# `ldap_index(options, [goptions], callback)`

Create new [index](index) for the OpenLDAP server.   

This implementation currently doesn't execute remote SSH commands. Instead, it
connects directly to the LDAP database and thus requires a specific port to be
accessible.   

## Options

*   `indexes`   
    Object with keys mapping to indexed attributes and values mapping to indices
    ("pres", "approx", "eq", "sub" and 'special').   
*   `url`   
    Specify URI referring to the ldap server, alternative to providing an
    [ldapjs client] instance.   
*   `binddn`   
    Distinguished Name to bind to the LDAP directory, alternative to providing
    an [ldapjs client] instance.   
*   `passwd`   
    Password for simple authentication, alternative to providing an
    [ldapjs client] instance.   
*   `ldap`   
    Instance of an pldapjs client][ldapclt], alternative to providing the `url`,
    `binddn` and `passwd` connection properties.   
*   `unbind`   
    Close the ldap connection, default to false if connection is an
    [ldapjs client][ldapclt] instance.   
*   `name`   
    Distinguish name storing the "olcAccess" property, using the database adress
    (eg: "olcDatabase={2}bdb,cn=config").   
*   `overwrite`   
    Overwrite existing "olcAccess", default is to merge.   

## Example

```js
require('mecano/alt/ldap_index')({
  url: 'ldap://openldap.server/',
  binddn: 'cn=admin,cn=config',
  passwd: 'password',
  name: 'olcDatabase={2}bdb,cn=config',
  indexes: {
    krbPrincipalName: 'sub,eq'
  }
}, function(err, modified){
  console.log(err ? err.message : "Index modified: " + !!modified);
});
```

    module.exports = (goptions, options, callback) ->
      wrap arguments, (options, next) ->
        client = null
        updated = false
        connect = ->
          # if options.ldap instanceof ldap_client
          if options.ldap?.url?.protocol?.indexOf('ldap') is 0
            client = options.ldap
            return get()
          # Open and bind connection
          client = ldap.createClient url: options.url
          client.bind options.binddn, options.passwd, (err) ->
            return end err if err
            get()
        get = ->
          client.search 'olcDatabase={2}bdb,cn=config',
              scope: 'base'
              attributes: ['olcDbIndex']
          , (err, search) ->
            olcDbIndex = null
            search.on 'searchEntry', (entry) ->
              olcDbIndex = entry.object.olcDbIndex
            search.on 'end', ->
              parse olcDbIndex
        parse = (arIndex) ->
          indexes = {}
          for index in arIndex
            [k,v] = index.split ' '
            indexes[k] = v
          do_diff indexes
        do_diff = (orgp) ->
          unless options.overwrite
            newp = misc.merge {}, orgp, options.indexes
          else
            newp = options.indexes
          okl = Object.keys(orgp).sort()
          nkl = Object.keys(newp).sort()
          for i in [0...Math.min(okl.length, nkl.length)]
            if i is okl.length or i is nkl.length or okl[i] isnt nkl[i] or orgp[okl[i]] isnt newp[nkl[i]]
              updated = true
              break
          if updated then stringifiy newp else unbind()
        stringifiy = (perms) ->
          indexes = []
          for k, v of perms
            indexes.push "#{k} #{v}"
          replace indexes
        replace = (indexes) ->
          change = new ldap.Change
            operation: 'replace'
            modification:
              olcDbIndex: indexes
          client.modify options.name, change, (err) ->
            unbind err
        unbind = (err) ->
          # return end err if options.ldap instanceof ldap_client and not options.unbind
          return end err if options.ldap?.url?.protocol?.indexOf('ldap') is 0 and not options.unbind
          client.unbind (e) ->
            return next e if e
            end err
        end = (err) ->
          next err, updated
        connect()

## Dependencies

    ldap = require 'ldapjs'
    misc = require '../misc'
    wrap = require '../misc/wrap'

[index]: http://www.zytrax.com/books/ldap/apa/indeces.html