Assert

Travis Status:

A simple php library which contains assertions and guard methods for input validation (not filtering!) in business-model, libraries and application low-level code. The library can be used to implement pre-/post-conditions on input data.

Idea is to reduce the amount of code for implementing assertions in your model and also simplify the code paths to implement assertions. When assertions fail, an exception is thrown, removing the necessity for if-clauses in your code.

The library is not using Symfony or Zend Validators for a reason: The checks have to be low-level, fast, non-object-oriented code to be used everywhere necessary. Using any of the two libraries requires instantiation of several objects, using a locale component, translations, you name it. Its too much bloat.

Installation

Using Composer:

{
    "require": {
        "beberlei/assert": "*"
    }
}

Example usages

<?php
use Assert\Assertion;

function duplicateFile($file, $times)
{
    Assertion::file($file);
    Assertion::digit($times);

    for ($i = 0; $i < $times; $i++) {
        copy($file, $file . $i);
    }
}

Real time usage with Azure Blob Storage:

<?php
public function putBlob($containerName = '', $blobName = '', $localFileName = '', $metadata = array(), $leaseId = null, $additionalHeaders = array())
{
    Assertion::notEmpty($containerName, 'Container name is not specified');
    self::assertValidContainerName($containerName);
    Assertion::notEmpty($blobName, 'Blob name is not specified.');
    Assertion::notEmpty($localFileName, 'Local file name is not specified.');
    Assertion::file($localFileName, 'Local file name is not specified.');
    self::assertValidRootContainerBlobName($containerName, $blobName);

    // Check file size
    if (filesize($localFileName) >= self::MAX_BLOB_SIZE) {
        return $this->putLargeBlob($containerName, $blobName, $localFileName, $metadata, $leaseId, $additionalHeaders);
    }

    // Put the data to Windows Azure Storage
    return $this->putBlobData($containerName, $blobName, file_get_contents($localFileName), $metadata, $leaseId, $additionalHeaders);
}

NullOr helper

A helper method (Assertion::nullOr*) is provided to check if a value is null OR holds for the assertion:

<?php
Assertion::nullOrMax(null, 42); // success
Assertion::nullOrMax(1, 42);    // success
Assertion::nullOrMax(1337, 42); // exception

All helper

The Assertion::all* method checks if all provided values hold for the assertion. It will throw an exception of the assertion does not hold for one of the values:

<?php
Assertion::allIsInstanceOf(array(new \stdClass, new \stdClass), 'stdClass'); // success
Assertion::allIsInstanceOf(array(new \stdClass, new \stdClass), 'PDO');      // exception

List of assertions

<?php
use Assert\Assertion;

Assertion::integer($value);
Assertion::digit($value);
Assertion::integerish($value);
Assertion::range($value, $minValue, $maxValue);
Assertion::boolean($value);
Assertion::notEmpty($value);
Assertion::noContent($value);
Assertion::notNull($value);
Assertion::string($value);
Assertion::regex($value, $regex);
Assertion::length($value, $length);
Assertion::minLength($value, $length);
Assertion::maxLength($value, $length);
Assertion::betweenLength($value, $minLength, $maxLength);
Assertion::startsWith($value, $needle);
Assertion::endsWith($value, $needle);
Assertion::isArray($value);
Assertion::contains($value, $needle);
Assertion::choice($value, $choices);
Assertion::inArray($value, $choices);
Assertion::numeric($value);
Assertion::keyExists($value, $key);
Assertion::notEmptyKey($value, $key);
Assertion::notBlank($value);
Assertion::isInstanceOf($value, $className);
Assertion::notIsInstanceOf($value, $className);
Assertion::classExists($value);
Assertion::subclassOf($value, $className);
Assertion::directory($value);
Assertion::file($value);
Assertion::readable($value);
Assertion::writeable($value);
Assertion::email($value);
Assertion::url($value);
Assertion::alnum($value);
Assertion::true($value);
Assertion::false($value);
Assertion::min($value, $min);
Assertion::max($value, $max);
Assertion::eq($actual, $expected);
Assertion::same($actual, $expected);
Assertion::implementsInterface($value, $interfaceName);
Assertion::isJsonString($value);
Assertion::uuid($value);

Remember: When a configuration parameter is necessary, it is always passed AFTER the value. The value is always the first parameter.

Exception & Error Handling

If any of the assertions fails a Assert\AssertionFailedException is thrown. You can pass an argument called $message to any assertion to control the exception message. Every exception contains a message code by default.

<?php
use Assert\Assertion;
use Assert\InvalidArgumentException;

try {
    Assertion::integer($value, "The pressure of gas is measured in integers.");
} catch(AssertionFailedException $e) {
    // error handling
}

Assert\AssertionFailedException is just an interface and the default implementation is Assert\InvalidArgumentException which extends the SPL InvalidArgumentException. You can change the exception being used on a package based level. To shield your library from bugs or misinterpretations inside Assert you should introduce a library/project based assertion subclass, where you can override the exception thrown as well:

namespace MyProject;

use Assert\Assertion as BaseAssertion;

class Assertion extends BaseAssertion
{
    protected static $exceptionClass = 'MyProject\AssertionFailedException';
}