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| author | Pratik Naik <pratiknaik@gmail.com> | 2009-01-24 15:39:48 +0000 |
|---|---|---|
| committer | Pratik Naik <pratiknaik@gmail.com> | 2009-01-24 15:39:48 +0000 |
| commit | d9412979002bdf0a30212880a2c595aa79d2539a (patch) | |
| tree | bb5173a9276cc2c410062d5f0801aecf0e805c10 /railties/doc/guides/html | |
| parent | 0aef4994515bafc1607db7b8d2d0d015a5aeea15 (diff) | |
| download | rails-d9412979002bdf0a30212880a2c595aa79d2539a.tar.gz rails-d9412979002bdf0a30212880a2c595aa79d2539a.tar.bz2 rails-d9412979002bdf0a30212880a2c595aa79d2539a.zip | |
Regenerate guides
Diffstat (limited to 'railties/doc/guides/html')
| -rw-r--r-- | railties/doc/guides/html/form_helpers.html | 106 |
1 files changed, 56 insertions, 50 deletions
diff --git a/railties/doc/guides/html/form_helpers.html b/railties/doc/guides/html/form_helpers.html index 978beb4223..91b7b02574 100644 --- a/railties/doc/guides/html/form_helpers.html +++ b/railties/doc/guides/html/form_helpers.html @@ -34,7 +34,7 @@ <a href="#_dealing_with_basic_forms">Dealing With Basic Forms</a> <ul> - <li><a href="#_generic_search_form">Generic search form</a></li> + <li><a href="#_a_generic_search_form">A Generic search form</a></li> <li><a href="#_multiple_hashes_in_form_helper_calls">Multiple hashes in form helper calls</a></li> @@ -80,6 +80,8 @@ <li><a href="#_common_options">Common options</a></li> + <li><a href="#_individual_components">Individual Components</a></li> + </ul> </li> <li> @@ -173,7 +175,7 @@ Find out where to look for complex forms Form contents
<% end %></tt></pre>
</div></div>
-<div class="paragraph"><p>When called without arguments like this, it creates a form element that has the current page for action attribute and "post" as method (some line breaks added for readability):</p></div>
+<div class="paragraph"><p>When called without arguments like this, it creates a form element that has the current page as its action and "post" as its method (some line breaks added for readability):</p></div>
<div class="listingblock">
<div class="title">Sample output from <tt>form_tag</tt></div>
<div class="content">
@@ -184,7 +186,7 @@ Find out where to look for complex forms Form contents
</form></tt></pre>
</div></div>
-<div class="paragraph"><p>If you carefully observe this output, you can see that the helper generated something you didn’t specify: a <tt>div</tt> element with a hidden input inside. This is a security feature of Rails called <strong>cross-site request forgery protection</strong> and form helpers generate it for every form whose action is not "get" (provided that this security feature is enabled).</p></div>
+<div class="paragraph"><p>If you carefully observe this output, you can see that the helper generated something you didn’t specify: a <tt>div</tt> element with a hidden input inside. This is a security feature of Rails called <strong>cross-site request forgery protection</strong> and form helpers generate it for every form whose action is not "get" (provided that this security feature is enabled). You can read more about this in the <a href="./security.html#_cross_site_reference_forgery_csrf">Ruby On Rails Security Guide</a>.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
@@ -193,7 +195,7 @@ Find out where to look for complex forms <td class="content">Throughout this guide, this <tt>div</tt> with the hidden input will be stripped away to have clearer code samples.</td>
</tr></table>
</div>
-<h3 id="_generic_search_form">1.1. Generic search form</h3>
+<h3 id="_a_generic_search_form">1.1. A Generic search form</h3>
<div class="paragraph"><p>Probably the most minimal form often seen on the web is a search form with a single text input for search terms. This form consists of:</p></div>
<div class="olist arabic"><ol class="arabic">
<li>
@@ -374,7 +376,7 @@ output: <h2 id="_dealing_with_model_objects">2. Dealing With Model Objects</h2>
<div class="sectionbody">
<h3 id="_model_object_helpers">2.1. Model object helpers</h3>
-<div class="paragraph"><p>A particularly common task for a form is editing or creating a model object. While the <tt>*_tag</tt> helpers could certainly be used for this task they are somewhat verbose as for each tag you would have to ensure the correct parameter name is used and set the default value of the input appropriately. Rails provides helpers tailored to this task. These helpers lack the _tag suffix, for example <tt>text_field</tt>, <tt>text_area</tt>.</p></div>
+<div class="paragraph"><p>A particularly common task for a form is editing or creating a model object. While the <tt>*_tag</tt> helpers can certainly be used for this task they are somewhat verbose as for each tag you would have to ensure the correct parameter name is used and set the default value of the input appropriately. Rails provides helpers tailored to this task. These helpers lack the _tag suffix, for example <tt>text_field</tt>, <tt>text_area</tt>.</p></div>
