1. NaviServer
  2. NaviServer Project
  3. nsldap

Overview

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# LDAP client library for NaviServer #

This is nsldap, an LDAP module for NaviServer. What this module does
is provide a new command (nsldap) inside the Tcl Interpreter in
NaviServer that implements a subset of the LDAP functionality.

The module is modelled after the DB API of NaviServer in the sense
that you define "pools" in your config file for NaviServer and then
get "handles" to the connections allowed in those pools from your
code.

The actual LDAP API is modelled after sensus consulting's ldap
extensions for Tcl. It is described later in this document.

Version: 0.9


A NOTE ABOUT ORACLE
-------------------

Oracle 8i provides an ldap implementation within the client
libraries which is not entirely compatible with OpenLDAP 
semantics. If you're running an NaviServer that uses the ora8.so
module (provided by ArsDigita) and you run into trouble with
nsldap.so (coredumping the nsd program in an ns_ldap add operation
for example) you should apply the following workaround courtesy
of Otto Solares <solca@galileo.edu>

WORKAROUND FOR RUNNING NSLDAP WITH ORACLE
-----------------------------------------
The problem is that the NaviServer nsd program loads the db drivers
first and then the rest of the modules. On some operating systems,
Solaris for instance, the dynamic linker resolves the symbols with
the first library that contains them. Since the libclntcsh provided
with oracle provides an implementation of all the LDAP API that
collides with OpenLDAP's API provided with libldap and liblber 
(which are linked with nsldap.so) the dynamic linker uses the Oracle
provided functions which are not fully compatible with nsldap.

As a workaround you can link the nsd (nsd8x or nsd7) binary directly
with OpenLDAP libraries to force the dynamic linker to resolve the
symbols using libldap and liblber. To do this, simply modify the
Makefile.global (in naviserver's include subdirectory) and change
the line

   LIBS+=-lsocket -lnsl -ldl -lposix4 -lthread -lresolv -R $(RPATH)

with

   LIBS+=-lsocket -lnsl -ldl -lposix4 -lthread -lresolv -lldap -llber -R $(RPATH)

where appropriate for your Operating System.

Configuring the nsldap Module in NaviServer's config.tcl file
------------------------------------------------------------

In order to use the ns_ldap command you should first configure the
pools in your NaviServer's config.tcl file. This is the file that you
pass to the nsd binary in the Command Line when you start it up. Note
that this is *after* compiling an installing the nsldap.so module.

You should add the following lines: 

   ns_section "ns/server/${servername}/modules"
   ns_param   nsldap          ${bindir}/nsldap.so

   # 
   # ldap pool ldap
   #

   ns_section "ns/ldap/pool/ldap"
   ns_param user "cn=Manager, o=Universidad Galileo"
   ns_param password "YourPasswordHere"
   ns_param host "ldap.galileo.edu"
   ns_param connections 1
   ns_param verbose On

   # 
   # ldap pools
   #
   ns_section "ns/ldap/pools"
   ns_param ldap ldap

   #
   # ldap default pool
   #
   ns_section "ns/server/${servername}/ldap"
   ns_param Pools *
   ns_param DefaultPool ldap

If you look at this carefully you'll see it's almost the same as the
database pools.


Application Programmer's Interface (API)
----------------------------------------

This module provides a new command called ns_ldap which is modelled
after the ns_db command in some respects.

ns_ldap pools

  - Gives the list of available pools

ns_ldap bouncepool <poolname>

  - Closes all handles on the Pool

ns_ldap gethandle ?-timeout timeout? ?pool? ?nhandles?  

  - gets a ?nhandles? handles from pool ?pool? or the defaultpool
  defined in the config file if ?pool? is omitted. If ?nhandles? is
  omitted, 1 handle is returned.
    
  An optional timeout ?timeout? can be specified.

ns_ldap poolname $ldaph

  - Returns the name of the pool referenced by the handle $ldaph

ns_ldap password $ldaph

  - Returns the password used to bind to the pool referenced by $ldaph

ns_ldap user $ldaph

  - Returns the BindDN used to bind to the pool referenced by $ldaph

ns_ldap host $ldaph

  - Returns the host to which the pool referenced by $ldaph is bound

ns_ldap disconnect $ldaph

  - Disconnects the pool referenced by $ldaph

ns_ldap releasehandle $ldaph

  - Releases the handle referenced by $ldaph (which was obtained using ns_ldap gethandle)

ns_ldap connected $ldaph

  - Checks if the handle $ldaph references a pool that is connected.

ns_ldap add $ldaph dn ?attr value?

  - Adds an object to the LDAP directory using the handle $ldaph.
  - dn is the DN of the object to be added
  - Pairs ?attr value? can be specified to set attributes to
  values. If the attribute is multivalued, a Tcl list can be provided.

ns_ldap compare $ldaph dn attr value

  - Issues a compare, returns 1 (true) if attr matches value, 0
  otherwise.

ns_ldap delete $ldaph dn

  - removes the object referenced by dn from the ldap tree. Most
  directories will not allow you to delete an object that has
  children.

ns_ldap modify $ldaph ?add: fld valList ...? ?mod: fld valList ...? ?del: fld valList ...?

  - modifies an entry in the directory. This is best shown by an example.
    The following adds two objectclass attributes, deletes the junkAttr
    attribute and replaces any existing cn attributes with the single value
    "Foo Bar": 

    ns_ldap modify $ldaph $dn add: objectclass [list person inetOrgPerson] del: junkAttr mod: cn [list "Foo Bar"]

ns_ldap modrdn $ldaph dn rdn ?deloldrdn?

  - renames an object (changes the rdn).

ns_ldap search $ldaph ?-scope [base onelevel subtree]? ?-attrs bool? ?-names bool? base ?filter?

  - perhaps the most useful command. it searches the LDAP tree for particular
    entries. Returns a list of entries where each entry is in itself a list
    of attr value pairs. This is suitable for use with array set. The values
    associated with the attr are a Tcl list since attributes can have multiple
    values.

    If no filter is provided, the default filter (objectclass=*) is used.
    If attribute names are provided after the filter, only the named 
    attributes will be returned. The available options are:

    -attrs bool 
       Returns only the names of the attributes in the matching objects.
       When this is true, the returned list contains lists in which the
       first entry is the dn of the matched object and the subsequent fields
       are the matched attributes.
       (default: false)

    -names bool
       Returns only the dn names of the matching objects. When this is true
       the returned list contains all matched dn's as elements.
       (default: false)

    -scope enum
       Specifies the scope of the search. Can be base, one, or sub.
       (default: base)