After thinking a bit about it, this file is, exactly,

[moodle.git] / lib / environmentlib.php

<?php  //$Id$

///////////////////////////////////////////////////////////////////////////
//                                                                       //
// NOTICE OF COPYRIGHT                                                   //
//                                                                       //
// Moodle - Modular Object-Oriented Dynamic Learning Environment         //
//          http://moodle.com                                            //
//                                                                       //
// Copyright (C) 2001-3001 Martin Dougiamas        http://dougiamas.com  //
//           (C) 2001-3001 Eloy Lafuente (stronk7) http://contiento.com  //
//                                                                       //
// This program is free software; you can redistribute it and/or modify  //
// it under the terms of the GNU General Public License as published by  //
// the Free Software Foundation; either version 2 of the License, or     //
// (at your option) any later version.                                   //
//                                                                       //
// This program is distributed in the hope that it will be useful,       //
// but WITHOUT ANY WARRANTY; without even the implied warranty of        //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         //
// GNU General Public License for more details:                          //
//                                                                       //
//          http://www.gnu.org/copyleft/gpl.html                         //
//                                                                       //
///////////////////////////////////////////////////////////////////////////

// This library includes all the necessary stuff to execute some standard
// tests of required versions and libraries to run Moodle. It can be
// used from the admin interface, and both at install and upgrade.
//
// All the info is stored in the admin/environment.xml file,
// supporting to have an updated version in moodledata/environment

require_once($CFG->libdir.'/xmlize.php');

define(NO_ERROR,                           0);
define(NO_VERSION_DATA_FOUND,              1);
define(NO_DATABASE_SECTION_FOUND,          2);
define(NO_DATABASE_VENDORS_FOUND,          3);
define(NO_DATABASE_VENDOR_MYSQL_FOUND,     4);
define(NO_DATABASE_VENDOR_POSTGRES_FOUND,  5);
define(DATABASE_OLD_VERSION,               6);
define(NO_PHP_SECTION_FOUND,               7);
define(NO_PHP_VERSION_FOUND,               8);
define(PHP_OLD_VERSION,                    9);
define(NO_PHP_EXTENSIONS_SECTION_FOUND,   10);
define(NO_PHP_EXTENSIONS_NAME_FOUND,      11);
define(NO_PHP_EXTENSION_WITH_NAME,        12);


/**
 * This function will perform the whole check, returning
 * true or false as final result. Also, he full array of
 * environment_result will be returned in the parameter list.
 * The function looks for the best version to compare and
 * everything. This is the only function that should be called
 * ever from the rest of Moodle.
 * @param string version version to check. 
 * @param array results array of results checked.
 * @return boolean true/false, depending of results
 */
function check_moodle_environment($version, &$environment_results) {

/// Get the more recent version before the requested
    if (!$version = get_latest_version_available($version)) {
        return false;
    }

/// Perform all the checks
    if(!$environment_results = environment_check($version)) {
        return false;
    }

/// Iterate over all the results looking for some error in required items
    foreach ($environment_results as $environment_result) {
        if (!$environment_result->getStatus() && $environment_result->getLevel() == 'required') {
            return false;
        }
    }

    return true;
}


/**
 * This function will normalize any version to just a serie of numbers
 * separated by dots. Everything else will be removed.
 * @param string $version the original version
 * @return string the normalized version
 */
function normalize_version($version) {
/// Replace everything but numbers and dots by dots
    $version = preg_replace('/[^\.\d]/', '.', $version);
/// Combine multiple dots in one
    $version = preg_replace('/(\.{2,})/', '.', $version);
/// Trim possible leading and trailing dots
    $version = trim($version, '.');

    return $version;
}


/**
 * This function will load the environment.xml file and xmlize it
 * @return mixed the xmlized structure or false on error
 */
function load_environment_xml() {
    
    global $CFG;