<div class="paragraph"><p>For these helpers the first argument is the name of an instance variable and the second is the name of a method (usually an attribute) to call on that object. Rails will set the value of the input control to the return value of that method for the object and set an appropriate input name. If your controller has defined <tt>@person</tt> and that person’s name is Henry then a form containing:</p></div>
<div class="listingblock">
<div class="content">
@@ -385,7 +387,7 @@ output: <div class="content">
<pre><tt><input id="person_name" name="person[name]" type="text" value="Henry"/></tt></pre>
</div></div>
-<div class="paragraph"><p>Upon form submission the value entered by the user will be stored in <tt>params[:person][:name]</tt>. The <tt>params[:person]</tt> hash is suitable for passing to <tt>Person.new</tt> or, if <tt>@person</tt> is an instance of Person, <tt>@person.update_attributes</tt>.</p></div>
+<div class="paragraph"><p>Upon form submission the value entered by the user will be stored in <tt>params[:person][:name]</tt>. The <tt>params[:person]</tt> hash is suitable for passing to <tt>Person.new</tt> or, if <tt>@person</tt> is an instance of Person, <tt>@person.update_attributes</tt>. While the name of an attribute is the most common second parameter to these helpers this is not compulsory. In the example above, as long as person objects have a <tt>name</tt> and a <tt>name=</tt> method Rails will be happy.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
@@ -449,7 +451,7 @@ Methods to create form controls are called <strong>on</strong> the form builder <input name="commit" type="submit" value="Create" />
</form></tt></pre>
</div></div>
-<div class="paragraph"><p>The name passed to <tt>form_for</tt> controls the key used in <tt>params</tt> for form’s values. Here the name is <tt>article</tt> and so all the inputs have names of the form <tt>article[attribute_name]</tt>. Accordingly, in the <tt>create</tt> action <tt>params[:article]</tt> will be a hash with keys <tt>:title</tt> and <tt>:body</tt>. You can read more about the significance of input names in the <a href="#parameter_names">parameter names</a> section.</p></div>
+<div class="paragraph"><p>The name passed to <tt>form_for</tt> controls the key used in <tt>params</tt> to access the form’s values. Here the name is <tt>article</tt> and so all the inputs have names of the form <tt>article[attribute_name]</tt>. Accordingly, in the <tt>create</tt> action <tt>params[:article]</tt> will be a hash with keys <tt>:title</tt> and <tt>:body</tt>. You can read more about the significance of input names in the <a href="#parameter_names">parameter names</a> section.</p></div>
<div class="paragraph"><p>The helper methods called on the form builder are identical to the model object helpers except that it is not necessary to specify which object is being edited since this is already managed by the form builder.</p></div>
<div class="paragraph"><p>You can create a similar binding without actually creating <tt><form></tt> tags with the <tt>fields_for</tt> helper. This is useful for editing additional model objects with the same form. For example if you had a Person model with an associated ContactDetail model you could create a form for editing both like so:</p></div>
<div class="listingblock">
@@ -471,7 +473,7 @@ Methods to create form controls are called <strong>on</strong> the form builder </div></div>
<div class="paragraph"><p>The object yielded by <tt>fields_for</tt> is a form builder like the one yielded by <tt>form_for</tt> (in fact <tt>form_for</tt> calls <tt>fields_for</tt> internally).</p></div>
<h3 id="_relying_on_record_identification">2.3. Relying on record identification</h3>
-<div class="paragraph"><p>The Article model is directly available to users of our application, so — following the best practices for developing with Rails — you should declare it <strong>a resource</strong>.</p></div>
+<div class="paragraph"><p>The Article model is directly available to users of the application, so — following the best practices for developing with Rails — you should declare it <strong>a resource</strong>.</p></div>
<div class="paragraph"><p>When dealing with RESTful resources, calls to <tt>form_for</tt> can get significantly easier if you rely on <strong>record identification</strong>. In short, you can just pass the model instance and have Rails figure out model name and the rest:</p></div>
<div class="listingblock">
<div class="content">
@@ -488,7 +490,7 @@ form_for(:article, @article, :url => article_path(@article), :method => "p form_for(@article)</tt></pre>
</div></div>
<div class="paragraph"><p>Notice how the short-style <tt>form_for</tt> invocation is conveniently the same, regardless of the record being new or existing. Record identification is smart enough to figure out if the record is new by asking <tt>record.new_record?</tt>. It also selects the correct path to submit to and the name based on the class of the object.</p></div>
-<div class="paragraph"><p>Rails will also automatically set the class and id of the form appropriately: a form creating an article would have id and class <tt>new_article</tt>. If you were editing the article with id 23 the class would be set to <tt>edit_article</tt> and the id to <tt>edit_article_23</tt>. The attributes will be omitted or brevity in the rest of this guide.</p></div>
