validates_exclusion_of <span style="color: #990000">:</span>format<span style="color: #990000">,</span> <span style="color: #990000">:</span><span style="font-weight: bold"><span style="color: #0000FF">in</span></span> <span style="color: #990000">=&gt;</span> <span style="color: #990000">%</span>w<span style="color: #990000">(</span>mov avi<span style="color: #990000">),</span>
<span style="color: #990000">:</span>message <span style="color: #990000">=&gt;</span> <span style="color: #FF0000">"Extension %s is not allowed"</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<div class="paragraph"><p>The <tt>validates_exclusion_of</tt> helper has an option <tt>:in</tt> that receives the set of values that will not be accepted for the validated attributes. The <tt>:in</tt> option has an alias called <tt>:within</tt> that you can use for the same purpose, if you&#8217;d like to. In the previous example we used the <tt>:message</tt> option to show how we can personalize it with the current attribute&#8217;s value, through the <tt>%s</tt> format mask.</p></div>
+<div class="paragraph"><p>The <tt>validates_exclusion_of</tt> helper has an option <tt>:in</tt> that receives the set of values that will not be accepted for the validated attributes. The <tt>:in</tt> option has an alias called <tt>:within</tt> that you can use for the same purpose, if you&#8217;d like to. This example uses the <tt>:message</tt> option to show how you can personalize it with the current attribute&#8217;s value, through the <tt>%s</tt> format mask.</p></div>
<div class="paragraph"><p>The default error message for <tt>validates_exclusion_of</tt> is "<em>is not included in the list</em>".</p></div>
-<h3 id="_the_tt_validates_format_of_tt_helper">3.5. The <tt>validates_format_of</tt> helper</h3>
-<div class="paragraph"><p>This helper validates the attributes&#8217;s values by testing if they match a given pattern. This pattern must be specified using a Ruby regular expression, which must be passed through the <tt>:with</tt> option.</p></div>
+<h3 id="_the_tt_validates_format_of_tt_helper">2.5. The <tt>validates_format_of</tt> helper</h3>
+<div class="paragraph"><p>This helper validates the attributes' values by testing whether they match a given pattern. This pattern must be specified using a Ruby regular expression, which is specified using the <tt>:with</tt> option.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -541,7 +541,7 @@ <h3 id="_the_tt_validates_format_of_tt_helper">3.5. The <tt>validates_format_of<
<span style="color: #990000">:</span>message <span style="color: #990000">=&gt;</span> <span style="color: #FF0000">"Only letters allowed"</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
<div class="paragraph"><p>The default error message for <tt>validates_format_of</tt> is "<em>is invalid</em>".</p></div>
-<h3 id="_the_tt_validates_inclusion_of_tt_helper">3.6. The <tt>validates_inclusion_of</tt> helper</h3>
+<h3 id="_the_tt_validates_inclusion_of_tt_helper">2.6. The <tt>validates_inclusion_of</tt> helper</h3>
<div class="paragraph"><p>This helper validates that the attributes' values are included in a given set. In fact, this set can be any enumerable object.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -552,10 +552,10 @@ <h3 id="_the_tt_validates_inclusion_of_tt_helper">3.6. The <tt>validates_inclusi
validates_inclusion_of <span style="color: #990000">:</span>size<span style="color: #990000">,</span> <span style="color: #990000">:</span><span style="font-weight: bold"><span style="color: #0000FF">in</span></span> <span style="color: #990000">=&gt;</span> <span style="color: #990000">%</span>w<span style="color: #990000">(</span>small medium large<span style="color: #990000">),</span>
<span style="color: #990000">:</span>message <span style="color: #990000">=&gt;</span> <span style="color: #FF0000">"%s is not a valid size"</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<div class="paragraph"><p>The <tt>validates_inclusion_of</tt> helper has an option <tt>:in</tt> that receives the set of values that will be accepted. The <tt>:in</tt> option has an alias called <tt>:within</tt> that you can use for the same purpose, if you&#8217;d like to. In the previous example we used the <tt>:message</tt> option to show how we can personalize it with the current attribute&#8217;s value, through the <tt>%s</tt> format mask.</p></div>
+<div class="paragraph"><p>The <tt>validates_inclusion_of</tt> helper has an option <tt>:in</tt> that receives the set of values that will be accepted. The <tt>:in</tt> option has an alias called <tt>:within</tt> that you can use for the same purpose, if you&#8217;d like to. The previous example uses the <tt>:message</tt> option to show how you can personalize it with the current attribute&#8217;s value, through the <tt>%s</tt> format mask.</p></div>
<div class="paragraph"><p>The default error message for <tt>validates_inclusion_of</tt> is "<em>is not included in the list</em>".</p></div>
-<h3 id="_the_tt_validates_length_of_tt_helper">3.7. The <tt>validates_length_of</tt> helper</h3>
-<div class="paragraph"><p>This helper validates the length of your attribute&#8217;s value. It can receive a variety of different options, so you can specify length contraints in different ways.</p></div>
+<h3 id="_the_tt_validates_length_of_tt_helper">2.7. The <tt>validates_length_of</tt> helper</h3>
+<div class="paragraph"><p>This helper validates the length of your attribute&#8217;s value. It includes a variety of different options, so you can specify length constraints in different ways:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -590,7 +590,7 @@ <h3 id="_the_tt_validates_length_of_tt_helper">3.7. The <tt>validates_length_of<
</p>
</li>
</ul></div>
-<div class="paragraph"><p>The default error messages depend on the type of length validation being performed. You can personalize these messages, using the <tt>:wrong_length</tt>, <tt>:too_long</tt> and <tt>:too_short</tt> options and the <tt>%d</tt> format mask as a placeholder for the number corresponding to the length contraint being used. You can still use the <tt>:message</tt> option to specify an error message.</p></div>
