From 059e0d95d0c28bc5060e87e146eaf7411f51bf90 Mon Sep 17 00:00:00 2001
From: George Halkiadakis <gchalkiadakis@sklavenitis.co.gr>
Date: Thu, 27 Apr 2023 03:47:30 +0300
Subject: skeleton commit; based on an anom project

---
 core/helpers/error_handling.php | 119 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 core/helpers/error_handling.php

(limited to 'core/helpers/error_handling.php')

diff --git a/core/helpers/error_handling.php b/core/helpers/error_handling.php
new file mode 100644
index 0000000..95db98c
--- /dev/null
+++ b/core/helpers/error_handling.php
@@ -0,0 +1,119 @@
+<?php
+/** ERROR HANDLING SECTION
+ * handles exceptions and errors (even fatal)
+ * -----------------------------------------------------------------------------
+ * The code...
+ * + Catches and handles all Errors and Throwable exceptions;
+ * - creates the error messages (for the requester and developer) 
+ * ? TODO: routes the error messages to the logging channels
+ */
+
+
+// Global array to save errors
+$anom_ERRORS = [];  // ok, Globals are not recommended, but...
+    // this one collects only errors (about the application);
+    // it is oriented for the developer; not for the request.
+
+
+/** Error handler,
+ * passes flow over the exception logger with new ErrorException.
+ */
+function handle_error(int $type, string $message, string $file, int $line)
+{
+    handle_exception( new ErrorException($message, 0, $type, $file, $line) );
+}
+
+
+/** Uncaught exception handler.
+*/
+function handle_exception(Throwable $e)
+{
+    global $anom_ERRORS;
+    
+    // full message description to be logged
+    $message = get_class($e) .": ". $e->getMessage()
+        . " on file '". $e->getFile() . "' at line {$e->getLine()}";
+
+    $anom_ERRORS[] = $message;      // store the error
+}
+
+
+/**
+ * Catch fatal error work-around
+ * (set_error_handler not working on fatal errors).
+ */
+function on_shutdown_check_for_fatal()
+{
+    global $anom_ERRORS;
+
+    $error = error_get_last();
+
+    if ($error != null) {       // ignore 'normal' system shutdowns [exit|die]() 
+
+        if ( $error["type"] == E_ERROR ) {      // get as much error-info
+            handle_error(
+                $error["type"] ?? -1,
+                $error["message"] ?? 'unknown error',
+                $error["file"] ?? 'unknown file',
+                $error["line"] ?? -1
+            );
+        }
+    }
+    
+    if (($anom_ERRORS != [])) {
+
+        // TODO:
+        // Implemetnig the design/layout of the error-messages
+        // output should not be an error's-handling task, thus
+        // shall be assigned to the Rendes/View level;
+        // Same about the log service channels
+
+        // TODO:
+        // FORWARD ERRORS into LOG-SYSTEM
+        // ex. into some file...
+        // file_put_contents("logs/thowable.log", $message_template .PHP_EOL, FILE_APPEND);
+        // or ...some other channer (Email, Slack, Database etc).
+        // Channes can be decided according to error severity;
+        // a file-system error loggin for backup is recommended
+        // partitioniong of errors onto file-system can be useful
+
+        // TODO:
+        // 1st: Log Errors
+        // 2nd: Show Errors
+
+        if (PRODUCTION) {
+            if (!defined('OUTPUT_STARTED')) {
+                // throw a prety-error message
+                Render::view('error/general', ['message' => 'Please forgive me, I know not what I do']);
+            }
+
+        } else {
+
+            if (!defined('OUTPUT_STARTED')) {
+                // no template loaded; render erros in general-error template
+                Render::view('error/general', ['message' => implode("<br/>And:<br/>", $anom_ERRORS)]);
+
+            } else {
+                 echo '<div style="padding:1em;background:#933;width:100%;color:#fff">
+                    Errors:<br />'. implode("<br/>And:<br/>", $anom_ERRORS) .'</div>';
+            }
+        }
+    }
+}
+
+
+// register callback on shutdown
+register_shutdown_function( "on_shutdown_check_for_fatal" );
+
+// register custom error handler callback
+set_error_handler( "handle_error" );
+
+// set custom exception handler function
+set_exception_handler( "handle_exception" );
+
+// send errors to stderr (instead of stdout)
+ini_set( "display_errors", "off" );
+
+// thow out all errors
+error_reporting( E_ALL );
+
-- 
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