+<div class="paragraph"><p>Rails will also automatically set the class and id of the form appropriately: a form creating an article would have id and class <tt>new_article</tt>. If you were editing the article with id 23 the class would be set to <tt>edit_article</tt> and the id to <tt>edit_article_23</tt>. These attributes will be omitted for brevity in the rest of this guide.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
@@ -510,7 +512,7 @@ form_for(@article)</tt></pre> </div></div>
<div class="paragraph"><p>For more information on Rails' routing system and the associated conventions, please see the <a href="./routing_outside_in.html">routing guide</a>.</p></div>
<h3 id="_how_do_forms_with_put_or_delete_methods_work">2.4. How do forms with PUT or DELETE methods work?</h3>
-<div class="paragraph"><p>Rails framework encourages RESTful design of your applications, which means you’ll be making a lot of "PUT" and "DELETE" requests (besides "GET" and "POST"). Still, most browsers <em>don’t support</em> methods other than "GET" and "POST" when it comes to submitting forms. How does this work, then?</p></div>
+<div class="paragraph"><p>Rails framework encourages RESTful design of your applications, which means you’ll be making a lot of "PUT" and "DELETE" requests (besides "GET" and "POST"). Still, most browsers <em>don’t support</em> methods other than "GET" and "POST" when it comes to submitting forms.</p></div>
<div class="paragraph"><p>Rails works around this issue by emulating other methods over POST with a hidden input named <tt>"_method"</tt> that is set to reflect the desired method:</p></div>
<div class="listingblock">
<div class="content">
@@ -525,7 +527,7 @@ output: </div>
...</tt></pre>
</div></div>
-<div class="paragraph"><p>When parsing POSTed data, Rails will take into account the special <tt>_method</tt> parameter and act as if the HTTP method was the one specified inside it ("PUT" in this example).</p></div>
+<div class="paragraph"><p>When parsing POSTed data, Rails will take into account the special <tt>_method</tt> parameter and acts as if the HTTP method was the one specified inside it ("PUT" in this example).</p></div>
</div>
<h2 id="_making_select_boxes_with_ease">3. Making select boxes with ease</h2>
<div class="sectionbody">
@@ -534,7 +536,7 @@ output: <div class="listingblock">
<div class="content">
<pre><tt><select name="city_id" id="city_id">
- <option value="1">Lisabon</option>
+ <option value="1">Lisbon</option>
<option value="2">Madrid</option>
...
<option value="12">Berlin</option>
@@ -545,26 +547,26 @@ output: <div class="paragraph"><p>The most generic helper is <tt>select_tag</tt>, which — as the name implies — simply generates the <tt>SELECT</tt> tag that encapsulates an options string:</p></div>
<div class="listingblock">
<div class="content">
-<pre><tt><%= select_tag(:city_id, '<option value="1">Lisabon</option>...') %></tt></pre>
+<pre><tt><%= select_tag(:city_id, '<option value="1">Lisbon</option>...') %></tt></pre>
</div></div>
-<div class="paragraph"><p>This is a start, but it doesn’t dynamically create our option tags. You can generate option tags with the <tt>options_for_select</tt> helper:</p></div>
+<div class="paragraph"><p>This is a start, but it doesn’t dynamically create the option tags. You can generate option tags with the <tt>options_for_select</tt> helper:</p></div>
<div class="listingblock">
<div class="content">
-<pre><tt><%= options_for_select([['Lisabon', 1], ['Madrid', 2], ...]) %>
+<pre><tt><%= options_for_select([['Lisbon', 1], ['Madrid', 2], ...]) %>
output:
-<option value="1">Lisabon</option>
+<option value="1">Lisbon</option>
<option value="2">Madrid</option>
...</tt></pre>
</div></div>
-<div class="paragraph"><p>For input data you use a nested array where each element has two elements: option text (city name) and option value (city id). The option value is what will get submitted to your controller. It is often true that the option value is the id of a corresponding database object but this does not have to be the case.</p></div>
+<div class="paragraph"><p>The first argument to <tt>options_for_select</tt> is a nested array where each element has two elements: option text (city name) and option value (city id). The option value is what will be submitted to your controller. Often this will be the id of a corresponding database object but this does not have to be the case.</p></div>
<div class="paragraph"><p>Knowing this, you can combine <tt>select_tag</tt> and <tt>options_for_select</tt> to achieve the desired, complete markup:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt><%= select_tag(:city_id, options_for_select(...)) %></tt></pre>
</div></div>
-<div class="paragraph"><p>Sometimes, depending on an application’s needs, you also wish a specific option to be pre-selected. The <tt>options_for_select</tt> helper supports this with an optional second argument:</p></div>
