Using Resource Owner Password Credentials setting with doorkeeper + devise

resource_owner_auth

Doorkeeper.configure do
  resource_owner_authenticator do |routes|
    current_user || warden.authenticate!(:scope => :user)
  end

  resource_owner_from_credentials do |routes|
    request.params[:user] = {:email => request.params[:username], :password => request.params[:password]}
    request.env["devise.allow_params_authentication"] = true
    request.env["warden"].authenticate!(:scope => :user)
  end
end

# test
$ curl -d client_id="XXXX" -d client_secret="XXXX" -d username="XXXX" -d password="XXXX" -d grant_type="password" http://IP/oauth/token

# res
{"access_token":"068935cabb4f867c70086bdee8f5e05d5868b3ca6f63c86f5809fe92fe33700e","token_type":"bearer","expires_in":7200}

# api ---------------------------------------
# routes.rb
namespace :api do
  namespace :v1 do
    get 'user/index'
  end
end

$rails g controller api/v1/user 
# user_controller.rb
class Api::V1::UserController < ApplicationController
  doorkeeper_for :all
  before_action :validate_token
  before_action :set_parameters
  skip_before_action :verify_authenticity_token                                                                          
  def index
    render json: current_user
  end
end

# test
curl -H "Authorization: Bearer 068935cabb4f867c70086bdee8f5e05d5868b3ca6f63c86f5809fe92fe33700e" http://IP/api/v1/user/index
{"id":1,"email":"XXXX","created_at":"2013-10-30T03:55:36.000+09:00","updated_at":"2013-11-01T04:22:17.000+09:00","username":null}

#AFNetworking2
- (IBAction)getToken:(id)sender {
    NSString *URLString = @"http://IP/oauth/token";
    NSDictionary *parameters = @{@"client_id":self.client_id, @"client_secret":self.client_secret, @"username":self.username , @"password":self.password, @"grant_type":@"password"};
    NSLog(@"parameters %@", parameters);
    NSURLRequest *request = [[AFHTTPRequestSerializer serializer] requestWithMethod:@"POST" URLString:URLString parameters:parameters];
    AFHTTPRequestOperation *op = [[AFHTTPRequestOperation alloc] initWithRequest:request];
    op.responseSerializer = [AFJSONResponseSerializer serializer];
    [op setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        NSLog(@"JSON: %@", responseObject);
        NSLog(@"access_token: %@", responseObject[@"access_token"]);
        self.token = responseObject[@"access_token"];
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error);
        self.token = nil;
    }];
    [[NSOperationQueue mainQueue] addOperation:op];
}

- (IBAction)getUser:(id)sender {
    NSString *URLString = @"http://IP/api/v1/user/index";
    AFHTTPRequestSerializer *requestSerializer = [AFHTTPRequestSerializer serializer];
    [requestSerializer setValue:[NSString stringWithFormat:@"Bearer %@", self.token] forHTTPHeaderField:@"Authorization"];
    NSURLRequest *request = [requestSerializer requestWithMethod:@"GET" URLString:URLString parameters:nil];
    AFHTTPRequestOperation *op = [[AFHTTPRequestOperation alloc] initWithRequest:request];
    op.responseSerializer = [AFJSONResponseSerializer serializer];
    [op setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        NSLog(@"JSON: %@", responseObject);
        self.token = responseObject[@"access_token"];
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error);
        self.token = nil;
    }];
    [[NSOperationQueue mainQueue] addOperation:op];
}

# devise error JSON ---------------------------------------
config/initializers/custom_auth_failure_app.rb
class CustomAuthFailure < Devise::FailureApp
  def respond
    if request.format == :json
      self.status = 401
      self.content_type = 'json'
      self.response_body = {"errors" => i18n_message}.to_json
    else
      super
    end
  end
end

config/initializers/devise.rb
config.warden do |manager|
  manager.failure_app = CustomAuthFailure
end