json request return html in rails

Question

I'm currently trying to make a Ajax script to communicate with an Rails server on my localhost (for now). The problem is that I specify in my $.ajax request that I want the format in 'json' but rails returns a 'html' format:

$(document).ready(function(){

$('form').on("submit",function(){
    $.ajax({
        contentType: 'application/json; charset=utf-8',
        url : "http://192.168.0.36:3000/?value=10",
        type : "GET",
        dataType : 'JSON',
        success: function(data){
            alert(JSONParsedata(data));
        },
        error: function(XMLHttpRequest, textStatus, errorThrown)
        {
            alert(textStatus +", " +errorThrown);
        }
    });


    return false;
})

In the console log of the rails server, I can read:

Processing by WelcomeControllerindex as HTML ... Completed 200 OK in 34ms...

I actually receive a response from the server, but in a HTML format instead of JSON.

I precise that my rails controller for welcomeController code contains the:

 respond_to do |format|
  format.html
  format.json { render :json => @z }
end

z is a variable I want to send back to the Ajax request and is defined before (i lighted the code to make it understandable)

As a result, Jquery is trying to parse the result in a JSON format and then finish by a : parsererror syntaxerror unexpected token '<' Which correspond to the first character of the full page!

I searched for hours and I don't know how to resolve this.

Thank you very much for your help

score 3 · Answer 1 · answered May 10 '17 at 03:11

3

Add header

'Accept: application/json'

answered May 10 '17 at 03:11

zires

554
6
16

score 0 · Answer 2 · answered Oct 24 '15 at 18:38

0

try changing { render :json => @z } to render json: { data: @z }

also change "JSON" to "json"

answered Oct 24 '15 at 18:38

ekhaliki

54
5

I changed those but it didn't worked either :/ Thank you for your help – leo Oct 24 '15 at 19:11
why are you doing JSONParsedata(data)? The data you get back should already be in json format. – ekhaliki Oct 24 '15 at 23:45
Yeah i removed this but it always rendering html instead of Json. I forced it to send me back Json with : format.html {render json: @z}. It renders Json but I can't detect when it's Json or when it's Html :/ – leo Oct 25 '15 at 07:22

score 0 · Accepted Answer · answered Oct 26 '15 at 15:27

Actually I solved this problem this morning:

This method worked in a basic browser such as Chrome but wasn't enough for "Rhomobile", an app IDE I'm using (even using the same Ajax request!). To solve this, I added a parameter "format" to the request and a value "json" (&format=json) and I added a condition to my controller: If the variable 'format' exists && format == 'json' then render the result to JSON. Else it renders in HTML. This works on both Rhomobile and Browser.

I am not sure why this worked on a basic browser and not on Rhomobile but I think it's due to the 'Cross-domain' request. (I used 'rack-cors' server-side). Now it works on both.

Thanks to all of you for your help.

score 0 · Answer 4 · answered Aug 16 '17 at 10:21

0

you can add a "json" postfix to your api like call http://host:port/api.json

answered Aug 16 '17 at 10:21

user4185181

1
1

Peter Gerdes · Answer 5 · 2021-07-22T13:34:33.383

Two other things to try:

Try adding .json to the end of your urls. For instance, if you were requesting the url http://server.org/foo you would instead make the request to http://server.org/foo.json (or from http://server.org/.json if the url was http://server.org/).

This is basically the same idea you are using but it's baked into rails.

Put a default format in your routes, e.g.,

resources :users, only: [:update, :index, :destroy, :show, :create], path: '/admin/users', defaults: { format: :json }

This is what fixed the problem when I had it despite having the appropriate accept headers set.

json request return html in rails

5 Answers5