Working onand , I believe many of the common needs of XML and JSON sources (and down the line, other sources like file directories) can be addressed with common base classes and interfaces:
- Specifying custom headers on a request
- Migrating from multiple specific files/URLs
- Paging through multiple requests ("next" links)
- Common specification of fields and IDs
migrate_plus seems like the natural place for the common framework, from which specific source plugins in their own modules can inherit.