log - PHP code example

Using the Logging Functions in PHP

Logging is a crucial part of developing PHP applications. It helps to track errors in the code and provide a detailed record of the problem for troubleshooting purposes. However, relying solely on static log files can deprive you of the real-time experience of watching how a website runs in the wild. Furthermore, logging in this fashion can be impractical for modern websites teeming with connections and network traffic.

To resolve these concerns, PHP ships with several logging functions, such as error_log() and var_dump(). These functions allow you to create logs in multiple formats and to route them to different locations, including databases and external collaboration tools. Moreover, they are compatible with popular PHP logging libraries like Monolog.

One of the most popular logging features in PHP is its ability to handle unhandled exceptions by generating a fatal error or sending them to the error log. This feature can be disabled by using the set_exception_handler() function, which allows you to customize your error handling and logging settings.

Another logging feature available in PHP is the ability to display error messages directly in the browser console. This is especially helpful when you are working on a live site and want to make sure that you can identify problems before they reach users. To do this, you must enable the display_errors configuration directive. You can also use the var_dump() function to output view variables without distorting the web page. The var_dump() function requires you to specify the output destination, which is typically a file on your server.

log example

match (true) {
                $chr < 32 || 127 === $chr => $control = 33,
                48 <= $chr && $chr <= 57 => $digit = 10,
                65 <= $chr && $chr <= 90 => $upper = 26,
                97 <= $chr && $chr <= 122 => $lower = 26,
                128 <= $chr => $other = 128,
                default => $symbol = 33,
            };
        }

        $pool = $lower + $upper + $digit + $symbol + $control + $other;
        $entropy = $chars * log($pool, 2) + ($length - $chars) * log($chars, 2);

        return match (true) {
            $entropy >= 120 => PasswordStrength::STRENGTH_VERY_STRONG,
            $entropy >= 100 => PasswordStrength::STRENGTH_STRONG,
            $entropy >= 80 => PasswordStrength::STRENGTH_MEDIUM,
            $entropy >= 60 => PasswordStrength::STRENGTH_WEAK,
            default => PasswordStrength::STRENGTH_VERY_WEAK,
        };
    }
}

    public function process(ContainerBuilder $container)
    {
        $parameterBag = $container->getParameterBag();
        $this->removedParameters = [];

        foreach ($parameterBag->all() as $name => $value) {
            if ('.' === ($name[0] ?? '')) {
                $this->removedParameters[$name] = $value;

                $parameterBag->remove($name);
                $container->log($this, sprintf('Removing build parameter "%s".', $name));
            }
        }
    }

    /** * @return array<string, mixed> */
    public function getRemovedParameters(): array
    {
        return $this->removedParameters;
    }
}

        $this->isDebug = filter_var(getenv('SYMFONY_COMPLETION_DEBUG'), \FILTER_VALIDATE_BOOL);
    }

    protected function execute(InputInterface $input, OutputInterface $output): int
    {
        try {
            // "symfony" must be kept for compat with the shell scripts generated by Symfony Console 5.4 - 6.1             $version = $input->getOption('symfony') ? '1' : $input->getOption('api-version');
            if ($version && version_compare($version, self::COMPLETION_API_VERSION, '<')) {
                $message = sprintf('Completion script version is not supported ("%s" given, ">=%s" required).', $version, self::COMPLETION_API_VERSION);
                $this->log($message);

                $output->writeln($message.' Install the Symfony completion script again by using the "completion" command.');

                return 126;
            }

            $shell = $input->getOption('shell');
            if (!$shell) {
                throw new \RuntimeException('The "--shell" option must be set.');
            }

$this->logCache = [];
        }
    }

    /** * System is unusable. * * @param string $message */
    public function emergency($message, array $context = []): bool
    {
        return $this->log('emergency', $message, $context);
    }

    /** * Action must be taken immediately. * * Example: Entire website down, database unavailable, etc. This should * trigger the SMS alerts and wake you up. * * @param string $message */
    public function alert($message, array $context = []): bool
    {

public static function getInterval()
    {
        return [
            ['foo', 3, '{1,2, 3 ,4}'],
            ['bar', 10, '{1,2, 3 ,4}'],
            ['bar', 3, '[1,2]'],
            ['foo', 1, '[1,2]'],
            ['foo', 2, '[1,2]'],
            ['bar', 1, ']1,2['],
            ['bar', 2, ']1,2['],
            ['foo', log(0), '[-Inf,2['],
            ['foo', -log(0), '[-2,+Inf]'],
        ];
    }

    /** * @dataProvider getChooseTests */
    public function testChoose($expected, $id, $number, $locale = null)
    {
        $translator = $this->getTranslator();

// see Symfony\Component\HttpKernel\Controller\ContainerControllerResolver                     $controllers[$id.':'.$action] = $argumentRef;

                    if ('__invoke' === $action) {
                        $controllers[$id] = $argumentRef;
                    }
                    continue;
                }
            }

            unset($controllers[$controller]);
            $container->log($this, $reason);
        }

        $controllerLocator->replaceArgument(0, $controllers);
    }
}

/** * {@inheritdoc} * * @see \Drupal\Tests\system\Functional\SecurityAdvisories\SecurityAdvisoriesTestTrait::assertServiceAdvisoryLoggedErrors() */
  public function log($level, $message, array $context = []): void {
    if ($level === LogLevel::ERROR) {
      $messages = $this->state->get('advisory_feed_test.error_messages', []);
      $messages[] = $message;
      $this->state->set('advisory_feed_test.error_messages', $messages);
    }
    $this->innerLogger->log($level, $message, $context);
  }

