Ruby on Rails - 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 %>

<%= form_tag( { :action => :save, }, { :method => :post }) %>

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

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

File Upload

Define a multipart form in your view −

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

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 %>

This will generate 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%>

This 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")

This 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")

This 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")

This will generate 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 dropdopwn 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"%>

End Form Tag

Use following syntax to create </form> tag −

<%= end_form_tag %>