[DRAFT] Publish collection membership data to purl

[cbeer]

This supports several desirable features in PURL, but most particularly generating IIIF collection manifests for our collections. Before going further I'd like some validation of the approach and some indication this is worth pursuing (over, say, querying purl-fetcher.. which we've resisted in order to keep the PURL application querying static filesystem-based resources instead of those new-fangled databases people keep talking about)

The symlinks from an item to its collection duplicate information from the public xml, but are necessary (in this approach) in order to clean up inbound relationship links from the collection to the items. A separate file or something could be used instead, but this approach struck me as more resilient to potential concurrency issues.

TODO:

• finish writing tests... planning to do it in the integration-test style used everywhere else in the spec except #transfer_metadata (formerly #publish, but the amount of stubbing was killing me)

[ndushay]

wow - this is old. Is it still useful? Can it be closed?