OCO redirection via htaccess

oc/.htaccess

@@ -1,4 +1,34 @@
 Header set Access-Control-Allow-Origin *
 Options +FollowSymLinks
 RewriteEngine on
+
+# OCO [start]
+RewriteRule ^ontology/([0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9])\.(html|xml|json|ttl|nt)$ https://opencitations.github.io/ontology/$1/ontology.$2 [R=303,L]
+RewriteRule ^ontology\.(html|xml|json|ttl|nt)$ https://opencitations.github.io/ontology/current/ontology.$1 [R=303,L]
+
+# Rewrite rule to serve HTML content from the vocabulary URI if requested
+RewriteCond %{HTTP_ACCEPT} html
+RewriteRule ^ontology(/[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9])?$ /oc/ontology$1.html [R=303,L]
+
+# Rewrite rule to serve RDF/XML content from the vocabulary URI if requested
+RewriteCond %{HTTP_ACCEPT} application/rdf\+xml [OR]
+RewriteCond %{HTTP_ACCEPT} application/xml
+RewriteRule ^ontology(/[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9])?$ /oc/ontology$1.xml [R=303,L]
+
+# Rewrite rule to serve Turtle content from the vocabulary URI if requested
+RewriteCond %{HTTP_ACCEPT} text/n3 [OR]
+RewriteCond %{HTTP_ACCEPT} text/turtle
+RewriteRule ^ontology(/[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9])?$ /oc/ontology$1.ttl [R=303,L]
+
+# Rewrite rule to serve Notation3 content from the vocabulary URI if requested
+RewriteCond %{HTTP_ACCEPT} application/n-triples [OR]
+RewriteCond %{HTTP_ACCEPT} text/plain
+RewriteRule ^ontology(/[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9])?$ /oc/ontology$1.nt [R=303,L]
+
+# Rewrite rule to serve JSON-LD content from the vocabulary URI if requested
+RewriteCond %{HTTP_ACCEPT} application/ld\+json [OR]
+RewriteCond %{HTTP_ACCEPT} application/json
+RewriteRule ^ontology(/[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9])?$ /oc/ontology$1.json [R=303,L]
+# OCO [end]
+
 RewriteRule ^(.*)$ http://opencitations.net/$1 [R=302,L]