Relax requirement for ODL feeds to have an OA acquisition link (PP-15…

…30) (#185) The spec defines an OPDS 2 + ODL feed as: - It must be a valid OPDS Feed as defined in OPDS-2 with one difference: - The requirement for the presence of an Acquisition Link is relaxed - Instead, each Publication listed in publications must either contain a licenses subcollection or an Open-Access Acquisition Link (http://opds-spec.org/acquisition/open-access) The requirement that each link be an Open-Access Acquisition Link is overly restrictive, and prevents us from importing mixed OPDS2 and OPDS2 + ODL feeds. We relax that requirement to: - Instead, each Publication listed in publications must either contain a licenses subcollection or an acquisition Link (link that starts with http://opds-spec.org/acquisition).
ThePalaceProject · Aug 1, 2024 · 2c63dc3 · 2c63dc3
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diff --git a/README.md b/README.md
@@ -12,6 +12,26 @@ A parser for the
 [Open Publication Distribution System 2.0 (OPDS 2.0)](https://drafts.opds.io/opds-2.0), and
 [Open Distribution to Libraries 1.0 (ODL)](https://drafts.opds.io/odl-1.0.html) formats.
 
+**Note**: This parser varys from the OPDS 2 + ODL spec in that it allows OPDS 2 + ODL feeds to contain
+non-open access acquisition links.
+
+The spec [defines](https://drafts.opds.io/odl-1.0.html#21-opds-20) an OPDS 2 + ODL feed as:
+
+- It must be a valid OPDS Feed as defined in [[OPDS-2](https://drafts.opds.io/odl-1.0.html#normative-references)] with
+  one difference:
+    - The requirement for the presence of an Acquisition Link is relaxed
+    - Instead, each Publication listed in publications must either contain a licenses subcollection or an Open-Access
+      Acquisition Link (http://opds-spec.org/acquisition/open-access)
+
+The requirement that each link be an Open-Access Acquisition Link is overly restrictive, and prevents us from importing
+mixed OPDS2 and OPDS2 + ODL feeds. We relax the requirement to:
+
+- It must be a valid OPDS Feed as defined in [[OPDS-2](https://drafts.opds.io/odl-1.0.html#normative-references)] with
+  one difference:
+    - The requirement for the presence of an Acquisition Link is relaxed
+    - Instead, each Publication listed in publications must either contain a licenses subcollection or an
+      **Acquisition Link** (http://opds-spec.org/acquisition)
+
 ## Usage
 
 Install the library with `pip`

diff --git a/src/webpub_manifest_parser/odl/semantic.py b/src/webpub_manifest_parser/odl/semantic.py
@@ -108,10 +108,10 @@ def _format_message(
     message="ODL feed '{0}' contains redundant 'navigation' subcollection",
 )
 
-ODL_PUBLICATION_MUST_CONTAIN_EITHER_LICENSES_OR_OA_ACQUISITION_LINK_ERROR = partial(
+ODL_PUBLICATION_MUST_CONTAIN_EITHER_LICENSES_OR_ACQUISITION_LINK_ERROR = partial(
     ODLPublicationSemanticError,
     message="ODL publication '{0}' contains neither 'licenses' subcollection nor "
-    "an Open-Access Acquisition Link (http://opds-spec.org/acquisition/open-access)",
+    "an Acquisition Link (http://opds-spec.org/acquisition)",
 )
 
 ODL_LICENSE_MUST_CONTAIN_SELF_LINK_TO_LICENSE_INFO_DOCUMENT_ERROR = partial(
@@ -195,12 +195,19 @@ def visit(self, node):
         """
         self._logger.debug(f"Started processing {encode(node)}")
 
+        links = node.links or []
+        acquisition_uri = OPDS2LinkRelationsRegistry.ACQUISITION.key
+        acquisition_links = [
+            l
+            for l in links
+            if any([rel.startswith(acquisition_uri) for rel in l.rels or []])
+        ]
+
         if (not node.licenses or len(node.licenses) == 0) and (
-            (not node.links or len(node.links) == 0)
-            or not node.links.get_by_rel(OPDS2LinkRelationsRegistry.OPEN_ACCESS.key)
+            (not node.links or len(node.links) == 0) or (len(acquisition_links) == 0)
         ):
             with self._record_errors():
-                raise ODL_PUBLICATION_MUST_CONTAIN_EITHER_LICENSES_OR_OA_ACQUISITION_LINK_ERROR(
+                raise ODL_PUBLICATION_MUST_CONTAIN_EITHER_LICENSES_OR_ACQUISITION_LINK_ERROR(
                     node=node, node_property=None
                 )
         elif node.licenses:

