Reading and saving binary image from OpenLDAP server using Groovy

Question

I'm trying to save an image from an OpenLDAP server. It's in binary format and all my code appears to work, however, the image is corrupted.

I then attempted to do this in PHP and was successful, but I'd like to do it in a Grails project.

PHP Example (works)

<?php
    $conn = ldap_connect('ldap.example.com') or die("Could not connect.\n");
    ldap_set_option($conn, LDAP_OPT_PROTOCOL_VERSION, 3);
    $dn = 'ou=People,o=Acme';
    $ldap_rs = ldap_bind($conn) or die("Can't bind to LDAP");
    $res = ldap_search($conn,$dn,"someID=123456789");
    $info = ldap_get_entries($conn, $res);
    $entry = ldap_first_entry($conn, $res);
    $jpeg_data = ldap_get_values_len( $conn, $entry, "someimage-jpeg");
    $jpeg_filename = '/tmp/' . basename( tempnam ('.', 'djp') );
    $outjpeg = fopen($jpeg_filename, "wb");
    fwrite($outjpeg, $jpeg_data[0]);
    fclose ($outjpeg);
    copy ($jpeg_filename, '/some/dir/test.jpg');
    unlink($jpeg_filename);
?>

Groovy Example (does not work)

def ldap = org.apache.directory.groovyldap.LDAP.newInstance('ldap://ldap.example.com/ou=People,o=Acme')

ldap.eachEntry (filter: 'someID=123456789') { entry ->

    new File('/Some/dir/123456789.jpg').withOutputStream {
        it.write entry.get('someimage-jpeg').getBytes()  // File is created, but image is corrupted (size also doesn't match the PHP version)
    }

}

How would I tell the Apache LDAP library that "image-jpeg" is actually binary and not a String? Is there a better simple library available to read binary data from an LDAP server? From looking at the Apache mailing list, someone else had a similar issue, but I couldn't find a resolution in the thread.

Technology Stack

• Grails 2.2.1
• Apache LDAP API 1.0.0 M16

Answer 1

I found the answer. The Apache Groovy LDAP library uses JNDI under the hood. When using JNDI certain entries are automatically read as binary, but if your LDAP server uses a custom name, the library will not know that it's binary.

For those people that come across this problem using Grails, here's the steps to set a specific entry to binary format.

• Create a new properties file call "jndi.properties" and add it to your grails-app/conf directory (all property files in this folder are automatically included in the classpath)

• Add a line in the properties file with the name of the image variable:

  java.naming.ldap.attributes.binary=some_custom_image

• Save the file and run the Grails application

Here is some sample code to save a binary entry to a file.

def ldap = LDAP.newInstance('ldap://some.server.com/ou=People,o=Acme')      
ldap.eachEntry (filter: 'id=1234567') { entry ->             
    new File('/var/dir/something.jpg').withOutputStream {          
        it.write entry.image          
    }         
}

Answer 2

Have you checked whether the image attribute value is base-64 encoded?