Graft provides an easy way to map XML and JSON data onto your Ruby classes.
Stable:
$ sudo gem install graft
Bleeding edge:
$ git clone git://github.com/reagent/graft.git $ cd graft && rake gem $ sudo gem install pkg/graft-<version>.gem
When interacting with APIs, it’s quite often the case that the data returned as part of the response is represented either as XML or JSON. The Graft library makes turning that data into Ruby objects pretty simple. This code was an extraction from my work on both the Fleakr and Etsy gems.
If you want to use Graft in XML mode, you’ll need to include the right library:
require 'rubygems' require 'graft/xml'
Once that is set up, you can take an XML string like this:
<rsp> <user nsid="3">reagent</user> <name>Patrick Reagan</name> </rsp>
And map it onto a Ruby class:
class User include Graft attribute :name attribute :username, :from => 'user' attribute :id, :from => 'user@nsid', :type => :integer end
There are a couple of ways to pull this data into the User object. The simplest is from the constructor:
user = User.new(xml)
There is also a populate_from instance method that will do the same:
user = User.new user.populate_from(xml)
This second method is useful if the data you want in your Ruby object comes from 2 separate XML files. Accessing it is simple:
>> user.name # => "Patrick Reagan" >> user.username # => "reagent" >> user.id # => 3
The process of mapping JSON is similar to XML, except:
-
You don’t need to declare the type of the attribute
-
You need to provide a full path to the JSON value
To get started, include the correct library:
require 'rubygems' require 'graft/json'
Then for simple JSON data:
{
"rsp": {
"user_id": 3,
"username": "reagent",
"name": "Patrick Reagan"
}
}
You can map it in a similar way:
class User include Graft attribute :name, :from => 'rsp/name' attribute :username, :from => 'rsp/username' attribute :id, :from => 'rsp/user_id' end
Again, you can initialize the values from both the constructor:
user = User.new(json)
Or the populate_from method:
user = User.new user.populate_from(json)
The results are the same:
>> user.name # => "Patrick Reagan" >> user.username # => "reagent" >> user.id # => 3
Copyright © 2009 Patrick Reagan (reaganpr@gmail.com)
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