diff --git a/tests/webpub_manifest_parser/odl/test_semantic.py b/tests/webpub_manifest_parser/odl/test_semantic.py
@@ -22,7 +22,7 @@
     ODL_FEED_MISSING_PUBLICATIONS_SUBCOLLECTION_ERROR,
     ODL_LICENSE_MUST_CONTAIN_CHECKOUT_LINK_TO_LICENSE_STATUS_DOCUMENT_ERROR,
     ODL_LICENSE_MUST_CONTAIN_SELF_LINK_TO_LICENSE_INFO_DOCUMENT_ERROR,
-    ODL_PUBLICATION_MUST_CONTAIN_EITHER_LICENSES_OR_OA_ACQUISITION_LINK_ERROR,
+    ODL_PUBLICATION_MUST_CONTAIN_EITHER_LICENSES_OR_ACQUISITION_LINK_ERROR,
     ODLSemanticAnalyzer,
 )
 from webpub_manifest_parser.opds2 import (
@@ -123,7 +123,7 @@ class ODLSemanticAnalyzerTest(AnalyzerTest):
                 ],
             ),
             (
-                "when_publication_does_not_contain_neither_licenses_nor_oa_link",
+                "when_publication_contains_neither_licenses_nor_acquisition_link",
                 ODLFeed(
                     metadata=OPDS2FeedMetadata(title="test"),
                     links=LinkList(
@@ -146,7 +146,7 @@ class ODLSemanticAnalyzerTest(AnalyzerTest):
                     ),
                 ),
                 [
-                    ODL_PUBLICATION_MUST_CONTAIN_EITHER_LICENSES_OR_OA_ACQUISITION_LINK_ERROR(
+                    ODL_PUBLICATION_MUST_CONTAIN_EITHER_LICENSES_OR_ACQUISITION_LINK_ERROR(
                         node=ODLPublication(
                             metadata=OPDS2PublicationMetadata(title="Publication 1")
                         ),
@@ -155,7 +155,7 @@ class ODLSemanticAnalyzerTest(AnalyzerTest):
                 ],
             ),
             (
-                "when_publication_does_not_contain_neither_licenses_nor_oa_link",
+                "when_publication_contains_neither_licenses_nor_acquisition_link",
                 ODLFeed(
                     metadata=OPDS2FeedMetadata(title="test"),
                     links=LinkList(
@@ -178,7 +178,7 @@ class ODLSemanticAnalyzerTest(AnalyzerTest):
                     ),
                 ),
                 [
-                    ODL_PUBLICATION_MUST_CONTAIN_EITHER_LICENSES_OR_OA_ACQUISITION_LINK_ERROR(
+                    ODL_PUBLICATION_MUST_CONTAIN_EITHER_LICENSES_OR_ACQUISITION_LINK_ERROR(
                         node=ODLPublication(
                             metadata=OPDS2PublicationMetadata(title="Publication 1")
                         ),
@@ -220,6 +220,74 @@ class ODLSemanticAnalyzerTest(AnalyzerTest):
                 ),
                 [],
             ),
+            (
+                "when_publication_does_not_contain_licenses_and_has_an_acquisition_link",
+                ODLFeed(
+                    metadata=OPDS2FeedMetadata(title="test"),
+                    links=LinkList(
+                        [
+                            Link(
+                                href="http://example.com",
+                                rels=[LinkRelationsRegistry.SELF.key],
+                            )
+                        ]
+                    ),
+                    publications=CollectionList(
+                        [
+                            ODLPublication(
+                                metadata=OPDS2PublicationMetadata(
+                                    title="Publication 1"
+                                ),
+                                links=LinkList(
+                                    [
+                                        Link(
+                                            href="http://example.com",
+                                            rels=[
+                                                OPDS2LinkRelationsRegistry.ACQUISITION.key
+                                            ],
+                                        )
+                                    ]
+                                ),
+                            )
+                        ]
+                    ),
+                ),
+                [],
+            ),
+            (
+                "when_publication_does_not_contain_licenses_and_has_an_unknown_acquisition_link",
+                ODLFeed(
+                    metadata=OPDS2FeedMetadata(title="test"),
+                    links=LinkList(
+                        [
+                            Link(
+                                href="http://example.com",
+                                rels=[LinkRelationsRegistry.SELF.key],
+                            )
+                        ]
+                    ),
+                    publications=CollectionList(
+                        [
+                            ODLPublication(
+                                metadata=OPDS2PublicationMetadata(
+                                    title="Publication 1"
+                                ),
+                                links=LinkList(
+                                    [
+                                        Link(
+                                            href="http://example.com",
+                                            rels=[
+                                                f"{OPDS2LinkRelationsRegistry.ACQUISITION.key}/unknown"
+                                            ],
+                                        )
+                                    ]
+                                ),
+                            )
+                        ]
+                    ),
+                ),
+                [],
+            ),
             (
                 "when_license_does_not_contain_self_link_and_borrow_link",
                 ODLFeed(