+<div class="paragraph"><p>The default error messages depend on the type of length validation being performed. You can personalize these messages, using the <tt>:wrong_length</tt>, <tt>:too_long</tt> and <tt>:too_short</tt> options and the <tt>%d</tt> format mask as a placeholder for the number corresponding to the length constraint being used. You can still use the <tt>:message</tt> option to specify an error message.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -599,10 +599,10 @@ <h3 id="_the_tt_validates_length_of_tt_helper">3.7. The <tt>validates_length_of<
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> Person <span style="color: #990000">&lt;</span> ActiveRecord<span style="color: #990000">::</span>Base
validates_length_of <span style="color: #990000">:</span>bio<span style="color: #990000">,</span> <span style="color: #990000">:</span>too_long <span style="color: #990000">=&gt;</span> <span style="color: #FF0000">"you're writing too much. %d characters is the maximum allowed."</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<div class="paragraph"><p>This helper has an alias called <tt>validates_size_of</tt>, it&#8217;s the same helper with a different name. You can use it if you&#8217;d like to.</p></div>
-<h3 id="_the_tt_validates_numericality_of_tt_helper">3.8. The <tt>validates_numericality_of</tt> helper</h3>
+<div class="paragraph"><p>The <tt>validates_size_of</tt> helper is an alias for <tt>validates_length_of</tt>.</p></div>
+<h3 id="_the_tt_validates_numericality_of_tt_helper">2.8. The <tt>validates_numericality_of</tt> helper</h3>
<div class="paragraph"><p>This helper validates that your attributes have only numeric values. By default, it will match an optional sign followed by a integral or floating point number. Using the <tt>:integer_only</tt> option set to true, you can specify that only integral numbers are allowed.</p></div>
-<div class="paragraph"><p>If you use <tt>:integer_only</tt> set to <tt>true</tt>, then it will use the <tt>/\A[+\-]?\d+\Z/+ regular expression to validate the attribute&#8217;s value. Otherwise, it will try to convert the value using +Kernel.Float</tt>.</p></div>
+<div class="paragraph"><p>If you set <tt>:integer_only</tt> to <tt>true</tt>, then it will use the <tt>/\A[+\-]?\d+\Z/+ regular expression to validate the attribute&#8217;s value. Otherwise, it will try to convert the value to a number using +Kernel.Float</tt>.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -613,8 +613,8 @@ <h3 id="_the_tt_validates_numericality_of_tt_helper">3.8. The <tt>validates_nume
validates_numericality_of <span style="color: #990000">:</span>games_played<span style="color: #990000">,</span> <span style="color: #990000">:</span>integer_only <span style="color: #990000">=&gt;</span> <span style="font-weight: bold"><span style="color: #0000FF">true</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
<div class="paragraph"><p>The default error message for <tt>validates_numericality_of</tt> is "<em>is not a number</em>".</p></div>
-<h3 id="_the_tt_validates_presence_of_tt_helper">3.9. The <tt>validates_presence_of</tt> helper</h3>
-<div class="paragraph"><p>This helper validates that the attributes are not empty. It uses the <tt>blank?</tt> method to check if the value is either <tt>nil</tt> or an empty string (if the string has only spaces, it will still be considered empty).</p></div>
+<h3 id="_the_tt_validates_presence_of_tt_helper">2.9. The <tt>validates_presence_of</tt> helper</h3>
+<div class="paragraph"><p>This helper validates that the specified attributes are not empty. It uses the <tt>blank?</tt> method to check if the value is either <tt>nil</tt> or an empty string (if the string has only spaces, it will still be considered empty).</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -628,7 +628,7 @@ <h3 id="_the_tt_validates_presence_of_tt_helper">3.9. The <tt>validates_presence
<td class="icon">
<img src="./images/icons/note.png" alt="Note" />
</td>
-<td class="content">If you want to be sure that an association is present, you&#8217;ll need to test if the foreign key used to map the association is present, and not the associated object itself.</td>
+<td class="content">If you want to be sure that an association is present, you&#8217;ll need to test whether the foreign key used to map the association is present, and not the associated object itself.</td>
</tr></table>
</div>
<div class="listingblock">
@@ -645,12 +645,12 @@ <h3 id="_the_tt_validates_presence_of_tt_helper">3.9. The <tt>validates_presence
<td class="icon">
<img src="./images/icons/note.png" alt="Note" />
</td>
-<td class="content">If you want to validate the presence of a boolean field (where the real values are true and false), you will want to use validates_inclusion_of :field_name, :in =&gt; [true, false] This is due to the way Object#blank? handles boolean values. false.blank? # =&gt; true</td>
+<td class="content">If you want to validate the presence of a boolean field (where the real values are true and false), you should use validates_inclusion_of :field_name, :in =&gt; [true, false] This is due to the way Object#blank? handles boolean values. false.blank? # =&gt; true</td>
</tr></table>
</div>
<div class="paragraph"><p>The default error message for <tt>validates_presence_of</tt> is "<em>can&#8217;t be empty</em>".</p></div>
-<h3 id="_the_tt_validates_uniqueness_of_tt_helper">3.10. The <tt>validates_uniqueness_of</tt> helper</h3>
-<div class="paragraph"><p>This helper validates that the attribute&#8217;s value is unique right before the object gets saved. It does not create a uniqueness constraint directly into your database, so it may happen that two different database connections create two records with the same value for a column that you wish were unique. To avoid that, you must create an unique index in your database.</p></div>
+<h3 id="_the_tt_validates_uniqueness_of_tt_helper">2.10. The <tt>validates_uniqueness_of</tt> helper</h3>
