Polymorphic refactor + improvements to select sql rewriting

pg4wp/driver_pgsql_rewrite.php

@@ -0,0 +1,204 @@
+<?php
+
+// Autoload function to automatically require rewriter classes from the "rewriters" folder
+spl_autoload_register(function ($className) {
+    $filePath = PG4WP_ROOT . '/rewriters/' . $className . '.php';
+    if (file_exists($filePath)) {
+        require_once $filePath;
+    }
+});
+
+
+function createSQLRewriter(string $sql): AbstractSQLRewriter
+{
+    $sql = trim($sql);
+    if (preg_match('/^(SELECT|INSERT|UPDATE|DELETE|SHOW TABLES|OPTIMIZE TABLE|SET NAMES|SHOW FULL COLUMNS)\b/i', $sql, $matches)) {
+        // Convert to a format suitable for class names (e.g., "SHOW TABLES" becomes "ShowTables")
+        $type = str_replace(' ', '', ucwords(str_replace('_', ' ', strtolower($matches[1]))));
+        $className = $type . 'SQLRewriter';
+
+        if (class_exists($className)) {
+            return new $className($sql);
+        } else {
+            throw new Exception("No class defined to handle SQL type: " . $type);
+        }
+    }
+    throw new Exception("Invalid or unsupported SQL statement.");
+}
+
+
+function pg4wp_rewrite($sql)
+{
+    // Note:  Can be called from constructor before $wpdb is set
+    global $wpdb;
+
+    $initial = $sql;
+    $logto = 'queries';
+    // The end of the query may be protected against changes
+    $end = '';
+
+    $rewriter = createSQLRewriter(trim($sql));
+    $sql = $rewriter->rewrite();
+    $logto = strtoupper($rewriter->type());
+    switch ($rewriter->type()) {
+        case 'Update':
+            // This will avoid modifications to anything following ' SET '
+            list($sql, $end) = explode(' SET ', $sql, 2);
+            $end = ' SET ' . $end;
+            break;
+        case 'Insert':
+            // This will avoid modifications to anything following ' VALUES'
+            list($sql, $end) = explode(' VALUES', $sql, 2);
+            $end = ' VALUES' . $end;
+
+            // When installing, the sequence for table terms has to be updated
+            if(defined('WP_INSTALLING') && WP_INSTALLING && false !== strpos($sql, 'INSERT INTO `' . $wpdb->terms . '`')) {
+                $end .= ';SELECT setval(\'' . $wpdb->terms . '_seq\', (SELECT MAX(term_id) FROM ' . $wpdb->terms . ')+1);';
+            }
+            break;
+        case 'Insert':
+            break;
+        default:
+    }
+
+    $sql = loadInstallFunctions($sql, $logto);
+    $sql = correctMetaValue($sql);
+    $sql = handleInterval($sql);
+    $sql = cleanAndCapitalize($sql);
+    $sql = correctEmptyInStatements($sql);
+    $sql = correctQuoting($sql);
+
+    // Put back the end of the query if it was separated
+    $sql .= $end;
+
+    // For insert ID catching
+    if($logto == 'INSERT') {
+        $pattern = '/INSERT INTO (\w+)\s+\([ a-zA-Z_"]+/';
+        preg_match($pattern, $sql, $matches);
+        $GLOBALS['pg4wp_ins_table'] = $matches[1];
+        $match_list = explode(' ', $matches[0]);
+        if($GLOBALS['pg4wp_ins_table']) {
+            $GLOBALS['pg4wp_ins_field'] = trim($match_list[3], ' ()	');
+            if(!$GLOBALS['pg4wp_ins_field']) {
+                $GLOBALS['pg4wp_ins_field'] = trim($match_list[4], ' ()	');
+            }
+        }
+        $GLOBALS['pg4wp_last_insert'] = $sql;
+    } elseif(isset($GLOBALS['pg4wp_queued_query'])) {
+        pg_query($GLOBALS['pg4wp_queued_query']);
+        unset($GLOBALS['pg4wp_queued_query']);
+    }
+
