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)"
){
}

Solution 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.

Solution 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' } } })

Comments

[Muhammad Shauket]

i am facing issue with rail serever when i send json via post man and all header set it works on postman but when same thing i send using my ios code it give me error 500 i am messed up from 5 days on this issue

[Leo]

Thanks, this was useful for getting PyCurl to send data in a Rails-compatible way and fix the 408 errors I was getting.