+<div class="paragraph"><p>This helper validates that the attribute&#8217;s value is unique right before the object gets saved. It does not create a uniqueness constraint directly into your database, so it may happen that two different database connections create two records with the same value for a column that you intend to be unique. To avoid that, you must create an unique index in your database.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -660,7 +660,7 @@ <h3 id="_the_tt_validates_uniqueness_of_tt_helper">3.10. The <tt>validates_uniqu
validates_uniqueness_of <span style="color: #990000">:</span>email
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
<div class="paragraph"><p>The validation happens by performing a SQL query into the model&#8217;s table, searching for a record where the attribute that must be validated is equal to the value in the object being validated.</p></div>
-<div class="paragraph"><p>There is a <tt>:scope</tt> option that you can use to specify other attributes that must be used to define uniqueness:</p></div>
+<div class="paragraph"><p>There is a <tt>:scope</tt> option that you can use to specify other attributes that are used to limit the uniqueness check:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -670,7 +670,7 @@ <h3 id="_the_tt_validates_uniqueness_of_tt_helper">3.10. The <tt>validates_uniqu
validates_uniqueness_of <span style="color: #990000">:</span>name<span style="color: #990000">,</span> <span style="color: #990000">:</span>scope <span style="color: #990000">=&gt;</span> <span style="color: #990000">:</span>year<span style="color: #990000">,</span>
<span style="color: #990000">:</span>message <span style="color: #990000">=&gt;</span> <span style="color: #FF0000">"Should happen once per year"</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<div class="paragraph"><p>There is also a <tt>:case_sensitive</tt> option that you can use to define if the uniqueness contraint will be case sensitive or not. This option defaults to true.</p></div>
+<div class="paragraph"><p>There is also a <tt>:case_sensitive</tt> option that you can use to define whether the uniqueness constraint will be case sensitive or not. This option defaults to true.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -680,7 +680,7 @@ <h3 id="_the_tt_validates_uniqueness_of_tt_helper">3.10. The <tt>validates_uniqu
validates_uniqueness_of <span style="color: #990000">:</span>name<span style="color: #990000">,</span> <span style="color: #990000">:</span>case_sensitive <span style="color: #990000">=&gt;</span> <span style="font-weight: bold"><span style="color: #0000FF">false</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
<div class="paragraph"><p>The default error message for <tt>validates_uniqueness_of</tt> is "<em>has already been taken</em>".</p></div>
-<h3 id="_the_tt_validates_each_tt_helper">3.11. The <tt>validates_each</tt> helper</h3>
+<h3 id="_the_tt_validates_each_tt_helper">2.11. The <tt>validates_each</tt> helper</h3>
<div class="paragraph"><p>This helper validates attributes against a block. It doesn&#8217;t have a predefined validation function. You should create one using a block, and every attribute passed to <tt>validates_each</tt> will be tested against it. In the following example, we don&#8217;t want names and surnames to begin with lower case.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -692,13 +692,13 @@ <h3 id="_the_tt_validates_each_tt_helper">3.11. The <tt>validates_each</tt> help
model<span style="color: #990000">.</span>errors<span style="color: #990000">.</span>add<span style="color: #990000">(</span>attr<span style="color: #990000">,</span> <span style="color: #FF0000">'Must start with upper case'</span><span style="color: #990000">)</span> <span style="font-weight: bold"><span style="color: #0000FF">if</span></span> value <span style="color: #990000">=~</span> <span style="color: #FF6600">/^[a-z]/</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<div class="paragraph"><p>The block receives the model, the attribute&#8217;s name and the attribute&#8217;s value. If your validation fails, you can add an error message to the model, therefore making it invalid.</p></div>
+<div class="paragraph"><p>The block receives the model, the attribute&#8217;s name and the attribute&#8217;s value. You can do anything you like to check for valid data within the block. If your validation fails, you can add an error message to the model, therefore making it invalid.</p></div>
</div>
-<h2 id="_common_validation_options">4. Common validation options</h2>
+<h2 id="_common_validation_options">3. Common Validation Options</h2>
<div class="sectionbody">
-<div class="paragraph"><p>There are some common options that all the validation helpers can use. Here they are, except for the <tt>:if</tt> and <tt>:unless</tt> options, which we&#8217;ll cover right at the next topic.</p></div>
-<h3 id="_the_tt_allow_nil_tt_option">4.1. The <tt>:allow_nil</tt> option</h3>
-<div class="paragraph"><p>You may use the <tt>:allow_nil</tt> option everytime you want to trigger a validation only if the value being validated is not <tt>nil</tt>. You may be asking yourself if it makes any sense to use <tt>:allow_nil</tt> and <tt>validates_presence_of</tt> together. Well, it does. Remember, validation will be skipped only for <tt>nil</tt> attributes, but empty strings are not considered <tt>nil</tt>.</p></div>
+<div class="paragraph"><p>There are some common options that all the validation helpers can use. Here they are, except for the <tt>:if</tt> and <tt>:unless</tt> options, which are discussed later in the conditional validation topic.</p></div>
+<h3 id="_the_tt_allow_nil_tt_option">3.1. The <tt>:allow_nil</tt> option</h3>
+<div class="paragraph"><p>The <tt>:allow_nil</tt> option skips the validation when the value being validated is <tt>nil</tt>. You may be asking yourself if it makes any sense to use <tt>:allow_nil</tt> and <tt>validates_presence_of</tt> together. Well, it does. Remember, the validation will be skipped only for <tt>nil</tt> attributes, but empty strings are not considered <tt>nil</tt>.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -708,8 +708,8 @@ <h3 id="_the_tt_allow_nil_tt_option">4.1. The <tt>:allow_nil</tt> option</h3>
