Weird JSON Javascript problem in Rails

Question

I'm trying to get my JSON from my controller to my view. In my controller I am doing:

@nodes = Node.all
@json = @nodes.as_json(:only => [:ID, :Lat, :Lon])

In my view I have tried:

1) var stuff = <%= @json %>
2) var stuff = <%= @json.to_json %>
3) var stuff = <%= @json.to_json.to_json %>

and all of those give me an error. I usually get an "Unexpected Syntax Error &" or "Unexpected Syntax Error {"

I have also tried using jquery and using respond_to within the controller, but that doesn't seem to work either.

My thoughts are that getting json to the view shouldn't be a big issue and shouldn't require jQuery, and currently, my page source looks like:

var stuff = [{&quot;node&quot;:{&quot;ID&quot;:1301499692582,&quot;Lat&quot;:42.3605063113369,&quot;Lon&quot;:-71.0870862191138}},{&quot;node&quot;:{&quot;ID&quot;:1301499691515,&quot;Lat&quot;:42.3605147089149,&quot;Lon&quot;:-71.0870533282532}},{&quot;node&quot;:{&quot;ID&quot;:1301431075499,&quot;Lat&quot;:42.3605456103,&quot;Lon&quot;:-71.0875239075536}} etc

I dont understand the &quot symbols (maybe thats where the syntax error is coming from) but when I do render :json => @nodes.to_json, the page renders a normal json that is valid:

[{"node":{"ID":1301499692582,"Lat":42.3605063113369,"Lon":-71.0870862191138}},{"node":{"ID":1301499691515,"Lat":42.3605147089149,"Lon":-71.0870533282532}},{"node":{"ID":1301431075499,"Lat":42.3605456103,"Lon":-71.0875239075536}}

Note: I've also tried doing var stuff = '<%= @json.to_json %> but when I do var json = JSON.parse(stuff), it gives me an illegal token error.

Can someone please help me with this? Thanks so much!

Laas · Accepted Answer · 2011-05-11 21:07:15Z

61

This is Rails html-encoding your string as is default in Rails 3.

You need to mark your JSON as html_safe:

var stuff = <%= @json.to_s.html_safe %>

Note that .to_s is needed because as_json gives Hash instead of string. You could do this instead:

# in controller
@json = @nodes.to_json(:only => [:ID, :Lat, :Lon]) 

#and in view
var stuff = <%= @json.html_safe %>

answered May 11, 2011 at 21:07

Laas

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6 Comments

readmymsg123 Over a year ago

Thanks so much! Now it shows up in the source as its supposed to be. If you don't mind, could you give me an example as to how I can access each object in the JSON? I would truly appreciate it!

Laas Over a year ago

Nice! Sorry, that I coudn't respond sooner.

Simon Over a year ago

Isn't this unsafe if @json contains untrusted data? Or does to_json escape dangerous stuff properly?

Laas Over a year ago

to_json should output valid JSON and that means that any Rails variable would be either integer or a properly quoted string (or an array /object made of them), no automatically executable JS code. Theorethically this means that code injection won't be possible (until you start blindly eval-ing the JSON).

Greg Blass Over a year ago

Thank you! As @Sid said (using Rails 4/5), you'll need to use .to_json.html_safe ... to_s uses key => value instead of key:value

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JSager · Accepted Answer · 2011-05-11 20:56:25Z

0

I think you need to put quotes around it, then you can ask jquery to parse the string into JSON.

answered May 11, 2011 at 20:56

JSager

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