+    if(PG4WP_DEBUG) {
+        if($initial != $sql) {
+            error_log('[' . microtime(true) . "] Converting :\n$initial\n---- to ----\n$sql\n---------------------\n", 3, PG4WP_LOG . 'pg4wp_' . $logto . '.log');
+        } else {
+            error_log('[' . microtime(true) . "] $sql\n---------------------\n", 3, PG4WP_LOG . 'pg4wp_unmodified.log');
+        }
+    }
+    return $sql;
+}
+
+/**
+ * Load upgrade and install functions as required.
+ *
+ * @param string $sql SQL query string
+ * @param string $logto Logging type
+ * @return string Modified SQL query string
+ */
+function loadInstallFunctions($sql, &$logto)
+{
+    $begin = strtoupper(substr($sql, 0, 3));
+    $search = array('SHO', 'ALT', 'DES', 'CRE', 'DRO');
+    if (in_array($begin, $search)) {
+        require_once(PG4WP_ROOT . '/driver_pgsql_install.php');
+        $sql = pg4wp_installing($sql, $logto);
+    }
+    return $sql;
+}
+
+/**
+ * Correct the meta_value field for WP 2.9.1 and add type cast.
+ *
+ * @param string $sql SQL query string
+ * @return string Modified SQL query string
+ */
+function correctMetaValue($sql)
+{
+    // WP 2.9.1 uses a comparison where text data is not quoted
+    $sql = preg_replace('/AND meta_value = (-?\d+)/', 'AND meta_value = \'$1\'', $sql);
+    // Add type cast for meta_value field when it's compared to number
+    $sql = preg_replace('/AND meta_value < (\d+)/', 'AND meta_value::bigint < $1', $sql);
+    return $sql;
+}
+
+/**
+ * Handle interval expressions in SQL query.
+ *
+ * @param string $sql SQL query string
+ * @return string Modified SQL query string
+ */
+function handleInterval($sql)
+{
+    // Generic "INTERVAL xx YEAR|MONTH|DAY|HOUR|MINUTE|SECOND" handler
+    $sql = preg_replace('/INTERVAL[ ]+(\d+)[ ]+(YEAR|MONTH|DAY|HOUR|MINUTE|SECOND)/', "'\$1 \$2'::interval", $sql);
+    // DATE_SUB handling
+    $sql = preg_replace('/DATE_SUB[ ]*\(([^,]+),([^\)]+)\)/', '($1::timestamp - $2)', $sql);
+    return $sql;
+}
+
+/**
+ * Clean SQL query from illegal characters and handle capitalization.
+ *
+ * @param string $sql SQL query string
+ * @return string Modified SQL query string
+ */
+function cleanAndCapitalize($sql)
+{
+    // Remove illegal characters
+    $sql = str_replace('`', '', $sql);
+    // Field names with CAPITALS need special handling
+    if (false !== strpos($sql, 'ID')) {
+        $patterns = [
+            '/ID([^ ])/' => 'ID $1',
+            '/ID$/' => 'ID ',
+            '/\(ID/' => '( ID',
+            '/,ID/' => ', ID',
+            '/[0-9a-zA-Z_]+ID/' => '"$0"',
+            '/\.ID/' => '."ID"',
+            '/[\s]ID /' => ' "ID" ',
+            '/"ID "/' => ' "ID" '
+        ];
+        foreach ($patterns as $pattern => $replacement) {
+            $sql = preg_replace($pattern, $replacement, $sql);
+        }
+    }
+    return $sql;
+}
+
+/**
+ * Correct empty IN statements in SQL query.
+ *
+ * @param string $sql SQL query string
+ * @return string Modified SQL query string
+ */
+function correctEmptyInStatements($sql)
+{
+    $search = ['IN (\'\')', 'IN ( \'\' )', 'IN ()'];
+    $replace = 'IN (NULL)';
+    $sql = str_replace($search, $replace, $sql);
+    return $sql;
+}
+
+/**
+ * Correct quoting for PostgreSQL 9.1+ compatibility.
+ *
+ * @param string $sql SQL query string
+ * @return string Modified SQL query string
+ */
+function correctQuoting($sql)
+{
+    $sql = str_replace("\\'", "''", $sql);
+    $sql = str_replace('\"', '"', $sql);
+    return $sql;
+}

