Handle DateTime objects in formatted messages (#940)

* Handle DateTime objects in formatted meessages

* Use interface to catch both DateTime and DateTimeImmutable

* Maintain formatting standards.

* Visibility to private.

1 files changed, 14 insertions, 0 deletions

diff --git a/src/Monolog/Processor/PsrLogMessageProcessor.php b/src/Monolog/Processor/PsrLogMessageProcessor.php
index b9a00a4..8078403 100644
--- a/src/Monolog/Processor/PsrLogMessageProcessor.php
+++ b/src/Monolog/Processor/PsrLogMessageProcessor.php
@@ -20,6 +20,18 @@ namespace Monolog\Processor;
  */
 class PsrLogMessageProcessor
 {
+    const SIMPLE_DATE = "Y-m-d\TH:i:sP";
+
+    private $dateFormat;
+
+    /**
+     * @param string $dateFormat The format of the timestamp: one supported by DateTime::format
+     */
+    public function __construct(string $dateFormat = null)
+    {
+        $this->dateFormat = null === $dateFormat ? static::SIMPLE_DATE : $dateFormat;
+    }
+
     /**
      * @param  array $record
      * @return array
@@ -34,6 +46,8 @@ class PsrLogMessageProcessor
         foreach ($record['context'] as $key => $val) {
             if (is_null($val) || is_scalar($val) || (is_object($val) && method_exists($val, "__toString"))) {
                 $replacements['{'.$key.'}'] = $val;
+            } elseif ($val instanceof \DateTimeInterface) {
+                $replacements['{'.$key.'}'] = $val->format($this->dateFormat);
             } elseif (is_object($val)) {
                 $replacements['{'.$key.'}'] = '[object '.get_class($val).']';
             } else {