E2560 Backend Final Project

app/controllers/export_controller.rb

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+# This controller handles exporting data from the application to various formats.
+class ExportController < ApplicationController
+  before_action :export_params
+
+  def index
+    klass = params[:class].constantize
+
+    render json: {
+      mandatory_fields: klass.mandatory_fields,
+      optional_fields: klass.optional_fields,
+      external_fields: klass.external_fields
+    }, status: :ok
+  rescue StandardError => e
+    render json: { error: e.message }, status: :unprocessable_entity
+  end
+
+  def export
+    # Parse ordered fields from JSON, if provided
+    ordered_fields =
+      begin
+        JSON.parse(params[:ordered_fields]) if params[:ordered_fields]
+      rescue JSON::ParserError
+        render json: { error: "Invalid JSON for ordered_fields" }, status: :unprocessable_entity
+        return
+      end
+
+    klass = params[:class].constantize
+
+    csv_file = Export.perform(klass, ordered_fields)
+
+    render json: {
+      message: "#{params[:class]} has been exported!",
+      file: csv_file
+    }, status: :ok
+
+  rescue StandardError => e
+    render json: { error: e.message }, status: :unprocessable_entity
+  end
+
+  private
+
+  def export_params
+    params.permit(:class, :ordered_fields)
+  end
+end

app/controllers/import_controller.rb

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+# This controller handles importing CSV data into any supported model.
+# It exposes two endpoints:
+#   • GET  /import        -> returns field requirements for the selected class
+#   • POST /import        -> processes the uploaded CSV file
+#
+# The controller delegates actual import logic to:
+#   klass.try_import_records(...)
+#
+# Each model that supports importing must implement:
+#   mandatory_fields
+#   optional_fields
+#   external_fields
+#   try_import_records(file, ordered_fields, use_header:)
+#
+
+class ImportController < ApplicationController
+  # Ensure strong parameters are processed before each action
+  before_action :import_params
+
+  ##
+  # GET /import
+  #
+  # Returns metadata about which fields a given class requires or accepts.
+  # The frontend uses this to build the mapping UI (drag/drop field matching).
+  #
+  def index
+    imported_class = params[:class].constantize
+
+    render json: {
+      mandatory_fields: imported_class.mandatory_fields,
+      optional_fields: imported_class.optional_fields,
+      external_fields: imported_class.external_fields,
+
+      # Import does not provide duplicate-resolution strategies (those apply to export)
+      available_actions_on_dup: imported_class.available_actions_on_duplicate.map{|klass| klass.class.name},
+    }, status: :ok
+  end
+
+  ##
+  # POST /import
+  #
+  # This action performs the actual import process. It:
+  #   1. Reads the uploaded CSV file
+  #   2. Determines whether the CSV includes headers
+  #   3. Applies user-chosen field ordering (if provided)
+  #   4. Hands off import logic to the model via `try_import_records`
+  #
+  def import
+    uploaded_file  = params[:csv_file]
+
+    # Convert use_headers ("true"/"false") into actual boolean
+    use_headers    = ActiveRecord::Type::Boolean.new.deserialize(params[:use_headers])
+
+    # If the user provided a custom field ordering, load it from JSON
+    ordered_fields = JSON.parse(params[:ordered_fields]) if params[:ordered_fields]
+
+    # Dynamically load the model class (e.g., "User", "Team", etc.)
+    klass = params[:class].constantize
+
+    # Load the chosen duplicate action (Skip, Update, Change)
+    dup_action = params[:dup_action].constantize
+
+    pp dup_action
+
+    importService = Import.new(klass: klass, file: uploaded_file, headers: ordered_fields, dup_action: dup_action.new)
+    result = importService.perform(use_headers)
+
+    # If no exceptions occur, return success
+    render json: { message: "#{klass.name} has been imported!", **result }, status: :created
+
+  rescue StandardError => e
+    # Catch any unexpected runtime errors
+    puts "An unexpected error occurred during import: #{e.message}"
+
+    render json: { error: e.message }, status: :unprocessable_entity
+  end
+
+  private
+
+  ##
+  # Strong parameters for import operations
+  #
+  def import_params
+    params.permit(:csv_file, :use_headers, :class, :ordered_fields, :dup_action)
+  end
+end