+<div class="paragraph"><p><tt>options_for_select</tt> allows you to pre-select an option by specify its value as the second argument:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt><%= options_for_select([['Lisabon', 1], ['Madrid', 2], ...], 2) %>
@@ -575,20 +577,19 @@ output: <option value="2" selected="selected">Madrid</option>
...</tt></pre>
</div></div>
-<div class="paragraph"><p>So whenever Rails sees that the internal value of an option being generated matches this value, it will add the <tt>selected</tt> attribute to that option.</p></div>
+<div class="paragraph"><p>Whenever Rails sees that the internal value of an option being generated matches this value, it will add the <tt>selected</tt> attribute to that option.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="./images/icons/tip.png" alt="Tip" />
</td>
<td class="content">
-<div class="paragraph"><p>The second argument to <tt>options_for_select</tt> must be exactly equal to the desired internal value. In particular if the internal value is the integer 2 you cannot pass "2" to <tt>options_for_select</tt> — you must pass 2. Be aware of values extracted from the <tt>params</tt> hash as they are all strings.</p></div>
+<div class="paragraph"><p>The second argument to <tt>options_for_select</tt> must be exactly equal to the desired internal value. In particular if the value is the integer 2 you cannot pass "2" to <tt>options_for_select</tt> — you must pass 2. Be aware of values extracted from the <tt>params</tt> hash as they are all strings.</p></div>
</td>
</tr></table>
</div>
<h3 id="_select_boxes_for_dealing_with_models">3.2. Select boxes for dealing with models</h3>
-<div class="paragraph"><p>Until now you’ve seen how to make generic select boxes, but in most cases our form controls will be tied to a specific database model. So, to continue from our previous examples, let’s assume that you have a "Person" model with a <tt>city_id</tt> attribute.</p></div>
-<div class="paragraph"><p>Consistent with other form helpers, when dealing with models you drop the <tt>_tag</tt> suffix from <tt>select_tag</tt>.</p></div>
+<div class="paragraph"><p>In most cases form controls will be tied to a specific database model and as you might expect Rails provides helpers tailored for that purpose. Consistent with other form helpers, when dealing with models you drop the <tt>_tag</tt> suffix from <tt>select_tag</tt>:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt># controller:
@@ -598,7 +599,7 @@ output: <%= select(:person, :city_id, [['Lisabon', 1], ['Madrid', 2], ...]) %></tt></pre>
</div></div>
<div class="paragraph"><p>Notice that the third parameter, the options array, is the same kind of argument you pass to <tt>options_for_select</tt>. One advantage here is that you don’t have to worry about pre-selecting the correct city if the user already has one — Rails will do this for you by reading from the <tt>@person.city_id</tt> attribute.</p></div>
-<div class="paragraph"><p>As before, if you were to use <tt>select</tt> helper on a form builder scoped to <tt>@person</tt> object, the syntax would be:</p></div>
+<div class="paragraph"><p>As with other helpers, if you were to use <tt>select</tt> helper on a form builder scoped to <tt>@person</tt> object, the syntax would be:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt># select on a form builder
@@ -610,22 +611,18 @@ output: <img src="./images/icons/warning.png" alt="Warning" />
</td>
<td class="content">
-<div class="paragraph"><p>If you are using <tt>select</tt> (or similar helpers such as <tt>collection_select</tt>, <tt>select_tag</tt>) to set a <tt>belongs_to</tt> association you must pass the name of the foreign key (in the example above <tt>city_id</tt>), not the name of association itself. If you specify <tt>city</tt> instead of `city_id Active Record will raise an error along the lines of</p></div>
+<div class="paragraph"><p>If you are using <tt>select</tt> (or similar helpers such as <tt>collection_select</tt>, <tt>select_tag</tt>) to set a <tt>belongs_to</tt> association you must pass the name of the foreign key (in the example above <tt>city_id</tt>), not the name of association itself.</p></div>
+<div class="paragraph"><p>If you specify <tt>city</tt> instead of <tt>city_id</tt> Active Record will raise an error along the lines of</p></div>
<div class="listingblock">
<div class="content">
-<pre><tt>ActiveRecord::AssociationTypeMismatch: City(#17815740) expected, got Fixnum(#1138750)</tt></pre>
+<pre><tt>ActiveRecord::AssociationTypeMismatch: City(#17815740) expected, got String(#1138750)</tt></pre>
</div></div>
<div class="paragraph"><p>when you pass the <tt>params</tt> hash to <tt>Person.new</tt> or <tt>update_attributes</tt>. Another way of looking at this is that form helpers only edit attributes.</p></div>
</td>
</tr></table>
</div>
<h3 id="_option_tags_from_a_collection_of_arbitrary_objects">3.3. Option tags from a collection of arbitrary objects</h3>
-<div class="paragraph"><p>Until now you were generating option tags from nested arrays with the help of <tt>options_for_select</tt> method. Data in our array were raw values:</p></div>
-<div class="listingblock">
