Server error when requestion jpegPhoto attribute in REST search request

Description

When using REST search request, a server error is returned if jpegPhoto is listed inside attributes array.

Distribution Name and Version

# cat /etc/debian_version 
9.11

FusionDirectory Version

# dpkg -l | grep fusiondirectory
ii  fusiondirectory                          1.4-2~jenkinsbuild543                        all          Web Based LDAP Administration Program
ii  fusiondirectory-plugin-dsa               1.4-2~jenkinsbuild543                        all          dsa plugin for FusionDirectory
ii  fusiondirectory-plugin-dsa-schema        1.4-2~jenkinsbuild543                        all          LDAP schema for FusionDirectory dsa plugin
ii  fusiondirectory-plugin-mail              1.4-2~jenkinsbuild543                        all          base mail plugin for FusionDirectory
ii  fusiondirectory-plugin-mail-schema       1.4-2~jenkinsbuild543                        all          LDAP schema for FusionDirectory mail plugin
ii  fusiondirectory-plugin-personal          1.4-2~jenkinsbuild543                        all          Personal plugin for FusionDirectory
ii  fusiondirectory-plugin-personal-schema   1.4-2~jenkinsbuild543                        all          LDAP schema for FusionDirectory personal Plugin
ii  fusiondirectory-plugin-ppolicy           1.4-2~jenkinsbuild543                        all          ppolicy overlay module plugin for FusionDirectory
ii  fusiondirectory-plugin-ppolicy-schema    1.4-2~jenkinsbuild543                        all          LDAP schema for FusionDirectory ppolicy Plugin
ii  fusiondirectory-plugin-webservice        1.4-2~jenkinsbuild543                        all          webservice plugin for FusionDirectory
ii  fusiondirectory-plugin-webservice-schema 1.4-2~jenkinsbuild543                        all          schema for the webservice plugin for FusionDirectory
ii  fusiondirectory-schema                   1.4-2~jenkinsbuild543                        all          LDAP schema for FusionDirectory
ii  fusiondirectory-smarty3-acl-render       1.4-2~jenkinsbuild543                        all          Provide FusionDirectory ACL based rendering for Smarty3

Plugin with the defect

Webservice

PHP version used

# php -v
PHP 7.0.33-0+deb9u6 (cli) (built: Oct 24 2019 18:50:20) ( NTS )
Copyright (c) 1997-2017 The PHP Group
Zend Engine v3.0.0, Copyright (c) 1998-2017 Zend Technologies
    with Zend OPcache v7.0.33-0+deb9u6, Copyright (c) 1999-2017, by Zend Technologies

Origin of php packages

Debian

Steps to Reproduce

Get a session token
Do a search request with jpegPhoto attribute

curl -H "Session-Token: XXXX" 'https://fd.pfptnbdev.io/rest.php/v1/objects/user?base=uid=coudot,ou=users,dc=kroqi,dc=fr&scope=base&attrs[jpegPhoto]=1'

Expected behavior:

Response with jpegPhoto value

Actual behavior:

Error:

[{"message":"Error while encoding JSON result: Malformed UTF-8 characters, possibly incorrectly encoded","line":137,"file":"/usr/share/fusiondirectory/html/rest.php"}]

Reproduces how often:

100%

Additional Information

I don't have the issue when jpegPhoto is requested like this:

curl -H "Session-Token: XXXX" 'https://fd.pfptnbdev.io/rest.php/v1/objects/user/uid=coudot,ou=users,dc=kroqi,dc=fr/user/jpegPhoto'

I tried to set debug to max in FD, but nothing is printed in the logs. As this is the webservice, I can't use the IHM to see logs.

How can we debug a webservice call?