Adds migration configs.

cdesai_migrate.info.yml

@@ -0,0 +1,14 @@
+type: module
+name: Demo Migration Module
+description: 'Migrate content from a CSV file. DO NOT INSTALL'
+package: Migration
+core: 8.x
+core_version_requirement: ^8 || ^9
+dependencies:
+  - migrate
+  - migrate_plus
+  - migrate_tools
+  - migrate_source_csv
+
+# Hides the module from the Admin UI.
+hidden: true

cdesai_migrate.install

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+<?php
+
+/**
+ * @file
+ * Install and update functions for the Demo Migrate module.
+ */
+
+/**
+ * Implements hook_requirements().
+ */
+function cdesai_migrate_requirements($phase) {
+  $requirements = [];
+  if ($phase == 'install') {
+
+    // Abort installation of this module since it is not ready.
+    $requirements['cdesai_migrate_not_ready'] = [
+      'description' => t('Demo Migration module is not ready for the installation. This module heavily redacted version of a module used in a project. Do not install.'),
+      'severity' => REQUIREMENT_ERROR,
+    ];
+  }
+
+  return $requirements;
+}

cdesai_migrate.links.menu.yml

@@ -0,0 +1,6 @@
+# Settings form
+cdesai_migrate.settings:
+  title: 'Demo Migrations'
+  description: 'Configure Demo migration settings.'
+  route_name: cdesai_migrate.settings
+  parent: system.admin_config_development

cdesai_migrate.permissions.yml

@@ -0,0 +1,3 @@
+administer demo migrate:
+  title: 'Administer Demo Migrate'
+  restrict access: true

cdesai_migrate.routing.yml

@@ -0,0 +1,7 @@
+cdesai_migrate.settings:
+  path: '/admin/config/development/cdesai/migrate'
+  defaults:
+    _form: '\Drupal\cdesai_migrate\Form\CDesaiMigrateSettings'
+    _title: 'Demo Migrations'
+  requirements:
+    _permission: 'administer demo migrate'

cdesai_migrate.services.yml

@@ -0,0 +1,5 @@
+services:
+  post_migration_subscriber:
+    class: '\Drupal\cdesai_migrate\EventSubscriber\DemoPostMigrationSubscriber'
+    tags:
+      - { name: 'event_subscriber' }

composer.json

@@ -0,0 +1,22 @@
+{
+    "name": "drupal/cdesai_migrate",
+    "description": "Demo of custom migration plugins.",
+    "type": "drupal-module",
+    "homepage": "https://wezbyte.com",
+    "keywords": ["Drupal", "Chintan", "Desai", "Migration"],
+    "minimum-stability": "dev",
+    "license": "GPL-2.0-or-later",
+    "authors": [
+        {
+            "name": "Chintan Desai",
+            "email": "chintan@wezbyte.com"
+        }
+    ],
+    "require": {
+        "drupal/core": "^8.9 || ^9.3",
+        "drupal/migrate_file": "^2.0",
+        "drupal/migrate_plus": "^5.1",
+        "drupal/migrate_source_csv": "^3.4",
+        "drupal/migrate_tools": "^5.0"
+    }
+}

config/install/migrate_plus.migration.cdesai_basic_pages.yml

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+# Migration configuration for importing basic pages.
+id: cdesai_basic_pages
+label: Import Basic Pages from CSV
+migration_group: CDESAI
+
+source:
+  # The custom CSV source plugin will fetch the source path from configs.
+  # Upload source files at /admin/config/development/cdesai/migrate.
+  plugin: 'cdesai_migrate_csv'
+  source_config_key: cdesai_migrate_basic_pages_source
+
+  delimiter: ','
+  enclosure: '"'
+  header_offset: 0
+
+  ids:
+    - page
+
+process:
+  langcode: en
+  moderation_state: draft
+  title: title
+
+  uid:
+    plugin: default_value
+    default_value: 1
+
+  field_content/target_id:
+    # Skips a row if skip_migration property is set to TRUE.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: skip_migration
+      value: 'TRUE'
+      method: row
+    -
+      plugin: migration_lookup
+      migration: cdesai_paragraph_parents
+      no_stub: true
+      source: page
+    -
+      plugin: extract
+      index:
+        - '0'
+  field_content/target_revision_id:
+    -
+      plugin: migration_lookup
+      migration: cdesai_paragraph_parents
+      no_stub: true
+      source: page
+    -
+      plugin: extract
+      index:
+        - 1
+
+  field_category:
+    # Do not process further if the category value is empty.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: category
+      value: ''
+      method: process
+
+    # The plugin looks up for an exiting term based on the value_key property.
+    # If no matching term is found, it creates one on the fly.
+    -
+      plugin: entity_generate
+      source: category
+      entity_type: taxonomy_term
+      bundle_key: vid
+      bundle: category
+      value_key: name
+      ignore_case: true
+
+  field_legacy_url: legacy_url
+
+  type:
+    plugin: default_value
+    default_value: basic_page
+
+destination:
+  plugin: 'entity:node'
+
+# make sure these migration execute before running current migration
+migration_dependencies:
+  required:
+    - cdesai_paragraphs
+    - cdesai_paragraph_parents
+
+# use forced module dependency so uninstall/reinstall works properly
+dependencies:
+  enforced:
+    module:
+      - cdesai_migrate

