Parse json to ruby object - ruby

Question

In ruby how can i parse a json to an array of objects?
Example: i have 2 classes:
class Person
attr_accessor :name, :address, :email, :address
end
And:
class Address
attr_accessor :street, :city, :state, :person
end
When i make a request i get the following json:
{
"data": [
{
"id": 9111316,
"name": "Mason Lee",
"email": "normanodonnell#biospan.com",
"address": {
"state": "American Samoa",
"street": "Cameron Court",
"city": "Wakulla"
}
},
{
"id": 500019,
"name": "Stella Weeks",
"email": "hansenwhitfield#candecor.com",
"address": {
"state": "Nevada",
"street": "Lake Street",
"city": "Wacissa"
}
}
]
}
This json should be parsed into an array of Person.
For now i'm doing:
#json gem
require 'json'
#...
#parse the json and get the 'data'
parsed_json = JSON.parse json
json_data = parsed_json['data']
objects = Array.new
if json_data.kind_of?(Array)
#add each person
json_data.each { |data|
current_person = Person.new
data.each { |k, v|
current_person.send("#{k}=", v)
}
objects.push(current_person)
}
end
#return the array of Person
objects
I have a lot of objects like the above example and do this parse manually is not desirable. There is an automated way to do this?
By "automated way" i mean something like in java with jackson:
ObjectMapper mapper = new ObjectMapper();
List<Person> myObjects = mapper.readValue(json, mapper.getTypeFactory().constructCollectionType(List.class, Person.class));

Answer 1

You can initialize the Person with the hash:
json_data = JSON.parse(json)['data']
json_data.map do |data|
Person.new data
end
class Person
attr_accessor :name, :email, :address
def initialize params
params.each { |k,v| klass.public_send("#{k}=",v) }
end
end
If you want to choose the class dynamically, you can use:
json_data.map do |data|
klass = 'Person'
klass.get_const.new data

Answer 2

Why not just make the method yourself? Example:
require 'json'
def parse_json_to_class_array(data,root_node,to_klass)
json_data = JSON.parse(data)[root_node]
if json_data.is_a?(Array)
objects = json_data.map do |item|
klass = to_klass.new
item.each { |k,v| klass.public_send("#{k}=",v) }
klass
end
end
objects ||= []
end
Then for your example you could call it like so
json ="{\"data\":[
{\"id\":9111316,
\"name\":\"Mason Lee\",
\"email\":\"normanodonnell#biospan.com\",
\"address\":{
\"state\":\"American Samoa\",
\"street\":\"Cameron Court\",
\"city\":\"Wakulla\"
}
},
{\"id\":500019,
\"name\":\"Stella Weeks\",
\"email\":\"hansenwhitfield#candecor.com\",
\"address\":{
\"state\":\"Nevada\",
\"street\":\"Lake Street\",
\"city\":\"Wacissa\"
}
}
]
}"
class Person
attr_accessor :id, :name,:email, :address
end
parse_json_to_class_array(json,'data',Person)
#=>[#<Person:0x2ede818 #id=9111316, #name="Mason Lee", #email="normanodonnell#biospan.com", #address={"state"=>"American Samoa", "street"=>"Cameron Court", "city"=>"Wakulla"}>,
#<Person:0x2ede7a0 #id=500019, #name="Stella Weeks", #email="hansenwhitfield#candecor.com", #address={"state"=>"Nevada", "street"=>"Lake Street", "city"=>"Wacissa"}>]
Obviously you can expand this implementation to support single objects as well as overwrite Person#address= to perform the same operation and turn the address Hash into an Address object as well but this was not shown in your example so I did not take it this far in my answer.
A more dynamic example can be found Here