node-ldapjs/docs/client.md

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ldapjs Client API

This document covers the ldapjs client API and assumes that you are familiar with LDAP. If you're not, read the guide first.

Create a client

The code to create a new client looks like:

var ldap = require('ldapjs');
var client = ldap.createClient({
  url: 'ldap://127.0.0.1:1389'
});

You can use ldap:// or ldaps://; the latter would connect over SSL (note that this will not use the LDAP TLS extended operation, but literally an SSL connection to port 636, as in LDAP v2). The full set of options to create a client is:

||url|| a valid LDAP url.|| ||socketPath|| If you're running an LDAP server over a Unix Domain Socket, use this.|| ||log|| You can optionally pass in a bunyan instance the client will use to acquire a logger. The client logs all messages at the trace level.|| ||timeout||How long the client should let operations live for before timing out. Default is Infinity.|| ||connectTimeout||How long the client should wait before timing out on TCP connections. Default is up to the OS.|| ||maxConnections||Whether or not to enable connection pooling, and if so, how many to maintain.||

If using connection pooling, you can additionally pass in:

||bindDN||The DN all connections should be bound as.|| ||bindCredentials||The credentials to use with bindDN.|| ||checkInterval||How often to schedule health checks.|| ||maxIdleTime||How long a client can sit idle before initiating a health check (subject to the frequency set by checkInterval).||

Connection management

As LDAP is a stateful protocol (as opposed to HTTP), having connections torn down from underneath you is difficult to deal with. That said, the "raw" client, which is what you get when maxConnections is either unset or <= 1, does not do anything for you here; you can handle that however you want.

More commonly, you probably want to use connection pooling, which performs health checks, and while you will see occasional errors from a client, those will be highly transient, as the pooling logic will purge them and create new ones for you.

It is highly recommended you just provide bindCredentials initially, as all clients used will be authenticated, but you can call bind at any given time. This is expensive though, as the pool must first drain, be destroyed, and then recreated. So try not to do that.

Common patterns

The last two parameters in every API are controls and callback. controls can be either a single instance of a Control or an array of Control objects. You can, and probably will, omit this option.

Almost every operation has the callback form of function(err, res) where err will be an instance of an LDAPError (you can use instanceof to switch). You probably won't need to check the res parameter, but it's there if you do.

bind

bind(dn, password, controls,callback)

Performs a bind operation against the LDAP server.

The bind API only allows LDAP 'simple' binds (equivalent to HTTP Basic Authentication) for now. Note that all client APIs can optionally take an array of Control objects. You probably don't need them though...

If you have more than 1 connection in the connection pool, you will be called back after all of the connections are bound, not just the first one.

Example:

client.bind('cn=root', 'secret', function(err) {
  assert.ifError(err);
});

add

add(dn, entry, controls, callback)

Performs an add operation against the LDAP server.

Allows you to add an entry (which is just a plain JS object), and as always, controls are optional.

Example:

var entry = {
  cn: 'foo',
  sn: 'bar',
  email: ['foo@bar.com', 'foo1@bar.com'],
  objectclass: 'fooPerson'
};
client.add('cn=foo, o=example', entry, function(err) {
  assert.ifError(err);
});

compare

compare(dn, attribute, value, controls, callback)

Performs an LDAP compare operation with the given attribute and value against the entry referenced by dn.

Example:

client.compare('cn=foo, o=example', 'sn', 'bar', function(err, matched) {
  assert.ifError(err);

  console.log('matched: ' + matched);
});

del

del(dn, controls, callbak)

Deletes an entry from the LDAP server.

Example:

client.del('cn=foo, o=example', function(err) {
  assert.ifError(err);
});

exop

exop(name, value, controls, callback)

Performs an LDAP extended operation against an LDAP server. name is typically going to be an OID (well, the RFC says it must be; however, ldapjs has no such restriction). value is completely arbitrary, and is whatever the exop says it should be.

Example (performs an LDAP 'whois' extended op):

client.exop('1.3.6.1.4.1.4203.1.11.3', function(err, value, res) {
  assert.ifError(err);

  console.log('whois: ' + value);
});

modify

modify(name, changes, controls, callback)

Performs an LDAP modify operation against the LDAP server. This API requires you to pass in a Change object, which is described below. Note that you can pass in a single Change or an array of Change objects.

