document option '-F'

[openldap] / servers / slapd / back-relay / README

diff --git a/servers/slapd/back-relay/README b/servers/slapd/back-relay/README
index ce781d303ddaee845118077c1128e727c75dd800..81f152c53cfd5c602581739b48a8b427f3e86556 100644 (file)
--- a/servers/slapd/back-relay/README
+++ b/servers/slapd/back-relay/README
@@ -1,24 +1,83 @@
-Relay backend automatically sets up a rewrite-remap overlay that maps 
-the virtual naming context to a real naming context that is available
-in the same server
+Relay backend sets up a relay virtual database that allows
+to access other databases in the same instance of slapd
+through different naming contexts and remapping attribute 
+values.
+
+The DN rewrite, filter rewrite and attributeType/objectClass
+mapping is done by means of the rewrite-remap overlay.
+
+The database containing the real naming context can be
+explicitly selected by means of the "relay" directive,
+which must contain the naming context of the target 
+database.  This also causes the rewrite-remap overlay 
+to be automatically instantiated.  If the optional keyword 
+"massage" is present, the rewrite-remap overlay is 
+automatically configured to map the virtual to the real 
+naming context and vice-versa.
+
+Otherwise, the rewrite-remap overlay must be explicitly
+instantiated, by using the "overlay" directive, as 
+illustrated below.  This allows much more freedom in target 
+database selection and DN rewriting.
+
+If the "relay" directive is not present, the backend is
+not bound to a single target database; on the contrary,
+the target database is selected on a per-operation basis.
+
+This allows, for instance, to relay one database for 
+authentication and anotheir for search/modify, or allows
+to use one target for persons and another for groups
+and so on.
+
+To summarize: the "relay" directive:
+- explicitly bounds the database to a single database 
+  holding the real naming context;
+- automatically instantiates the rewrite-remap overlay;
+- automatically configures the naming context massaging
+  if the optional "massage" keyword is added
+
+If the "relay" directive is not used, the rewrite-remap
+overlay must be explicitly instantiated and the massaging
+must be configured, either by using the "suffixmassage"
+directive, or by issuing more sophisticate rewrite 
+instructions.
+
+AttributeType/objectClass mapping must be explicitly
+required.
+
+Note that the rewrite-remap overlay is not complete nor 
+production- ready yet.
+Examples are given of all the suggested usages. 
 
 # automatically massage from virtual to real naming context
 database       relay
 suffix         "dc=virtual,dc=naming,dc=context"
+relay          "dc=real,dc=naming,dc=context" massage
+
+# explicitly massage (same as above)
+database       relay
+suffix         "dc=virtual,dc=naming,dc=context"
 relay          "dc=real,dc=naming,dc=context"
+suffixmassage  "dc=virtual,dc=naming,dc=context" \
+                       "dc=real,dc=naming,dc=context"
 
-# explicitly massage
+# explicitly massage (same as above, but dynamic backend resolution)
 database       relay
 suffix         "dc=virtual,dc=naming,dc=context"
 overlay                rewrite-remap
-suffixmassage  "dc=virtual,dc=naming,dc=context" "dc=real,dc=naming,dc=context"
+suffixmassage  "dc=virtual,dc=naming,dc=context" \
+                       "dc=real,dc=naming,dc=context"
 
-# old fashioned suffixalias...
+# old fashioned suffixalias, applied also to DN-valued attributes
+# from virtual to real naming context, but not the reverse...
 database       relay
 suffix         "dc=virtual,dc=naming,dc=context"
-overlay                rewrite-remap
-rewriteEngine  on
+relay          "dc=real,dc=naming,dc=context"
 rewriteContext default
 rewriteRule    "(.*)dc=virtual,dc=naming,dc=context$" \
-                       "\1dc=real,dc=naming,dc=context"
+                       "$1dc=real,dc=naming,dc=context"
+rewriteContext searchFilter
+rewriteContext searchResult
+rewriteContext searchResultAttrDN
+rewriteContext matchedDN