web/lib/Db.php

615 lines
19 KiB
PHP

<?
use Safe\DateTimeImmutable;
use function Safe\preg_match;
use function Safe\posix_getpwuid;
class Db{
protected static \PDO $Link; // This is `protected` because we may want to subclass this class to connect to another instance of a database, like Sphinx.
public static int $QueryCount = 0;
public static int $LastQueryAffectedRowCount = 0;
/**
* Returns a single integer value for the first column database query result.
*
* This is useful for queries that return a single integer as a result, like `count(*)`, `sum(*)`, or `insert ... returning`.
*
* @param string $query
* @param array<mixed> $args
*
* @throws Exceptions\DuplicateDatabaseKeyException If a unique key constraint has been violated.
* @throws Exceptions\DatabaseQueryException If an error occurs during execution of the query.
*/
public static function QueryInt(string $query, array $args = []): int{
$result = static::Query($query, $args);
if(sizeof($result) > 0){
return current((Array)$result[0]);
}
return 0;
}
/**
* Returns a single float value for the first column database query result.
*
* This is useful for queries that return a single float as a result, like `avg(*)` or `sum(*)`.
*
* @param string $query
* @param array<mixed> $args
*
* @throws Exceptions\DatabaseQueryException If an error occurs during execution of the query.
*/
public static function QueryFloat(string $query, array $args = []): float{
$result = static::Query($query, $args);
if(sizeof($result) > 0){
return current((Array)$result[0]);
}
return 0;
}
/**
* Returns a single boolean value for the first column database query result.
*
* This is useful for queries that return a boolean as a result, like `select exists()`.
*
* @param string $query
* @param array<mixed> $args
*
* @throws Exceptions\DatabaseQueryException If an error occurs during execution of the query.
*/
public static function QueryBool(string $query, array $args = []): bool{
$result = static::Query($query, $args);
if(sizeof($result) > 0){
return (bool)current((array)$result[0]);
}
return false;
}
/**
* Returns an SQL query string appropriate for set membership.
*
* This is useful for queries of the form `WHERE var IN (?,?,?)` and the length of the set is dynamic.
*
* @param array<mixed> $arr
*/
public static function CreateSetSql(array $arr): string{
$sql = '(';
for($i = 0; $i < sizeof($arr); $i++){
$sql .= '?,';
}
return rtrim($sql, ',') . ')';
}
/**
* Create a database connection.
*
* @param ?string $defaultDatabase The default database to connect to, or `null` not to define one.
* @param string $host The database hostname.
* @param ?string $user The user to connect to, or `null` to log in as the current Unix user via a local socket.
* @param string $password The password to use, or an empty string if no password is required.
* @param bool $forceUtf8 If **TRUE**, issue `set names utf8mb4 collate utf8mb4_unicode_ci` when starting the connection.
*/
public static function Connect(?string $defaultDatabase = null, string $host = 'localhost', ?string $user = null, string $password = '', bool $forceUtf8 = true): void{
if(isset(static::$Link)){
return;
}
if($user === null){
// Get the user running the script for local socket login.
$user = posix_getpwuid(posix_geteuid())['name'];
}
$connectionString = 'mysql:';
if(mb_stripos($host, ':') !== false){
$port = null;
preg_match('/([^:]*):([0-9]+)/ius', $host, $matches);
if(sizeof($matches) > 1){
$host = $matches[1];
}
if(sizeof($matches) > 2){
$port = $matches[2];
}
$connectionString .= 'host=' . $host;
if($port !== null){
$connectionString .= ';port=' . $port;
}
}
else{
$connectionString .= 'host=' . $host;
}
if($defaultDatabase !== null){
$connectionString .= ';dbname=' . $defaultDatabase;
}
// We can't use persistent connections (connection pooling) because we would have race conditions with `last_insert_id()`.
$params = [\PDO::ATTR_EMULATE_PREPARES => false, \PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION, \PDO::ATTR_PERSISTENT => false];
if($forceUtf8){
$params[\PDO::MYSQL_ATTR_INIT_COMMAND] = 'set names utf8mb4 collate utf8mb4_unicode_ci;';
}
static::$Link = new \PDO($connectionString, $user, $password, $params);
}
/**
* Execute a generic query in the database.
*
* @template T
*
* @param string $sql The SQL query to execute.
* @param array<mixed> $params An array of parameters to bind to the SQL statement.
* @param class-string<T> $class The type of object to return in the return array.
*
* @return array<T> An array of objects of type `$class`, or `stdClass` if `$class` is `null`.
*
* @throws Exceptions\DuplicateDatabaseKeyException If a unique key constraint has been violated.
* @throws Exceptions\DatabaseQueryException If an error occurs during execution of the query.