Example:

var change = new ldap.Change({
  operation: 'add',
  modification: {
    pets: ['cat', 'dog']
  }
});

client.modify('cn=foo, o=example', change, function(err) {
  assert.ifError(err);
});

Change

A Change object maps to the LDAP protocol of a modify change, and requires you to set the operation and modification. The operation is a string, and must be one of:

||replace||Replaces the attribute referenced in modification. If the modification has no values, it is equivalent to a delete.|| ||add||Adds the attribute value(s) referenced in modification. The attribute may or may not already exist.|| ||delete||Deletes the attribute (and all values) referenced in modification.||

modification is just a plain old JS object with the values you want.

modifyDN

modifyDN(dn, newDN, controls, callback)

Performs an LDAP modifyDN (rename) operation against an entry in the LDAP server. A couple points with this client API:

• There is no ability to set "keep old dn." It's always going to flag the old dn to be purged.
• The client code will automagically figure out if the request is a "new superior" request ("new superior" means move to a different part of the tree, as opposed to just renaming the leaf).

Example:

client.modifyDN('cn=foo, o=example', 'cn=bar', function(err) {
  assert.ifError(err);
});

search

search(base, options, controls, callback)

Performs a search operation against the LDAP server.

The search operation is more complex than the other operations, so this one takes an options object for all the parameters. However, ldapjs makes some defaults for you so that if you pass nothing in, it's pretty much equivalent to an HTTP GET operation (i.e., base search against the DN, filter set to always match).

Like every other operation, base is a DN string. Options has the following fields:

||scope||One of base, one, or sub. Defaults to base.|| ||filter||A string version of an LDAP filter (see below), or a programatically constructed Filter object. Defaults to (objectclass=*).|| ||attributes||attributes to select and return (if these are set, the server will return only these attributes). Defaults to the empty set, which means all attributes.|| ||attrsOnly||boolean on whether you want the server to only return the names of the attributes, and not their values. Borderline useless. Defaults to false.|| ||sizeLimit||the maximum number of entries to return. Defaults to 0 (unlimited).|| ||timeLimit||the maximum amount of time the server should take in responding, in seconds. Defaults to 10. Lots of servers will ignore this.||

Responses from the search method are an EventEmitter where you will get a notification for each searchEntry that comes back from the server. You will additionally be able to listen for a searchReference, error and end event. Note that the error event will only be for client/TCP errors, not LDAP error codes like the other APIs. You'll want to check the LDAP status code (likely for 0) on the end event to assert success. LDAP search results can give you a lot of status codes, such as time or size exceeded, busy, inappropriate matching, etc., which is why this method doesn't try to wrap up the code matching.

Example:

var opts = {
  filter: '(&(l=Seattle)(email=*@foo.com))',
  scope: 'sub'
};

client.search('o=example', opts, function(err, res) {
  assert.ifError(err);

  res.on('searchEntry', function(entry) {
    console.log('entry: ' + JSON.stringify(entry.object));
  });
  res.on('searchReference', function(referral) {
    console.log('referral: ' + referral.uris.join());
  });
  res.on('error', function(err) {
    console.error('error: ' + err.message);
  });
  res.on('end', function(result) {
    console.log('status: ' + result.status);
  });
});

Filter Strings

The easiest way to write search filters is to write them compliant with RFC2254, which is "The string representation of LDAP search filters." Note that ldapjs doesn't support extensible matching, since it's one of those features that almost nobody actually uses in practice.

Assuming you don't really want to read the RFC, search filters in LDAP are basically are a "tree" of attribute/value assertions, with the tree specified in prefix notation. For example, let's start simple, and build up a complicated filter. The most basic filter is equality, so let's assume you want to search for an attribute email with a value of foo@bar.com. The syntax would be:

(email=foo@bar.com)

ldapjs requires all filters to be surrounded by '()' blocks. Ok, that was easy. Let's now assume you want to find all records where the email is actually just anything in the "@bar.com" domain, and the location attribute is set to Seattle:

(&(email=*@bar.com)(l=Seattle))

Now our filter is actually three LDAP filters. We have an and filter, an equality filter (the l=Seattle), and a substring filter. Substrings are wildcard filters. Now, let's say we want to also set our filter to include a specification that either the employeeType not be a manager or a secretary:

(&(email=*@bar.com)(l=Seattle)(!(|(employeeType=manager)(employeeType=secretary))))

It gets a little bit complicated, but it's actually quite powerful, and lets you find almost anything you're looking for.

unbind

unbind(callback)

Performs an unbind operation against the LDAP server.

The unbind operation takes no parameters other than a callback, and will unbind (and disconnect) all of the connections in the pool.

Example:

client.unbind(function(err) {
  assert.ifError(err);
});