implement audit logger

dummy.php

@@ -7,6 +7,7 @@ const ROOT = __DIR__;
 class Container
 {
     static SokoWeb\Interfaces\Database\IConnection $dbConnection;
+    static SokoWeb\Interfaces\Database\IAuditLogger $auditLogger;
     static SokoWeb\Routing\RouteCollection $routeCollection;
     static SokoWeb\Interfaces\Session\ISessionHandler $sessionHandler;
     static SokoWeb\Interfaces\Request\IRequest $request;

src/Database/AuditLoggerBase.php

@@ -0,0 +1,75 @@
+<?php namespace SokoWeb\Database;
+
+use SokoWeb\Interfaces\Database\IAuditLogger;
+use SokoWeb\Interfaces\Database\IConnection;
+
+abstract class AuditLoggerBase implements IAuditLogger
+{
+    const LOG_TYPE_INSERT = 'insert';
+    const LOG_TYPE_UPDATE = 'update';
+    const LOG_TYPE_DELETE = 'delete';
+
+    private IConnection $connection;
+
+    private string $logTable;
+
+    public function __construct(IConnection $connection, string $logTable)
+    {
+        $this->connection = $connection;
+        $this->logTable = $logTable;
+    }
+
+    public function logInsert(string $localTable, $localId): void
+    {
+        $data = [
+            'local_table' => $localTable,
+            'local_id' => $localId,
+            'type' => static::LOG_TYPE_INSERT,
+            'modifier_id' => $this->getModifierId(),
+        ];
+
+        $query = 'INSERT INTO ' . Utils::backtick($this->logTable) . ' SET ' . Utils::generateColumnsWithBinding(array_keys($data));
+        $stmt = $this->connection->prepare($query);
+        $stmt->execute($data);
+    }
+
+    public function logUpdate(string $localTable, $localId, array $diff): void
+    {
+        $data = [
+            'local_table' => $localTable,
+            'local_id' => $localId,
+            'type' => static::LOG_TYPE_UPDATE,
+            'modifier_id' => $this->getModifierId(),
+            'column' => null,
+            'old' => null,
+            'new' => null,
+        ];
+
+        $query = 'INSERT INTO ' . Utils::backtick($this->logTable) . ' SET ' . Utils::generateColumnsWithBinding(array_keys($data));
+        $stmt = $this->connection->prepare($query);
+
+        foreach ($diff as $name => $values) {
+            $data['column'] = $name;
+            $data['old'] = $values['old'];
+            $data['new'] = $values['new'];
+            $stmt->execute($data);
+        }
+    }
+
+    public function logDelete(string $localTable, $localId, array $attributes): void
+    {
+        $data = [
+            'local_table' => $localTable,
+            'local_id' => $localId,
+            'type' => static::LOG_TYPE_DELETE,
+            'modifier_id' => $this->getModifierId(),
+            'old' => $attributes,
+        ];
+
+        $query = 'INSERT INTO ' . Utils::backtick($this->logTable) . ' SET ' . Utils::generateColumnsWithBinding(array_keys($data));
+        $stmt = $this->connection->prepare($query);
+        $stmt->execute($data);
+    }
+
+    abstract protected function getModifierId();
+}

src/Database/Query/Modify.php

@@ -2,6 +2,8 @@
 
 use SokoWeb\Interfaces\Database\IConnection;
 use SokoWeb\Database\Utils;
+use SokoWeb\Interfaces\Database\IAuditLogger;
+use SokoWeb\Interfaces\Database\IResultSet;
 
 class Modify
 {
@@ -9,6 +11,8 @@ class Modify
 
     private string $table;
 
+    private ?IAuditLogger $auditLogger;
+
     private string $idName = 'id';
 
     private array $attributes = [];
@@ -17,10 +21,13 @@ class Modify
 
     private bool $autoIncrement = true;
 
-    public function __construct(IConnection $connection, string $table)
+    private ?array $diff = null;
+
+    public function __construct(IConnection $connection, string $table, ?IAuditLogger $auditLogger = null)
     {
         $this->connection = $connection;
         $this->table = $table;
+        $this->auditLogger = $auditLogger;
     }
 
     public function setIdName(string $idName): Modify
@@ -65,6 +72,13 @@ class Modify
         return $this;
     }
 
+    public function setDiff(array $diff): Modify
+    {
+        $this->diff = $diff;
+
+        return $this;
+    }
+
     public function getId()
     {
         return $this->attributes[$this->idName];
@@ -89,6 +103,10 @@ class Modify
 
         $stmt = $this->connection->prepare($query);
         $stmt->execute([$this->idName => $this->attributes[$this->idName]]);
+
+        if ($this->auditLogger !== null) {
+            $this->auditLogger->logDelete($this->table, $this->attributes[$this->idName], $this->attributes);
+        }
     }
 
     private function insert(): void
@@ -99,7 +117,7 @@ class Modify
             $this->attributes[$this->idName] = $this->generateKey();
         }
 