*/
public static function Query(string $sql, array $params = [], string $class = 'stdClass'): array{
$handle = static::PreparePdoHandle($sql, $params);
$result = [];
$deadlockRetries = 0;
$done = false;
while(!$done){
try{
$result = static::ExecuteQuery($handle, $class);
$done = true;
}
catch(\PDOException $ex){
if(isset($ex->errorInfo[1]) && $ex->errorInfo[1] == 1213 && $deadlockRetries < 3){
// InnoDB deadlock, this is normal and happens occasionally. All we have to do is retry the query.
$deadlockRetries++;
usleep(500000 * $deadlockRetries); // Give the deadlock some time to clear up. Start at .5 seconds
}
elseif(isset($ex->errorInfo[1]) && $ex->errorInfo[1] == 1062){
// Duplicate key, bubble this up without logging it so the business logic can handle it
throw new Exceptions\DuplicateDatabaseKeyException(str_replace('SQLSTATE[23000]: Integrity constraint violation: 1062 ', '', $ex->getMessage() . '. Query: ' . $sql . '. Parameters: ' . vds($params)));
}
else{
throw static::CreateDetailedException($ex, $sql, $params);
}
}
}
static::$QueryCount++;
return $result;
}
/**
* Execute a select query that returns a join against multiple tables.
*
* For example, `select * from Users inner join Posts on Users.UserId = Posts.UserId`.
*
* The result is an array of objects generated from the object's `FromMultiTableRow()` method. The `FromMultiTableRow()` method must have this signature:
*
* ```php
* public static function FromMultiTableRow(array $row): T
* ```
*
* **Important note:** If the two tables are joined via `using (Id)` instead of `on TableA.Id = TableB.Id`, the SQL query would return only one column for the join key (`Id` in this case). Therefore, if both objects require that column, the `FromMultiTableRow()` must explicitly assign the column to the object that's missing it, typically the second table in the join.
*
* @template T
*
* @param string $sql The SQL query to execute.
* @param array<mixed> $params An array of parameters to bind to the SQL statement.
* @param class-string<T> $class The class to instantiate for each row.
*
* @return array<T> An array of `$class`.
*
* @throws Exceptions\MultiSelectMethodNotFoundException If the class doesn't have a `FromMultiTableRow()` method.
* @throws Exceptions\DatabaseQueryException If an error occurs during execution of the query.
*/
public static function MultiTableSelect(string $sql, array $params, string $class): array{
if(!method_exists($class, 'FromMultiTableRow')){
throw new Exceptions\MultiSelectMethodNotFoundException($class);
}
$handle = static::PreparePdoHandle($sql, $params);
$result = [];
$deadlockRetries = 0;
$done = false;
while(!$done){
try{
/** @var array<T> $result */
$result = static::ExecuteMultiTableSelect($handle, $class);
$done = true;
}
catch(\PDOException $ex){
if(isset($ex->errorInfo[1]) && $ex->errorInfo[1] == 1213 && $deadlockRetries < 3){
// InnoDB deadlock, this is normal and happens occasionally. All we have to do is retry the query.
$deadlockRetries++;
usleep(500000 * $deadlockRetries); // Give the deadlock some time to clear up. Start at .5 seconds.
}
else{
throw static::CreateDetailedException($ex, $sql, $params);
}
}
}
static::$QueryCount++;
return $result;
}
/**
* Execute a select query that returns a join against multiple tables.
*
* For example, `select * from Users inner join Posts on Users.UserId = Posts.UserId`.
*
* The result is an array of rows. Each row is an array of objects, with each object containing its columns and values. For example,
*
* ```php
* [
* [
* 'Users' => {
* 'UserId' => 111,
* 'Name' => 'Alice'
* },
* 'Posts' => {
* 'PostId' => 222,
* 'UserId' => 111,
* 'Title' => 'Lorem Ipsum'
* }
* ],
* [
* 'Users' => {
* 'UserId' => 333,
* 'Name' => 'Bob'
* },
* 'Posts' => {
* 'PostId' => 444,
* 'UserId' => 333,
* 'Title' => 'Dolor sit'
* }
* ]
* ]
* ```
*
* **Important note:** If the two tables are joined via `using (Id)` instead of `on TableA.Id = TableB.Id`, the SQL query would return only one column for the join key (`Id` in this case).
*
* @param string $sql The SQL query to execute.
* @param array<mixed> $params An array of parameters to bind to the SQL statement.
*
* @return array<array<string, stdClass>> An array of `$class` if `$class` is not `null`, otherwise an array of rows of the form `["LeftTableName" => $stdClass, "RightTableName" => $stdClass]`.
*
* @throws Exceptions\DatabaseQueryException If an error occurs during execution of the query.
