Question

I’m new to Ruby and had a question. I’m trying to create a .rb file that converts JSON to CSV.

I came across some disparate sources that got me to make:

require "rubygems"
require 'fastercsv'
require 'json'

csv_string = FasterCSV.generate({}) do |csv|
   JSON.parse(File.open("small.json").read).each do |hash|
    csv << hash
  end
end

puts csv_string

Now, it does in fact output text but they are all squashed together without spaces, commas etc. How do I make it more customised, clear for a CSV file so I can export that file?

The JSON would look like:

        {
            "results": [
                {
                    "reportingId": "s", 
                    "listingType": "Business", 
                    "hasExposureProducts": false, 
                    "name": "Medeco Medical Centre World Square", 
                    "primaryAddress": {
                        "geoCodeGranularity": "PROPERTY", 
                        "addressLine": "Shop 9.01 World Sq Shopng Cntr 644 George St", 
                        "longitude": "151.206172", 
                        "suburb": "Sydney", 
                        "state": "NSW", 
                        "postcode": "2000", 
                        "latitude": "-33.876416", 
                        "type": "VANITY"
                    }, 

                    "primaryContacts": [
                        {
                            "type": "PHONE", 
                            "value": "[phone]"
                        }
                    ]
                },xxx
        }

The CSV to just have something like:

        reportingId, s, listingType, Business, name, Medeco Medical...., addressLine, xxxxx, longitude, xxxx, latitude, xxxx, state, NSW, postcode, 2000, type, phone, value, [phone]             

Answer 1

Since your JSON structure is a mix of hashes and lists, and also has levels of different heights, it is not as trivial as the code you show. However (assuming your input files always look the same) it shouldn’t be hard to write an appropriate converter. On the lowest level, you can transform a hash to CSV by

hash.to_a.flatten

E.g.

input = JSON.parse(File.open("small_file.json").read)
writer = FasterCSV.open("out.csv", "w")
writer << input["results"][0]["primaryAddress"].to_a.flatten

will give you

type,VANITY,latitude,-33.876416,postcode,2000,state,NSW,suburb,Sydney,longitude,151.206172,addressLine,Shop 9.01 World Sq Shopng Cntr 644 George St,geoCodeGranularity,PROPERTY

Hope that guides you the direction.

Btw, your JSON looks invalid. You should change the },xxx line to }].