validates_inclusion_of <span style="color: #990000">:</span>size<span style="color: #990000">,</span> <span style="color: #990000">:</span><span style="font-weight: bold"><span style="color: #0000FF">in</span></span> <span style="color: #990000">=&gt;</span> <span style="color: #990000">%</span>w<span style="color: #990000">(</span>small medium large<span style="color: #990000">),</span>
<span style="color: #990000">:</span>message <span style="color: #990000">=&gt;</span> <span style="color: #FF0000">"%s is not a valid size"</span><span style="color: #990000">,</span> <span style="color: #990000">:</span>allow_nil <span style="color: #990000">=&gt;</span> <span style="font-weight: bold"><span style="color: #0000FF">true</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<h3 id="_the_tt_allow_blank_tt_option">4.2. The <tt>:allow_blank</tt> option</h3>
-<div class="paragraph"><p>In compliment to <tt>:allow_nil</tt> we have <tt>:allow_blank</tt>. This option will let validation pass if the attribute&#8217;s value is <tt>nil</tt> or an empty string, i.e., any value that returns <tt>true</tt> for <tt>blank?</tt>.</p></div>
+<h3 id="_the_tt_allow_blank_tt_option">3.2. The <tt>:allow_blank</tt> option</h3>
+<div class="paragraph"><p>The <tt>:allow_blank: option is similar to the +:allow_nil</tt> option. This option will let validation pass if the attribute&#8217;s value is <tt>nil</tt> or an empty string, i.e., any value that returns <tt>true</tt> for <tt>blank?</tt>.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -721,10 +721,10 @@ <h3 id="_the_tt_allow_blank_tt_option">4.2. The <tt>:allow_blank</tt> option</h3
Topic<span style="color: #990000">.</span>create<span style="color: #990000">(</span><span style="color: #FF0000">"title"</span> <span style="color: #990000">=&gt;</span> <span style="color: #FF0000">""</span><span style="color: #990000">).</span>valid? <span style="font-style: italic"><span style="color: #9A1900"># =&gt; true</span></span>
Topic<span style="color: #990000">.</span>create<span style="color: #990000">(</span><span style="color: #FF0000">"title"</span> <span style="color: #990000">=&gt;</span> <span style="font-weight: bold"><span style="color: #0000FF">nil</span></span><span style="color: #990000">).</span>valid? <span style="font-style: italic"><span style="color: #9A1900"># =&gt; true</span></span></tt></pre></div></div>
-<h3 id="_the_tt_message_tt_option">4.3. The <tt>:message</tt> option</h3>
-<div class="paragraph"><p>As stated before, the <tt>:message</tt> option lets you specify the message that will be added to the <tt>errors</tt> collection when validation fails. When this option is not used, Active Record will use the respective default error message for each validation helper.</p></div>
-<h3 id="_the_tt_on_tt_option">4.4. The <tt>:on</tt> option</h3>
-<div class="paragraph"><p>As stated before, the <tt>:on</tt> option lets you specify when the validation should happen. The default behaviour for all the built-in validation helpers is to be ran on save (both when you&#8217;re creating a new record and when you&#8217;re updating it). If you want to change it, you can use <tt>:on =&gt; :create</tt> to run the validation only when a new record is created or <tt>:on =&gt; :update</tt> to run the validation only when a record is updated.</p></div>
+<h3 id="_the_tt_message_tt_option">3.3. The <tt>:message</tt> option</h3>
+<div class="paragraph"><p>As you&#8217;ve already seen, the <tt>:message</tt> option lets you specify the message that will be added to the <tt>errors</tt> collection when validation fails. When this option is not used, Active Record will use the respective default error message for each validation helper, together with the attribute name.</p></div>
+<h3 id="_the_tt_on_tt_option">3.4. The <tt>:on</tt> option</h3>
+<div class="paragraph"><p>The <tt>:on</tt> option lets you specify when the validation should happen. The default behavior for all the built-in validation helpers is to be ran on save (both when you&#8217;re creating a new record and when you&#8217;re updating it). If you want to change it, you can use <tt>:on =&gt; :create</tt> to run the validation only when a new record is created or <tt>:on =&gt; :update</tt> to run the validation only when a record is updated.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
@@ -737,14 +737,14 @@ <h3 id="_the_tt_on_tt_option">4.4. The <tt>:on</tt> option</h3>
<span style="font-style: italic"><span style="color: #9A1900"># =&gt; it will be possible to create the record with a 'non-numerical age'</span></span>
validates_numericality_of <span style="color: #990000">:</span>age<span style="color: #990000">,</span> <span style="color: #990000">:</span>on <span style="color: #990000">=&gt;</span> <span style="color: #990000">:</span>update
- <span style="font-style: italic"><span style="color: #9A1900"># =&gt; the default</span></span>
+ <span style="font-style: italic"><span style="color: #9A1900"># =&gt; the default (validates on both create and update)</span></span>
validates_presence_of <span style="color: #990000">:</span>name<span style="color: #990000">,</span> <span style="color: #990000">:</span>on <span style="color: #990000">=&gt;</span> <span style="color: #990000">:</span>save
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
</div>
-<h2 id="_conditional_validation">5. Conditional validation</h2>
+<h2 id="_conditional_validation">4. Conditional validation</h2>
<div class="sectionbody">
<div class="paragraph"><p>Sometimes it will make sense to validate an object just when a given predicate is satisfied. You can do that by using the <tt>:if</tt> and <tt>:unless</tt> options, which can take a symbol, a string or a Ruby Proc. You may use the <tt>:if</tt> option when you want to specify when the validation <strong>should</strong> happen. If you want to specify when the validation <strong>should not</strong> happen, then you may use the <tt>:unless</tt> option.</p></div>
-<h3 id="_using_a_symbol_with_the_tt_if_tt_and_tt_unless_tt_options">5.1. Using a symbol with the <tt>:if</tt> and <tt>:unless</tt> options</h3>
+<h3 id="_using_a_symbol_with_the_tt_if_tt_and_tt_unless_tt_options">4.1. Using a symbol with the <tt>:if</tt> and <tt>:unless</tt> options</h3>