-<div class="content">
-<pre><tt><%= options_for_select([['Lisabon', 1], ['Madrid', 2], ...]) %></tt></pre>
-</div></div>
-<div class="paragraph"><p>But what if you had a <strong>City</strong> model (perhaps an Active Record one) and you wanted to generate option tags from a collection of those objects? One solution would be to make a nested array by iterating over them:</p></div>
+<div class="paragraph"><p>Generating options tags with <tt>options_for_select</tt> requires that you create an array containing the text and value for each option. But what if you had a City model (perhaps an Active Record one) and you wanted to generate option tags from a collection of those objects? One solution would be to make a nested array by iterating over them:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt><% cities_array = City.find(:all).map { |city| [city.name, city.id] } %>
@@ -636,17 +633,17 @@ output: <div class="content">
<pre><tt><%= options_from_collection_for_select(City.all, :id, :name) %></tt></pre>
</div></div>
-<div class="paragraph"><p>As the name implies, this only generates option tags. To generate a working select box you would need to use it in conjunction with <tt>select_tag</tt>, just as you would with <tt>options_for_select</tt>. A method to go along with it is <tt>collection_select</tt>:</p></div>
+<div class="paragraph"><p>As the name implies, this only generates option tags. To generate a working select box you would need to use it in conjunction with <tt>select_tag</tt>, just as you would with <tt>options_for_select</tt>. When working with model objects, just as <tt>select</tt> combines <tt>select_tag</tt> and <tt>options_for_select</tt>, <tt>collection_select</tt> combines <tt>select_tag</tt> with <tt>options_from_collection_for_select</tt>.</p></div>
<div class="listingblock">
<div class="content">
<pre><tt><%= collection_select(:person, :city_id, City.all, :id, :name) %></tt></pre>
</div></div>
<div class="paragraph"><p>To recap, <tt>options_from_collection_for_select</tt> is to <tt>collection_select</tt> what <tt>options_for_select</tt> is to <tt>select</tt>.</p></div>
<h3 id="_time_zone_and_country_select">3.4. Time zone and country select</h3>
-<div class="paragraph"><p>To leverage time zone support in Rails, you have to ask our users what time zone they are in. Doing so would require generating select options from a list of pre-defined TimeZone objects using <tt>collection_select</tt>, but you can simply use the <tt>time_zone_select</tt> helper that already wraps this:</p></div>
+<div class="paragraph"><p>To leverage time zone support in Rails, you have to ask your users what time zone they are in. Doing so would require generating select options from a list of pre-defined TimeZone objects using <tt>collection_select</tt>, but you can simply use the <tt>time_zone_select</tt> helper that already wraps this:</p></div>
<div class="listingblock">
<div class="content">
-<pre><tt><%= time_zone_select(:person, :city_id) %></tt></pre>
+<pre><tt><%= time_zone_select(:person, :time_zone) %></tt></pre>
</div></div>
<div class="paragraph"><p>There is also <tt>time_zone_options_for_select</tt> helper for a more manual (therefore more customizable) way of doing this. Read the API documentation to learn about the possible arguments for these two methods.</p></div>
<div class="paragraph"><p>Rails <em>used</em> to have a <tt>country_select</tt> helper for choosing countries but this has been extracted to the <a href="http://github.com/rails/country_select/tree/master">country_select plugin</a>. When using this do be aware that the exclusion or inclusion of certain names from the list can be somewhat controversial (and was the reason this functionality was extracted from rails).</p></div>
@@ -657,12 +654,12 @@ output: <div class="olist arabic"><ol class="arabic">
<li>
<p>
-Unlike other attributes you might typically have, dates and times are not representable by a single input element. Instead you have several, one for each component (year, month, day etc...). So in particular, there is no single value in your <tt>params</tt> hash with your date or time.
+Dates and times are not representable by a single input element. Instead you have several, one for each component (year, month, day etc.) and so there is no single value in your <tt>params</tt> hash with your date or time.
</p>
</li>
<li>
<p>
-Other helpers use the _tag suffix to indicate whether a helper is a barebones helper or one that operates on model objects. With dates and times, <tt>select\_date</tt>, <tt>select\_time</tt> and <tt>select_datetime</tt> are the barebones helpers, <tt>date_select</tt>, <tt>time_select</tt> and <tt>datetime_select</tt> are the equivalent model object helpers
+Other helpers use the _tag suffix to indicate whether a helper is a barebones helper or one that operates on model objects. With dates and times, <tt>select\_date</tt>, <tt>select\_time</tt> and <tt>select_datetime</tt> are the barebones helpers, <tt>date_select</tt>, <tt>time_select</tt> and <tt>datetime_select</tt> are the equivalent model object helpers.