config/install/migrate_plus.migration.cdesai_paragraph_parents.yml

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+# Migration configuration for attaching paragraphs to parent paragraphs (row).
+id: cdesai_paragraph_parents
+label: 'Parent (Row) Paragraphs'
+migration_group: CDESAI
+
+source:
+  # Upload source files at /admin/config/development/cdesai/migrate.
+  plugin: cdesai_paragraph_migrate_source
+
+process:
+  langcode: en
+  field_bundles/target_id:
+    # Skips a row if skip_migration property is set to TRUE.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: skip_migration
+      value: 'TRUE'
+      method: row
+    # Skips a row if scrapped property is set to FALSE.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: scrapped
+      value: 'FALSE'
+      method: row
+    -
+      plugin: migration_lookup
+      migration: cdesai_paragraphs
+      no_stub: true
+      source: page
+    -
+      plugin: extract
+      index:
+        - '0'
+  field_bundles/target_revision_id:
+    -
+      plugin: migration_lookup
+      migration: cdesai_paragraphs
+      no_stub: true
+      source: page
+    -
+      plugin: extract
+      index:
+        - '1'
+
+destination:
+  plugin: 'entity_reference_revisions:paragraph'
+  default_bundle: row
+
+# make sure these migration execute before running current migration
+migration_dependencies:
+  required:
+    - cdesai_paragraphs
+
+# use forced module dependency so uninstall/reinstall works properly
+dependencies:
+  enforced:
+    module:
+      - cdesai_migrate

config/install/migrate_plus.migration.cdesai_paragraphs.yml

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+# Migration configuration for importing content paragraphs.
+id: cdesai_paragraphs
+label: Import Content Paragraphs from Text File Archive
+migration_group: CDESAI
+
+source:
+  # Upload source files at /admin/config/development/cdesai/migrate.
+  plugin: cdesai_paragraph_migrate_source
+
+process:
+  langcode: en
+
+  field_body/value:
+    # Skips a row if skip_migration property is set to TRUE.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: skip_migration
+      value: 'TRUE'
+      method: row
+    # Skips a row if scrapped property is set to FALSE.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: scrapped
+      value: 'FALSE'
+      method: row
+    # Uses the custom process plugin to extract paragraph contents from a text file.
+    -
+      plugin: extract_file_contents
+      source: content_file
+
+  field_body/format:
+    plugin: default_value
+    default_value: rich_text
+
+destination:
+  plugin: 'entity_reference_revisions:paragraph'
+  default_bundle: basic
+
+# use forced module dependency so uninstall/reinstall works properly
+dependencies:
+  enforced:
+    module:
+      - cdesai_migrate

config/install/migrate_plus.migration.cdesai_profile_pages.yml

@@ -0,0 +1,145 @@
+# Migration configuration for importing profile pages.
+id: cdesai_profile_pages
+label: Import Profile Pages from CSV
+migration_group: CDESAI
+
+source:
+  # The custom CSV source plugin will fetch the source path from configs.
+  # Upload source files at /admin/config/development/cdesai/migrate.
+  plugin: 'cdesai_migrate_csv'
+  source_config_key: cdesai_migrate_profile_pages_source
+
+  delimiter: ','
+  enclosure: '"'
+  header_offset: 0
+
+  ids:
+    - page
+
+process:
+  langcode: en
+  moderation_state: draft
+  title: title
+  field_legacy_url: legacy_url
+  field_year_birth: year_birth
+  field_year_death: year_death
+
+  uid:
+    plugin: default_value
+    default_value: 1
+
+  body/value:
+    # Skips a row if skip_migration property is set to TRUE.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: skip_migration
+      value: 'TRUE'
+      method: row
+    # Skips a row if scrapped property is set to FALSE.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: scrapped
+      value: 'FALSE'
+      method: row
+    -
+      plugin: migration_lookup
+      migration: cdesai_paragraphs
+      no_stub: true
+      source: page
+    -
+      plugin: extract_cdesai_migrate_paragraph
+
+  field_body/format:
+    plugin: default_value
+    default_value: rich_text
+
+  field_position:
+    # Do not process further if the position value is empty.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: position
+      value: ''
+      method: process
+
+    # The plugin looks up for an exiting term based on the value_key property.
+    # If no matching term is found, it creates one on the fly.
+    -
+      plugin: entity_generate
+      source: position
+      entity_type: taxonomy_term
+      bundle_key: vid
+      bundle: position
+      value_key: name
+      ignore_case: true
+
+  field_agency:
+    # Do not process further if the position value is empty.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: agency
+      value: ''
+      method: process
+
+    # The plugin looks up for an exiting term based on the value_key property.
+    # If no matching term is found, it creates one on the fly.
+    -
+      plugin: entity_generate
+      source: agency
+      entity_type: taxonomy_term
+      bundle_key: vid
+      bundle: agency
+      value_key: name
+      ignore_case: true
+
+  field_years_in_office:
+    -
+      plugin: skip_on_empty
+      source: years_in_office
+      method: process
+      message: 'Row does not contain years_in_office.'
+    -
+      plugin: explode
+      delimiter: ','
+    -
+      plugin: callback
+      callable: trim
+
+  field_media/target_id:
+    # Skips a row if has_images property is set to FALSE.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: has_images
+      value: 'FALSE'
+      method: row
+    -
+      plugin: skip_on_empty
+      method: row
+      message: 'Cannot import image file with an empty url.'
+    -
+      plugin: migration_lookup
+      migration: cdesai_profile_pages_media_items
+      source: page
+
+  type:
+    plugin: default_value
+    default_value: profile
+
+destination:
+  plugin: 'entity:node'
+
+# make sure these migration execute before running current migration
+migration_dependencies:
+  required:
+    - cdesai_profile_pages_media_items
+    - cdesai_basic_pages
+
+# use forced module dependency so uninstall/reinstall works properly
+dependencies:
+  enforced:
+    module:
+      - cdesai_migrate

