How do I run a ldap query using R?

I've written a function here to parse ldap output into a dataframe, and I used the examples provided as a reference for getting everything going.

I hope it helps someone!

library(RCurl)
library(gtools)

parseldap<-function(url, userpwd=NULL)
{
  ldapraw<-getURL(url, userpwd=userpwd)
  # seperate by two new lines
  ldapraw<-gsub("(DN: .*?)\n", "\\1\n\n", ldapraw)
  ldapsplit<-strsplit(ldapraw, "\n\n")
  ldapsplit<-unlist(ldapsplit)
  # init list and count
  mylist<-list()
  count<-0
  for (ldapline in ldapsplit) {
    # if this is the beginning of the entry
    if(grepl("^DN:", ldapline)) {
      count<-count+1
      # after the first 
      if(count == 2 ) {
        df<-data.frame(mylist)
        mylist<-list()
      }
      if(count > 2) {
        df<-smartbind(df, mylist)
        mylist<-list()
      }
      mylist["DN"] <-gsub("^DN: ", "", ldapline)
    } else {
      linesplit<-unlist(strsplit(ldapline, "\n"))
      if(length(linesplit) > 1) {
        for(line in linesplit) {
          linesplit2<-unlist(strsplit(line, "\t"))
          linesplit2<-unlist(strsplit(linesplit2[2], ": "))
          if(!is.null(unlist(mylist[linesplit2[1]]))) {
            x<-strsplit(unlist(mylist[linesplit2[1]]), "|", fixed=TRUE)

            x<-append(unlist(x), linesplit2[2])
            x<-paste(x, sep="", collapse="|")
            mylist[linesplit2[1]] <- x
          } else {
            mylist[linesplit2[1]] <- linesplit2[2]  
          }
        }
      } else {
        ldaplinesplit<-unlist(strsplit(ldapline, "\t"))
        ldaplinesplit<-unlist(strsplit(ldaplinesplit[2], ": "))
        mylist[ldaplinesplit[1]] <- ldaplinesplit[2]
      }

    }

  }
  if(count == 1 ) {
    df<-data.frame(mylist)
  } else {
    df<-smartbind(df, mylist)
  }
  return(df)
}

loginLDAP <- function(username, password) {

  ldap_url <- "ldap://SERVER-NAME-01.companyname.com"

  handle <- curl::new_handle(timeout = 10)

  curl::handle_setopt(handle = handle, userpwd = paste0("companyname\\", username, ":", password))

  tryCatch(
    {
      response <- curl::curl_fetch_memory(url = ldap_url, handle = handle)

      if (response$status_code == 0) {
        return(list(success = TRUE, username = username))
      } else {
        print("Invalid login credentials.")
      }
    },
    error = function(e) {
      return(list(success = FALSE, username = username))
    }
  )
}

I wrote a R library for accessing ldap servers using the openldap library. In detail, the function searchldap is a wrapper for the openldap method searchldap. https://github.com/LukasK13/ldapr

I followed this strategy:

1. run a Perl script with an LDAP query, write data to disc as JSON.
2. read in the json structure with R, create a dataframe.

For step (1), I used this script:

#use Modern::Perl;
use strict;
use warnings;
use feature 'say';
use Net::LDAP;
use JSON;
chdir("~/git/_my/R_one-offs/R_grabbag");
my $ldap = Net::LDAP->new( 'ldap.mydomain.de' ) or die "$@";
my $outfile = "ldapentries_mydomain_ldap.json";
my $mesg = $ldap->bind ;    # an anonymous bind
# get all cn's (= all names)
$mesg = $ldap->search(
                base   => " ou=People,dc=mydomain,dc=de",
                filter => "(cn=*)"
              );

my $json_text = "";
my @entries;

foreach my $entry ($mesg->entries){
 my %entry;
 foreach my $attr ($entry->attributes) {
    foreach my $value ($entry->get_value($attr)) {
      $entry{$attr} = $value;
    }
  }
  push @entries, \%entry;
}

$json_text = to_json(\@entries);
say "Length json_text: " . length($json_text);


open(my $FH, ">", $outfile);
print $FH $json_text;
close($FH);
$mesg = $ldap->unbind;

You might need check the a max size limit of entries returned by the ldap server. See https://serverfault.com/questions/328671/paging-using-ldapsearch

For step (2), I used this R code:

setwd("~/git/_my/R_one-offs/R_grabbag")
library(rjson)
# read into R list, from file, created from perl script
json <- rjson::fromJSON(file="ldapentries_mydomain_ldap.json",method = "C")
head(json)

# create a data frame from list
library(reshape2)
library(dplyr)
library(tidyr)

# not really efficient, maybe thre's a better way to do it
df.ldap <- json %>% melt %>% spread( L2,value)

# optional:
# turn factors into characters
i <- sapply(df.ldap, is.factor)
df.ldap[i] <- lapply(df.ldap[i], as.character)