</p>
</li>
</ol></div>
@@ -673,27 +670,27 @@ Other helpers use the _tag suffix to indicate whether a helper is a barebones he <div class="content">
<pre><tt><%= select_date Date::today, :prefix => :start_date %></tt></pre>
</div></div>
-<div class="paragraph"><p>outputs (with the actual option values omitted for brevity)</p></div>
+<div class="paragraph"><p>outputs (with actual option values omitted for brevity)</p></div>
<div class="listingblock">
<div class="content">
<pre><tt><select id="start_date_year" name="start_date[year]"> ... </select>
<select id="start_date_month" name="start_date[month]"> ... </select>
<select id="start_date_day" name="start_date[day]"> ... </select></tt></pre>
</div></div>
-<div class="paragraph"><p>The above inputs would result in <tt>params[:start_date]</tt> being a hash with keys :year, :month, :day. To get an actual Time or Date object you would have to extract these values and pass them to the appropriate constructor, for example</p></div>
+<div class="paragraph"><p>The above inputs would result in <tt>params[:start_date]</tt> being a hash with keys <tt>:year</tt>, <tt>:month</tt>, <tt>:day</tt>. To get an actual Time or Date object you would have to extract these values and pass them to the appropriate constructor, for example</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>Date::civil(params[:start_date][:year].to_i, params[:start_date][:month].to_i, params[:start_date][:day].to_i)</tt></pre>
</div></div>
-<div class="paragraph"><p>The :prefix option controls where in the <tt>params</tt> hash the date components will be placed. Here it was set to <tt>start_date</tt>, if omitted it will default to <tt>date</tt>.</p></div>
+<div class="paragraph"><p>The <tt>:prefix</tt> option is the key used to retrieve the hash of date components from the <tt>params</tt> hash. Here it was set to <tt>start_date</tt>, if omitted it will default to <tt>date</tt>.</p></div>
<h3 id="_model_object_helpers_2">4.2. Model object helpers</h3>
<div class="paragraph"><p><tt>select_date</tt> does not work well with forms that update or create Active Record objects as Active Record expects each element of the <tt>params</tt> hash to correspond to one attribute.
-The model object helpers for dates and times submit parameters with special names. When Active Record sees parameters with such names it knows they must be combined with the other parameters and given to a constructor appropriate to the column type. For example</p></div>
+The model object helpers for dates and times submit parameters with special names, when Active Record sees parameters with such names it knows they must be combined with the other parameters and given to a constructor appropriate to the column type. For example:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt><%= date_select :person, :birth_date %></tt></pre>
</div></div>
-<div class="paragraph"><p>outputs (with the actual option values omitted for brevity)</p></div>
+<div class="paragraph"><p>outputs (with actual option values omitted for brevity)</p></div>
<div class="listingblock">
<div class="content">
<pre><tt><select id="person_birth_date_1i" name="person[birth_date(1i)]"> ... </select>
@@ -705,7 +702,7 @@ The model object helpers for dates and times submit parameters with special name <div class="content">
<pre><tt>{:person => {'birth_date(1i)' => '2008', 'birth_date(2i)' => '11', 'birth_date(3i)' => '22'}}</tt></pre>
</div></div>
-<div class="paragraph"><p>When this is passed to <tt>Person.new</tt>, Active Record spots that these parameters should all be used to construct the <tt>birth_date</tt> attribute and uses the suffixed information to determine in which order it should pass these parameters to functions such as <tt>Date::civil</tt>.</p></div>
+<div class="paragraph"><p>When this is passed to <tt>Person.new</tt> (or <tt>update_attributes</tt>), Active Record spots that these parameters should all be used to construct the <tt>birth_date</tt> attribute and uses the suffixed information to determine in which order it should pass these parameters to functions such as <tt>Date::civil</tt>.</p></div>
<h3 id="_common_options">4.3. Common options</h3>
<div class="paragraph"><p>Both families of helpers use the same core set of functions to generate the individual select tags and so both accept largely the same options. In particular, by default Rails will generate year options 5 years either side of the current year. If this is not an appropriate range, the <tt>:start_year</tt> and <tt>:end_year</tt> options override this. For an exhaustive list of the available options, refer to the <a href="http://api.rubyonrails.org/classes/ActionView/Helpers/DateHelper.html">API documentation</a>.</p></div>
<div class="paragraph"><p>As a rule of thumb you should be using <tt>date_select</tt> when working with model objects and <tt>select_date</tt> in others cases, such as a search form which filters results by date.</p></div>
@@ -717,6 +714,15 @@ The model object helpers for dates and times submit parameters with special name <td class="content">In many cases the built in date pickers are clumsy as they do not aid the user in working out the relationship between the date and the day of the week.</td>
</tr></table>
</div>
+<h3 id="_individual_components">4.4. Individual Components</h3>