config/install/migrate_plus.migration.cdesai_profile_pages_image_files.yml

@@ -0,0 +1,73 @@
+# Migration configuration for importing image files.
+id: cdesai_profile_pages_image_files
+label: Import Profile Page Files
+migration_group: CDESAI_MEDIA
+
+source:
+  # The custom CSV source plugin will fetch the source path from configs.
+  # Upload source files at /admin/config/development/cdesai/migrate.
+  plugin: 'cdesai_migrate_csv'
+  source_config_key: cdesai_migrate_profile_pages_source
+
+  delimiter: ','
+  enclosure: '"'
+  header_offset: 0
+
+  constants:
+    DRUPAL_FILE_DIRECTORY: 'public://images/profile/'
+
+  ids:
+    - page
+
+process:
+  uid:
+    plugin: default_value
+    default_value: 1
+
+  pseudo_destination_filename:
+    # Skips a row if has_images property is set to FALSE.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: has_images
+      value: 'FALSE'
+      method: row
+    -
+      plugin: skip_on_empty
+      method: row
+      message: 'Cannot import image file with an empty url.'
+    -
+      plugin: callback
+      callable: basename
+      source: image_url
+  pseudo_destination_path:
+    -
+      plugin: concat
+      source:
+        - constants/DRUPAL_FILE_DIRECTORY
+        - '@pseudo_destination_filename'
+  uri:
+    -
+      plugin: skip_on_empty
+      method: process
+      source: image_url
+    -
+      plugin: file_copy
+      source:
+        - image_url
+        - '@pseudo_destination_path'
+      file_exists: rename
+      move: false
+
+destination:
+  plugin: 'entity:file'
+
+
+# make sure these migration execute before running current migration
+migration_dependencies: null
+
+# use forced module dependency so uninstall/reinstall works properly
+dependencies:
+  enforced:
+    module:
+      - cdesai_migrate

config/install/migrate_plus.migration.cdesai_profile_pages_media_items.yml

@@ -0,0 +1,72 @@
+# Migration configuration for creating media items.
+id: cdesai_profile_pages_media_items
+label: Import Profile Page Media
+migration_group: CDESAI_MEDIA
+
+source:
+  # The custom CSV source plugin will fetch the source path from configs.
+  # Upload source files at /admin/config/development/cdesai/migrate.
+  plugin: 'cdesai_migrate_csv'
+  source_config_key: cdesai_migrate_profile_pages_source
+
+  delimiter: ','
+  enclosure: '"'
+  header_offset: 0
+
+  ids:
+    - page
+
+process:
+  pseudo_destination_filename:
+    # Skips a row if has_images property is set to FALSE.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: has_images
+      value: 'FALSE'
+      method: row
+    -
+      plugin: skip_on_empty
+      method: row
+      message: 'Cannot import image file with an empty url.'
+    -
+      plugin: callback
+      callable: basename
+      source: image_url
+
+  name: '@pseudo_destination_filename'
+
+  field_media_image/target_id:
+    plugin: migration_lookup
+    migration: cdesai_profile_pages_image_files
+    source: page
+
+  field_media_image/alt: title
+
+  thumbnail/target_id:
+    plugin: migration_lookup
+    migration: cdesai_profile_pages_image_files
+    source: page
+
+  thumbnail/alt: title
+
+  uid:
+    plugin: default_value
+    default_value: 1
+
+  langcode: en
+
+destination:
+  plugin: 'entity:media'
+  default_bundle: image
+
+# make sure these migration execute before running current migration
+migration_dependencies:
+  required:
+    - cdesai_profile_pages_image_files
+
+# use forced module dependency so uninstall/reinstall works properly
+dependencies:
+  enforced:
+    module:
+      - cdesai_migrate

config/install/migrate_plus.migration.cdesai_redirects.yml

@@ -0,0 +1,65 @@
+# Migration configuration for generating redirects from legacy url to Drupal nodes.
+id: cdesai_migrate_page_redirects
+label: 'Legacy Page Redirects'
+migration_group: CDESAI
+
+source:
+  # Upload source files at /admin/config/development/cdesai/migrate.
+  plugin: cdesai_paragraph_migrate_source
+
+process:
+  language:
+    plugin: default_value
+    source: language
+    default_value: und
+
+  uid:
+    plugin: default_value
+    default_value: 1
+
+  status_code:
+    plugin: default_value
+    default_value: 301
+
+  redirect_source/path:
+    # Skips a row if skip_migration property is set to TRUE.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: skip_migration
+      value: 'TRUE'
+      method: row
+    # Skips a row if legacy_url property is EMPTY.
+    -
+      plugin: skip_on_value
+      equals: true
+      source: legacy_url
+      value: ''
+      method: row
+    -
+      plugin: substr
+      source: legacy_url
+      start: 1
+
+  redirect_redirect/title: ''
+
+  redirect_redirect/uri:
+    # Uses the custom process plugin to extract paragraph contents from a text file.
+    -
+      plugin: generate_redirect_uri
+      source: legacy_url
+
+destination:
+  plugin: entity:redirect
+
+# make sure these migration execute before running current migration
+migration_dependencies:
+  required:
+    - cdesai_articles
+    - cdesai_basic_pages
+
+# use forced module dependency so uninstall/reinstall works properly
+dependencies:
+  enforced:
+    module:
+      - cdesai_migrate