<div class="paragraph"><p>You can associate the <tt>:if</tt> and <tt>:unless</tt> options with a symbol corresponding to the name of a method that will get called right before validation happens. This is the most commonly used option.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -758,7 +758,7 @@ <h3 id="_using_a_symbol_with_the_tt_if_tt_and_tt_unless_tt_options">5.1. Using a
payment_type <span style="color: #990000">==</span> <span style="color: #FF0000">"card"</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<h3 id="_using_a_string_with_the_tt_if_tt_and_tt_unless_tt_options">5.2. Using a string with the <tt>:if</tt> and <tt>:unless</tt> options</h3>
+<h3 id="_using_a_string_with_the_tt_if_tt_and_tt_unless_tt_options">4.2. Using a string with the <tt>:if</tt> and <tt>:unless</tt> options</h3>
<div class="paragraph"><p>You can also use a string that will be evaluated using <tt>:eval</tt> and needs to contain valid Ruby code. You should use this option only when the string represents a really short condition.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -768,7 +768,7 @@ <h3 id="_using_a_string_with_the_tt_if_tt_and_tt_unless_tt_options">5.2. Using a
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> Person <span style="color: #990000">&lt;</span> ActiveRecord<span style="color: #990000">::</span>Base
validates_presence_of <span style="color: #990000">:</span>surname<span style="color: #990000">,</span> <span style="color: #990000">:</span><span style="font-weight: bold"><span style="color: #0000FF">if</span></span> <span style="color: #990000">=&gt;</span> <span style="color: #FF0000">"name.nil?"</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<h3 id="_using_a_proc_object_with_the_tt_if_tt_and_tt_unless_tt_options">5.3. Using a Proc object with the <tt>:if</tt> and :<tt>unless</tt> options</h3>
+<h3 id="_using_a_proc_object_with_the_tt_if_tt_and_tt_unless_tt_options">4.3. Using a Proc object with the <tt>:if</tt> and :<tt>unless</tt> options</h3>
<div class="paragraph"><p>Finally, it&#8217;s possible to associate <tt>:if</tt> and <tt>:unless</tt> with a Ruby Proc object which will be called. Using a Proc object can give you the hability to write a condition that will be executed only when the validation happens and not when your code is loaded by the Ruby interpreter. This option is best suited when writing short validation methods, usually one-liners.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -780,7 +780,7 @@ <h3 id="_using_a_proc_object_with_the_tt_if_tt_and_tt_unless_tt_options">5.3. Us
<span style="color: #990000">:</span><span style="font-weight: bold"><span style="color: #0000FF">unless</span></span> <span style="color: #990000">=&gt;</span> Proc<span style="color: #990000">.</span>new <span style="color: #FF0000">{</span> <span style="color: #990000">|</span>a<span style="color: #990000">|</span> a<span style="color: #990000">.</span>password<span style="color: #990000">.</span>blank? <span style="color: #FF0000">}</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
</div>
-<h2 id="_writing_your_own_validation_methods">6. Writing your own validation methods</h2>
+<h2 id="_writing_your_own_validation_methods">5. Writing your own validation methods</h2>
<div class="sectionbody">
<div class="paragraph"><p>When the built-in validation helpers are not enough for your needs, you can write your own validation methods. You can do that by implementing methods that verify the state of your models and add messages to their <tt>errors</tt> collection when they are invalid. You must then register those methods by using one or more of the <tt>validate</tt>, <tt>validate_on_create</tt> or <tt>validate_on_update</tt> class methods, passing in the symbols for the validation methods' names. You can pass more than one symbol for each class method and the respective validations will be ran in the same order as they were registered.</p></div>
<div class="listingblock">
@@ -830,7 +830,7 @@ <h2 id="_writing_your_own_validation_methods">6. Writing your own validation met
validates_email_format_of <span style="color: #990000">:</span>email_address
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
</div>
-<h2 id="_manipulating_the_tt_errors_tt_collection">7. Manipulating the <tt>errors</tt> collection</h2>
+<h2 id="_manipulating_the_tt_errors_tt_collection">6. Manipulating the <tt>errors</tt> collection</h2>
<div class="sectionbody">
<div class="paragraph"><p>You can do more than just call <tt>valid?</tt> upon your objects based on the existance of the <tt>errors</tt> collection. Here is a list of the other available methods that you can use to manipulate errors or ask for an object&#8217;s state.</p></div>
<div class="ulist"><ul>
@@ -943,7 +943,7 @@ <h2 id="_manipulating_the_tt_errors_tt_collection">7. Manipulating the <tt>error
p<span style="color: #990000">.</span>errors<span style="color: #990000">.</span>on<span style="color: #990000">(:</span>name<span style="color: #990000">)</span>
<span style="font-style: italic"><span style="color: #9A1900"># =&gt; ["can't be blank", "is too short (minimum is 3 characters)"]</span></span></tt></pre></div></div>
</div>
-<h2 id="_using_the_tt_errors_tt_collection_in_your_view_templates">8. Using the <tt>errors</tt> collection in your view templates</h2>
+<h2 id="_using_the_tt_errors_tt_collection_in_your_view_templates">7. Using the <tt>errors</tt> collection in your view templates</h2>
<div class="sectionbody">
<div class="paragraph"><p>Rails provides built-in helpers to display the error messages of your models in your view templates. It may be useful to display those messages when you&#8217;re trying to create or edit a record and validation fails. If you&#8217;re using the <tt>form_for</tt> helper to create a form, you can use it to call the <tt>error_messages</tt> method, which creates a <tt>div</tt> element containing all the error messages for the model associated with the form. Here is a simple example, using a <tt>Product</tt> model and the view template generated with the scaffold script.</p></div>
<div class="listingblock">
