How to use "POST url" JSON file in RoR website?

I am using Ruby on Rails and Kibana to show visualisation in my website(Ruby2.6.0, Rails5.2.3, Kibana6.6.1). By using Xpack->Share->Generate PDF/PNG, I find 'copy POST url'. I can get the following JSON file from the POST url by python script, but how can I use POST url in my RoR website to show visualisation PNG file for users? To download PDG file in 'assets' folder?

JSON file from POST url: {'path': '/api/reporting/jobs/download/jvds4zs10qv79d0062b9cel6', 'job': {'id': 'jvds4zs10qv79d0062b9cel6', 'index': '.reporting-2019.05.05', 'type': 'esqueue', 'jobtype': 'PNG', 'created_by': False, 'payload': {'type': 'visualization', 'title': '[eCommerce] Sales by Gender', 'relativeUrl': "/app/kibana#/visualize/edit/ed8436b0-b88b-11e8-a6d9-e546fe2bba5f?_g=(refreshInterval:(pause:!t,value:0),time:(from:now-60d,mode:quick,to:now))&_a=(filters:!(),linked:!f,query:(language:lucene,query:''),uiState:(),vis:(aggs:!((enabled:!t,id:'1',params:(),schema:metric,type:count),(enabled:!t,id:'2',params:(field:customer_gender,json:'',missingBucket:!f,missingBucketLabel:Missing,order:desc,orderBy:'1',otherBucket:!f,otherBucketLabel:Other,size:5),schema:segment,type:terms)),params:(addLegend:!t,addTooltip:!t,isDonut:!t,labels:(last_level:!t,show:!t,truncate:100,values:!t),legendPosition:right,type:pie),title:'%5BeCommerce%5D+Sales+by+Gender',type:pie))", 'headers': 'uxY4w6gCRwwLZyFkDX0ujVlANYq7ae5UuNJAN0GpbTOX7vw5aPuCuyr37nNcpz3vtA8kNVaL6Gacs24mPjZfwl4mB9xRKGA62CkCLo8Xz1amuIEthI+BtKPGo5QAk2k2+7zLvLgX3KouVvYdd61U5rLAvfjv4TydcpH9qJ4qrL5OELkzAJGrNdujtDLWaoy2Qj9YXbLnh7gSdI+lrNml6usZIh4pMzz8qdRo597iO/4AeSJRa2JfAruyGB3zYInZRtMuCbA4f3ANvT2WeAn6lpiwThB993uEjwu4LBVUZuo2XL0TcB29YNNa9oMCUEhWjdJ1ase5VQdz8V2IOgecQ1W52V5JuVTvl9SkVvFWSBhXJg==', 'browserTimezone': 'Europe/Zurich', 'layout': {'dimensions': {'height': 589.234375, 'width': 866}}, 'basePath': '', 'forceNow': '2019-05-07T12:38:12.768Z'}, 'timeout': 120000, 'max_attempts': 3, 'priority': 10, 'browser_type': 'chromium'}}

I am trying to use 'net/http', What I added in controller:

class MaisonController < ApplicationController

require 'net/http'

def require_post
    uri = URI.parse("http://localhost:5601/api/reporting/generate/png?jobParams=(browserTimezone:Europe%2FZurich,layout:(dimensions:(height:589.234375,width:866)),objectType:visualization,relativeUrl:%27%2Fapp%2Fkibana%23%2Fvisualize%2Fedit%2Fed8436b0-b88b-11e8-a6d9-e546fe2bba5f%3F_g%3D(refreshInterval:(pause:!!t,value:0),time:(from:now-60d,mode:quick,to:now))%26_a%3D(filters:!!(),linked:!!f,query:(language:lucene,query:!%27!%27),uiState:(),vis:(aggs:!!((enabled:!!t,id:!%271!%27,params:(),schema:metric,type:count),(enabled:!!t,id:!%272!%27,params:(field:customer_gender,json:!%27!%27,missingBucket:!!f,missingBucketLabel:Missing,order:desc,orderBy:!%271!%27,otherBucket:!!f,otherBucketLabel:Other,size:5),schema:segment,type:terms)),params:(addLegend:!!t,addTooltip:!!t,isDonut:!!t,labels:(last_level:!!t,show:!!t,truncate:100,values:!!t),legendPosition:right,type:pie),title:!%27%255BeCommerce%255D%2BSales%2Bby%2BGender!%27,type:pie))%27,title:%27%5BeCommerce%5D%20Sales%20by%20Gender%27)")
    http = Net::HTTP.new(uri.host,uri.port)

    request = Net::HTTP::Post.new(uri.request_uri)
    response = http.request(request)
    render :json => response.body
end
end