src/DemoMigrateConstantsInterface.php

@@ -0,0 +1,60 @@
+<?php
+
+namespace Drupal\cdesai_migrate;
+
+/**
+ * Configuration form.
+ */
+interface DemoMigrateConstantsInterface {
+  const CONFIG_NAME = 'cdesai_migrate.settings';
+
+  const FILE_TYPES = [
+    'spreadsheet' => ['csv'],
+    'archive' => ['zip'],
+    'text' => ['txt'],
+  ];
+
+  const SOURCES = [
+    'cdesai_migrate_basic_pages_source' => [
+      'label' => 'Basic Pages Source',
+      'directory' => 'private://migration/sources',
+      'description' => 'File must be a CSV file.',
+      'source_file_type' => 'spreadsheet',
+      'required_columns' => [
+        'page',
+        'skip_migration',
+        'scrapped',
+        'category',
+        'title',
+        'legacy_url',
+      ],
+    ],
+    'cdesai_migrate_profile_pages_source' => [
+      'label' => 'Profile Pages Source',
+      'directory' => 'private://migration/sources',
+      'description' => 'File must be a CSV file.',
+      'source_file_type' => 'spreadsheet',
+      'required_columns' => [
+        'page',
+        'skip_migration',
+        'scrapped',
+        'position',
+        'title',
+        'legacy_url',
+        'year_birth',
+        'year_death',
+        'years_in_office',
+        'agency',
+        'image_url',
+      ],
+    ],
+    'cdesai_migrate_paragraphs_source' => [
+      'label' => 'Paragraphs Source',
+      'directory' => 'private://migration/sources',
+      'description' => 'File must be a ZIP archive containing one or more .txt files.',
+      'source_file_type' => 'archive',
+      'archive_content_file_types' => 'text',
+    ],
+  ];
+
+}

src/EventSubscriber/DemoPostMigrationSubscriber.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace Drupal\cdesai_migrate\EventSubscriber;
+
+use Drupal\migrate\Event\MigrateEvents;
+use Drupal\migrate\Event\MigratePostRowSaveEvent;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Class PostMigrationSubscriber.
+ *
+ * Run our user flagging after the last node migration is run.
+ *
+ * @package Drupal\YOUR_MODULE
+ */
+class DemoPostMigrationSubscriber implements EventSubscriberInterface {
+
+  /**
+   * Get subscribed events.
+   *
+   * @inheritdoc
+   */
+  public static function getSubscribedEvents(): array {
+    $events[MigrateEvents::POST_ROW_SAVE][] = ['onMigratePostImport'];
+    return $events;
+  }
+
+  /**
+   * Callback for MigrateEvents::POST_ROW_SAVE event.
+   *
+   * @param \Drupal\migrate\Event\MigratePostRowSaveEvent $event
+   *   The import event object.
+   */
+  public function onMigratePostImport(MigratePostRowSaveEvent $event) {
+    if ($event->getMigration()->getBaseId() == 'cdesai_basic_pages') {
+      // CODE REDACTED
+    }
+  }
+
+}

