HTML redirect to Prez UI (#279)

* Enable HTML redirects through PREZ_UI_URL

* Redirect unknown resources to Prez UI /object

* Fix whitespace

* Use /404 for not found

prez/config.py

@@ -84,6 +84,7 @@ class Settings(BaseSettings):
     configuration_mode: bool = False
     temporal_predicate: Optional[URIRef] = SDO.temporal
     endpoint_to_template_query_filename: Optional[Dict[str, str]] = {}
+    prez_ui_url: Optional[str] = None
 
     @field_validator("prez_version")
     @classmethod

prez/services/link_generation.py

@@ -25,13 +25,14 @@
 log = logging.getLogger(__name__)
 
 
-async def add_prez_links(graph: Graph, repo: Repo, endpoint_structure):
+async def add_prez_links(graph: Graph, repo: Repo, endpoint_structure, uris: list[URIRef] | None = None):
     """
     Adds internal links to the given graph for all URIRefs that have a class and endpoint associated with them.
     """
     t_start = time.time()
     # get all URIRefs - if Prez can find a class and endpoint for them, an internal link will be generated.
-    uris = [uri for uri in graph.all_nodes() if isinstance(uri, URIRef)]
+    if uris is None:
+        uris = [uri for uri in graph.all_nodes() if isinstance(uri, URIRef)]
     uri_to_klasses = {}
     t = time.time()
     # for uri in uris:

prez/services/objects.py

@@ -1,10 +1,12 @@
 import io
 import json
 import logging
+import re
 import time
+import urllib.parse
 from urllib.parse import urlencode
 
-from fastapi.responses import PlainTextResponse
+from fastapi.responses import PlainTextResponse, RedirectResponse
 from rdf2geojson import convert
 from rdflib import RDF, URIRef, RDFS
 from rdflib.namespace import GEO
@@ -89,6 +91,17 @@ async def object_function(
     query_start_time = time.time()
     item_graph, _ = await data_repo.send_queries([query], [])
     log.debug(f"Query time: {time.time() - query_start_time}")
+    if settings.prez_ui_url:
+        # If HTML or no specific media type requested
+        if pmts.requested_mediatypes[0][0] in ('text/html', '*/*'):
+            item_uri = URIRef(profile_nodeshape.focus_node.value)
+            await add_prez_links(item_graph, data_repo, endpoint_structure, [item_uri])
+            prez_link = item_graph.value(subject=item_uri, predicate=URIRef("https://prez.dev/link"), any=True)
+            prez_ui_url = re.sub(r'/+$', '', settings.prez_ui_url)
+            if prez_link:
+                return RedirectResponse(prez_ui_url + str(prez_link))
+            else:
+                return RedirectResponse(prez_ui_url + '/404?uri=' + urllib.parse.quote_plus(item_uri))
     if "anot+" in pmts.selected["mediatype"]:
         await add_prez_links(item_graph, data_repo, endpoint_structure)
     return await return_from_graph(