ruby 34 lines · 7 steps

The new/create pattern in a Rails controller

How a Rails controller scopes records to the current account and handles the save-or-re-render flow.

Explained by highlit

Rails Intermediate mvc strong-parameters tenant-scoping form-handling eager-loading

1class ProjectsController < ApplicationController
def new
  @project = current_account.projects.build
  load_form_collections
end
6 
def create
  @project = current_account.projects.build(project_params)
9 
  if @project.save
    redirect_to @project, notice: "Project created."
  else
    load_form_collections
    render :new, status: :unprocessable_entity
  end
end
17 
private
19 
def load_form_collections
  @clients = current_account.clients
                            .includes(:contacts)
                            .active
                            .order(:name)
25 
  @team_members = current_account.memberships
                                 .includes(:user)
                                 .order("users.last_name")
end
30 
def project_params
  params.require(:project).permit(:name, :client_id, :lead_id, :due_on)
end
34end

01 / 01

STEP 01

Walkthrough

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Three takeaways

1Building records through an association like current_account.projects keeps every query and creation scoped to the right tenant automatically.
2Re-rendering :new with an unprocessable_entity status on failure preserves user input and validation errors while signaling the error correctly.
3Extracting shared setup like form collections into a private method keeps new and create in sync without duplication.

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