Ruby on Rails 2.1 - HTML Forms

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Form

To create a form tag with the specified action and with POST request, use the following syntax −

<% form_tag :action => 'update', :id => @some_object do %>
Ruby Block
<% end %>

or

<% form_tag( { :action => :save, }, { :method => :post }) do %>
Ruby Block
<% end %>

Use :multipart => true to define a MIME-multipart form (for file uploads).

<% form_tag( {:action => 'upload'}, :multipart => true ) do %>
Ruby Block
<% end %>

File Upload

Define a multipart form in your view −

<% form_tag( { :action => 'upload' }, :multipart => true ) do %>
   Upload file: <%= file_field( "form", "file" ) %>
   <br />
   <%= submit_tag( "Upload file" ) %>
<% end %>

Handle the upload in the controller −

def upload
   file_field = @params['form']['file'] rescue nil
   # file_field is a StringIO object
   file_field.content_type # 'text/csv'
   file_field.full_original_filename
   ...
end

Text Fields

To create a text field, use the following syntax −

<%= text_field :modelname, :attribute_name, options %>

Have a look at the following example −

<%= text_field "person", "name", "size" => 20 %>

It will generate the following code −

<input type="text" id="person_name" name="person[name]"
   size="20" value="<%= @person.name %>" />

To create hidden fields, use the following syntax −

<%= hidden_field ... %>

To create password fields, use the following syntax −

<%= password_field ... %>

To create file upload fields, use the following syntax −

<%= file_field ... %>

Text Area

To create a text area, use the following syntax −

<%= text_area ... %>

Have a look at the following example −

<%= text_area "post", "body", "cols" => 20, "rows" => 40%>

It will generate the following code −

<textarea cols="20" rows="40" id="post_body" name="post[body]">
<%={@post.body}%>
</textarea>

Radio Button

To create a Radio Button, use the following syntax −

<%= radio_button :modelname, :attribute, :tag_value, options %>

Have a look at the following example −

radio_button("post", "category", "rails")
radio_button("post", "category", "java")

It will generate the following code −

<input type="radio" id="post_category" name="post[category]" 
   value="rails" checked="checked" />
<input type="radio" id="post_category" name="post[category]" 
   value="java" />

Checkbox Button

To create a Checkbox Button use the following syntax −

<%= check_box :modelname, :attribute,options,on_value,off_value%>

Have a look at the following example−

 check_box("post", "validated")

It will generate the following code −

<input type="checkbox" id="post_validate" name="post[validated]" 
   value="1" checked="checked" />
<input name="post[validated]" type="hidden" value="0" />

Let's check another example −

check_box("puppy", "gooddog", {}, "yes", "no")

It will generate the following code −

<input type="checkbox" id="puppy_gooddog" name="puppy[gooddog]" 
   value="yes" />
<input name="puppy[gooddog]" type="hidden" value="no" />

Options

To create a dropdown list, use the following syntax −

<%= select :variable,:attribute,choices,options,html_options%>

Have a look at the following example −

select("post", "person_id", Person.find(:all).collect {|p| [ p.name, p.id ] })

This could generate the following code. It depends on what value is available in your database.

<select name="post[person_id]">
   <option value="1">David</option>
   <option value="2">Sam</option>
   <option value="3">Tobias</option>
</select>

Date Time

Following is the syntax to use data and time −

<%= date_select :variable, :attribute, options %>
<%= datetime_select :variable, :attribute, options %>

Following are examples of usage −

<%=date_select "post", "written_on"%>
<%=date_select "user", "birthday", :start_year => 1910%>
<%=date_select "user", "cc_date", :start_year => 2005,
   :use_month_numbers => true,
   :discard_day => true,
   :order => [:year, :month]%>
<%=datetime_select "post", "written_on"%>