Overcome backwards xl-id form by handling both

common.py

@@ -11,6 +11,7 @@
     context="sys/context/base.jsonld",
     system_base_iri="",
     union="common.jsonld.lines",
+    last_backwards_id_time="2022-10-14T16:26:16Z"
 )
 
 if __name__ == "__main__":

lxltools/datacompiler.py

@@ -33,7 +33,8 @@ def __init__(self, *,
                  context=None,
                  record_thing_link='mainEntity',
                  system_base_iri=None,
-                 union='all.jsonld.lines'):
+                 union='all.jsonld.lines',
+                 last_backwards_id_time=None):
         self.datasets_description = datasets_description
         self.datasets = {}
         self.current_ds_resources = set()
@@ -49,6 +50,11 @@ def __init__(self, *,
         self.current_ds_file = None
         self.no_records = False
 
+        self.last_backwards_id_time = (
+            timeutil.w3c_dtz_to_ms(last_backwards_id_time)
+            if isinstance(last_backwards_id_time, str)
+            else None)
+
         if datasets_description:
             self._handlers_from_datasets_description(datasets_description)
 
@@ -155,7 +161,8 @@ def _compile_dataset(self, name, result):
             data = self.to_jsonld(data)
 
         ds_url = urljoin(self.dataset_id, name)
-        self._create_dataset_description(ds_url, ds_created_ms, ds_modified_ms)
+        self._create_dataset_description(
+            ds_url, ds_created_ms, ds_created_ms=ds_created_ms)
 
         base_id = urljoin(self.dataset_id, base)
 
@@ -172,10 +179,6 @@ def _compile_dataset(self, name, result):
             modified_ms = None
             fpath = urlparse(nodeid).path[1:]
 
-            if self.no_records:
-                self.write(node, fpath)
-                continue
-
             meta = node.pop('meta', None)
             if meta:
                 if 'created' in meta:
@@ -189,10 +192,25 @@ def _compile_dataset(self, name, result):
                     node,
                     created_ms,
                     modified_ms,
-                    datasets=[self.dataset_id, ds_url])
-            self.write(desc, fpath)
+                    datasets=[self.dataset_id, ds_url],
+                    ds_created_ms=ds_created_ms)
+
+            # Keep sameAs "forwards" form in meta even if no_records is used
+            if self.no_records:
+                meta = meta or {}
+                sameas = meta.setdefault('sameAs', [])
+                rec = desc['@graph'][0]
+                if 'sameAs' in rec:
+                    sameas.append({"@id": rec['@id']})
+                for same in rec.get('sameAs', []):
+                    sameas.append(same)
+                node['meta'] = meta
+                self.write(node, fpath)
+            else:
+                self.write(desc, fpath)
 
-    def _create_dataset_description(self, ds_url, created_ms, modified_ms=None, label=None):
+    def _create_dataset_description(self, ds_url, created_ms, modified_ms=None,
+            label=None, ds_created_ms=None):
         if not label:
             label = ds_url.rsplit('/', 1)[-1]
         ds = {
@@ -211,7 +229,7 @@ def _create_dataset_description(self, ds_url, created_ms, modified_ms=None, labe
             return
 
         desc = self._to_node_description(ds, created_ms, modified_ms,
-                datasets={self.dataset_id, ds_url})
+                datasets={self.dataset_id, ds_url}, ds_created_ms=ds_created_ms)
 
         record = desc['@graph'][0]
         if self.tool_id:
@@ -220,14 +238,16 @@ def _create_dataset_description(self, ds_url, created_ms, modified_ms=None, labe
         self.write(desc, ds_path)
 
     def _to_node_description(self, node, created_ms,
-            modified_ms=None, datasets=None):
+            modified_ms=None, datasets=None, ds_created_ms=None):
         assert self.record_thing_link not in node
 
         node_id = node['@id']
 
         record = OrderedDict()
         record['@type'] = 'Record'
-        record['@id'] = self.generate_record_id(created_ms, node_id)
+
+        self.set_record_id(record, created_ms, node_id, ds_created_ms)
+
         record[self.record_thing_link] = {'@id': node_id}
 
         # Add provenance
@@ -241,9 +261,19 @@ def _to_node_description(self, node, created_ms,
 
         return {'@graph': items}
 
-    def generate_record_id(self, created_ms, node_id):
-        # FIXME: backwards_form=created_ms < 2015
-        slug = lxlslug.librisencode(created_ms, lxlslug.checksum(node_id))
+    def set_record_id(self, record, created_ms, node_id, ds_created_ms=None):
+        if ds_created_ms is None:
+            ds_created_ms = created_ms
+        backwards_form = ds_created_ms < self.last_backwards_id_time
+        # TODO: use normal form and keep backwards_form as sameAs until "GC:able"?
+        record['@id'] = self.generate_record_id(created_ms, node_id, backwards_form)
+        if backwards_form:
+            record['sameAs'] = [{'@id': self.generate_record_id(created_ms, node_id)}]
+
+    def generate_record_id(self, created_ms, node_id, backwards_form=False):
+        slug = lxlslug.librisencode(
+            created_ms, lxlslug.checksum(node_id), backwards_form=backwards_form
+        )
         return urljoin(self.system_base_iri, slug)
 
     def write(self, node, name):

lxltools/lxlslug.py

@@ -1,6 +1,5 @@
 #!/usr/bin/env python
-from __future__ import unicode_literals, print_function
-
+from typing import Any
 from zlib import crc32
 import string
 import time
@@ -32,9 +31,12 @@ def rotate(c):
 def checksum(data):
     return crc32(data.encode('utf-8')) & 0xffffffff
 
-def librisencode(a, b):
+def librisencode(a, b, backwards_form=False):
     alphabet = lower_consonants_numbers
-    timepart = "".join(reversed(caesarize(alphabet, tobase(alphabet, a))))
+    chars = caesarize(alphabet, tobase(alphabet, a))
+    if backwards_form:
+        chars = reversed(chars)
+    timepart = "".join(chars)
     codepart = tobase(alphabet, b)
     codelen = len(codepart)
     if codelen < 7:
@@ -53,7 +55,7 @@ def librisencode(a, b):
         print("Usage: %s TIMESTAMP IDENTIFIER" % (cmd), file=sys.stderr)
         exit(1)
 
-    timestamp = args.pop(0)
+    timestamp: Any = args.pop(0)
     identifiers = args
 
     try:

syscore.py

@@ -31,7 +31,8 @@ def _get_repo_version():
                     context='sys/context/base.jsonld',
                     record_thing_link='mainEntity',
                     system_base_iri='',
-                    union='syscore.jsonld.lines')
+                    union='syscore.jsonld.lines',
+                    last_backwards_id_time='2022-11-20T00:00:00Z')
 
 
 @compiler.handler
@@ -145,7 +146,7 @@ def _insert_record(graph, created_ms, dataset_id):
     record = {'@type': 'SystemRecord'}
     record[compiler.record_thing_link] = {'@id': entity['@id']}
     graph.insert(0, record)
-    record['@id'] = compiler.generate_record_id(created_ms, entity['@id'])
+    compiler.set_record_id(record, created_ms, entity['@id'])
     record['inDataset'] = [{'@id': compiler.dataset_id}, {'@id': dataset_id}]