+<div class="paragraph"><p>Occasionally you need to display just a single date component such as a year or a month. Rails provides a series of helpers for this, one for each component <tt>select_year</tt>, <tt>select_month</tt>, <tt>select_day</tt>, <tt>select_hour</tt>, <tt>select_minute</tt>, <tt>select_second</tt>. These helpers are fairly straightforward. By default they will generate a input named after the time component (for example "year" for <tt>select_year</tt>, "month" for <tt>select_month</tt> etc.) although this can be override with the <tt>:field_name</tt> option. The <tt>:prefix</tt> option works in the same way that it does for <tt>select_date</tt> and <tt>select_time</tt> and has the same default value.</p></div>
+<div class="paragraph"><p>The first parameter specifies which value should be selected and can either be an instance of a Date, Time or DateTime, in which case the relevant component will be extracted, or a numerical value. For example</p></div>
+<div class="listingblock">
+<div class="content">
+<pre><tt><%= select_year(2009) %>
+<%= select_year(Time.now) %></tt></pre>
+</div></div>
+<div class="paragraph"><p>Will produce the same output if the current year is 2009 and the value chosen by the user can be retrieved by <tt>params[:date][:year]</tt>.</p></div>
</div>
<h2 id="_uploading_files">5. Uploading Files</h2>
<div class="sectionbody">
@@ -856,18 +862,18 @@ http://www.gnu.org/software/src-highlite --> <input name="addresses[][city]" type="text"/></tt></pre>
</div></div>
<div class="paragraph"><p>This would result in <tt>params[:addresses]</tt> being an array of hashes with keys <tt>line1</tt>, <tt>line2</tt> and <tt>city</tt>. Rails decides to start accumulating values in a new hash whenever it encounters a input name that already exists in the current hash.</p></div>
-<div class="paragraph"><p>The one restriction is that although hashes can be nested arbitrarily deep then can be only one level of "arrayness". Frequently arrays can be usually replaced by hashes, for example instead of having an array of model objects one can have a hash of model objects keyed by their id.</p></div>
+<div class="paragraph"><p>The one restriction is that although hashes can be nested arbitrarily deep then can be only one level of "arrayness". Arrays can be usually replaced by hashes, for example instead of having an array of model objects one can have a hash of model objects keyed by their id, an array index or some other parameter.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="./images/icons/warning.png" alt="Warning" />
</td>
-<td class="content">Array parameters do not play well with the <tt>check_box</tt> helper. According to the HTML specification unchecked checkboxes submit no value. However it is often convenient for a checkbox to always submit a value. The <tt>check_box</tt> helper fakes this by creating a second hidden input with the same name. If the checkbox is unchecked only the hidden input is submitted. If the checkbox is checked then both are submitted but the value submitted by the checkbox takes precedence. When working with array parameters this duplicate submission will confuse Rails since duplicate input names are how it decides when to start a new hash. It is preferable to either use <tt>check_box_tag</tt> or to use hashes instead of arrays.</td>
+<td class="content">Array parameters do not play well with the <tt>check_box</tt> helper. According to the HTML specification unchecked checkboxes submit no value. However it is often convenient for a checkbox to always submit a value. The <tt>check_box</tt> helper fakes this by creating a second hidden input with the same name. If the checkbox is unchecked only the hidden input is submitted and if it is checked then both are submitted but the value submitted by the checkbox takes precedence. When working with array parameters this duplicate submission will confuse Rails since duplicate input names are how it decides when to start a new array element. It is preferable to either use <tt>check_box_tag</tt> or to use hashes instead of arrays.</td>
</tr></table>
</div>
<h3 id="_using_form_helpers">7.3. Using form helpers</h3>
-<div class="paragraph"><p>The previous sections did not use the Rails form helpers at all. While you can craft the input names yourself and pass them directly to helpers such as <tt>text_field_tag</tt> Rails also provides higher level support. The two tools at your disposal here are the name parameter to <tt>form_for</tt>/<tt>fields_for</tt> and the <tt>:index</tt> option.</p></div>
-<div class="paragraph"><p>You might want to render a form with a set of edit fields for each of a person’s addresses. Something a little like this will do the trick</p></div>
+<div class="paragraph"><p>The previous sections did not use the Rails form helpers at all. While you can craft the input names yourself and pass them directly to helpers such as <tt>text_field_tag</tt> Rails also provides higher level support. The two tools at your disposal here are the name parameter to <tt>form_for</tt> and <tt>fields_for</tt> and the <tt>:index</tt> option that helpers take.</p></div>
+<div class="paragraph"><p>You might want to render a form with a set of edit fields for each of a person’s addresses. For example:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt><% form_for @person do |person_form| %>
@@ -879,7 +885,7 @@ http://www.gnu.org/software/src-highlite --> <% end %>
<% end %></tt></pre>
</div></div>
-<div class="paragraph"><p>Assuming our person had two addresses, with ids 23 and 45 this would create output similar to this:</p></div>
+<div class="paragraph"><p>Assuming the person had two addresses, with ids 23 and 45 this would create output similar to this:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt><form action="/people/1" class="edit_person" id="edit_person_1" method="post">
