Reading and saving binary image from OpenLDAP server using Groovy - grails

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

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

Answer 2

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
}
}