How should I format a JSON POST request to my rails app?

Question

My Rails app has a player class that works perfectly. Players can be created, deleted, and updated from my rails control panel without any issues.

I would like a remote counterpart to be able to join in the fun by creating players using a JSON request. Following the advice of the auto generated Rails comments above my create method : # POST /players.json I have started sending requests to localhost:3000/players.json

The JSON

{     "player": {     "name": "test",     "room_id": 0,     "skin_id": 1,     "head_id": 2,     "torso_id": 3,     "legs_id": 4,     "x_position": 5,     "y_position": 6,     "direction": 7,     "action": "",     "gender": "f"     } } 

However, I am running into this error message:

ActionController::ParameterMissing in PlayersController#create param not found: player

So I guess my question is: How should I structure the JSON I am sending?

Additional info:

• Ruby Version: 2.0
• Rails Version: 4.0
• I have tried sending my requests using Postman

Update - Player Params

Here is the player params method from my controller (as requested):

def player_params     params.require(:player).permit(:name, :room_id, :skin_id, :head_id, :torso_id, :legs_id, :x_position, :y_position, :direction, :action, :gender) end 

Update 2 - Player controller

class PlayersController < ApplicationController   before_action :set_player, only: [:show, :edit, :update, :destroy]   skip_before_filter :verify_authenticity_token, :if => Proc.new { |c| c.request.format == 'application/json' }    # GET /players   # GET /players.json   def index     @players = Player.all   end    # GET /players/1   # GET /players/1.json   def show   end    # GET /players/new   def new     @player = Player.new   end    # GET /players/1/edit   def edit     @rooms = Room.all.map { |room| [room.name, room.id] }   end    # POST /players   # POST /players.json   def create     @player = Player.new(player_params)      respond_to do |format|       if @player.save         format.html { redirect_to @player, notice: 'Player was successfully created.' }         format.json { render action: 'show', status: :created, location: @player }       else         format.html { render action: 'new' }         format.json { render json: @player.errors, status: :unprocessable_entity }       end     end   end    # PATCH/PUT /players/1   # PATCH/PUT /players/1.json   def update     respond_to do |format|       if @player.update(player_params)         format.html { redirect_to @player, notice: 'Player was successfully updated.' }         format.json { head :no_content }       else         format.html { render action: 'edit' }         format.json { render json: @player.errors, status: :unprocessable_entity }       end     end   end    # DELETE /players/1   # DELETE /players/1.json   def destroy     @player.destroy     respond_to do |format|       format.html { redirect_to players_url }       format.json { head :no_content }     end   end    def manage_furni     @player = Player.find(params[:id])     @furni = Furni.all   end    def add_furni     player = Player.find(params[:id])     player.furnis << Furni.find(params[:furni])     redirect_to manage_furni_path(player)   end    def remove_furni     player = Player.find(params[:id])     item = InventoryItem.find(params[:item])     player.inventory_items.delete(item)     redirect_to manage_furni_path(player)   end    private     # Use callbacks to share common setup or constraints between actions.     def set_player       @player = Player.find(params[:id])     end      # Never trust parameters from the scary internet, only allow the white list through.     def player_params       params.require(:player).permit(:name, :room_id, :skin_id, :head_id, :torso_id, :legs_id, :x_position, :y_position, :direction, :action, :gender)     end end 

Update 3: logs

(     "Processing by PlayersController#create as JSON",     "Completed 400 Bad Request in 31ms",     "ActionController::ParameterMissing (param not found: player):",     "app/controllers/players_controller.rb:103:in `player_params'",     "app/controllers/players_controller.rb:40:in `create'",     "Rendered /Users/drewwyatt/.rvm/gems/ruby-2.0.0-p247/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/rescues/_source.erb (0.5ms)",     "Rendered /Users/drewwyatt/.rvm/gems/ruby-2.0.0-p247/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/rescues/_trace.erb (0.9ms)",     "Rendered /Users/drewwyatt/.rvm/gems/ruby-2.0.0-p247/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (0.8ms)",     "Rendered /Users/drewwyatt/.rvm/gems/ruby-2.0.0-p247/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (16.3ms)" ){ } 

Answer 1

First of all, I think your data format is ok and is not the problem here. When I ran exactly into the same problem it was because I did not send the Content-Type: application/json header along with my request.

In Postman, you can select the 'raw' data format and then 'JSON (application/json)' to include this header. In my case it looks like this:

Alternatively, you can also try it with curl (source):

curl -X POST -H "Content-Type: application/json" -d '{"player": {"name": "test","room_id": 0,"skin_id": 1,"head_id": 2,"torso_id": 3,"legs_id": 4,"x_position": 5,"y_position": 6,"direction": 7,"action": "","gender": "f"}}' localhost:3000/players.json

If you omit the -H "Content-Type: application/json", then you will receive a 400 response with the "param not found" error, if you include it it should work.

Answer 2

If you are trying this:

via Postman - Under form-data tab, you need to have the vars as :

player[name] player[room_id] . . 

via jQuery:

$.ajax({ url: 'url', type: 'post', data: { player: { name: 'Test', room_id: '0' } } })