@@ -1025,7 +1025,7 @@ <h2 id="_using_the_tt_errors_tt_collection_in_your_view_templates">8. Using the
</p>
</li>
</ul></div>
-<h3 id="_changing_the_way_form_fields_with_errors_are_displayed">8.1. Changing the way form fields with errors are displayed</h3>
+<h3 id="_changing_the_way_form_fields_with_errors_are_displayed">7.1. Changing the way form fields with errors are displayed</h3>
<div class="paragraph"><p>By default, form fields with errors are displayed enclosed by a <tt>div</tt> element with the <tt>fieldWithErrors</tt> CSS class. However, we can write some Ruby code to override the way Rails treats those fields by default. Here is a simple example where we change the Rails behaviour to always display the error messages in front of each of the form fields with errors. The error messages will be enclosed by a <tt>span</tt> element with a <tt>validation-error</tt> CSS class. There will be no <tt>div</tt> element enclosing the <tt>input</tt> element, so we get rid of that red border around the text field. You can use the <tt>validation-error</tt> CSS class to style it anyway you want.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -1061,10 +1061,10 @@ <h3 id="_changing_the_way_form_fields_with_errors_are_displayed">8.1. Changing t
</li>
</ul></div>
</div>
-<h2 id="_callbacks">9. Callbacks</h2>
+<h2 id="_callbacks">8. Callbacks</h2>
<div class="sectionbody">
<div class="paragraph"><p>Callbacks are methods that get called at certain moments of an object&#8217;s lifecycle. With callbacks it&#8217;s possible to write code that will run whenever an Active Record object is created, saved, updated, deleted or loaded from the database.</p></div>
-<h3 id="_callbacks_registration">9.1. Callbacks registration</h3>
+<h3 id="_callbacks_registration">8.1. Callbacks registration</h3>
<div class="paragraph"><p>In order to use the available callbacks, you need to registrate them. You can do that by implementing them as an ordinary methods, and then using a macro-style class method to register then as callbacks.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -1103,10 +1103,10 @@ <h3 id="_callbacks_registration">9.1. Callbacks registration</h3>
</tr></table>
</div>
</div>
-<h2 id="_conditional_callbacks">10. Conditional callbacks</h2>
+<h2 id="_conditional_callbacks">9. Conditional callbacks</h2>
<div class="sectionbody">
<div class="paragraph"><p>Like in validations, we can also make our callbacks conditional, calling then only when a given predicate is satisfied. You can do that by using the <tt>:if</tt> and <tt>:unless</tt> options, which can take a symbol, a string or a Ruby Proc. You may use the <tt>:if</tt> option when you want to specify when the callback <strong>should</strong> get called. If you want to specify when the callback <strong>should not</strong> be called, then you may use the <tt>:unless</tt> option.</p></div>
-<h3 id="_using_a_symbol_with_the_tt_if_tt_and_tt_unless_tt_options_2">10.1. Using a symbol with the <tt>:if</tt> and <tt>:unless</tt> options</h3>
+<h3 id="_using_a_symbol_with_the_tt_if_tt_and_tt_unless_tt_options_2">9.1. Using a symbol with the <tt>:if</tt> and <tt>:unless</tt> options</h3>
<div class="paragraph"><p>You can associate the <tt>:if</tt> and <tt>:unless</tt> options with a symbol corresponding to the name of a method that will get called right before the callback. If this method returns <tt>false</tt> the callback won&#8217;t be executed. This is the most common option. Using this form of registration it&#8217;s also possible to register several different methods that should be called to check the if the callback should be executed.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -1116,7 +1116,7 @@ <h3 id="_using_a_symbol_with_the_tt_if_tt_and_tt_unless_tt_options_2">10.1. Usin
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> Order <span style="color: #990000">&lt;</span> ActiveRecord<span style="color: #990000">::</span>Base
before_save <span style="color: #990000">:</span>normalize_card_number<span style="color: #990000">,</span> <span style="color: #990000">:</span><span style="font-weight: bold"><span style="color: #0000FF">if</span></span> <span style="color: #990000">=&gt;</span> <span style="color: #990000">:</span>paid_with_card?
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<h3 id="_using_a_string_with_the_tt_if_tt_and_tt_unless_tt_options_2">10.2. Using a string with the <tt>:if</tt> and <tt>:unless</tt> options</h3>
+<h3 id="_using_a_string_with_the_tt_if_tt_and_tt_unless_tt_options_2">9.2. Using a string with the <tt>:if</tt> and <tt>:unless</tt> options</h3>
<div class="paragraph"><p>You can also use a string that will be evaluated using <tt>:eval</tt> and needs to contain valid Ruby code. You should use this option only when the string represents a really short condition.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -1126,7 +1126,7 @@ <h3 id="_using_a_string_with_the_tt_if_tt_and_tt_unless_tt_options_2">10.2. Usin
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> Order <span style="color: #990000">&lt;</span> ActiveRecord<span style="color: #990000">::</span>Base
before_save <span style="color: #990000">:</span>normalize_card_number<span style="color: #990000">,</span> <span style="color: #990000">:</span><span style="font-weight: bold"><span style="color: #0000FF">if</span></span> <span style="color: #990000">=&gt;</span> <span style="color: #FF0000">"paid_with_card?"</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<h3 id="_using_a_proc_object_with_the_tt_if_tt_and_tt_unless_tt_options_2">10.3. Using a Proc object with the <tt>:if</tt> and :<tt>unless</tt> options</h3>
+<h3 id="_using_a_proc_object_with_the_tt_if_tt_and_tt_unless_tt_options_2">9.3. Using a Proc object with the <tt>:if</tt> and :<tt>unless</tt> options</h3>
<div class="paragraph"><p>Finally, it&#8217;s possible to associate <tt>:if</tt> and <tt>:unless</tt> with a Ruby Proc object. This option is best suited when writing short validation methods, usually one-liners.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -1137,7 +1137,7 @@ <h3 id="_using_a_proc_object_with_the_tt_if_tt_and_tt_unless_tt_options_2">10.3.