*/
public static function MultiTableSelectGeneric(string $sql, array $params): array{
$handle = static::PreparePdoHandle($sql, $params);
$result = [];
$deadlockRetries = 0;
$done = false;
while(!$done){
try{
/** @var array<array<string, stdClass>> $result */
$result = static::ExecuteMultiTableSelect($handle, stdClass::class);
$done = true;
}
catch(\PDOException $ex){
if(isset($ex->errorInfo[1]) && $ex->errorInfo[1] == 1213 && $deadlockRetries < 3){
// InnoDB deadlock, this is normal and happens occasionally. All we have to do is retry the query.
$deadlockRetries++;
usleep(500000 * $deadlockRetries); // Give the deadlock some time to clear up. Start at .5 seconds.
}
else{
throw static::CreateDetailedException($ex, $sql, $params);
}
}
}
static::$QueryCount++;
return $result;
}
/**
* Given a string of SQL, prepare a PDO handle by binding the parameters to the query.
*
* @param string $sql The SQL query to execute.
* @param array<mixed> $params An array of parameters to bind to the SQL statement.
*
* @return \PDOStatement The `\PDOStatement` to be used to execute the query.
*
* @throws Exceptions\DatabaseQueryException If an error occurs during execution of the query.
*/
protected static function PreparePdoHandle(string $sql, array $params): \PDOStatement{
try{
/** @throws \PDOException */
$handle = static::$Link->prepare($sql);
}
catch(\PDOException $ex){
throw static::CreateDetailedException($ex, $sql, $params);
}
$name = 0;
foreach($params as $parameter){
$name++;
if($parameter instanceof DateTimeInterface){
$handle->bindValue($name, $parameter->format('Y-m-d H:i:s'));
}
elseif(is_bool($parameter)){
// MySQL strict mode requires `0` or `1` instead of `true` or `false`.
// We can't use `PDO::PARAM_BOOL`, it just doesn't work.
$handle->bindValue($name, $parameter ? 1 : 0, PDO::PARAM_INT);
}
elseif($parameter instanceof BackedEnum){
$handle->bindValue($name, $parameter->value);
}
elseif(is_int($parameter)){
$handle->bindValue($name, $parameter, PDO::PARAM_INT);
}
else{
$handle->bindValue($name, $parameter);
}
}
return $handle;
}
/**
* Execute a regular query and return the result as an array of objects.
*
* @template T
*
* @param \PDOStatement $handle The PDO handle to execute.
* @param class-string<T> $class The type of object to return in the return array.
*
* @return array<T> An array of objects of type `$class`, or `stdClass` if `$class` is `null`.
*
* @throws \PDOException If an error occurs during execution of the query.
*/
protected static function ExecuteQuery(\PDOStatement $handle, string $class = 'stdClass'): array{
$handle->execute();
static::$LastQueryAffectedRowCount = $handle->rowCount();
$result = [];
do{
try{
$columnCount = $handle->columnCount();
if($columnCount == 0){
continue;
}
$metadata = [];
for($i = 0; $i < $columnCount; $i++){
$metadata[$i] = $handle->getColumnMeta($i);
}
$rows = $handle->fetchAll(\PDO::FETCH_NUM);
$useObjectFillMethod = method_exists($class, 'FromRow');
foreach($rows as $row){
if($useObjectFillMethod){
$object = new stdClass();
}
else{
$object = new $class();
}
for($i = 0; $i < $handle->columnCount(); $i++){
if($metadata[$i] === false){
continue;
}
if($useObjectFillMethod){
// Don't specify a class so that we don't perform an enum check at this point.
// We'll check for enum types in the class's `FromRow()` method.
$object->{$metadata[$i]['name']} = static::GetColumnValue($row[$i], $metadata[$i]);
}
else{
$object->{$metadata[$i]['name']} = static::GetColumnValue($row[$i], $metadata[$i], $class);
}
}
if($useObjectFillMethod){
$result[] = $class::FromRow($object);
}
else{
$result[] = $object;
}
}
}
catch(\PDOException $ex){
// `HY000` is thrown when there is no result set, e.g. for an update operation.
// If anything besides that is thrown, then send it up the stack.
if(!isset($ex->errorInfo[0]) || $ex->errorInfo[0] != "HY000"){
throw $ex;
}
}
}
while($handle->nextRowset());
return $result;
}
/**
* Execute a multi-table select query.
*
* @template T
*
* @param \PDOStatement $handle The PDO handle to execute.
* @param class-string<T> $class The class to instantiate for each row, or `stdClass` to return an array of rows.
*
* @return array<T>|array<array<string, stdClass>> An array of `$class` if `$class` is not `stdClass`, otherwise an array of rows of the form `["LeftTableName" => $stdClass, "RightTableName" => $stdClass]`.
