Enabling OCS Inventory WebService interface for querying assets data

How to enable the OCS Inventory interface described in OCS WebServices? Is there a sample code for using this Web Service in PHP?

Solution

The OCS interface is disabled by default, it is necessary to turn it on before use it. OCS has a core code developed in Perl and it runs over Apache HTTP.

First, edit the file /etc/apache2/conf-enabled/z-ocsinventory-server.conf changing the option value for OCS_OPT_WEB_SERVICE_ENABLED to 1. If the web service is not enabled you should get a 401 Forbidden response. This is a SOAP WebService and there's no WSDL to describe the features, just the docs available in OCS WS Documentation.

Check if the location tag for /ocsinterface looks like the following snippet:

 <Location /ocsinterface>
      SetHandler perl-script
      PerlHandler Apache::Ocsinventory::SOAP
      # By default, you can query web service from everywhere with a valid user
      Order deny,allow
      Allow from all
      AuthType Basic
      AuthName "OCS Inventory SOAP Area"
      # Use htpasswd to create/update soap-user (or another granted user)
      AuthUserFile "/etc/apache2/passwd/soapinterface"
      Require valid-user
 </Location>

You should create a password for this location for security purposes, however, to turn the authentication off just comment out all Auth... and Require attributes.

Restart apache server, and use the PHP code below to test the web service integration

<?php
$proto = 'http';
$host = 'localhost';
$port = '80';
$user = ''; //basic authentication, if necessary
$pass = ''; 

$options = array(
    'location' => "$proto://$host:$port/ocsinterface",
    'uri' => "$proto://$host:$port/Apache/Ocsinventory/Interface",
    'login' => $user,
    'password' => $pass,
    'trace' => TRUE,
    'soap_version' => SOAP_1_1,
);

$request = '
        <REQUEST>
            <ENGINE>FIRST</ENGINE>
            <ASKING_FOR>META</ASKING_FOR>
            <CHECKSUM>131071</CHECKSUM>
            <OFFSET>0</OFFSET>
            <WANTED>131071</WANTED>
        </REQUEST>';

try {
    $client = new SoapClient(NULL, $options);
} catch (Exception $e) {
    echo "<b>Construct Error</b>: " . $e->getMessage() . "<br>";
}

try {
    $result = $client->get_computers_V1($request);
    echo "<b>Headers:</b><pre>" . $client->__getLastRequestHeaders() . " </pre><br>";
    echo "<b>Request:</b><pre>" . $client->__getLastRequest() . "</pre><br>";
    echo "<b>Result:</b><pre>";
    var_dump($result);
    echo "</pre><br>";
} catch (Exception $e) {
    echo "<b>Connection Error</b>: " . $e->getMessage() . "<br><br>";
    echo "<b>Headers:</b><pre>\r\n" . $client->__getLastRequestHeaders() . " </pre><br>";
echo "<b>Request:</b><pre>\r\n" . $client->__getLastRequest() . "</pre>";
}

If you get a HTTP 500 Internal Server Error, check apache error log (tail -f /var/log/apache2/error.log -n 100) for the following error message:

Illegal field name 'APR::Table=HASH(0x7ff114bd75a8)' at /usr/local/share/perl/5.18.2/SOAP/Transport/HTTP2.pm line 103.\n

That error happens due to an incompatibility issue found in HTTP::Message perl module. The following links describes the problem and solution related to it:

To fix it, you need to downgrade the HTTP::Message perl module to version 6.04. Use the command cpan -D HTTP::Message in your console to check which version you're using. This module version is a little bit old, so you won't find it in Search CPAN. In this regard, you should download the module HTTP-Message-6.04.tar.gz and install it manually by typing the following commands on your terminal:

decompress it using tar -zxf HTTP-Message-6.04.tar.gz
call the new directory cd HTTP-Message-6.04/
perl Makefile.PL
make
make test
make install
and finally, check if the module got downgraded successfully by typing cpan -D HTTP::Message(it should output ... Installed: 6.04 ...)
restart the server - service apache2 restart

Run the PHP snippet shown above to test it again.