d3 reading JSON data in Rails app

[Patrick Johnson]

Hey all, 

Huge thanks for any help from this group. 

So I'm running into an issue in my rails app when it comes to using d3. Currently, I can't get the data to display from within the rails app. 

We are generating the json data via rails, then within the particular view, trying to access it with d3. 

EX: 

// assigning the json data to a variable

var data = <%= raw(bar_chart_report.data.to_json) %>;

// trying to access that data with d3

d3.json(data, function(error, data){

    if (error) {alert('error');}

    else {console.log(data);}

    });

I've ran a quick for/loop to make sure the data is obtainable via JS in general, and so far so good. I just can't access the data when using d3. Curious if anyone has some knowledge to help lead me in the right direction. 

Thanks!

[Nanda Yadav]

The d3.json requires first parameter to be a url/endpoint that returns the json data. What you could is have a dedicate endpoint in rails app controller to return that json data, which d3.json can call to. sth like this:

//Controller action

def bar_chart

  respond_to do |format|

    format.any { render :json => bar_chart_report.data.to_json }

  end

end

then on js side, (assuming route is defined as bar_chart in routes.rb

d3.json("/bar_chart", function(error, data){ 

  //do sth

});

[Phuoc Do]

You can also use format.json:

respond_to do |format|

  format.json { render :json => bar_chart_report.data.to_json }

end

[Akram Khan]

Where do I put the json file? I have got geojson file called us-states.json I want to render it in my rails application using d3, how can I go about that ?

[Phuoc Do]

If you just need to serve static json file, you can put it in public/ folder. Then access it with:

$.get('/us-states.json', function(data) {

});

Phuoc

All files in Rails public/ folder will be accessible