Harry B. Harry B. - 1 year ago 77
Ruby Question

Rails: Displaying a user post form_for on a user page with nested routes

I'm building a facebook clone, and I'm trying to have a text area on each user's page to allow them to make posts. I've tried a whole bunch of different things with no success, but right now I am getting this error when trying to access the user's show page:

First argument in form cannot contain nil or be empty

with this code:

Rails.application.routes.draw do
resources :friends, only: [:index, :destroy]
resources :posts

resources :friend_requests
devise_for :users
devise_scope :user do
root 'devise/sessions#new'

resources :users, only: [:index, :show] do
resources :posts

get 'about', to: 'static_pages#about'
# For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html


<%= form_for [@user, @post] do |f| %>
<%= f.text_area :content, size: "60x12", placeholder: "What do you want to say?" %>
<%= f.submit "Post" %>
<% end %>

class PostsController < ApplicationController

def index
@posts = Post.all

def new
@post = Post.new
@user = User.find(params[:user_id])

def create
@post = current_user.posts.build(post_params)
if @post.save
flash[:success] = "Posted!"
redirect_to user_path(current_user)
flash[:notice] = "Post could not be submitted"
redirect_to users_path


def post_params

class UsersController < ApplicationController

def index
@users = User.all

def show
@user = User.find(params[:id])



<h4>You are signed in as <%= current_user.email %>! </h4>

<% if @user == current_user %>
<%= render "notifications" %>
<%= render 'shared/post_form' %>
<% end %>

<%= params.inspect %>
<%= current_user.id %>

server log:
Processing by UsersController#show as HTML
Parameters: {"id"=>"4"}
User Load (0.4ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2 [["id", 4], ["LIMIT", 1]]
User Load (0.4ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT $2 [["id", 4], ["LIMIT", 1]]
Rendering users/show.html.erb within layouts/application
FriendRequest Load (0.5ms) SELECT "friend_requests".* FROM "friend_requests" WHERE "friend_requests"."friend_id" = $1 ORDER BY "friend_requests"."id" ASC LIMIT $2 [["friend_id", 4], ["LIMIT", 1000]]
Rendered users/_notifications.html.erb (2.0ms)
Rendered shared/_post_form.html.erb (3.0ms)
Rendered users/show.html.erb within layouts/application (10.2ms)
Completed 500 Internal Server Error in 23ms (ActiveRecord: 1.3ms)

ActionView::Template::Error (First argument in form cannot contain nil or be empty):
1: <%= form_for [@user, @post] do |f| %>
2: <%= f.text_area :content, size: "60x12", placeholder: "What do you want to say?" %>
3: <%= f.submit "Post" %>
4: <% end %>

app/views/shared/_post_form.html.erb:1:in `_app_views_shared__post_form_html_erb___99030300856795657_70237723952000'
app/views/users/show.html.erb:5:in `_app_views_users_show_html_erb___3196827877852207953_70237724137160'
Rendering /usr/local/lib/ruby/gems/2.3.0/gems/actionpack- within rescues/layout
Rendering /usr/local/lib/ruby/gems/2.3.0/gems/actionpack-

Rendered /usr/local/lib/ruby/gems/2.3.0/gems/actionpack- (6.7ms)
Rendering /usr/local/lib/ruby/gems/2.3.0/gems/actionpack-
Rendered /usr/local/lib/ruby/gems/2.3.0/gems/actionpack- (5.0ms)
Rendering /usr/local/lib/ruby/gems/2.3.0/gems/actionpack-
Rendered /usr/local/lib/ruby/gems/2.3.0/gems/actionpack- (1.1ms)
Rendered /usr/local/lib/ruby/gems/2.3.0/gems/actionpack- ` within rescues/layout (96.4ms)

Ren Ren
Answer Source

You say that your form is having a problem rendering on the user's show page. If you have this form w/ nested resource setup like this:

form_for [@user, @post]

It means your form needs access to both the @user and the @post instance variable whereever the form is to be rendered. In this case, it is in the show action in your users controller. So your users controller should have something like this:

def show
    @user = User.find(params[:id])
    @post = @user.posts.build
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