# Hiding contents of a js array in the view

**URL:** <https://www.ruby-forum.com/t/hiding-contents-of-a-js-array-in-the-view/80369>\
**Category:** Rails\
**Created:** [December 25, 2006, 10:09am UTC](https://www.ruby-forum.com/t/hiding-contents-of-a-js-array-in-the-view/80369 "2006-12-25T10:09:26Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![alan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/a87d85/32.png) [@alan](https://www.ruby-forum.com/u/alan)\
**Post date:** [December 25, 2006, 10:09am UTC](https://www.ruby-forum.com/t/hiding-contents-of-a-js-array-in-the-view/80369/1 "2006-12-25T10:09:26Z")

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Hi.

I am using the LocalAutocompleter and therefore the autocompleter object  
needs to include an inlined javascript array that includes all the  
possible results. I generate the array in the controller and pass it to  
the view. The problem is that the whole array is included in the html  
and users can see it if they look at the html source. I want to hide  
this information from the user for 2 reasons: 1) it makes the html  
source huge and 2) more important I want to only let users access it  
through the autocomplete functionality. I don’t want them to see all the  
options.

Any help is appreciated!

Here is the relevant code:

Controller

# rubyarray includes 2500 text entries

rubyarray = array.inspect # ‘inspect’ makes array ‘javascript-like’

View  
  
var jsarray = new Array();  
jsarray = \<%= @rubyarray %\> \<-- here is where the array contents get  
exposed

…

 new Autocompleter.Local(..., ..., jsarray , {...} );

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<div class="post-metadata">

**Author:** ![alan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/a87d85/32.png) [@alan](https://www.ruby-forum.com/u/alan)\
**Post date:** [December 26, 2006, 9:15am UTC](https://www.ruby-forum.com/t/hiding-contents-of-a-js-array-in-the-view/80369/2 "2006-12-26T09:15:24Z")

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bump. still interested in an answer if anyone has one!

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<div class="post-metadata">

**Author:** ![alan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/a87d85/32.png) [@alan](https://www.ruby-forum.com/u/alan)\
**Post date:** [December 26, 2006, 9:41am UTC](https://www.ruby-forum.com/t/hiding-contents-of-a-js-array-in-the-view/80369/3 "2006-12-26T09:41:13Z")

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hi,  
try json if it fits your need  
in my autocompleter I used it.  
regards  
gaurav

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<div class="post-metadata">

**Author:** ![alan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/a87d85/32.png) [@alan](https://www.ruby-forum.com/u/alan)\
**Post date:** [December 26, 2006, 3:02pm UTC](https://www.ruby-forum.com/t/hiding-contents-of-a-js-array-in-the-view/80369/4 "2006-12-26T15:02:56Z")

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These are all excellent suggestions! I really like the encryption idea  
which could be simple enough to do and I’ll also check out ujs4rails  
which if it does just what you suggest could be perfect.  
thanks for taking the time for the reply! very appreciated.

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**Author:** ![alan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/a87d85/32.png) [@alan](https://www.ruby-forum.com/u/alan)\
**Post date:** [December 26, 2006, 4:33pm UTC](https://www.ruby-forum.com/t/hiding-contents-of-a-js-array-in-the-view/80369/5 "2006-12-26T16:33:39Z")

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On 12/26/06, Gustav P. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Autocompleter handles that variable (I’ve never used Autocompleter.Local  
> in a regular Autocompleter would have taken to respond (if I’m correct)  
> some\_array = #populate some\_array  
> end
> 
> encoded\_array = [‘bc’, ‘cb’]
> 
> telling it to? I don’t know how they do it) other than the html source  
> of the page.
> 
> I can’t think of any other ways at the moment, but maybe someone else in  
> here has faced a similar problem?
> 
> Cheery-o  
> Gustav P.
> 
> >

Unobtrusive JavaScript is simply for PrototypeHelper calls, it’s not  
going  
to magically move all Javascript out of the HTML. With this plugin, any  
call  
to remote\_form\_for, etc gets an entry in ujs.js (something liek that)  
which  
registers the associated DOM elements with AJAX calls, leaving your HTML  
clean of JS with a bonus of being sure that your site works when  
javascript  
is turned off.

As for hiding information from people, you _don’t_ put it in Javascript.  
It  
doesn’t matter how hard you try, if you want something hidden, keep it  
on  
the server because JavaScript and HTML sources are impossible to “hide”.  
Seeing as you want autocomplete, you’re going at it entirely wrong.  
Autocomplete should be AJAX calls back to the server as the contents of  
the  
text-field change for the reason you mentioned earlier: the list of  
possible  
choices can be HUGE.