before_save <span style="color: #990000">:</span>normalize_card_number<span style="color: #990000">,</span>
<span style="color: #990000">:</span><span style="font-weight: bold"><span style="color: #0000FF">if</span></span> <span style="color: #990000">=&gt;</span> Proc<span style="color: #990000">.</span>new <span style="color: #FF0000">{</span> <span style="color: #990000">|</span>order<span style="color: #990000">|</span> order<span style="color: #990000">.</span>paid_with_card? <span style="color: #FF0000">}</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<h3 id="_multiple_conditions_for_callbacks">10.4. Multiple Conditions for Callbacks</h3>
+<h3 id="_multiple_conditions_for_callbacks">9.4. Multiple Conditions for Callbacks</h3>
<div class="paragraph"><p>When writing conditional callbacks, it&#8217;s possible to mix both <tt>:if</tt> and <tt>:unless</tt> in the same callback declaration.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -1149,10 +1149,10 @@ <h3 id="_multiple_conditions_for_callbacks">10.4. Multiple Conditions for Callba
<span style="color: #990000">:</span><span style="font-weight: bold"><span style="color: #0000FF">unless</span></span> <span style="color: #990000">=&gt;</span> Proc<span style="color: #990000">.</span>new <span style="color: #FF0000">{</span> <span style="color: #990000">|</span>comment<span style="color: #990000">|</span> comment<span style="color: #990000">.</span>post<span style="color: #990000">.</span>ignore_comments? <span style="color: #FF0000">}</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
</div>
-<h2 id="_available_callbacks">11. Available callbacks</h2>
+<h2 id="_available_callbacks">10. Available callbacks</h2>
<div class="sectionbody">
<div class="paragraph"><p>Here is a list with all the available Active Record callbacks, listed in the same order in which they will get called during the respective operations.</p></div>
-<h3 id="_callbacks_called_both_when_creating_or_updating_a_record">11.1. Callbacks called both when creating or updating a record.</h3>
+<h3 id="_callbacks_called_both_when_creating_or_updating_a_record">10.1. Callbacks called both when creating or updating a record.</h3>
<div class="ulist"><ul>
<li>
<p>
@@ -1180,7 +1180,7 @@ <h3 id="_callbacks_called_both_when_creating_or_updating_a_record">11.1. Callbac
</p>
</li>
</ul></div>
-<h3 id="_callbacks_called_only_when_creating_a_new_record">11.2. Callbacks called only when creating a new record.</h3>
+<h3 id="_callbacks_called_only_when_creating_a_new_record">10.2. Callbacks called only when creating a new record.</h3>
<div class="ulist"><ul>
<li>
<p>
@@ -1208,7 +1208,7 @@ <h3 id="_callbacks_called_only_when_creating_a_new_record">11.2. Callbacks calle
</p>
</li>
</ul></div>
-<h3 id="_callbacks_called_only_when_updating_an_existing_record">11.3. Callbacks called only when updating an existing record.</h3>
+<h3 id="_callbacks_called_only_when_updating_an_existing_record">10.3. Callbacks called only when updating an existing record.</h3>
<div class="ulist"><ul>
<li>
<p>
@@ -1236,7 +1236,7 @@ <h3 id="_callbacks_called_only_when_updating_an_existing_record">11.3. Callbacks
</p>
</li>
</ul></div>
-<h3 id="_callbacks_called_when_removing_a_record_from_the_database">11.4. Callbacks called when removing a record from the database.</h3>
+<h3 id="_callbacks_called_when_removing_a_record_from_the_database">10.4. Callbacks called when removing a record from the database.</h3>
<div class="ulist"><ul>
<li>
<p>
@@ -1255,16 +1255,16 @@ <h3 id="_callbacks_called_when_removing_a_record_from_the_database">11.4. Callba
</li>
</ul></div>
<div class="paragraph"><p>The <tt>before_destroy</tt> and <tt>after_destroy</tt> callbacks will only be called if you delete the model using either the <tt>destroy</tt> instance method or one of the <tt>destroy</tt> or <tt>destroy_all</tt> class methods of your Active Record class. If you use <tt>delete</tt> or <tt>delete_all</tt> no callback operations will run, since Active Record will not instantiate any objects, accessing the records to be deleted directly in the database.</p></div>
-<h3 id="_the_tt_after_initialize_tt_and_tt_after_find_tt_callbacks">11.5. The <tt>after_initialize</tt> and <tt>after_find</tt> callbacks</h3>
+<h3 id="_the_tt_after_initialize_tt_and_tt_after_find_tt_callbacks">10.5. The <tt>after_initialize</tt> and <tt>after_find</tt> callbacks</h3>
<div class="paragraph"><p>The <tt>after_initialize</tt> callback will be called whenever an Active Record object is instantiated, either by direcly using <tt>new</tt> or when a record is loaded from the database. It can be useful to avoid the need to directly override your Active Record <tt>initialize</tt> method.</p></div>
<div class="paragraph"><p>The <tt>after_find</tt> callback will be called whenever Active Record loads a record from the database. When used together with <tt>after_initialize</tt> it will run first, since Active Record will first read the record from the database and them create the model object that will hold it.</p></div>
<div class="paragraph"><p>The <tt>after_initialize</tt> and <tt>after_find</tt> callbacks are a bit different from the others, since the only way to register those callbacks is by defining them as methods. If you try to register <tt>after_initialize</tt> or <tt>after_find</tt> using macro-style class methods, they will just be ignored. This behaviour is due to performance reasons, since <tt>after_initialize</tt> and <tt>after_find</tt> will both be called for each record found in the database, significantly slowing down the queries.</p></div>
</div>