}

    public static function fromRandom(int $length = 16, string $alphabet = null): self
    {
        if ($length <= 0) {
            throw new InvalidArgumentException(sprintf('A strictly positive length is expected, "%d" given.', $length));
        }

        $alphabet ??= self::ALPHABET_ALPHANUMERIC;
        $alphabetSize = \strlen($alphabet);
        $bits = (int) ceil(log($alphabetSize, 2.0));
        if ($bits <= 0 || $bits > 56) {
            throw new InvalidArgumentException('The length of the alphabet must in the [2^1, 2^56] range.');
        }

        $ret = '';
        while ($length > 0) {
            $urandomLength = (int) ceil(2 * $length * $bits / 8.0);
            $data = random_bytes($urandomLength);
            $unpackedData = 0;
            $unpackedBits = 0;
            for ($i = 0; $i < $urandomLength && $length > 0; ++$i) {

// Serialize strings if they could be confused with serialized objects or arrays             if ('N;' === $value || (isset($value[2]) && ':' === $value[1])) {
                return serialize($value);
            }
        } elseif (!\is_scalar($value)) {
            try {
                $serialized = serialize($value);
            } catch (\Exception $e) {
                unset($this->values[$key], $this->tags[$key]);
                $type = get_debug_type($value);
                $message = sprintf('Failed to save key "{key}" of type %s: %s', $type, $e->getMessage());
                CacheItem::log($this->logger, $message, ['key' => $key, 'exception' => $e, 'cache-adapter' => get_debug_type($this)]);

                return null;
            }
            // Keep value serialized if it contains any objects or any internal references             if ('C' === $serialized[0] || 'O' === $serialized[0] || preg_match('/;[OCRr]:[1-9]/', $serialized)) {
                return $serialized;
            }
        }

        return $value;
    }

'severity' => RfcLogLevel::INFO,
      'type' => 'my-module',
    ];

    $logger_factory = $this->container->get('logger.factory');
    foreach ($entries as $entry) {
      $entry += [
        'type' => 'test-views',
        'severity' => RfcLogLevel::NOTICE,
        'variables' => [],
      ];
      $logger_factory->get($entry['type'])->log($entry['severity'], $entry['message'], $entry['variables']);
    }
    return $entries;
  }

}

public function hasItem(mixed $key): bool
    {
        $id = $this->getId($key);

        if (isset($this->deferred[$key])) {
            $this->commit();
        }

        try {
            return $this->doHave($id);
        } catch (\Exception $e) {
            CacheItem::log($this->logger, 'Failed to check if key "{key}" is cached: '.$e->getMessage(), ['key' => $key, 'exception' => $e, 'cache-adapter' => get_debug_type($this)]);

            return false;
        }
    }

    public function clear(string $prefix = ''): bool
    {
        $this->deferred = [];
        if ($cleared = $this->versioningIsEnabled) {
            if ('' === $namespaceVersionToClear = $this->namespaceVersion) {
                foreach ($this->doFetch([static::NS_SEPARATOR.$this->namespace]) as $v) {

'_12', '_12'],
            ['12_', 12],
            ['"quoted string"', 'quoted string'],
            ["'quoted string'", 'quoted string'],
            ['1234.0', 1234.0],
            ['12.30e+02', 12.30e+02],
            ['123.45_67', 123.4567],
            ['0x4D2', 0x4D2],
            ['0x_4_D_2_', 0x4D2],
            ['0o2333', 02333],
            ['0o_2_3_3_3', 02333],
            ['.Inf', -log(0)],
            ['-.Inf', log(0)],
            ["'686e444'", '686e444'],
            ['686e444', 646e444],
            ['123456789123456789123456789123456789', '123456789123456789123456789123456789'],
            ['"foo\r\nbar"', "foo\r\nbar"],
            ["'foo#bar'", 'foo#bar'],
            ["'foo # bar'", 'foo # bar'],
            ["'#cfcfcf'", '#cfcfcf'],
            ['::form_base.html.twig', '::form_base.html.twig'],

            // Pre-YAML-1.2 booleans

parent::process($container);
        $this->replacements = [];
    }

    protected function processValue(mixed $value, bool $isRoot = false): mixed
    {
        if ($value instanceof Reference && isset($this->replacements[$referenceId = (string) $value])) {
            // Perform the replacement             $newId = $this->replacements[$referenceId];
            $value = new Reference($newId, $value->getInvalidBehavior());
            $this->container->log($this, sprintf('Changed reference of service "%s" previously pointing to "%s" to "%s".', $this->currentId, $referenceId, $newId));
        }

        return parent::processValue($value, $isRoot);
    }
}

if (str_contains($definedTag, $tag) || levenshtein($tag, $definedTag) <= \strlen($tag) / 3) {
                    $candidates[] = $definedTag;
                }
            }

            $services = array_keys($container->findTaggedServiceIds($tag));
            $message = sprintf('Tag "%s" was defined on service(s) "%s", but was never used.', $tag, implode('", "', $services));
            if ($candidates) {
                $message .= sprintf(' Did you mean "%s"?', implode('", "', $candidates));
            }

            $container->log($this, $message);
        }
    }
}