Script for parsing Nagios object.cache file and returning it as JSON.

nagios_json.php

<?php
header( 'Content-type: application/json;' );

// Change it according to your nagios.cfg
$data = file_get_contents( '/var/ramdrive/objects.cache' );
$matches = array();
$object_matches = array();
$output = array();

preg_match_all( '/(?|define (?<section>\w+) \{\n([^\}]+)+)/i', $data, $matches );

foreach ( $matches['section'] as $object_id=>$section_name ) {
    $parsed_object = array();
    $object_data = $matches[2][$object_id];
    preg_match_all( '/\s+(?<key>\w+)\s+(?<value>.+)/', $object_data, $object_matches );
    foreach($object_matches['key'] as $key_index => $key_name) {
        if($key_name == 'members') {
                $value_data = explode( ",", $object_matches['value'][$key_index] );
        } else {
                $value_data = $object_matches['value'][$key_index];
        }
        $parsed_object[$key_name] = $value_data;
    }
    $object_name = $section_name . '_name';
    $output[$section_name][$parsed_object[$object_name]] = $parsed_object;
}

echo json_encode( $output );

The posted solution chokes on objects with no _name parameter.  Here is one that works:

header ( 'Content-type: application/json;' );

$data = file_get_contents ( '/var/nagiosramdisk/objects.cache' );

$matches = array ( );
$object_matches = array ( );
$output = array ( );

preg_match_all ( '/(?|define (?
\w+) \{\n([^\}]+)+)/i', $data, $matches );

foreach ( $matches [ 'section' ] as $object_id=>$section_name )
{
    $parsed_object = array ( );
    $object_data = $matches [ 2 ] [ $object_id ];
    preg_match_all ( '/\s+(?\w+)\s+(?.+)/', $object_data, $object_matches );
    foreach ( $object_matches['key'] as $key_index => $key_name)
    {
        if ($key_name == 'members')
        {
                $value_data = explode ( ",", $object_matches['value'][$key_index] );
        }
        else
        {
                $value_data = $object_matches['value'][$key_index];
        }
        $parsed_object[$key_name] = $value_data;
    }

#    printf ( "\n" );
#    printf ( "section_name: %s\n", $section_name );
#    printf ( "object_name: %s\n", $object_name );
#    printf ( "\n" );

    switch ( $section_name )
    {
        case "service":
            $output [ $section_name ] [ $parsed_object [ 'host_name' ] ] [ $parsed_object [ 'service_description' ] ] = $parsed_object;
            break;
        case "serviceescalation":
            $output [ $section_name ]
                [ $parsed_object [ 'host_name' ] ]
                [ $parsed_object [ 'service_description' ] ]
                [ $parsed_object [ 'first_notification' ] ]
                = $parsed_object;
            break;
        case "hostescalation":
            $output [ $section_name ]
                [ $parsed_object [ 'host_name' ] ]
                [ $parsed_object [ 'first_notification' ] ]
                = $parsed_object;
            break;
        default:
            $object_name = $section_name . '_name';
            $output [ $section_name ]
                [ $parsed_object [ $object_name ] ]
                = $parsed_object;
    }

}

Thanks a lot. This was very helpful.
Updated the code to disregard comments ("#" ) from Nagios objects file.

function parseNagios($filePath)
{
// $data = file_get_contents($filePath);
$clean = array();
$lines = file($filePath);
foreach ($lines as $word) {
if ((substr($word, 0, 1) === "#")) {
} else {
array_push($clean, $word);
}
}
// console_log(implode($clean));
$data = implode($clean);

$matches = array();
$object_matches = array();
$output = array();
preg_match_all( '/(?|define (?

\w+) {\n([^\}]+)+)/i', $data, $matches );
foreach ( $matches['section'] as $object_id=>$section_name ) {
$parsed_object = array();
$object_data = $matches[2][$object_id];
preg_match_all( '/\s+(?\w+)\s+(?.+)/', $object_data, $object_matches );
foreach($object_matches['key'] as $key_index => $key_name) {
if($key_name == 'members') {
$value_data = explode( ",", $object_matches['value'][$key_index] );
} else {
$value_data = $object_matches['value'][$key_index];
}
$parsed_object[$key_name] = $value_data;
}
$object_name = $section_name . '_name';
$output[$section_name][$parsed_object[$object_name]] = $parsed_object;
}
return json_encode($output);

}