Merge pull request #365 from ResearchObject/legacy-root-finder

Remove heuristic for nested ro-crate metadata files

docs/_specification/1.2-DRAFT/appendix/changelog.md

@@ -29,6 +29,7 @@ excerpt: List of changes in releases of this specifications
 # APPENDIX: Changelog
 
 * RO-Crate 1.2.0
+  * Clarified that the [RO-Crate Metadata Descriptor MUST have `@id` of `ro-crate-metadata.json`](../root-data-entity#ro-crate-metadata-descriptor) by removing conflicting statements elsewhere in the specification [#365](https://github.com/ResearchObject/ro-crate/pull/365)
   * Updated the Bioschemas namespace for properties from `https://bioschemas.org/ComputationalWorkflow#` to `https://bioschemas.org/properties/`. This change affects only the `input` and `output` properties in the [JSON-LD context](../ro-crate-metadata.json).
   * **Change**: Replaced [name-based algorithm for finding root](../root-data-entity.html#finding-the-root-data-entity)  [#198](https://github.com/ResearchObject/ro-crate/issues/198) [#365](https://github.com/ResearchObject/ro-crate/pull/365)
   * Updated [algorithm to always use string filter to find root](../appendix/relative-uris.html#finding-ro-crate-root-in-rdf-triple-stores)  [#189](https://github.com/ResearchObject/ro-crate/issues/189)

docs/_specification/1.2-DRAFT/root-data-entity.md

@@ -79,11 +79,6 @@ start with `https://w3id.org/ro/crate/`.
 > The `conformsTo` property MAY be an array, to additionally indicate 
 specializing [RO-Crate profiles](profiles).
 
-If the root data entity `@id` is an absolute URI, the RO-Crate is considered
-web-based: in this case, the metadata descriptor SHOULD also have an absolute
-URI as its `@id`, which MUST have `ro-crate-metadata.json` (or
-`ro-crate-metadata.jsonld` in legacy crates) as its last path segment.
-
 ### Finding the Root Data Entity
 
 In most cases, consumers processing the RO-Crate as a JSON-LD graph can thus
@@ -110,54 +105,6 @@ metadata_entity = entity_map["ro-crate-metadata.json"]
 root_entity = entity_map[metadata_entity["about"]["@id"]]
 ```
 
-More generally, the metadata id can be a URI whose last path segment is
-`ro-crate-metadata.json`, so the above lookup can fail in non-conforming crates, 
-e.g. a JSON-LD file that has imported an RO-Crate using Linked Data mechanisms.
-
-In this case we can look for the root entity by executing a 
-heuristic algorithm similar to the one shown above,
-with the only difference that step 2 must be replaced by:
-
-2. .. if the `@id`'s last path segment is `ro-crate-metadata.json`
-
-It is possible to build an RO-Crate having more than one entity whose `@id`
-has `ro-crate-metadata.json` as its last path segment. For instance, the crate
-could reference a collection of sample _RO-Crate metadata file_s available from
-different web sites, or from the same web site but at different locations. In
-order to facilitate consumption, data entities representing such files SHOULD
-NOT have an `about` property pointing to a [Dataset] in the crate, so they can
-be told apart from the actual Metadata Descriptor. A scenario that can
-potentially lead to confusion is when a dataset in the crate is itself an
-RO-Crate (_nested_ RO-Crate): again, the crate could be a collection of
-RO-Crate examples. In this case, the top-level crate SHOULD NOT list any files
-or directories belonging to the nested crates, but only the nested crates
-themselves as [Dataset] entries. For instance:
-
-```json
-{
-  "@context": "https://w3id.org/ro/crate/1.2-DRAFT/context",
-  "@graph": [
-    {
-      "@id": "http://example.org/crate/ro-crate-metadata.json",
-      "@type": "CreativeWork",
-      "about": {"@id": "http://example.org/crate/"},
-      "conformsTo": {"@id": "https://w3id.org/ro/crate/1.2-DRAFT"}
-    },
-    {
-      "@id": "http://example.org/crate/",
-      "@type": "Dataset",
-      "hasPart": [
-        {"@id": "http://example.org/crate/nested/"}
-      ]
-    },
-    {
-      "@id": "http://example.org/crate/nested/",
-      "@type": "Dataset"
-    }
-  ]
-}
-```
-
 See also the appendix on
 [finding RO-Crate Root in RDF triple stores](appendix/relative-uris#finding-ro-crate-root-in-rdf-triple-stores).