Besides, Rails already includes everything you need for autocomplete:  
[http://api.rubyonrails.com/classes/ActionController/Macros/AutoComplete/ClassMethods.html](http://api.rubyonrails.com/classes/ActionController/Macros/AutoComplete/ClassMethods.html)

Jason

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<div class="post-metadata">

**Author:** ![alan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/a87d85/32.png) [@alan](https://www.ruby-forum.com/u/alan)\
**Post date:** [December 26, 2006, 10:31am UTC](https://www.ruby-forum.com/t/hiding-contents-of-a-js-array-in-the-view/80369/6 "2006-12-26T10:31:15Z")

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Hi

> The problem is that the whole array is included in the html  
> and users can see it if they look at the html source. I want to hide  
> this information from the user for 2 reasons:
> 
> 1. it makes the html source huge  
> One way would be to simply define jsarray as a global variable in the  
> head of your HTML file on first page load. Then populate it with a  
> second ajax call after the page loads. I don’t know how the  
> Autocompleter handles that variable (I’ve never used Autocompleter.Local  
> before), it looks as though updating jsarray after the page loads (with  
> the Autocompleter already initialized) won’t do much. If this is the  
> case, you could try setting the Autocompleter with the same rjs you’re  
> using to set jsarray.

Sadly, this approach will mean that you will have to spend two requests  
per page load (the first being the actual page load, and the second an  
ajax call to populate the array) If this is an in-house project or will  
otherwise be receiving relatively little traffic this shouldn’t be much  
of a problem. Also, this ajax call will take as long as typing something  
in a regular Autocompleter would have taken to respond (if I’m correct)  
so its not exactly blasphemous…

This could be done with something like the following

#view  
\<%=javascript\_tag(“var jsarray = new Array();”)%\>  
\<%=javascript\_tag(remote\_function(:url =\> {…}))%\>

#controller  
def foo  
some\_array = #populate some\_array

```
render(:update) do |page|
   page.assign('jsarray', some_array.inspect)
   #cool use of inspect btw,
   #rails has 'array_or_string_for_javascript',
   #but inspect is pretty cool

    page << "new Autocompleter.Local(..., ..., jsarray , {...} ); "

```

#the line from your view  
end  
end

> 1. more important I want to only let users access it through the  
> autocomplete functionality. I don’t want them to see all the options.  
> If this is your greatest issue, you could try looking at encoding the  
> array so humans will have a difficult time seeing the values?

jsarray = [‘f^o^o’, ‘b^a^r’]  
for (int i=0; i \< jsarray.length; i++)  
jsarray[i].replace(/^/, ‘’);

Of course you should use slightly better encryption 😉

You could have a hash that maps encoded letters to their real  
counterparts?

enc\_hash = {b: “a”,  
c: “b”,  
…}

jsarray = new Array();  
//these are the ‘encrypted’ values that the original jsarray would have  
had  
encoded\_array = [‘bc’, ‘cb’]

for(int word=0; word \< encoded\_array.length; word++)  
{  
endstr = “”;  
for(int letter=0; letter \< encoded\_array[word].length; letter++)  
endstr += enc\_hash[encoded\_array[word][letter]];  
jsarray.push(enstr)  
}

jsarray == [‘ab’, ‘ba’] // true

It’s been a while since I did anything with javascript so the above  
might not work, but I got carried away and couldn’t stop 😉

A third possibility would be to look at the Unobtrusive Javascript  
Plugin ([http://ujs4rails.com](http://ujs4rails.com)). I’ve never used it, but it sounded like  
they magically got all your regular JS out of the html file being served  
to the client? I might have misunderstood what they do but it should  
still be a good source of inspiration? This could let you define the  
jsarray exactly as you do now, but have it somewhere (an automatically  
generated .js file that gets served alongside the html without you  
telling it to? I don’t know how they do it) other than the html source  
of the page.

I can’t think of any other ways at the moment, but maybe someone else in  
here has faced a similar problem?

Cheery-o  
Gustav P.

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<div class="post-metadata">

**Author:** ![alan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/a87d85/32.png) [@alan](https://www.ruby-forum.com/u/alan)\
**Post date:** [December 30, 2006, 10:18pm UTC](https://www.ruby-forum.com/t/hiding-contents-of-a-js-array-in-the-view/80369/7 "2006-12-30T22:18:00Z")

</div>

> As for hiding information from people, you _don’t_ put it in Javascript.  
> It  
> doesn’t matter how hard you try, if you want something hidden, keep it  
> on  
> the server because JavaScript and HTML sources are impossible to “hide”.  
> Seeing as you want autocomplete, you’re going at it entirely wrong.  
> Autocomplete should be AJAX calls back to the server as the contents of  
> the  
> text-field change for the reason you mentioned earlier: the list of  
> possible  
> choices can be HUGE.
> 
> Besides, Rails already includes everything you need for autocomplete:  
> [Peak Obsession](http://api.rubyonrails.com/classes/ActionController/Macros/AutoComplete/ClassMethods.html)

THanks Jason.

I already done it this way but it was slowwww. _Every key the user  
enters_ contacts the server over the network, issues a query against the  
database (against about 2500 entries that pretty much don’t change) and  
returns the results. The overhead is too much (At least for my use case)  
and therefore I chose to use the LocalAutocompleter which requires you  
to pass in a javascript array instead of querying the database on the  
server. And that’s where my problem comes from. According to you there  
is no solution to hiding it?

Alon.