    static $data; //Only load and xmlize once by request

    if (!empty($data)) {
        return $data;
    }

/// First of all, take a look inside $CFG->moodledata/environment/environment.xml
    $file = $CFG->moodledata.'/environment/environment.xml';
    if (!is_file($file) || !is_readable($file) || !$contents = file_get_contents($file)) {
    /// Fallback to fixed admin/environment.xml
        $file = $CFG->dirroot.'/admin/environment.xml';
        if (!is_file($file) || !is_readable($file) || !$contents = file_get_contents($file)) {
            return false;
        }
    }
/// XML the whole file
    $data = xmlize($contents);

    return $data;
}


/**
 * This function will return the list of Moodle versions available
 * @return mixed array of versions. False on error.
 */
function get_list_of_environment_versions ($contents) {

    static $versions = array();

    if (!empty($versions)) {
        return $versions;
    }

    if (isset($contents['COMPATIBILITY_MATRIX']['#']['MOODLE'])) {
        foreach ($contents['COMPATIBILITY_MATRIX']['#']['MOODLE'] as $version) {
            $versions[] = $version['@']['version'];
        }
    }

    return $versions;
}


/**
 * This function will return the most recent version in the environment.xml
 * file previous or equal to the version requested
 * @param string version top version from which we start to look backwards
 * @return string more recent version or false if not found
 */
function get_latest_version_available ($version) {

/// Normalize the version requested
    $version = normalize_version($version);

/// Load xml file
    if (!$contents = load_environment_xml()) {
        return false;
    }

/// Detect available versions
    if (!$versions = get_list_of_environment_versions($contents)) {
        return false;
    }
/// First we look for exact version
    if (in_array($version, $versions)) {
        return $version;
    } else {
        $found_version = false;
    /// Not exact match, so we are going to iterate over the list searching
    /// for the latest version before the requested one
        foreach ($versions as $arrversion) {
            if (version_compare($arrversion, $version, '<')) {
                $found_version = $arrversion;
            }
        }
    }

    return $found_version;
}


/** 
 * This function will return the xmlized data belonging to one Moodle version
 * @return mixed the xmlized structure or false on error
 */
function get_environment_for_version($version) {
   
/// Normalize the version requested
    $version = normalize_version($version);

/// Load xml file
    if (!$contents = load_environment_xml()) {
        return false;
    }

/// Detect available versions
    if (!$versions = get_list_of_environment_versions($contents)) {
        return false;
    }

/// If the version requested is available
    if (!in_array($version, $versions)) {
        return false;
    }

/// We now we have it. Extract from full contents.
    $fl_arr = array_flip($versions);
    
    return $contents['COMPATIBILITY_MATRIX']['#']['MOODLE'][$fl_arr[$version]];
}


/** 
 * This function will check for everything (DB, PHP and PHP extensions for now)
 * returning an array of environment_result objects.
 * @param string $version xml version we are going to use to test this server
 * @return array array of results encapsulated in one environment_result object
 */
function environment_check($version) {

/// Normalize the version requested
    $version = normalize_version($version);

    $results = array(); //To store all the results

    $results[] = environment_check_database($version);
    $results[] = environment_check_php($version);

    $phpext_results = environment_check_php_extensions($version);

    $results = array_merge ($results, $phpext_results);

    return $results;
}


/**
 * This function will check if php extensions requirements are satisfied
 * @param string $version xml version we are going to use to test this server
 * @return array array of results encapsulated in one environment_result object
 */
function environment_check_php_extensions($version) {

    $results = array();

/// Get the enviroment version we need
    if (!$data = get_environment_for_version($version)) {
    /// Error. No version data found
        $result = new environment_results('php_extensions');
        $result->setStatus(false);
        $result->setErrorCode(NO_VERSION_DATA_FOUND);
        return $result;
    }

