reactiveData/sys/sys.php

<?php
/* 
*   
*     3. SYS-Level 
*     
*       
*/

function get_db_connection($db_host = null, $db_user = null, $db_pass = null, $db_name = null) {
    global $db;

    // If custom credentials or a custom DB are provided, create a fresh, temporary connection
    if ($db_host !== null || $db_user !== null || $db_pass !== null || $db_name !== null) {
        $host = $db_host ?? DB_HOST;
        $user = $db_user ?? DB_USER;
        $pass = $db_pass ?? DB_PASS;
        $name = $db_name ?? (defined('DB_NAME') ? DB_NAME : '');

        $dsn_base = "mysql:host=" . $host . ";";
        $dsn_full = $dsn_base . (!empty($name) ? "dbname=" . $name . ";" : "");

        try {
            return new PDO($dsn_full, $user, $pass);
        } catch (PDOException $e) {
            // MySQL Error 1049 is "Unknown database". If caught, fallback to connection without DB.
            if (strpos($e->getMessage(), '1049') !== false) {
                return new PDO($dsn_base, $user, $pass);
            }
            throw $e; // Re-throw if it's a real connection/auth issue
        }
    }

    // Otherwise, use or initialize the global connection using constants
    if (!isset($db) || is_null($db)) {
        $dsn_base = "mysql:host=" . DB_HOST . ";";
        $name = defined('DB_NAME') ? DB_NAME : '';
        $dsn_full = $dsn_base . (!empty($name) ? "dbname=" . $name . ";" : "");

        try {
            $db = new PDO($dsn_full, DB_USER, DB_PASS);
        } catch (PDOException $e) {
            if (strpos($e->getMessage(), '1049') !== false) {
                $db = new PDO($dsn_base, DB_USER, DB_PASS);
            } else {
                throw $e;
            }
        }
    }
    return $db;
}

function sql_read($query, $db_host = null, $db_user = null, $db_pass = null, $db_name = null) {
    $pdo = get_db_connection($db_host, $db_user, $db_pass, $db_name);
    $stmt = $pdo->prepare($query);

    if ($stmt->execute() === false) {
        return ["status" => "error", "query" => $query];
    }
    return $stmt->fetchAll(PDO::FETCH_ASSOC);
}

function sql_write($query, $db_host = null, $db_user = null, $db_pass = null, $db_name = null) {
    $pdo = get_db_connection($db_host, $db_user, $db_pass, $db_name);
    $stmt = $pdo->prepare($query);

    if ($stmt->execute() === false) {
        die("sql error: $query");
    }
    return $stmt->rowCount();
}

function sql($query, $db_host = null, $db_user = null, $db_pass = null, $db_name = null) {
	if (
		stripos(trim($query), "SHOW") === 0 
		|| stripos(trim($query), "DESCRIBE") === 0
		|| stripos(trim($query), "SELECT") === 0
	) {
        return sql_read($query, $db_host, $db_user, $db_pass, $db_name);
    } else {
        return sql_write($query, $db_host, $db_user, $db_pass, $db_name);
    }
}


function runProcess($cmd, $stdin, &$stdout, &$stderr) {
    $descriptorspec = array(
        0 => array("pipe", "r"),  // stdin is a pipe that the child will read from
        1 => array("pipe", "w"),  // stdout is a pipe that the child will write to
        2 => array("pipe", "w")   // stderr is a pipe that the child will write to
    );

    $process = proc_open($cmd, $descriptorspec, $pipes);

    if (is_resource($process)) {
        // Write to stdin and close it
        fwrite($pipes[0], $stdin);
        fclose($pipes[0]);

        // Read the output of the command
        $stdout = stream_get_contents($pipes[1]);
        fclose($pipes[1]);

        // Read the error output of the command
        $stderr = stream_get_contents($pipes[2]);
        fclose($pipes[2]);

        // It's important to close all pipes before calling proc_close in order to avoid a deadlock
        $return_value = proc_close($process);

        return $return_value;
    } else {
        // Return an error code if the process could not be started
        return -1;
    }
}
function getTblPrimaryKeyColName($tblName) {
        $dbName = explode(".",$tblName)[0];
        $tblName = explode(".",$tblName)[1];

        $cols = [];
        foreach(sql("SELECT COLUMN_NAME PksColName FROM information_schema.KEY_COLUMN_USAGE WHERE TABLE_SCHEMA = '$dbName' AND TABLE_NAME = '$tblName' AND CONSTRAINT_NAME = 'PRIMARY';") as $row)
                $cols[] = $row["PksColName"];
        return $cols;
}

/**
 * Executes a SELECT query and hydrates any foreign key columns with the
 * referenced row data.
 *
 * The query should target a single table (e.g., "SELECT * FROM db.table WHERE …").
 * For each foreign key in that table, an additional key named
 * `<column>_ref` is added to each returned row containing the referenced row
 * from the foreign table.
 *
 * @param string $query SQL SELECT statement for a single table.
 * @return array        Result set with hydrated foreign key data.
 */
function sql_read_and_hydrate($query) {
    $rows = sql_read($query);
    if (empty($rows)) {
        return $rows;
    }

    if (!preg_match('/FROM\s+([`\w\.]+)/i', $query, $m)) {
        return $rows; // Unable to determine table
    }

    $table = str_replace('`', '', $m[1]);
    if (strpos($table, '.') !== false) {
        list($dbName, $tblName) = explode('.', $table, 2);
    } else {
        $dbName = DB_NAME;
        $tblName = $table;
    }

    $fks = sql_read(
        "SELECT COLUMN_NAME, REFERENCED_TABLE_SCHEMA, REFERENCED_TABLE_NAME, " .
        "REFERENCED_COLUMN_NAME FROM information_schema.KEY_COLUMN_USAGE " .
        "WHERE TABLE_SCHEMA = '$dbName' AND TABLE_NAME = '$tblName' " .
        "AND REFERENCED_TABLE_NAME IS NOT NULL"
    );

    if (empty($fks)) {
        return $rows; // no foreign keys
    }

    foreach ($rows as &$row) {
        foreach ($fks as $fk) {
            $col = $fk['COLUMN_NAME'];
            if (!isset($row[$col])) continue;

            $val = $row[$col];
            if ($val === null) {
                $row[$col . '_ref'] = null;
                continue;
            }

            $refTable = $fk['REFERENCED_TABLE_SCHEMA'] . '.' . $fk['REFERENCED_TABLE_NAME'];
            $refCol = $fk['REFERENCED_COLUMN_NAME'];
            $condition = is_numeric($val)
                ? "$refCol = $val"
                : "$refCol = '" . str_replace("'", "''", $val) . "'";
            $refRow = sql_read("SELECT * FROM $refTable WHERE $condition LIMIT 1");
            $row[$col . '_ref'] = $refRow[0] ?? null;
        }
    }
    unset($row);

    return $rows;
}