Doing a json put request saves unedited field as blank - ruby-on-rails

Question

In my Rails app I have made an api for an iOS app to consume.
I have a user model with a association to a profile:
class User < ActiveRecord::Base
has_one :personal_profile
accepts_nested_attributes_for :personal_profile
end
class PersonalProfile < Profile
belongs_to :user
end
The users_controller.rb looks like this:
class Api::V1::UsersController < Api::V1::ApiController
before_filter :authenticate_api_user, only: [:show, :update]
def create
#user = User.new(user_params)
if #user.save
#user
else
render json: { errors: #user.errors.full_messages }, status: 422
end
end
def show
#user
end
def update
if #user.update(user_params)
#user
else
render json: { errors: #user.errors.full_messages }, status: 422
end
end
private
def user_params
params.require(:user).permit(:name, :email, :birthday, :gender, :password, :password_confirmation, personal_profile_attributes: [:website, :location, :description, :tagline, :tag_tokens, :image, :image_cache])
end
def authenticate_api_user
authenticate_or_request_with_http_token do |token, options|
#user = User.find_by(auth_token: token)
end
end
end
When I do a put request like this:
curl -H 'Authorization: Token token=AUTH_TOKEN' -H 'Content-Type: application/json' -X PUT -d '{"user": {"name": "Frank", "personal_profile_attributes": { "tagline": "New tagline" }}}' http://localhost:3000/api/user
I get this response:
{"errors":["Personal profile title can't be blank."]}
And it's like the server doesn't recognize my params:
Started PUT "/api/user" for ::1 at 2016-01-19 10:16:33 +0100
Processing by Api::V1::UsersController#update as JSON
Parameters: {"user"=>{"name"=>"Frank", "personal_profile_attributes"=>{"tagline"=>"New tagline"}}}
User Load (1.0ms) SELECT "users".* FROM "users" WHERE "users"."auth_token" = $1 LIMIT 1 [["auth_token", AUTH_TOKEN]]
(0.8ms) BEGIN
PersonalProfile Load (1.2ms) SELECT "profiles".* FROM "profiles" WHERE "profiles"."type" IN ('PersonalProfile') AND "profiles"."user_id" = $1 ORDER BY title asc LIMIT 1 [["user_id", 1]]
SQL (1.3ms) UPDATE "profiles" SET "user_id" = $1, "updated_at" = $2 WHERE "profiles"."id" = $3 [["user_id", nil], ["updated_at", "2016-01-19 09:16:33.629907"], ["id", 1]]
User Exists (1.3ms) SELECT 1 AS one FROM "users" WHERE (LOWER("users"."email") = LOWER('d#friis.me') AND "users"."id" != 1) LIMIT 1
(0.8ms) ROLLBACK
Completed 422 Unprocessable Entity in 19ms (Views: 0.3ms | ActiveRecord: 6.5ms)
I have another controller setup for the web app, which is pretty standard and works just fine!
Any help is much appreciated!

Answer 1

Okay, so the problem was that I did not pass an ID for the associated record with the request params. This meant that a new associated record was created with the attributes I was trying to update.
Setting the ID solved the problem and updated the record as expected.
{
"user" => {
"personal_profile_attributes" => {
"id" => 1,
"tagline" => "New tagline"
}
}
}