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MDL-16658 users pre-check. Committing current *disabled* code to have it
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already under CVS control and better handling
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@stronk7
stronk7 committed Nov 24, 2009
1 parent 5459e76 commit 5929c00
Showing 1 changed file with 270 additions and 0 deletions.
270 changes: 270 additions & 0 deletions backup/restorelib.php
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Original file line number Original file line Diff line number Diff line change
Expand Up @@ -683,6 +683,258 @@ function restore_print_course_header ($course_header) {
return $status; return $status;
} }


/**
* Given one user object (from backup file), perform all the neccesary
* checks is order to decide how that user will be handled on restore.
*
* Note the function requires $user->mnethostid to be already calculated
* so it's caller responsibility to set it
*
* This function is used both by @restore_precheck_users() and
* @restore_create_users() to get consistent results in both places
*
* It returns:
* - one user object (from DB), if match has been found and user will be remapped
* - boolean true if the user needs to be created
* - boolean false if some conflict happened and the user cannot be handled
*
* Each test is responsible for returning its results and interrupt
* execution. At the end, boolean true (user needs to be created) will be
* returned if no test has interrupted that.
*
* Here it's the logic applied, keep it updated:
*
* If restoring users from same site backup:
* 1A - If match by id and username and mnethost => ok, return target user
* 1B - If match by id and mnethost and user is deleted in DB and
* match by email LIKE 'backup_email%' => ok, return target user
* 1C - If match by id and mnethost and user is deleted in backup file
* and match by email = email_without_time(backup_email) => ok, return target user
* 1D - If match by username and mnethost and doesn't match by id => conflict, return false
* 1E - else => user needs to be created, return true
*
* if restoring from another site backup:
* 2A - If match by username and mnethost and
* (email or non-zero firstaccess) => ok, return target user
* 2B - Note: we cannot handle "deleted" situations here as far
* as username gets modified and id cannot be used here
* 2C - If match by username and mnethost and not
* by (email or non-zero firstaccess) => conflict, return false
* 2D - else => user needs to be created, return true
*/
function restore_check_user($restore, $user) {
global $CFG;

// Verify mnethostid is set, return error if not
// it's parent responsibility to define that before
// arriving here
if (empty($user->mnethostid)) {
debugging("restore_check_user() wrong use, mnethostid not set for user $user->username", DEBUG_DEVELOPER);
return false;
}

// Handle checks from same site backups
if (backup_is_same_site($restore)) {

// 1A - If match by id and username and mnethost => ok, return target user
if ($rec = get_record('user', 'id', $user->id, 'username', addslashes($user->username), 'mnethostid', $user->mnethostid)) {
return $rec; // Matching user found, return it
}

// 1B - Handle users deleted in DB and "alive" in backup file
// 1B1- If match by id and mnethost and user is deleted in DB and
// match by email LIKE 'backup_email.%' => ok, return target user
// Note: for deleted users email is stored in username field, hence we
// are looking there for emails in the query below. See delete_user()
if ($rec = get_record_sql("SELECT *
FROM {$CFG->prefix}user u
WHERE id = $user->id
AND mnethostid = $user->mnethostid
AND deleted = 1
AND username LIKE '$user->email.%'")) {
return $rec; // Matching user, deleted in DB found, return it
}

// 1C - Handle users deleted in backup file and "alive" in DB
// 1C1- If match by id and mnethost and user is deleted in backup file
// and match by email = email_without_time(backup_email) => ok, return target user
if ($user->deleted) {
// Trim time() from email
// Note: for deleted users email is stored in username field, hece
// we are trimming the username field to get the email. See delete_user()
$trimemail = preg_replace('/(.*?)\.[0-9]+.?$/', '\\1', $user->username);
if ($rec = get_record_sql("SELECT *
FROM {$CFG->prefix}user u
WHERE id = $user->id
AND mnethostid = $user->mnethostid
AND email = '$trimemail'")) {
return $rec; // Matching user, deleted in backup file found, return it
}
}

// 1D - If match by username and mnethost and doesn't match by id => conflict, return false
if ($rec = get_record('user', 'username', addslashes($user->username), 'mnethostid', $user->mnethostid)) {
if ($user->id != $rec->id) {
return false; // Conflict, username already exists and belongs to another id
}
}

// Handle checks from different site backups
} else {

// 2A - If match by username and mnethost and
// (email or non-zero firstaccess) => ok, return target user
if ($rec = get_record_sql("SELECT *
FROM {$CFG->prefix}user u
WHERE username = '$user->username'
AND mnethostid = $user->mnethostid
AND (
email = '$user->email'
OR (
firstaccess != 0
AND firstaccess = $user->firstaccess
)
)")) {
return $rec; // Matching user
}

// 2B - Handle users deleted in DB and "alive" in backup file
// Note: for deleted users email is stored in username field, hence we
// are looking there for emails in the query below. See delete_user()
// Note: for deleted users md5(username) is stored *sometimes* in the
// email field, hence we are looking there for usernames in the query below
// 2B - Note: we cannot handle "deleted" situations here as far
// as username gets modified and id cannot be used either
// 2B1-deleted = 1 AND email = md5(username) AND mnsethostid AND (username like $user->email.% OR firstaccess)
// 2B2 deleted and mnsethostid AND username like $user->email.% AND firstaccess