-<h2 id="_halting_execution">12. Halting Execution</h2>
+<h2 id="_halting_execution">11. Halting Execution</h2>
<div class="sectionbody">
<div class="paragraph"><p>As you start registering new callbacks for your models, they will be queued for execution. This queue will include all your model&#8217;s validations, the registered callbacks and the database operation to be executed. However, if at any moment one of the <tt>before_create</tt>, <tt>before_save</tt>, <tt>before_update</tt> or <tt>before_destroy</tt> callback methods returns a boolean <tt>false</tt> (not <tt>nil</tt>) value or raise and exception, this execution chain will be halted and the desired operation will not complete: your model will not get persisted in the database, or your records will not get deleted and so on. It&#8217;s because the whole callback chain is wrapped in a transaction, so raising an exception or returning <tt>false</tt> fires a database ROLLBACK.</p></div>
</div>
-<h2 id="_callback_classes">13. Callback classes</h2>
+<h2 id="_callback_classes">12. Callback classes</h2>
<div class="sectionbody">
<div class="paragraph"><p>Sometimes the callback methods that you&#8217;ll write will be useful enough to be reused at other models. Active Record makes it possible to create classes that encapsulate the callback methods, so it becomes very easy to reuse them.</p></div>
<div class="paragraph"><p>Here&#8217;s an example where we create a class with a after_destroy callback for a PictureFile model.</p></div>
@@ -1309,7 +1309,7 @@ <h2 id="_callback_classes">13. Callback classes</h2>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
<div class="paragraph"><p>You can declare as many callbacks as you want inside your callback classes.</p></div>
</div>
-<h2 id="_observers">14. Observers</h2>
+<h2 id="_observers">13. Observers</h2>
<div class="sectionbody">
<div class="paragraph"><p>Active Record callbacks are a powerful feature, but they can pollute your model implementation with code that&#8217;s not directly related to the model&#8217;s purpose. In object-oriented software, it&#8217;s always a good idea to design your classes with a single responsibility in the whole system. For example, it wouldn&#8217;t make much sense to have a <tt>User</tt> model with a method that writes data about a login attempt to a log file. Whenever you&#8217;re using callbacks to write code that&#8217;s not directly related to your model class purposes, it may be a good moment to create an Observer.</p></div>
<div class="paragraph"><p>An Active Record Observer is an object that links itself to a model and registers its methods for callbacks. Your model&#8217;s implementation remains clean, while you can reuse the code in the Observer to add behaviour to more than one model class. OK, you may say that we can also do that using callback classes, but it would still force us to add code to our model&#8217;s implementation.</p></div>
@@ -1335,7 +1335,7 @@ <h2 id="_observers">14. Observers</h2>
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> Auditor <span style="color: #990000">&lt;</span> ActiveRecord<span style="color: #990000">::</span>Observer
observe User<span style="color: #990000">,</span> Registration<span style="color: #990000">,</span> Invoice
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<h3 id="_registering_observers">14.1. Registering observers</h3>
+<h3 id="_registering_observers">13.1. Registering observers</h3>
<div class="paragraph"><p>If you paid attention, you may be wondering where Active Record Observers are referenced in our applications, so they get instantiated and begin to interact with our models. For observers to work we need to register them somewhere. The usual place to do that is in our application&#8217;s <strong>config/environment.rb</strong> file. In this file there is a commented-out line where we can define the observers that our application should load at start-up.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
@@ -1346,10 +1346,10 @@ <h3 id="_registering_observers">14.1. Registering observers</h3>
config<span style="color: #990000">.</span>active_record<span style="color: #990000">.</span>observers <span style="color: #990000">=</span> <span style="color: #990000">:</span>registration_observer<span style="color: #990000">,</span> <span style="color: #990000">:</span>auditor</tt></pre></div></div>
<div class="paragraph"><p>You can uncomment the line with <tt>config.active_record.observers</tt> and change the symbols for the name of the observers that should be registered.</p></div>
<div class="paragraph"><p>It&#8217;s also possible to register callbacks in any of the files living at <strong>config/environments/</strong>, if you want an observer to work only in a specific environment. There is not a <tt>config.active_record.observers</tt> line at any of those files, but you can simply add it.</p></div>
-<h3 id="_where_to_put_the_observers_source_files">14.2. Where to put the observers' source files</h3>
+<h3 id="_where_to_put_the_observers_source_files">13.2. Where to put the observers' source files</h3>
<div class="paragraph"><p>By convention, you should always save your observers' source files inside <strong>app/models</strong>.</p></div>
</div>
-<h2 id="_changelog">15. Changelog</h2>
+<h2 id="_changelog">14. Changelog</h2>
<div class="sectionbody">
<div class="paragraph"><p><a href="http://rails.lighthouseapp.com/projects/16213/tickets/26-active-record-validations-and-callbacks">http://rails.lighthouseapp.com/projects/16213/tickets/26-active-record-validations-and-callbacks</a></p></div>
</div>

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