Migrate Process File

This is a Migrate process[1] that imports files into Drupal as a side-effect of a migration. It takes a URL as input, downloads the file at that URL, and yields the ID of the newly-created file.

There is an example of using this process in the migrate_process_file_example module. The simplest way to use it is in your migration YAML file, like so:

id: my_migration
...
process:
  field_image:
    - source: uri_field
      plugin: migrate_process_file

[1] https://www.drupal.org/node/2129651

Caveats

The following abilities would be useful, but are not built-in:

• Error handling
• Multiple item handling ("handles_multiples")
• An option to not download a file if it already exists
• An option to choose a non-conflicting filename, if the destination exists
• An option for the new file's destination
• Rollback of imported files
• Dependency injection and unit tests

Also, none of this is tested at all in Drupal 8.1.