// 2C - Handle users deleted in backup file and "alive" in DB

// 2D - If match by username and mnethost and not
// by (email or non-zero firstaccess) => conflict, return false
if ($rec = get_record_sql("SELECT *
FROM {$CFG->prefix}user u
WHERE username = '$user->username'
AND mnethostid = $user->mnethostid
AND NOT (
email = '$user->email'
OR (
firstaccess != 0
AND firstaccess = $user->firstaccess
)
)")) {
return false; // Conflict, username/mnethostid already exist and belong to another user (by email/firstaccess)
}
}

// Arrived here, return true as the user will need to be created and no
// conflicts have been found in the logic above. This covers:
// 1E - else => user needs to be created, return true
// 2D - else => user needs to be created, return true
return true;
}

/**
* For all the users being restored, check if they are going to cause problems
* before executing the restore process itself, detecting situations like:
* - conflicts preventing restore to continue - provided by @restore_check_user()
* - prevent creation of users if not allowed - check some global settings/caps
*/
function restore_precheck_users($xml_file, $restore, &$problems) {
global $CFG;

$status = true; // Init $status

// We aren't restoring users, nothing to check, allow continue
if ($restore->users == 2) {
return true;
}

// Get array of users from xml file and load them in backup_ids table
if (!$info = restore_read_xml_users($restore,$xml_file)) {
return true; // No users, nothing to check, allow continue
}

// We are going to map mnethostid, so load all the available ones
$mnethosts = get_records('mnet_host', '', '', 'wwwroot', 'wwwroot, id');

// Calculate the context we are going to use for capability checking
if (!empty($restore->course_id)) { // Know the target (existing) course, check capabilities there
$context = get_context_instance(CONTEXT_COURSE, $restore->course_id);
} else if (!empty($restore->restore_restorecatto)) { // Know the category, check capabilities there
$context = get_context_instance(CONTEXT_COURSECAT, $restore->restore_restorecatto);
} else { // Last resort, check capabilities at system level
$context = get_context_instance(CONTEXT_SYSTEM);
}

// Calculate if we have perms to create users, by checking:
// to 'moodle/restore:createuser' and 'moodle/restore:userinfo'
// and also observe $CFG->disableusercreationonrestore
$cancreateuser = false;
if (has_capability('moodle/restore:createuser', $context) and
has_capability('moodle/restore:userinfo', $context) and
empty($CFG->disableusercreationonrestore)) { // Can create users

$cancreateuser = true;
}

// Iterate over all users, checking if they are likely to cause problems on restore
$counter = 0;
foreach ($info->users as $userid) {
$rec = backup_getid($restore->backup_unique_code, 'user', $userid);
$user = $rec->info;

// Find the correct mnethostid for user before performing any further check
if (empty($user->mnethosturl) || $user->mnethosturl===$CFG->wwwroot) {
$user->mnethostid = $CFG->mnet_localhost_id;
} else {
// fast url-to-id lookups
if (isset($mnethosts[$user->mnethosturl])) {
$user->mnethostid = $mnethosts[$user->mnethosturl]->id;
} else {
$user->mnethostid = $CFG->mnet_localhost_id;
}
}

// Calculate the best way to handle this user from backup file
$usercheck = restore_check_user($restore, $user);

if (is_object($usercheck)) { // No problem, we have found one user in DB to be mapped to

} else if ($usercheck === false) { // Found conflict, report it as problem
$problems[] = get_string('restoreuserconflict', '', $user->username);
$status = false;

} else if ($usercheck === true) { // User needs to be created, check if we are able
if (!$cancreateuser) { // Cannot create, report as problem

$problems[] = get_string('restorecannotcreateuser', '', $user->username);
$status = false;
}

} else { // Shouldn't arrive here ever, something is for sure wrong in restore_check_user()
if (!defined('RESTORE_SILENTLY')) {
notify('Unexpected error pre-checking user ' . s($user->username) . ' from backup file');
return false;
}
}

// Do some output
$counter++;
if ($counter % 10 == 0) {
if (!defined('RESTORE_SILENTLY')) {
echo ".";
if ($counter % 200 == 0) {
echo "<br />";
}
}
backup_flush(300);
}
}

return $status;
}

//This function create a new course record. //This function create a new course record.
//When finished, course_header contains the id of the new course //When finished, course_header contains the id of the new course
function restore_create_new_course($restore,&$course_header) { function restore_create_new_course($restore,&$course_header) {
Expand Down Expand Up @@ -7948,6 +8200,24 @@ function restore_execute(&$restore,$info,$course_header,&$errorstr) {
} }
} }


// Precheck the users section, detecting various situations that can lead to problems, so
// we stop restore before performing any further action
/*
if (!defined('RESTORE_SILENTLY')) {
echo '<li>'.get_string('restoreusersprecheck').'</li>';
}
if (!restore_precheck_users($xml_file, $restore, $problems)) {
$errorstr = get_string('restoreusersprecheckerror');
if (!empty($problems)) {
$errorstr .= ' (' . implode(', ', $problems) . ')';
}
if (!defined('RESTORE_SILENTLY')) {
notify($errorstr);
}
return false;
}
*/

//If we've selected to restore into new course //If we've selected to restore into new course
//create it (course) //create it (course)
//Saving conversion id variables into backup_tables //Saving conversion id variables into backup_tables
Expand Down

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