/// Extract the php_extension part
    if (!isset($data['#']['PHP_EXTENSIONS']['0']['#']['PHP_EXTENSION'])) {
    /// Error. No PHP section found
        $result = new environment_results('php_extensions');
        $result->setStatus(false);
        $result->setErrorCode(NO_PHP_EXTENSIONS_SECTION_FOUND);
        return $result;
    } else {
    /// Iterate over extensions checking them and creating the needed environment_results
        foreach($data['#']['PHP_EXTENSIONS']['0']['#']['PHP_EXTENSION'] as $extension) {
            $result = new environment_results('php_extensions');
        /// Check for level
            if (isset($extension['@']['level'])) {
                $level = $extension['@']['level'];
                if ($level != 'optional') {
                    $level = 'required';
                }
            }
        /// Check for extension name
            if (!isset($extension['@']['name'])) {
                $result->setStatus(false);
                $result->setErrorCode(NO_PHP_EXTENSIONS_NAME_FOUND);
            } else {
                $extension_name = $extension['@']['name'];
            /// The name exists. Just check if it's an installed extension
                if (!extension_loaded($extension_name)) {
                    $result->setStatus(false);
                    $result->setErrorCode(NO_PHP_EXTENSION_WITH_NAME);
                } else {
                    $result->setStatus(true);
                }
                $result->setLevel($level);
                $result->setInfo($extension_name);
            }
        /// Add the result to the array of results
            $results[] = $result;
        }
    }

    return $results;
}


/**
 * This function will check if php requirements are satisfied
 * @param string $version xml version we are going to use to test this server
 * @return object results encapsulated in one environment_result object
 */
function environment_check_php($version) {

    $result = new environment_results('php');

/// Get the enviroment version we need
    if (!$data = get_environment_for_version($version)) {
    /// Error. No version data found
        $result->setStatus(false);
        $result->setErrorCode(NO_VERSION_DATA_FOUND);
        return $result;
    }

/// Extract the php part
    if (!isset($data['#']['PHP'])) {
    /// Error. No PHP section found
        $result->setStatus(false);
        $result->setErrorCode(NO_PHP_SECTION_FOUND);
        return $result;
    } else {
    /// Extract level and version
        if (isset($data['#']['PHP']['0']['@']['level'])) {
            $level = $data['#']['PHP']['0']['level'];
            if ($level != 'optional') {
                $level = 'required';
            }
        }
        if (!isset($data['#']['PHP']['0']['@']['version'])) {
            $result->setStatus(false);
            $result->setErrorCode(NO_PHP_VERSION_FOUND);
            return $result;
        } else {
            $needed_version = $data['#']['PHP']['0']['@']['version'];
        }
    }

/// Now search the version we are using
    $current_version = normalize_version(phpversion());

/// And finally compare them, saving results
    if (version_compare($current_version, $needed_version, '>=')) {
        $result->setStatus(true);
    } else {
        $result->setStatus(false);
        $result->setErrorCode(PHP_OLD_VERSION);
    }
    $result->setLevel($level);   
    $result->setCurrentVersion($current_version);
    $result->setNeededVersion($needed_version);

    return $result;
}


/**
 * This function will check if database requirements are satisfied
 * @param string $version xml version we are going to use to test this server
 * @return object results encapsulated in one environment_result object
 */
function environment_check_database($version) {

    global $db;

    $result = new environment_results('database');

    $vendors = array();  //Array of vendors in version

/// Get the enviroment version we need
    if (!$data = get_environment_for_version($version)) {
    /// Error. No version data found
        $result->setStatus(false);
        $result->setErrorCode(NO_VERSION_DATA_FOUND);
        return $result;
    }

/// Extract the database part
    if (!isset($data['#']['DATABASE'])) {
    /// Error. No DATABASE section found
        $result->setStatus(false);
        $result->setErrorCode(NO_DATABASE_SECTION_FOUND);
        return $result;
    } else {
    /// Extract level
        if (isset($data['#']['DATABASE']['0']['@']['level'])) {
            $level = $data['#']['DATABASE']['0']['level'];
            if ($level != 'optional') {
                $level = 'required';
            }
        }
    }

