Ruby on Rails: render form on a shared folder - ruby-on-rails

Question

I want to put the form on a shared folder for DRY the code and render this form for [:admin, :posts] and :posts.
So I create a folder and put the form on app/views/shared/_form.html.slim
- if params[:admin][:posts]
post = [:admin, #post]
- if params[:posts]
post = #post
= simple_form_for(post, :html => { :multipart => true }) do |f|
= f.association :categories, label: "Select the Categories:", as: :check_boxes , collection: #categories.map{|c| [c.name, c.id]}, include_hidden: false
= f.input :title
= f.input :subtitle
- if #post.attachment.present?
.attachment
p
= image_tag(#post.attachment.thumb.url, alt: 'Image', class: "img-responsive img-thumbnail")
= f.check_box :remove_attachment
| Remove image
br
.text-center
small
sample
= "File_size #{number_to_human_size(#post.attachment.size)}"
= f.input :attachment, as: :file, label: "File"
= f.input :attachment_cache, as: :hidden
= f.input :remote_attachment_url, label: "Enter URL to an image"
= f.input :content, size: "150x150"
= f.button :submit, class: 'btn-primary'
and then on
app/views/admin/post/new.html.slim and app/views/posts/edit.html.slim
I added the render:
== render 'shared/form', post: #post
So I tried to run and I have this error:
ActionView::Template::Error (undefined method `[]' for nil:NilClass):
1: - if params[:admin][:posts]
2: post = [:admin, #post]
3: - if params[:posts]
4: post = #post
This is just an idea that I have. it's ok for do this in this case or forget to do this?
routes:
rake routes | grep post
Running via Spring preloader in process 2187
admin_posts POST /admin/posts(.:format) admin/posts#create
new_admin_post GET /admin/posts/new(.:format) admin/posts#new
admin_post DELETE /admin/posts/:id(.:format) admin/posts#destroy
nullify_posts_admin_user PATCH /admin/users/:id/nullify_posts(.:format) admin/users#nullify_posts
root GET / posts#index
published_posts GET /posts/published(.:format) posts#published
draft_posts GET /posts/draft(.:format) posts#draft
recent_posts GET /posts/recent(.:format) posts#recent
publish_post PATCH /posts/:id/publish(.:format) posts#publish
unpublish_post PATCH /posts/:id/unpublish(.:format) posts#unpublish
posts GET /posts(.:format) posts#index
edit_post GET /posts/:id/edit(.:format) posts#edit
post GET /posts/:id(.:format) posts#show
PATCH /posts/:id(.:format) posts#update
PUT /posts/:id(.:format) posts#update

Answer 1

I see that what you're trying to do is figure out whether you're in the admin section or the standard post section and change the url of the form that way.
This is a bit of a non-standard way of doing it.
Generally speaking, what I've seen is that only the body of the form is in the shared form section, but the action is saved in the outside partial so eg:
app/views/admin/post/new.html.slim:
= simple_form_for(post, :html => { :multipart => true }) do |f|
== render 'shared/post_form', f: f, post: post
app/views/shared/_post_form.html.slim:
= f.association :categories, label: "Select the Categories:", as: :check_boxes , collection: #categories.map{|c| [c.name, c.id]}, include_hidden: false
= f.input :title
= f.input :subtitle
- if post.attachment.present?
.attachment
p
= image_tag(post.attachment.thumb.url, alt: 'Image', class: "img-responsive img-thumbnail")
= f.check_box :remove_attachment
| Remove image
br
.text-center
small
sample
= "File_size #{number_to_human_size(post.attachment.size)}"
= f.input :attachment, as: :file, label: "File"
= f.input :attachment_cache, as: :hidden
= f.input :remote_attachment_url, label: "Enter URL to an image"
= f.input :content, size: "150x150"
= f.button :submit, class: 'btn-primary'
Note: if you pass post as a local variable into a form, you should use it with post not #post (because #post completely ignores the local variable you passed in and goes back to whatever came from the controller, in which case why bother passing in the local variable?)
You should also probably never call another variable post inside the template... as it overrides the old post variable and is then gone. Name it something different eg in this case, if you REALLY wanted to use the template the way you have been, you could call it post_url_params

Answer 2

So following the idea of the #Taryn East, I put this and work's:
app/views/admin/posts/new.html.slim
= title("New Post")
.header
h1 New Post
== render 'form', post: #post
app/views/admin/posts/edit.html.slim
= title("Edit Post", #post.title)
.header
h1 Edit Post
== render "form", post: #post
app/views/admin/posts/_form.html.slim
= simple_form_for([:admin, post], :html => { :multipart => true }) do |f|
== render "shared/post_form", f: f, post: post
app/views/posts/_form.html.slim
= simple_form_for(post, :html => { :multipart => true }) do |f|
== render "shared/post_form", f: f, post: post
app/shared/_post_form.html.slim
= f.association :categories, label: "Select the Categories:", as: :check_boxes , collection: #categories.map{|c| [c.name, c.id]}, include_hidden: false
= f.input :title
= f.input :subtitle
- if post.attachment.present?
.attachment
p
= image_tag(post.attachment.thumb.url, alt: 'Image', class: "img-responsive img-thumbnail")
= f.check_box :remove_attachment
| Remove image
br
.text-center
small
sample
= "File_size #{number_to_human_size(post.attachment.size)}"
= f.input :attachment, as: :file, label: "File"
= f.input :attachment_cache, as: :hidden
= f.input :remote_attachment_url, label: "Enter URL to an image"
= f.input :content, input_html: { rows: '15' }
= f.button :submit, class: 'btn-primary'