Add scalar value formatter

README.mdown

@@ -181,6 +181,7 @@ Formatters
 - _ChromePHPFormatter_: Used to format log records into the ChromePHP format, only useful for the ChromePHPHandler.
 - _GelfFormatter_: Used to format log records into Gelf message instances, only useful for the GelfHandler.
 - _LogstashFormatter_: Used to format log records into [logstash](http://logstash.net/) event json, useful for any handler listed under inputs [here](http://logstash.net/docs/1.1.5/).
+- _ScalarFormatter_: Used to format log records into an associative array of scalar values.
 
 Processors
 ----------

src/Monolog/Formatter/ScalarFormatter.php

@@ -0,0 +1,125 @@
+<?php
+
+/*
+ * This file is part of the Monolog package.
+ *
+ * (c) Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Monolog\Formatter;
+
+use Monolog\Formatter\FormatterInterface;
+
+/**
+ * Formats data into an associative array of scalar values.
+ * Objects and arrays will be JSON encoded.
+ *
+ * @author Andrew Lawson <adlawson@gmail.com>
+ */
+class ScalarFormatter implements FormatterInterface
+{
+    /**
+     * @var string
+     */
+    protected $dateFormat;
+
+    /**
+     * @param string $dateFormat
+     */
+    public function __construct($dateFormat = \DateTime::ISO8601)
+    {
+        $this->dateFormat = $dateFormat;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function format(array $record)
+    {
+        $formatted = array();
+        $record = $this->exposeContext($record);
+
+        foreach ($record as $key => $value) {
+            $formatted[$key] = $this->normalizeValue($value);
+        }
+
+        return $formatted;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function formatBatch(array $records)
+    {
+        $formatted = array();
+
+        foreach ($records as $record) {
+            $formatted[] = $this->format($record);
+        }
+
+        return $formatted;
+    }
+
+    /**
+     * @param mixed $data
+     * @return string
+     */
+    protected function encodeData($data)
+    {
+        return json_encode($data, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_AMP | JSON_HEX_QUOT);
+    }
+
+    /**
+     * @param array $record
+     * @return array
+     */
+    protected function exposeContext(array $record)
+    {
+        if (isset($record['context'])) {
+            $context = $record['context'];
+
+            if (isset($context['exception'])) {
+                $record['context']['exception'] = $this->normalizeException($context['exception']);
+            }
+        }
+
+        return $record;
+    }
+
+    /**
+     * @param Exception $e
+     * @return string
+     */
+    protected function normalizeException(\Exception $e)
+    {
+        return array(
+            'message' => $e->getMessage(),
+            'code'  => $e->getCode(),
+            'class' => get_class($e),
+            'file' => $e->getFile(),
+            'line' => $e->getLine(),
+            'trace' => $e->getTraceAsString(),
+            'debug' => $e->getTrace()
+        );
+    }
+
+    /**
+     * @param mixed $value
+     * @return mixed
+     */
+    protected function normalizeValue($value)
+    {
+        if ($value instanceof \DateTime) {
+            return $value->format($this->dateFormat);
+        } elseif ($value instanceof \Exception) {
+            return $this->encodeData($this->normalizeException($value));
+        } elseif (is_array($value) || is_object($value)) {
+            return $this->encodeData($value);
+        }
+
+        return $value;
+    }
+}

tests/Monolog/Formatter/ScalarFormatterTest.php

@@ -0,0 +1,83 @@
+<?php
+namespace Monolog\Formatter;
+
+class ScalarFormatterTest extends \PHPUnit_Framework_TestCase
+{
+    public function setUp()
+    {
+        $this->formatter = new ScalarFormatter();
+    }
+
+    public function encodeJson($data)
+    {
+        return json_encode($data, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_AMP | JSON_HEX_QUOT);
+    }
+
+    public function testFormat()
+    {
+        $exception = new \Exception('foo');
+        $formatted = $this->formatter->format(array(
+            'foo' => 'string',
+            'bar' => 1,
+            'baz' => false,
+            'bam' => array(1,2,3),
+            'bat' => array('foo' => 'bar'),
+            'bap' => \DateTime::createFromFormat(\DateTime::ISO8601, '1970-01-01T00:00:00+0000'),
+            'ban' => $exception
+        ));
+
+        $this->assertSame(array(
+            'foo' => 'string',
+            'bar' => 1,
+            'baz' => false,
+            'bam' => $this->encodeJson(array(1,2,3)),
+            'bat' => $this->encodeJson(array('foo' => 'bar')),
+            'bap' => '1970-01-01T00:00:00+0000',
+            'ban' => $this->encodeJson(array(
+                'message' => $exception->getMessage(),
+                'code'    => $exception->getCode(),
+                'class'   => get_class($exception),
+                'file'    => $exception->getFile(),
+                'line'    => $exception->getLine(),
+                'trace'   => $exception->getTraceAsString(),
+                'debug'   => $exception->getTrace()
+            ))
+        ), $formatted);
+    }
+
+    public function testFormatWithErrorContext()
+    {
+        $context = array('file' => 'foo', 'line' => 1);
+        $formatted = $this->formatter->format(array(
+            'context' => $context
+        ));
+
+        $this->assertSame(array(
+            'context' => $this->encodeJson($context)
+        ), $formatted);
+    }
+
+    public function testFormatWithExceptionContext()
+    {
+        $exception = new \Exception('foo');
+        $formatted = $this->formatter->format(array(
+            'context' => array(
+                'exception' => $exception
+            )
+        ));
+
+        $this->assertSame(array(
+            'context' => $this->encodeJson(array(
+                'exception' => array(
+                    'message' => $exception->getMessage(),
+                    'code'    => $exception->getCode(),
+                    'class'   => get_class($exception),
+                    'file'    => $exception->getFile(),
+                    'line'    => $exception->getLine(),
+                    'trace'   => $exception->getTraceAsString(),
+                    'debug'   => $exception->getTrace()
+                )
+            ))
+        ), $formatted);
+    }
+}