-        $set = $this->generateColumnsWithBinding(array_keys($this->attributes));
+        $set = Utils::generateColumnsWithBinding(array_keys($this->attributes));
 
         $query = 'INSERT INTO ' . Utils::backtick($this->table) . ' SET ' . $set;
 
@@ -109,32 +127,62 @@ class Modify
         if ($this->autoIncrement) {
             $this->attributes[$this->idName] = $this->connection->lastId();
         }
+
+        if ($this->auditLogger !== null) {
+            $this->auditLogger->logInsert($this->table, $this->attributes[$this->idName]);
+        }
     }
 
     private function update(): void
     {
+        if ($this->auditLogger !== null) {
+            $this->generateDiff();
+            if (count($this->diff) === 0) {
+                return;
+            }
+        }
+
         $attributes = $this->attributes;
         unset($attributes[$this->idName]);
 
-        $set = $this->generateColumnsWithBinding(array_keys($attributes));
+        $set = Utils::generateColumnsWithBinding(array_keys($attributes));
 
         $query = 'UPDATE ' . Utils::backtick($this->table) . ' SET ' . $set . ' WHERE ' . Utils::backtick($this->idName) . '=?';
 
         $stmt = $this->connection->prepare($query);
         $stmt->execute(array_merge($attributes, [$this->idName => $this->attributes[$this->idName]]));
-    }
 
-    public static function generateColumnsWithBinding(array $columns): string
-    {
-        array_walk($columns, function(&$value, $key) {
-            $value = Utils::backtick($value) . '=?';
-        });
-
-        return implode(',', $columns);
+        if ($this->auditLogger !== null) {
+            $this->auditLogger->logUpdate($this->table, $this->attributes[$this->idName], $this->diff);
+        }
     }
 
     private function generateKey(): string
     {
         return substr(hash('sha256', serialize($this->attributes) . random_bytes(5) . microtime()), 0, 7);
     }
+
+    private function generateDiff(): void
+    {
+        if (isset($this->diff)) {
+            return;
+        }
+
+        $this->diff = [];
+        $original = $this->readFromDb(array_keys($this->attributes));
+        foreach ($original as $key => $value) {
+            if ($value !== $this->attributes[$key]) {
+                $this->diff[$key] = ['old' => $value, 'new' => $this->attributes[$key]];
+            }
+        }
+    }
+
+    private function readFromDb($columns): array
+    {
+        return (new Select($this->connection, $this->table))
+            ->columns($columns)
+            ->where($this->idName, '=', $this->attributes[$this->idName])
+            ->execute()
+            ->fetch(IResultSet::FETCH_ASSOC);
+    }
 }

src/Database/Utils.php

@@ -5,4 +5,13 @@ class Utils {
     {
         return '`' . $name . '`';
     }
+
+    public static function generateColumnsWithBinding(array $columns): string
+    {
+        array_walk($columns, function(&$value, $key) {
+            $value = static::backtick($value) . '=?';
+        });
+
+        return implode(',', $columns);
+    }
 }

src/Interfaces/Database/IAuditLogger.php

@@ -0,0 +1,10 @@
+<?php namespace SokoWeb\Interfaces\Database;
+
+interface IAuditLogger
+{
+    public function logInsert(string $localTable, $localId): void;
+
+    public function logUpdate(string $localTable, $localId, array $diff): void;
+
+    public function logDelete(string $localTable, $localId, array $attributes): void;
+}

src/PersistentData/PersistentDataManager.php

@@ -117,19 +117,23 @@ class PersistentDataManager
         $modified = $model->toArray();
         $id = $model->getId();
 
-        $modify = new Modify(\Container::$dbConnection, $model::getTable());
+        $modify = new Modify(\Container::$dbConnection, $model::getTable(), \Container::$auditLogger);
 
         if ($id !== null) {
             $original = $model->getSnapshot();
+            $diff = [];
 
             foreach ($original as $key => $value) {
                 if ($value === $modified[$key]) {
                     unset($modified[$key]);
+                } else {
+                    $diff[$key] = ['old' => $value, 'new' => $modified[$key]];
                 }
             }
 
             if (count($modified) > 0) {
                 $modify->setId($id);
+                $modify->setDiff($diff);
                 $modify->fill($modified);
                 $modify->save();
             }
@@ -145,8 +149,9 @@ class PersistentDataManager
 
     public function deleteFromDb(Model $model): void
     {
-        $modify = new Modify(\Container::$dbConnection, $model::getTable());
+        $modify = new Modify(\Container::$dbConnection, $model::getTable(), \Container::$auditLogger);
         $modify->setId($model->getId());
+        $modify->fill($model->toArray());
         $modify->delete();
 
         $model->setId(null);