Use the `:html` hash:  

    = form_for @user, :html =&gt; {:class =&gt; &#39;x&#39;, &#39;data-bar&#39; =&gt; &#39;baz&#39;} do |f|

Or

    = form_for @user, html: {class: &#39;x&#39;, data: { bar: &#39;baz&#39; } } do |f|

Rails 4.0.3, Ruby 2.1.0p0  -&gt; this worked for me =&gt; 
 

    &lt;%= form_for(@contact, :html =&gt; {:class =&gt; &#39;form_height&#39;}) do |f| %&gt;&lt;% if     @contact.errors.any? %&gt;

I had the same problem but was puzzled that another form elsewhere in my app was working fine.

I realized that I had accidentally added a **form_for** inside another **form_for** which once removed cured the problem.

Secondly, I should add that this syntax works for me in Rails 4.2:

    &lt;%= form_for @type, html: {class: &quot;form-horizontal&quot;} do |f| %&gt;

I find it preferable to the punctuation-soup of the other answers here (which were perhaps based on an older Rails version).

On mostly helpers, the last arg is a hash of html options for the element.

    = form_for @user, :html =&gt; {:class =&gt; &#39;x&#39;, &#39;data-bar&#39; =&gt; &#39;baz&#39;} %&gt;

You can also check other alternatives in the documentation [ActionsView::Helpers::FormHelper][1]


  [1]: http://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-form_for

I tried the above with no luck but found a solution.
I&#39;m using rails 4.1.6.

This didn&#39;t work

    = form_for @user, :html =&gt; {:class =&gt; &#39;x&#39;, &#39;data-bar&#39; =&gt; &#39;baz&#39;} %&gt;

This did

    = form_for @user, html: {:class =&gt; &#39;x&#39;, &#39;data-bar&#39; =&gt; &#39;baz&#39;} %&gt;

notice the difference with the html option, hope this helps

From http://golang.org/src/pkg/database/sql/driver/types.go:

    type ValueConverter interface {
    	// ConvertValue converts a value to a driver Value.
    	ConvertValue(v interface{}) (Value, error)
    }

    var Bool boolType
    
    type boolType struct{}
    
    var _ ValueConverter = boolType{} // line 58
    
    func (boolType) String() string { return &quot;Bool&quot; }
    
    func (boolType) ConvertValue(src interface{}) (Value, error) {....}


I known that ValueConverter is an interface name. Line 58 seems to declare that boolType implement interface ValueConverter, but is that necessary? I deleted line 58 and the code works well.

What does an underscore and interface name after keyword var mean?

I have a following method...which actually takes the list of sentences and splits each sentence into words. Here is it:

    public List&lt;String&gt; getWords(List&lt;String&gt; strSentences){
   	allWords = new ArrayList&lt;String&gt;();
    	Iterator&lt;String&gt; itrTemp = strSentences.iterator();
    	while(itrTemp.hasNext()){
    		String strTemp = itrTemp.next();
    		allWords = Arrays.asList(strTemp.toLowerCase().split(&quot;\\s+&quot;));    		
    	}
    	return allWords;
    }

I have to pass this list into a hashmap in the following format     
    
    HashMap&lt;String, ArrayList&lt;String&gt;&gt;

so this method returns List and I need an ArrayList? If I try to cast it doesn&#39;t work out... any suggestions?

Also, if I change the ArrayList to List in a HashMap, I get       

    java.lang.UnsupportedOperationException

because of this line in my code 

    sentenceList.add(((Element)sentenceNodeList.item(sentenceIndex)).getTextContent());

Any better suggestions?



List&lt;String&gt; to ArrayList&lt;String&gt; conversion issue

`form_for` seems to ignore any &#39;extra&#39; attributes like a `data-foo` attribute or `class` passed as `options` in its second argument.

    = form_for @user, {:url =&gt; &#39;foo&#39;, :class =&gt; &#39;x&#39;, &#39;data-bar&#39; =&gt; &#39;baz&#39; } do |f|
      # ...

The output is a `&lt;form&gt;` tag with no `x` class or `data-bar` attribute.

What’s the fix?

Or, how can I grab a `FormBuilder` instance without using `form_for`?

Use Rails’ form_for but set custom classes, attributes on &lt;form&gt; element?

<code>form_for</code> seems to ignore any 'extra' attributes like a <code>data-foo</code> attribute or <code>class</code> passed as <code>options</code> in its second argument.
<pre><code class="hljs language-ruby">= form_for @user, {:url => 'foo', :class => 'x', 'data-bar' => 'baz' } do |f|
 # ...
</code></pre>
The output is a <code>&#x3C;form></code> tag with no <code>x</code> class or <code>data-bar</code> attribute.
What’s the fix?
Or, how can I grab a <code>FormBuilder</code> instance without using <code>form_for</code>?

I have created an app in Rails on Heroku using a PostgreSQL database.