pg4wp/rewriters/AbstractSQLRewriter.php

@@ -0,0 +1,26 @@
+<?php
+
+abstract class AbstractSQLRewriter
+{
+    protected string $originalSQL;
+
+    public function __construct(string $sql)
+    {
+        $this->originalSQL = $sql;
+    }
+
+    abstract public function rewrite(): string;
+
+    public function original(): string
+    {
+        return $this->originalSQL;
+    }
+
+    public function type(): string
+    {
+        // Get the called class name and remove the "SQLRewriter" suffix to get the SQL type
+        $className = get_called_class();
+        $type = str_replace('SQLRewriter', '', $className);
+        return $type;
+    }
+}

pg4wp/rewriters/DeleteSQLRewriter.php

@@ -0,0 +1,60 @@
+<?php
+
+class DeleteSQLRewriter extends AbstractSQLRewriter
+{
+    public function rewrite(): string
+    {
+        global $wpdb;
+
+        $sql = $this->original();
+
+        // ORDER BY is not supported in DELETE queries, and not required
+        // when LIMIT is not present
+        if(false !== strpos($sql, 'ORDER BY') && false === strpos($sql, 'LIMIT')) {
+            $pattern = '/ORDER BY \S+ (ASC|DESC)?/';
+            $sql = preg_replace($pattern, '', $sql);
+        }
+
+        // LIMIT is not allowed in DELETE queries
+        $sql = str_replace('LIMIT 1', '', $sql);
+        $sql = str_replace(' REGEXP ', ' ~ ', $sql);
+
+        // This handles removal of duplicate entries in table options
+        if(false !== strpos($sql, 'DELETE o1 FROM ')) {
+            $sql = "DELETE FROM $wpdb->options WHERE option_id IN " .
+                "(SELECT o1.option_id FROM $wpdb->options AS o1, $wpdb->options AS o2 " .
+                "WHERE o1.option_name = o2.option_name " .
+                "AND o1.option_id < o2.option_id)";
+        }
+        // Rewrite _transient_timeout multi-table delete query
+        elseif(0 === strpos($sql, 'DELETE a, b FROM wp_options a, wp_options b')) {
+            $where = substr($sql, strpos($sql, 'WHERE ') + 6);
+            $where = rtrim($where, " \t\n\r;");
+            // Fix string/number comparison by adding check and cast
+            $where = str_replace('AND b.option_value', 'AND b.option_value ~ \'^[0-9]+$\' AND CAST(b.option_value AS BIGINT)', $where);
+            // Mirror WHERE clause to delete both sides of self-join.
+            $where2 = strtr($where, array('a.' => 'b.', 'b.' => 'a.'));
+            $sql = 'DELETE FROM wp_options a USING wp_options b WHERE ' .
+                '(' . $where . ') OR (' . $where2 . ');';
+        }
+
+        // Rewrite _transient_timeout multi-table delete query
+        elseif(0 === strpos($sql, 'DELETE a, b FROM wp_sitemeta a, wp_sitemeta b')) {
+            $where = substr($sql, strpos($sql, 'WHERE ') + 6);
+            $where = rtrim($where, " \t\n\r;");
+            // Fix string/number comparison by adding check and cast
+            $where = str_replace('AND b.meta_value', 'AND b.meta_value ~ \'^[0-9]+$\' AND CAST(b.meta_value AS BIGINT)', $where);
+            // Mirror WHERE clause to delete both sides of self-join.
+            $where2 = strtr($where, array('a.' => 'b.', 'b.' => 'a.'));
+            $sql = 'DELETE FROM wp_sitemeta a USING wp_sitemeta b WHERE ' .
+                '(' . $where . ') OR (' . $where2 . ');';
+        }
+
+        // Akismet sometimes doesn't write 'comment_ID' with 'ID' in capitals where needed ...
+        if(false !== strpos($sql, $wpdb->comments)) {
+            $sql = str_replace(' comment_id ', ' comment_ID ', $sql);
+        }
+
+        return $sql;
+    }
+}