src/Form/CDesaiMigrateSettings.php

@@ -0,0 +1,333 @@
+<?php
+
+namespace Drupal\cdesai_migrate\Form;
+
+use Drupal\cdesai_migrate\DemoMigrateConstantsInterface;
+use Drupal\Core\Archiver\ArchiverManager;
+use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\File\Exception\FileException;
+use Drupal\Core\File\FileSystemInterface;
+use Drupal\Core\Form\ConfigFormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\StreamWrapper\StreamWrapperManager;
+use Drupal\file\Entity\File;
+use Drupal\file\FileInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Configuration form.
+ */
+class CDesaiMigrateSettings extends ConfigFormBase {
+  const FORM_ID = 'cdesai_migrate_settings';
+
+  /**
+   * The module handler.
+   *
+   * @var \Drupal\Core\Extension\ModuleHandlerInterface
+   */
+  protected ModuleHandlerInterface $moduleHandler;
+
+  /**
+   * The file system.
+   *
+   * @var \Drupal\Core\File\FileSystemInterface
+   */
+  protected FileSystemInterface $fileSystem;
+
+  /**
+   * The archive manager.
+   *
+   * @var \Drupal\Core\Archiver\ArchiverManager
+   */
+  protected ArchiverManager $archiveManager;
+
+  /**
+   * Constructs a ThemeSettingsForm object.
+   *
+   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
+   *   The factory for configuration objects.
+   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
+   *   The module handler instance to use.
+   * @param \Drupal\Core\File\FileSystemInterface $file_system
+   *   The file system.
+   * @param \Drupal\Core\Archiver\ArchiverManager $archive_manager
+   *   The archive manager.
+   */
+  public function __construct(ConfigFactoryInterface $config_factory, ModuleHandlerInterface $module_handler, FileSystemInterface $file_system, ArchiverManager $archive_manager) {
+    parent::__construct($config_factory);
+
+    $this->moduleHandler = $module_handler;
+    $this->fileSystem = $file_system;
+    $this->archiveManager = $archive_manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('config.factory'),
+      $container->get('module_handler'),
+      $container->get('file_system'),
+      $container->get('plugin.manager.archiver')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getEditableConfigNames(): array {
+    return [
+      DemoMigrateConstantsInterface::CONFIG_NAME,
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId(): string {
+    return self::FORM_ID;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state): array {
+    $configs = $this->config(DemoMigrateConstantsInterface::CONFIG_NAME);
+
+    foreach (DemoMigrateConstantsInterface::SOURCES as $sourceKey => $source) {
+
+      $currentPath = $configs->get($sourceKey . '_path');
+      $text = $this->t('Upload a file');
+      if ($currentPath && $this->validatePath($currentPath)) {
+        $text = $currentPath;
+      }
+
+      $form[$sourceKey . '_current_path'] = [
+        '#type' => 'markup',
+        '#markup' =>
+        "<strong>Current {$source['label']} file:</strong> " . $text,
+      ];
+
+      $form[$sourceKey . '_upload'] = [
+        '#type' => 'file',
+        '#title' => $this->t('Upload %title file', ['%title' => $source['label']]),
+        '#description' => $source['description'],
+        '#upload_validators' => [
+          'file_validate_extensions' => DemoMigrateConstantsInterface::FILE_TYPES[$source['source_file_type']],
+        ],
+        '#suffix' => '<hr/>',
+      ];
+    }
+
+    return parent::buildForm($form, $form_state);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateForm(array &$form, FormStateInterface $form_state) {
+    parent::validateForm($form, $form_state);
+
+    if ($this->moduleHandler->moduleExists('file')) {
+      foreach (DemoMigrateConstantsInterface::SOURCES as $sourceKey => $source) {
+        // Validate file only if a new file was uploaded.
+        $upload_key = $sourceKey . '_upload';
+        $file = _file_save_upload_from_form($form[$upload_key], $form_state, 0, FileSystemInterface::EXISTS_REPLACE);
+        if ($file) {
+          if ($source['source_file_type'] === 'archive') {
+            $contentFileExts = DemoMigrateConstantsInterface::FILE_TYPES[$source['archive_content_file_types']];
+            $this->validateArchiveFile($upload_key, $contentFileExts, $file, $form_state);
+          }
+          else {
+            $this->validateCsvFile($upload_key, $source['required_columns'], $file, $form_state);
+          }
+        }
+
+      }
+
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    parent::submitForm($form, $form_state);
+
+    $configs = $this->config(DemoMigrateConstantsInterface::CONFIG_NAME);
+
+    // Exclude unnecessary elements before saving.
+    $form_state->cleanValues();
+    $values = $form_state->getValues();
+
+    foreach (DemoMigrateConstantsInterface::SOURCES as $sourceKey => $source) {
+      // Check for a newly uploaded file.
+      $upload_key = $sourceKey . '_upload';
+      $path_key = $sourceKey . '_path';
+
+      try {
+        if (isset($values[$upload_key]) && $values[$upload_key] instanceof File) {
+          $this->fileSystem->mkdir($source['directory'], NULL, TRUE);
+          $filename = $this->fileSystem->copy($values[$upload_key]->getFileUri(), $source['directory'], FileSystemInterface::EXISTS_RENAME);
+          $configs->set($path_key, $filename);
+        }
+      }
+      catch (FileException $e) {
+        // Ignore.
+        $this->logger('Demo Migration')->error($e->getMessage());
+        $this->messenger()->addError($e->getMessage());
+      }
+
+    }
+
+    $configs->save();
+  }
+
+  /**
+   * Helper function for the cdesai_migrate_settings form.
+   *
+   * Attempts to validate normal system paths, paths relative to the public
+   * files directory, or stream wrapper URIs. If the given path is any of the
+   * above, returns a valid path or URI that the theme system can display.
+   *
+   * @param string $path
+   *   A path relative to the Drupal root or to the public files directory, or
+   *   a stream wrapper URI.
+   *
+   * @return false|string
+   *   A valid path that can be displayed through the theme system, or FALSE if
+   *   the path could not be validated.
+   */
+  protected function validatePath(string $path) {
+    // Absolute local file paths are invalid.
+    if ($this->fileSystem->realpath($path) == $path) {
+      return FALSE;
+    }
+
+    // A path relative to the Drupal root or a fully qualified URI is valid.
+    if (is_file($path)) {
+      return $path;
+    }
+
+    // Prepend 'private://' for relative file paths within private filesystem.
+    if (StreamWrapperManager::getScheme($path) === FALSE) {
+      $path = 'private://' . $path;
+
+      if (is_file($path)) {
+        return $path;
+      }
+    }
+
+    return FALSE;
+  }
+
+  /**
+   * Validate the archive file.
+   *
+   * @param string $key
+   *   Form field key.
+   * @param array $allowed_file_extensions
+   *   File extensions allowed in the archive.
+   * @param \Drupal\file\FileInterface $file
+   *   The file being uploaded.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The current state of the form.
+   */
+  private function validateArchiveFile(string $key, array $allowed_file_extensions, FileInterface $file, FormStateInterface $form_state) {
+    $filepath = $this->fileSystem->realpath($file->getFileUri());
+    /** @var \Drupal\Core\Archiver\ArchiverInterface $archiver */
+    $archiver = $this->archiveManager->getInstance([
+      'filepath' => $filepath,
+    ]);
+
+    if ($archiver && !empty($archiver->listContents())) {
+      $otherExt = FALSE;
+      foreach ($archiver->listContents() as $fileInArchive) {
+        $ext = pathinfo($fileInArchive, PATHINFO_EXTENSION);
+        if (!in_array($ext, $allowed_file_extensions)) {
+          $otherExt = TRUE;
+          break;
+        }
+      }
+
+      if ($otherExt) {
+        $form_state->setErrorByName($key, $this->t('Archive contains one or more files with an invalid extension. Allowed extensions are: %ext', [
+          '%ext' => implode(', ', $allowed_file_extensions),
+        ]));
+      }
+      else {
+        // Put the temporary file in form_values so we can save it
+        // on submit.
+        $form_state->setValue($key, $file);
+      }
+    }
+    else {
+      $form_state->setErrorByName($key, $this->t('Not a valid archive file.'));
+    }
+  }
+
+  /**
+   * Validate the CSV file.
+   *
+   * @param string $key
+   *   Form field key.
+   * @param array $required_columns
+   *   An array column keys that should be in the CSV.
+   * @param \Drupal\file\FileInterface $file
+   *   The file being uploaded.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The current state of the form.
+   */
+  private function validateCsvFile(string $key, array $required_columns, FileInterface $file, FormStateInterface $form_state) {
+    $readFile = FALSE;
+
+    if (($handle = fopen($file->getFileUri(), 'r')) !== FALSE) {
+      $row = fgetcsv($handle, 1000);
+      if ($row !== FALSE) {
+        $readFile = TRUE;
+
+        // Sanitize keys in the header.
+        $header = array_map([__CLASS__, 'sanitizeKey'], $row);
+        // Check for required keys.
+        if ($required_columns) {
+          $missingRequiredKeys = array_diff($required_columns, $header);
+          if (!empty($missingRequiredKeys)) {
+            $form_state->setErrorByName($key, $this->t('CSV file is missing required columns: %columns', [
+              '%columns' => implode(', ', $missingRequiredKeys),
+            ]));
+          }
+          else {
+            // Put the temporary file in form_values so we can save it
+            // on submit.
+            $form_state->setValue($key, $file);
+          }
+        }
+      }
+
+      fclose($handle);
+    }
+
+    if (!$readFile) {
+      $form_state->setErrorByName($key, $this->t('Unable to read from the file.'));
+    }
+
+  }
+
+  /**
+   * Remove whitespaces form a string and converts it to lowercase.
+   *
+   * @param string $key
+   *   A string to sanitize.
+   *
+   * @return string
+   *   A sanitized string.
+   */
+  public static function sanitizeKey(string $key): string {
+    $key = trim($key);
+    $key = str_replace(' ', '_', $key);
+    return strtolower($key);
+  }
+
+}