*
* @throws \PDOException If an error occurs during execution of the query.
*/
protected static function ExecuteMultiTableSelect(\PDOStatement $handle, string $class): array{
$handle->execute();
static::$LastQueryAffectedRowCount = $handle->rowCount();
$result = [];
do{
$columnCount = $handle->columnCount();
if($columnCount == 0){
continue;
}
$metadata = [];
for($i = 0; $i < $columnCount; $i++){
$metadata[$i] = $handle->getColumnMeta($i);
}
$rows = $handle->fetchAll(\PDO::FETCH_NUM);
foreach($rows as $row){
$resultRow = [];
for($i = 0; $i < $handle->columnCount(); $i++){
if($metadata[$i] === false || !isset($metadata[$i]['table'])){
continue;
}
$object = $resultRow[$metadata[$i]['table']] ?? new stdClass();
$object->{$metadata[$i]['name']} = static::GetColumnValue($row[$i], $metadata[$i]);
$resultRow[$metadata[$i]['table']] = $object;
}
if($class == stdClass::class){
$result[] = $resultRow;
}
else{
$result[] = $class::FromMultiTableRow($resultRow);
}
}
}
while($handle->nextRowset());
return $result;
}
/**
* Given a column value and its database driver metadata, return a strongly-typed value.
*
* @param mixed $column The value of the column, most likely either a string or integer.
* @param array<mixed> $metadata An array of metadata returned from the database driver.
* @param string $class The type of object that this return value will be part of.
*
* @return mixed The strongly-typed column value.
*/
protected static function GetColumnValue(mixed $column, array $metadata, string $class = 'stdClass'): mixed{
if($column === null){
return null;
}
else{
switch($metadata['native_type'] ?? null){
case 'DATE':
case 'DATETIME':
case 'TIMESTAMP':
/** @throws void */
/** @var string $column */
return new DateTimeImmutable($column);
case 'LONG':
case 'TINY':
case 'SHORT':
case 'INT24':
case 'LONGLONG':
/** @var int $column */
return intval($column);
case 'FLOAT':
case 'DOUBLE':
case 'NEWDECIMAL':
/** @var string $column */
return floatval($column);
case 'STRING':
// We don't check the type `VAR_STRING` here because in MariaDB, enums are always of type `STRING`.
// Since this check is slow, we don't want to run it unnecessarily.
if($class == 'stdClass'){
return $column;
}
else{
// If the column is a string and we're filling a typed object, check if the object property is a backed enum. If so, generate it using `type::from()`. Otherwise, fill it with a string.
// Note: Using `ReflectionProperty` in this way is pretty slow. Maybe we'll think of a better way to automatically fill enum types later.
try{
$rp = new ReflectionProperty($class, $metadata['name']);
/** @var ?ReflectionNamedType $property */
$property = $rp->getType();
if($property !== null){
$type = $property->getName();
if(is_a($type, 'BackedEnum', true)){
/** @var string $column */
return $type::from($column);
}
else{
return $column;
}
}
else{
return $column;
}
}
catch(\Exception){
return $column;
}
}
default:
return $column;
}
}
}
/**
* Create a detailed `Exceptions\DatabaseQueryException` from a `\PDOException`.
*
* @param \PDOException $ex The exception to create details from.
* @param string $sql The prepared SQL that caused the exception.
* @param array<mixed> $params The parameters passed to the prepared SQL.
*
* @return Exceptions\DatabaseQueryException A more detailed exception to be thrown further up the stack.
*/
protected static function CreateDetailedException(\PDOException $ex, string $sql, array $params): Exceptions\DatabaseQueryException{
// Throw a custom exception that includes more information on the query and paramaters.
return new Exceptions\DatabaseQueryException('Error when executing query: ' . $ex->getMessage() . '. Query: ' . $sql . '. Parameters: ' . vds($params));
}
/**
* Given a list of arguments to pass to an SQL query whose last two arguments are integers representing the values in a `limit` clause, recalculate the last item to a value close to infinity if that value is zero.
*
* For example, passing array `['bob', 0, 0]` would return `['bob', 0, 999999999]`. This would be useful to pass to a query with a `limit` clause, like:
*
* ```sql
* select * from Users where Username = ? limit ?, ?;
* ```
*
* @param array<mixed> $args A list of SQL query arguments, with two integers representing limits as the last two items.
*
* @return array<mixed>
*/
public static function ParseLimits(array $args): array{
if(sizeof($args) >= 2){
if($args[sizeof($args) - 2] == 0 && ($args[sizeof($args) - 1] === 0 || $args[sizeof($args) - 1] === null)){
$args[sizeof($args) - 1] = 999999999; // Close enough to infinity.
}
}
return $args;
}
}