How to clean up nicely

[hardillb]

Calling client.search(base,opts, function(err, res){}) with a malformed filter (e.g. (uid=)) means you can't clean up the client connection without triggering an error as the outstanding search message's error callback is triggered.

When client.ubind() called there is still a message on the queue. Has the search not returned an err then I could have used the messageID with client.abandon() but I can't see how to clear the message queue without an id.

Example

const ldapjs = require('ldapjs');

let client = ldapjs.createClient({
	url: "ldap://ldap.forumsys.com"
})

client.on('close', function(){
	console.log("connection closed")
})

client.on('connect', function(){
	console.log("connected")

  const options = {
    filter: 'uid=',
    scope: 'sub'
  }


  client.search("dc=example,dc=com",options, function(err, res) {
    if (err) {
      console.log(err)
      client.unbind();
    } else {
      res.on('searchEntry', function(entry){

      })
      res.on('error', function(error){

      })
      res.on('end', function(result){

      })
    }
  });
})

[jsumners]

The unbind() will terminate the connection to the LDAP server. Therefore, no new messages will be received. What else should be done?

[hardillb]

It's been a LONG time since I raised this, but I think my problem is that calling client.unbind() as part of dealing with the search error triggers the callback a second time again with a different error. I have updated the testcase again to show the problem a little clearer.

const ldapjs = require('ldapjs');
let client = ldapjs.createClient({
	url: "ldap://ldap.forumsys.com"
})

client.on('close', function(){
	console.log("connection closed")
})

client.on('connect', function(){
	console.log("connected")

  const options = {
    filter: 'uid=',
    scope: 'sub'
  }

  client.search("dc=example,dc=com",options, function(err, res) {
    if (err) {
      console.log("Error in search callback")
      console.log(err)
      try {
        console.log("calling unbind")
        client.unbind();
      } catch (error) {
        console.log("second error")
        console.log(error)
      }
    } else {
      res.on('searchEntry', function(entry){

      })
      res.on('error', function(error){

      })
      res.on('end', function(result){

      })
    }
  });
})

Which give the following output:

connected
Error in search callback
AssertionError [ERR_ASSERTION]: The expression evaluated to a falsy value:

  assert.ok(len)

    at Writer._ensure (/home/hardillb/temp/ldap/node_modules/asn1/lib/ber/writer.js:298:10)
    at Writer.writeBuffer (/home/hardillb/temp/ldap/node_modules/asn1/lib/ber/writer.js:157:8)
    at EqualityFilter._toBer (/home/hardillb/temp/ldap/node_modules/ldapjs/lib/filters/equality_filter.js:57:7)
    at EqualityFilter.toBer (/home/hardillb/temp/ldap/node_modules/ldapjs/lib/filters/filter.js:51:16)
    at SearchRequest._toBer (/home/hardillb/temp/ldap/node_modules/ldapjs/lib/messages/search_request.js:122:11)
    at SearchRequest.LDAPMessage.toBer (/home/hardillb/temp/ldap/node_modules/ldapjs/lib/messages/message.js:93:36)
    at Client._sendSocket (/home/hardillb/temp/ldap/node_modules/ldapjs/lib/client/client.js:1278:31)
    at Client._send (/home/hardillb/temp/ldap/node_modules/ldapjs/lib/client/client.js:1169:17)
    at sendRequest (/home/hardillb/temp/ldap/node_modules/ldapjs/lib/client/client.js:611:17)
    at Client.search (/home/hardillb/temp/ldap/node_modules/ldapjs/lib/client/client.js:640:5) {
  generatedMessage: true,
  code: 'ERR_ASSERTION',
  actual: 0,
  expected: true,
  operator: '=='
}
calling unbind
connection closed
Error in search callback
ConnectionError: 1__ldap://ldap.forumsys.com closed
    at /home/hardillb/temp/ldap/node_modules/ldapjs/lib/client/client.js:1083:17
    at /home/hardillb/temp/ldap/node_modules/ldapjs/lib/client/message-tracker/index.js:113:7
    at Map.forEach (<anonymous>)
    at Object.purgeMessages [as purge] (/home/hardillb/temp/ldap/node_modules/ldapjs/lib/client/message-tracker/index.js:110:14)
    at Client._onClose (/home/hardillb/temp/ldap/node_modules/ldapjs/lib/client/client.js:1081:11)
    at Object.onceWrapper (node:events:640:26)
    at Socket.emit (node:events:520:28)
    at TCP.<anonymous> (node:net:687:12) {
  lde_message: '1__ldap://ldap.forumsys.com closed',
  lde_dn: null
}
calling unbind

Why is the search callback being triggered twice?

[jsumners]

🤔

Likely a bug. If I'm not mistaken, there's an internal tracking of pending messages. This queue could be emptied in the unbind invocation prior to actually sending the unbind message. But I could be mis-remembering things.

Ideally, we'd add a failing integration test in out integration suite and solve from there.

[jsumners]

👋

On February 22, 2023, we released version 3 of this library. As a result, we are closing this issue/pull request.

Please see issue #839 for more information, including how to proceed if you feel this closure is in error.