src/Plugin/migrate/process/ExtractFileContents.php

@@ -0,0 +1,54 @@
+<?php
+
+namespace Drupal\cdesai_migrate\Plugin\migrate\process;
+
+use Drupal\migrate\MigrateSkipRowException;
+use Drupal\migrate\Row;
+use Drupal\migrate\ProcessPluginBase;
+use Drupal\migrate\MigrateExecutableInterface;
+use Drush\Drush;
+
+/**
+ * Provides a 'Extract File Contents' migrate process plugin.
+ *
+ * Extracts contents of a file.
+ *
+ * @MigrateProcessPlugin(
+ *  id = "extract_file_contents"
+ * )
+ */
+class ExtractFileContents extends ProcessPluginBase {
+
+  /**
+   * {@inheritdoc}
+   *
+   * @throws \Drupal\migrate\MigrateSkipRowException
+   */
+  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
+    $error = FALSE;
+    $page = $row->get('page');
+
+    if (is_null($value) || trim($value) === '') {
+      $error = "Skipping because content filepath is empty for {$page}.";
+    }
+    elseif (!is_file($value)) {
+      $error = "Skipping because content file is missing for {$page}.";
+    }
+    else {
+      $contents = file_get_contents($value);
+      if ($contents !== FALSE) {
+        return $contents;
+      }
+
+      $error = "Skipping because content file is unreadable for {$page}.";
+    }
+
+    if ($error) {
+      Drush::output()->writeln($error);
+      throw new MigrateSkipRowException($error);
+    }
+
+    return '';
+  }
+
+}

src/Plugin/migrate/process/ExtractFromParagraph.php

@@ -0,0 +1,55 @@
+<?php
+
+namespace Drupal\cdesai_migrate\Plugin\migrate\process;
+
+use Drupal\migrate\ProcessPluginBase;
+use Drupal\migrate\MigrateException;
+use Drupal\migrate\MigrateExecutableInterface;
+use Drupal\migrate\Row;
+use Drupal\paragraphs\Entity\Paragraph;
+
+/**
+ * Provides a 'Extract Paragraph' migrate process plugin.
+ *
+ * Extracts content of field_body from a paragraph entity.
+ *
+ * @MigrateProcessPlugin(
+ *   id = "extract_cdesai_migrate_paragraph",
+ *   handle_multiples = TRUE
+ * )
+ */
+class ExtractFromParagraph extends ProcessPluginBase {
+
+  /**
+   * {@inheritdoc}
+   *
+   * @throws \Drupal\migrate\MigrateException
+   * @throws \Drupal\Core\TypedData\Exception\MissingDataException
+   */
+  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
+    if (!is_array($value)) {
+      throw new MigrateException(sprintf("Input should be an array, instead it was of type '%s'", gettype($value)));
+    }
+
+    if (count($value) != 2) {
+      throw new MigrateException(sprintf("Input array should have exactly two (2) elements, instead it had '%s'", count($value)));
+    }
+
+    $paragraph = Paragraph::load($value[0]);
+
+    if ($paragraph->hasField('field_body')) {
+      $body = $paragraph->get('field_body');
+      $item = $body->get(0);
+
+      if ($item) {
+        return $item->getValue()['value'];
+      }
+    }
+    else {
+      throw new MigrateException("Paragraph does not have field_body.");
+    }
+
+    throw new MigrateException("Unable to find paragraph.");
+  }
+
+}

