add record links to ogc-api records item (geopython#880)

* add record links to ogc-api records item

* Update records.py

---------

Co-authored-by: Genuchten <paul.vangenuchten@wur.nl>
Co-authored-by: Tom Kralidis <tomkralidis@gmail.com>

pycsw/ogc/api/records.py

@@ -33,7 +33,7 @@
 import json
 import logging
 import os
-from urllib.parse import urlencode
+from urllib.parse import urlencode, quote
 
 from pygeofilter.parsers.ecql import parse as parse_ecql
 from pygeofilter.parsers.cql2_json import parse as parse_cql2_json
@@ -1129,6 +1129,19 @@ def record2json(record, url, collection, stac_item=False):
 
             rdl.append(link2)
 
+    for lnk in [record.parentidentifier, record.relation]:
+        if lnk and len(lnk.strip()) > 0:
+            if not lnk.startswith('http'):
+                lnk = f"{url}/collections/{collection}/items/{quote(lnk)}"
+            record_dict['links'].append({
+                'rel': 'related',
+                'href': lnk,
+                'name': 'related record',
+                'description': 'related record',
+                'type': 'application/json'
+            })
+
+
     record_dict['links'].append({
         'rel': 'collection',
         'type': 'application/json',