It has a couple of tables designed to be able to sync with mobile devices where data can be created on different places. Therefor I have a uuid field that is a string storing a GUID in addition to an auto increment primary key. The uuid is the one that is communicated between the server and the clients.

I realised after implementing the sync engine on the server side that this leads to performance issues when needing to map between uuid&lt;-&gt;id all the time (when writing objects, I need to query for the uuid to get the id before saving and the opposite when sending back data).

I&#39;m now thinking about switching to only using UUID as primary key making the writing and reading much simpler and faster.

I&#39;ve read that UUID as primary key can sometimes give bad index performance (index fragmentation) when using clustered primary key index. Does PostgreSQL suffer from this problem or is it OK to use UUID as primary key?

I already have a UUID column today so storage wise it will be better because I drop the regular id column.



Will UUID as primary key in PostgreSQL give bad index performance?

I would like to give visitors the option to download some pdf. 
I have tried:

    &lt;%= link_to &quot;abc&quot;, &quot;/data/abc.pdf&quot;%&gt;
    
    &lt;%= link_to &quot;abc&quot;, &quot;/data/abc.pdf&quot;, :format =&gt; &#39;pdf&#39; %&gt;

and some variations but they don&#39;t seem to work. I keep getting `No route matches [GET] &quot;/data/abc.pdf&quot;`

I have the pdf files in a folder called data, located in the assets folder.
Any help would be appreciated.

file download link in rails

I have this testingdatabase which, by now, is stuffed with junk. Now I&#39;ve done a few Table.destroy_all commands in the rails console which deletes all records and dependencies which is awesome. However; I&#39;d like to truncate everything so the ID&#39;s etc. start at 1 again. Is there any way in Rails 3?

Truncate table(s) with rails console

I want to make sure I&#39;m using them for the correct occasion and want to know of any subtleties.  They seem to function the same way, which is to check to see if a object field has been defined, when I use them via the console and there isn&#39;t a whole lot information online when I did a google search. Thanks!

What is the difference between using .exists?, and .present? in Ruby?

If I, say, loop through all the instances of a given model and output something from each, at the end, irb will still print the entire object. 

If the object ends up taking hundreds of lines, it&#39;ll be a long way up before I see what I was actually looking for. Is there a way to disable this in the rails console?

Stop rails console from printing out the object at the end of a loop

I have a link that I need to submit a post request with. Normally, I&#39;d use jQuery and prevent the link&#39;s default behavior and then submit a form to the destination. This seems like something Rails should be able to help me out with. Sure enough, the `link_to` method has an option for specifying a POST http method:

    link_to &quot;Profile&quot;, &#39;http://example.com/profile&#39;, method: :post

That works, but I need to add 2 parameters too. I tried:

    link_to &quot;Profile&quot;, &#39;http://example.com/profile&#39;, method: post, param1: &#39;value1&#39;, param2: &#39;value2&#39;

That just added those parameters to the `&lt;a&gt;` HTML element, but didn&#39;t submit those when clicking the link:

    &lt;a rel=&quot;nofollow&quot; param1=&quot;value1&quot; param2=&quot;value2&quot; data-method=&quot;post&quot; href=&quot;http://example.com/profile&quot;&gt;Profile&lt;/a&gt;

Is there a way to do a POST request with parameters using `link_to` or any other Rails method? I&#39;m using Rails 3.2.9.

Using Rails link_to for links that post

I have some Ruby methods certain (or all) controllers need. I tried putting them in `/app/helpers/application_helper.rb`. I&#39;ve used that for methods to be used in views. But controllers don&#39;t see those methods. Is there another place I should put them or do I need to access those helper methods differently?

Using latest stable Rails.

Where to put Ruby helper methods for Rails controllers?

I want to make a `migration` in Rails, referencing another table. Usually, I would do something like:

    add_column :post, :user, :references

This creates a column named `user_id` in `posts` table. But what if, instead of `user_id`, I want something like `author_id`? How can I do that?

Content Type	Original Author	Original Content on Stackoverflow
Question	Alan H.	View Question on Stackoverflow
Solution 1 - Ruby on-Rails	MurifoX	View Answer on Stackoverflow
Solution 2 - Ruby on-Rails	zero_cool	View Answer on Stackoverflow
Solution 3 - Ruby on-Rails	MSC	View Answer on Stackoverflow
Solution 4 - Ruby on-Rails	felipeclopes	View Answer on Stackoverflow
Solution 5 - Ruby on-Rails	doz87	View Answer on Stackoverflow

Use Rails’ form_for but set custom classes, attributes on <form> element?

Ruby on-Rails Problem Overview

Ruby on-Rails Solutions

Solution 1 - Ruby on-Rails

Solution 2 - Ruby on-Rails

Solution 3 - Ruby on-Rails

Solution 4 - Ruby on-Rails

Solution 5 - Ruby on-Rails

List<String> to ArrayList<String> conversion issue

What does an underscore and interface name after keyword var mean?

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