@@ -895,7 +901,7 @@ by Lorenzo Bettini http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="color: #FF0000">{</span><span style="color: #FF0000">'person'</span> <span style="color: #990000">=></span> <span style="color: #FF0000">{</span><span style="color: #FF0000">'name'</span> <span style="color: #990000">=></span> <span style="color: #FF0000">'Bob'</span><span style="color: #990000">,</span> <span style="color: #FF0000">'address'</span> <span style="color: #990000">=></span> <span style="color: #FF0000">{</span> <span style="color: #FF0000">'23'</span> <span style="color: #990000">=></span> <span style="color: #FF0000">{</span><span style="color: #FF0000">'city'</span> <span style="color: #990000">=></span> <span style="color: #FF0000">'Paris'</span><span style="color: #FF0000">}</span><span style="color: #990000">,</span> <span style="color: #FF0000">'45'</span> <span style="color: #990000">=></span> <span style="color: #FF0000">{</span><span style="color: #FF0000">'city'</span> <span style="color: #990000">=></span> <span style="color: #FF0000">'London'</span><span style="color: #FF0000">}</span> <span style="color: #FF0000">}}}</span></tt></pre></div></div>
-<div class="paragraph"><p>Rails knows that all these inputs should be part of the person hash because you called <tt>fields_for</tt> on the first form builder. By specifying an <tt>:index</tt> option you’re telling rails that instead of naming the inputs <tt>person[address][city]</tt> it should insert that index surrounded by [] between the address and the city. If you pass an Active Record object as we did then Rails will call <tt>to_param</tt> on it, which by default returns the database id. This is often useful it is then easy to locate which Address record should be modified but you could pass numbers with some other significance, strings or even nil (which will result in an array parameter being created).</p></div>
+<div class="paragraph"><p>Rails knows that all these inputs should be part of the person hash because you called <tt>fields_for</tt> on the first form builder. By specifying an <tt>:index</tt> option you’re telling rails that instead of naming the inputs <tt>person[address][city]</tt> it should insert that index surrounded by [] between the address and the city. If you pass an Active Record object as we did then Rails will call <tt>to_param</tt> on it, which by default returns the database id. This is often useful as it is then easy to locate which Address record should be modified. You can pass numbers with some other significance, strings or even nil (which will result in an array parameter being created).</p></div>
<div class="paragraph"><p>To create more intricate nestings, you can specify the first part of the input name (<tt>person[address]</tt> in the previous example) explicitly, for example</p></div>
<div class="listingblock">
<div class="content">
@@ -908,7 +914,7 @@ http://www.gnu.org/software/src-highlite --> <div class="content">
<pre><tt><input id="person_address_primary_1_city" name="person[address][primary][1][city]" size="30" type="text" value="bologna" /></tt></pre>
</div></div>
-<div class="paragraph"><p>As a general rule the final input name is the concatenation of the name given to <tt>fields_for</tt>/<tt>form_for</tt>, the index value and the name of the attribute. You can also pass an <tt>:index</tt> option directly to helpers such as <tt>text_field</tt>, but usually it is less repetitive to specify this at the form builder level rather than on individual input controls.</p></div>
+<div class="paragraph"><p>As a general rule the final input name is the concatenation of the name given to <tt>fields_for</tt>/<tt>form_for</tt>, the index value and the name of the attribute. You can also pass an <tt>:index</tt> option directly to helpers such as <tt>text_field</tt>, but it is usually less repetitive to specify this at the form builder level rather than on individual input controls.</p></div>
<div class="paragraph"><p>As a shortcut you can append [] to the name and omit the <tt>:index</tt> option. This is the same as specifing <tt>:index => address</tt> so</p></div>
<div class="listingblock">
<div class="content">
@@ -920,7 +926,7 @@ http://www.gnu.org/software/src-highlite --> </div>
<h2 id="_building_complex_forms">8. Building Complex forms</h2>
<div class="sectionbody">
-<div class="paragraph"><p>Many apps grow beyond simple forms editing a single object. For example when creating a Person instance you might want to allow the user to (on the same form) create multiple address records (home, work etc.). When later editing that person the user should be able to add, remove or amend addresses as necessary. While this guide has shown you all the pieces necessary to handle this, Rails does not yet have a standard end-to-end way of accomplishing this, but many have come up with viable approaches. These include:</p></div>
+<div class="paragraph"><p>Many apps grow beyond simple forms editing a single object. For example when creating a Person you might want to allow the user to (on the same form) create multiple address records (home, work etc.). When later editing that person the user should be able to add, remove or amend addresses as necessary. While this guide has shown you all the pieces necessary to handle this, Rails does not yet have a standard end-to-end way of accomplishing this, but many have come up with viable approaches. These include:</p></div>
<div class="ulist"><ul>
<li>
<p>
|