src/Plugin/migrate/process/GenerateRedirectUri.php

@@ -0,0 +1,62 @@
+<?php
+
+namespace Drupal\cdesai_migrate\Plugin\migrate\process;
+
+use Drupal\Component\Plugin\Exception\PluginException;
+use Drupal\migrate\MigrateSkipRowException;
+use Drupal\migrate\Row;
+use Drupal\migrate\ProcessPluginBase;
+use Drupal\migrate\MigrateExecutableInterface;
+use Drush\Drush;
+
+/**
+ * Provides a 'Generate Redirect Uri' migrate process plugin.
+ *
+ * Generates a redirect URI from the legacy url.
+ *
+ * @MigrateProcessPlugin(
+ *  id = "generate_redirect_uri"
+ * )
+ */
+class GenerateRedirectUri extends ProcessPluginBase {
+
+  /**
+   * {@inheritdoc}
+   *
+   * @throws \Drupal\migrate\MigrateSkipRowException
+   */
+  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
+    $redirect = '';
+
+    if (is_null($value) || trim($value) === '') {
+      $error = "Skipping because legacy_url is null or empty.";
+      Drush::output()->writeln($error);
+      throw new MigrateSkipRowException($error);
+    }
+
+    /** @var \Drupal\node\NodeStorageInterface $nodeStorage */
+    try {
+      $nodeStorage = \Drupal::entityTypeManager()->getStorage('node');
+      $nodes = $nodeStorage->loadByProperties([
+        'field_legacy_url' => trim($value),
+      ]);
+
+      if (!empty($nodes)) {
+        $redirect = 'entity:node/' . reset($nodes)->id();
+      }
+    }
+    catch (PluginException $e) {
+      $redirect = '';
+    }
+
+    if (!$redirect) {
+      $error = sprintf('Skipped... Unable to map legacy url "%s" to a node.', $value);
+      Drush::output()->writeln($error);
+      throw new MigrateSkipRowException($error);
+    }
+
+    Drush::output()->writeln($redirect);
+    return $redirect;
+  }
+
+}

src/Plugin/migrate/source/CDesaiCSV.php

@@ -0,0 +1,103 @@
+<?php
+
+namespace Drupal\cdesai_migrate\Plugin\migrate\source;
+
+use Drupal\cdesai_migrate\DemoMigrateConstantsInterface;
+use Drupal\Core\Url;
+use Drupal\migrate\Plugin\MigrationInterface;
+use Drupal\migrate_source_csv\Plugin\migrate\source\CSV;
+use League\Csv\Reader;
+
+/**
+ * Source for CSV files (overridden to make source path dynamic).
+ *
+ * @see \Drupal\migrate_source_csv\Plugin\migrate\source\CSV
+ *
+ * Available configuration options:
+ * @see \Drupal\migrate_source_csv\Plugin\migrate\source\CSV for all options.
+ *
+ *
+ * Example with minimal options:
+ * @code
+ * source:
+ *   plugin: cdesai_migrate_csv
+ *   source_config_key: cdesai_migrate_basic_pages_source
+ *   ids: [id]
+ *   delimiter: '|'
+ *   enclosure: "'"
+ *   escape: '`'
+ *   header_offset: 0
+ *   fields:
+ *     -
+ *       name: id
+ *       label: ID
+ *     -
+ *       name: country
+ *       label: Country
+ *
+ * @MigrateSource(
+ *   id = "cdesai_migrate_csv",
+ *   source_module = "cdesai_migrate"
+ * )
+ */
+class CDesaiCSV extends CSV {
+
+  /**
+   * {@inheritdoc}
+   *
+   * @throws \InvalidArgumentException
+   * @throws \Drupal\migrate\MigrateException
+   */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration) {
+    $configuration['path'] = 'provided by the configs';
+
+    // Source config key is required.
+    if (empty($this->configuration['source_config_key'])) {
+      throw new \InvalidArgumentException('You must declare the "source_config_key" in your source settings.');
+    }
+    // Source config key must be one of the valid values.
+    elseif (!array_key_exists($this->configuration['source_config_key'], DemoMigrateConstantsInterface::SOURCES)) {
+      throw new \InvalidArgumentException('Invalid value for "source_config_key".');
+    }
+
+    parent::__construct($configuration, $plugin_id, $plugin_definition, $migration);
+  }
+
+  /**
+   * Return a string representing the source file path.
+   *
+   * @return string
+   *   The file path.
+   */
+  public function __toString() {
+    return $this->getSourceFileName();
+  }
+
+  /**
+   * Construct a new CSV reader.
+   *
+   * @return \League\Csv\Reader
+   *   The reader.
+   */
+  protected function createReader(): Reader {
+    $path = $this->getSourceFileName();
+    if (!file_exists($path)) {
+      throw new \RuntimeException(sprintf('File "%s" was not found.', $path));
+    }
+    $csv = fopen($path, 'r');
+    if (!$csv) {
+      throw new \RuntimeException(sprintf('File "%s" could not be opened.', $path));
+    }
+    return Reader::createFromStream($csv);
+  }
+
+  /**
+   * Get source path from configs.
+   */
+  private function getSourceFileName(): string {
+    // CODE REDACTED
+
+    return "REDACTED";
+  }
+
+}

