21.05.2026 | Lothar Ferreira Neumann

Aggregate heterogeneous media fields for structured Drupal migration

migration_field_merge.yml

  field_media:
    - plugin: merge
      source:
        - field_image
        - field_images
    - plugin: sub_process
      process:
        target_id:
          - plugin: migration_lookup
            source: fid
            migration:
              - my_migration_media_image

Issue:

You want to combine multiple image fields from a legacy system into a single media field in a new Drupal system during migration.

Solution:

The code uses the migration API of Drupal to merge multiple source image fields into a single media field. It employs the merge plugin to combine the fields and a sub-process to transform the references into media entities using a migration lookup.

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Weitere DevBits

15.01.2026 | Lothar Ferreira Neumann

How to migrate latitude & longitude geodata into a unified geocode field

geofield_migration.yml

field_geofield:
  plugin: geofield_latlon
  source:
    - field_latitude
    - field_longitude

yml

geodata

Migration

13.11.2025 | Lothar Ferreira Neumann

How to place HTML elements into webforms via the Source tab

You can add headlines to a webform using the code below. To get to the source section, navigate to the form you want to alter, click on build and then on the source tab like in the screenshot.

Screenshot of the menu to add code to webform

This is just a short example on how to add a headline.

webform_headline.yml

personal_data:
  '#type': html_tag
  '#tag': h3
  '#value': 'Personal data'

It will look something like this:

yml

html

manipulating forms

backend