/// Extract DB vendors. At least 2 are mandatory (mysql & postgres)
    if (!isset($data['#']['DATABASE']['0']['#']['VENDOR'])) {
    /// Error. No VENDORS found
        $result->setStatus(false);
        $result->setErrorCode(NO_DATABASE_VENDORS_FOUND);
        return $result;
    } else {
    /// Extract vendors
        foreach ($data['#']['DATABASE']['0']['#']['VENDOR'] as $vendor) {
            if (isset($vendor['@']['name']) && isset($vendor['@']['version'])) {
                $vendors[$vendor['@']['name']] = $vendor['@']['version'];
            }
        }
    }
/// Check we have the mysql vendor version
    if (empty($vendors['mysql'])) {
        $result->setStatus(false);
        $result->setErrorCode(NO_DATABASE_VENDOR_MYSQL_FOUND);
        return $result;
    }
/// Check we have the postgres vendor version
    if (empty($vendors['postgres'])) {
        $result->setStatus(false);
        $result->setErrorCode(NO_DATABASE_VENDOR_POSTGRES_FOUND);
        return $result;
    }

/// Now search the version we are using (depending of vendor)
    $current_vendor = $db->databaseType;
    $dbinfo = $db->ServerInfo();
    $current_version = normalize_version($dbinfo['version']);
    $needed_version = $vendors[$current_vendor];

/// And finally compare them, saving results
    if (version_compare($current_version, $needed_version, '>=')) {
        $result->setStatus(true);
    } else {
        $result->setStatus(false);
        $result->setErrorCode(DATABASE_OLD_VERSION);
    }
    $result->setLevel($level);   
    $result->setCurrentVersion($current_version);
    $result->setNeededVersion($needed_version);
    $result->setInfo($current_vendor);

    return $result;

}


//--- Helper Class to return results to caller ---//


/** 
 * This class is used to return the results of the environment
 * main functions (environment_check_xxxx)
 */
class environment_results {

    var $part;            //which are we checking (database, php, php_extensions)
    var $status;          //true/false
    var $error_code;      //integer. See constants at the beginning of the file
    var $level;           //required/optional
    var $current_version; //current version detected
    var $needed_version;  //version needed
    var $info;            //Aux. info (DB vendor, library...)

    /**
     * Constructor of the environment_result class. Just set default values
     */
    function environment_results($part) {
        $this->part=$part;
        $this->status=false;
        $this->error_code=NOTHING_CHECKED_YET;
        $this->level='required';
        $this->current_version='';
        $this->needed_version='';
        $this->info='';
    }

    /**
     * Set the status
     * @param boolean the status (true/false)
     */
    function setStatus($status) {
        $this->status=$status;
        if ($status) {
            $this->setErrorCode(NO_ERROR);
        }
    }

    /**
     * Set the error_code
     * @param integer the error code (see constants above)
     */
    function setErrorCode($error_code) {
        $this->error_code=$error_code;
    }

    /**
     * Set the level
     * @param string the level (required, optional)
     */
    function setLevel($level) {
        $this->level=$level;
    }

    /**
     * Set the current version
     * @param string the current version
     */
    function setCurrentVersion($current_version) {
        $this->current_version=$current_version;
    }

    /**
     * Set the needed version
     * @param string the needed version
     */
    function setNeededVersion($needed_version) {
        $this->needed_version=$needed_version;
    }

    /**
     * Set the auxiliary info
     * @param string the auxiliary info
     */
     function setInfo($info) {
         $this->info=$info;
     }

    /**
     * Get the status
     * @return boolean result
     */
    function getStatus() {
        return $this->status;
    }

    /**
     * Get the error code
     * @return integer error code
     */
    function getErrorCode() {
        return $this->error_code;
    }

    /**
     * Get the level
     * @return string level
     */
    function getLevel() {
        return $this->level;
    }

    /**
     * Get the current version 
     * @return string current version
     */
    function getCurrentVersion() {
        return $this->current_version;
    }

    /**
     * Get the needed version
     * @return string needed version
     */
    function getNeededVersion() {
        return $this->needed_version;
    }

    /**
     * Get the aux info
     * @return string info
     */
    function getInfo() {
        return $this->info;
    }

    /**
     * Get the part this result belongs to
     * @return string part
     */
    function getPart() {
        return $this->part;
    }
}

?>