src/Plugin/migrate/source/CDesaiParagraphMigrateSource.php

@@ -0,0 +1,169 @@
+<?php
+
+namespace Drupal\cdesai_migrate\Plugin\migrate\source;
+
+use Drupal\cdesai_migrate\DemoMigrateConstantsInterface;
+use Drupal\Core\Url;
+use Drupal\migrate\MigrateException;
+use Drupal\migrate\Plugin\migrate\source\SourcePluginBase;
+use Drupal\migrate\Plugin\MigrationInterface;
+
+/**
+ * Source plugin to import paragraphs from content files.
+ *
+ * @MigrateSource(
+ *   id = "cdesai_paragraph_migrate_source"
+ * )
+ */
+class CDesaiParagraphMigrateSource extends SourcePluginBase {
+
+  /**
+   * The paragraph contents archive file containing one or more text files.
+   *
+   * @var string
+   */
+  protected string $paragraphsSourceFile;
+
+  /**
+   * The CSV source files for pages.
+   *
+   * @var string[]
+   */
+  protected array $pageSourceFiles;
+
+  /**
+   * {@inheritdoc}
+   *
+   * @throws \Drupal\migrate\MigrateException
+   */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration) {
+    parent::__construct($configuration, $plugin_id, $plugin_definition, $migration);
+    $configs = \Drupal::config(DemoMigrateConstantsInterface::CONFIG_NAME);
+    $this->paragraphsSourceFile = (string) $configs->get('cdesai_migrate_paragraphs_source_path');
+    $this->pageSourceFiles = [
+      (string) $configs->get('cdesai_migrate_articles_source_path'),
+      (string) $configs->get('cdesai_migrate_basic_pages_source_path'),
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getIds(): array {
+    return [
+      'page' => [
+        'type' => 'string',
+      ],
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function fields(): array {
+    return [
+      'page' => $this->t("Page"),
+      'skip_migration' => $this->t('Skip Migration'),
+      'scrapped' => $this->t('Scrapped Content'),
+      'content_file' => $this->t('Paragraph Content File'),
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function __toString() {
+    $this->initializeIterator();
+
+    return "Content Archive: \n\t{$this->paragraphsSourceFile} \n"
+      . "Page Metadata Files:\n\t" . implode("\n\t", $this->pageSourceFiles);
+  }
+
+  /**
+   * {@inheritdoc}
+   *
+   * @throws \Drupal\migrate\MigrateException
+   */
+  protected function initializeIterator() {
+    $this->requiredFilesExist();
+    $pages = $this->extractPageData();
+
+    // CODE REDACTED
+
+    // Migrate needs an Iterator class, not just an array.
+    return new \ArrayIterator($pages);
+  }
+
+  /**
+   * Make sure all required source files exists.
+   *
+   * @throws \Drupal\migrate\MigrateException
+   */
+  private function requiredFilesExist() {
+    $fileExists = TRUE;
+
+    // CODE REDACTED
+
+    if (!$fileExists) {
+      $fileUploadUri = Url::fromRoute('cdesai_migrate.settings')->getInternalPath();
+      throw new MigrateException('Upload required source files at ' . $fileUploadUri);
+    }
+  }
+
+  /**
+   * Retrieves paragraph content files from the archive.
+   *
+   * @throws \Drupal\migrate\MigrateException
+   */
+  private function getParagraphContentFiles(string $archive_file): array {
+    $contentFiles = [];
+    $extractedDir = $this->extractArchiveFile($archive_file);
+    /** @var \Drupal\Core\File\FileSystem $fileSystem */
+    $fileSystem = \Drupal::service('file_system');
+    $files = $fileSystem->scanDirectory($extractedDir, '/.*txt/');
+    if (empty($files)) {
+      throw new MigrateException('There was an issue extracting files form ' . $archive_file);
+    }
+
+    foreach ($files as $file) {
+      $key = substr($file->filename, 0, strlen($file->filename) - 4);
+      $contentFiles[$key] = $file->uri;
+    }
+
+    return $contentFiles;
+  }
+
+  /**
+   * Extract the archive in a temp directory.
+   *
+   * @param string $filepath
+   *   The file path.
+   *
+   * @return string
+   *   The temp directory path containing the extracted archive file.
+   */
+  private function extractArchiveFile(string $filepath): string {
+    /** @var \Drupal\Core\Archiver\ArchiverInterface $archiver */
+    $archiveManager = \Drupal::service('plugin.manager.archiver');
+    $tempPath = "";
+
+    // CODE REDACTED
+
+    return 'temporary://' . $tempPath;
+  }
+
+  /**
+   * Extract page data from CSV source files.
+   *
+   * @return array
+   *   An associative array containing page data.
+   */
+  private function extractPageData(): array {
+    $pages = [];
+
+    // CODE REDACTED
+
+    return $pages;
+  }
+
+}