Can't get values from json stored in database - ruby-on-rails

Question

I'm trying to write app which logs json msgs to db. That part I got. The problem comes with getting that json back. I can't get values from it.
I've tried to get raw msgs from db and getting values from this ( json gem seems not to see it as json)
I've tried to parse it via .to_json , but it doesn't seem to work either. Maby you have some idea how to get it?
Thanks in advance
table:
mjl_pk bigserial
mjl_body text <- JSON is stored here
mjl_time timestamp
mjl_issuer varchar
mjl_status varchar
mjl_action varchar
mjl_object varchar
mjl_pat_id varchar
mjl_stu_id varchar
code:
#Include config catalog, where jsonadds is
$LOAD_PATH << 'config'
#Requirements
require 'sinatra'
require 'active_record'
require 'json'
require 'jsonadds'
require 'RestClient'
#Class for db
class Mjl < ActiveRecord::Base
#table name
self.table_name = "msg_json_log"
#serialization
serialize :properties, JSON
#overwrite ActiveRecord id with "mjl_pk"
def self.primary_key
"mjl_pk"
end
end
#Get json msg and write it to db
post '/logger' do
content_type :json
#Check if msg is json
if JSON.is_json?(params[:data])
#insert data into db
msg = Mjl.create(:mjl_body => params[:data] ,:mjl_issuer => 'LOGGER', :mjl_action => 'test', :mjl_object =>'obj')
else
#else return error
puts "Not a JSON \n" + params[:data]
end
end
#Get json with id = params[:id]
get '/json/:id' do
content_type :json
#Get json from db
json_body = Mjl.where(mjl_pk: params[:id]).pluck(:mjl_body)
puts json_body
json_body = json_body.to_json
puts json_body
#Get 'patientData' from json
puts json_body['key']
puts json_body[0]['key']
end
Output:
{
"key": "I am a value",
"group": {
"key2": "Next value",
"key3": "Another one"
},
"val1": "Val"
}
["{\n \"key\": \"I am a value\",\n \"group\": {\n \"key2\": \"Next value\",\n \"key3\": \"Another one\"\n },\n \"val1\": \"Val\"\n}"]
key
<--empty value from 'puts json_body[0]['key']'

Answer 1

I've also created a JSON Log in my project like this, this might help you...
In Controller
current_time = Time.now.strftime("%d-%m-%Y %H:%M")
#status_log = {}
#arr = {}
#arr[:status_id] = "2.1"
#arr[:status_short_desc] = "Order confirmed"
#arr[:status_long_desc] = "Order item has been packed and ready for shipment"
#arr[:time] = current_time
#status_log[2.1] = #arr
#status_log_json = JSON.generate(#status_log)
StoreStock.where(:id => params[:id]).update_all(:status_json => #status_log_json)
In View
#json_status = JSON.parse(ps.status_json) # ps.status_json contails raw JSON Log
= #json_status['2.1']['status_long_desc']
Hope this might help you.

Answer 2

when you are doing
json_body = Mjl.where(mjl_pk: params[:id]).pluck(:mjl_body)
you already have json
so no need doing
json_body = json_body.to_json
Since doing this you get the string representation of json, just remove that line and you will get all the values.

Answer 3

Finally I've found how to do it.
I saw explanation on JSON methods at:
from json to a ruby hash?
Code which works for me:
json_body = Mjl.where(mjl_pk: params[:id]).pluck(:mjl_body)
puts json_body
jparsed = JSON.parse(json_body[0])
puts jparsed['key']