helpers

Miscellaneous Helpers for PHP and Laravel

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Miscellaneous Helpers for PHP and Laravel

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About this Package

This is a collection of miscellanous utilities gathered in one package for you:

  • Supervisor: safely run a piece of code in an infinite loop.
  • Data Objects: easily convert json decoded data from API calls and database models into objects with type hints, relations and you own logic.
  • Eloquent Cache: a tiny cache repository for your eloquent models.
  • Redis lock: highly performant concurrency management with blocking atomic lock (without calling sleep()).
  • Process: A version of Symfony\Process with fewer features that doesn’t fall into infinite loops!
  • NumCrypt: obfuscate auto-incrementing integers.

Supervisor

Supervisor helps you with running a command in an infinite loop, enabling you to monitor and control it.
Supervisor is a generalization of the laravel daemon queue implementation.

  • Supervisor prevents the command from consuming too much memory, getting frozen or taking too long.
  • Supervisor gracefully stops the loop of executing the given command if:
    • artisan queue:restart command is issued,
    • or memory limit is reached,
    • or SIGTERM signal is received.
  • Supervisor pauses the loop when:
    • artisan down command is issued,
    • orSIGUSR2 signal is received.
  • Supervisor is highly configuration via event listeners:
    • If a listener to LoopBeginning event returns false, the supervisor pauses the loop.
    • If a listener to LoopCompleting event returns false, the supervisor stops and terminates the process.
    • Extra management and monitoring power is achievable by listening to RunSucceed, RunFailed, and SupervisorStopping events.
use Halaei\Helpers\Supervisor\Supervisor;

app(Supervisor::class)->supervise(GetTelegramUpdates::class);

class GetTelegramUpdates
{
    function handle(Api $api)
    {
        $updates = $api->getUpdates(...);
        $this->queueUpdates($updates);
    }
    function queueUpdates($updates)
    {
        ...
    }
}

To configure the behaviour of supervisor, you can pass an instance of Halaei\Helpers\Supervisor\SupervisorOptions as the second argument to the supervise() method.

Graceful QuitsOnSignals trait.

To gracefully terminate a command on receiving signals, use QuitsOnSignals trait as shown in this example:

use Halaei\Helpers\Supervisor\QuitsOnSignals;

class SomeCommand
{
    use QuitsOnSignals;

    public function handle()
    {
        $this->listenToSignals();
        try {
            while(someConditionHolds()) {
                $this->process(); // a process that must be atomic (it shouldn't abort in the middle).
                $this->quitIfSignaled();
            }
        } finally {
            //Optional. Required if this process has other stuff to do after handle().
            $this->stopListeningToSignals();
        }
    }
}

Data Object

An instance of DataObject is an object-oriented representation of a key-value array.
The constructor of a data object accepts a key-value array and convert its items into types that are defined in the class relations() method.
Magic methods are defined to make properties of a data-object accessible via

  • $object->some_property properties,
  • $object->getSomeProperty() getter methods,
  • and $object->setSomeProperty('new value') setter methods.

Data objects are Arrayable, Jsonable, and Rawable, having toArray(), toJson() and toRaw() methods.

use Halaei\Helpers\Objects\DataObject;

class Order extends DataObject
{
    public static function relations()
    {
        return [
            'items' => [Item::class], // items is a collection of objects of type Item.
            'destination' => Location::class, //delivered_to is an object of type Location
            'customer_mobile' => [Mobile::class, 'decode'], // customer mobile is a string that can be casted to a Mobile object via 'decode' static function.
        ];
    }
}

/**
 * @property string $item_code
 * @property int $quantity
 * @property float $unit_price
 * @property float $total_price
 */
class Item extends DataObject
{
}

/**
 * @property float $lat
 * @property float $lon
 */
class Location extends DataObject
{
}

class Mobile extends DataObject
{
    public static function decode($str)
    {
        if (preg_match('/^\+(\d+)-(\d+)$/', $str, $parts)) {
            return new self(['code' => $parts[1], 'number' => $parts[2]]);
        }
    }

    public function toRaw()
    {
        return '+'.$this->code.'-'.$this->number;
    }
}

$array = [
    'id' => 1234,
    'items' => [
        [
            'item_code' => '#100',
            'quantity' => 5,
            'unit_price' => 24,
            'total_price' => 120,
        ],
        [
            'item_code' => '#200',
            'quantity' => 1,
            'unit_price' => 80,
            'total_price' => 80,
        ],
    ],
    'final_price' => 200,
    'delivered_to' => [
        'lat' => 37.74123543,
        'lon' => 49.43254355,
    ],
    'customer_mobile' => '+98-9131231212',
];
$order = new Order($array);
echo get_class($order->delivered_to); // Location
echo $order->items[0]->quantity;// 5
var_dump($order->toArray()['mobile_number']); // ['code' => '+98', 'number' => '9131231212']
var_dump($order->toRaw()['mobile_number']); // +98-9131231212

Cast model attributes to data objects and collections

To cast model attributes to objects, use HasCastables trait and define the casts via static $castables like the way
relations are defined in DataObject classes. This trait is designed for document-oriented databases like mongodb -
works great with jenssegers/laravel-mongodb package. To work with SQL databases, $casts attributes should also be
used to handle json encoding/decoding.

class Order extends DataObject
{
    protected static $castables = [
        'items' => [Item::class],
        'destination' => Location::class,
        'customer_mobile' => [Mobile::class, 'decode'],
    ];
}

Eloquent Cache

The EloquentCache class is a key-value repository for your eloquent models with caching features.
If you want to cache your models using this repository, you may optionally let your model implement the Cacheable interface.
The implementation of Cacheable is also available via CacheableTrait.
Features include:

  1. Caching find by id queries via EloquentCache::find() method.
  2. Caching find by secondary key queries via EloquentCache::findBySecondaryKey() method.
  3. Invalidating the cache for a specific model via EloquentCache::invalidateCache, so that other processes don’t use cache for that model.
  4. Cleaning the cache when updating and deleting the model via EloquentCache::update() and EloquentCache::delete() methods.

Eloquent Batch Update & Insert Ignore

When performance does matter, it is important to update multiple rows of a table at once using a single update query.
To do so, use the Collection::update macro:

$newSensorData = [
    12 => ['value' => 32, 'observed_at' => '2016-06-30 12:30:01'],
    13 => ['value' => 33, 'observed_at' => '2016-06-30 12:30:05'],
    16 => ['value' => 30, 'observed_at' => '2016-06-30 12:30:05'],
];
$sensors = Sensor::whereIn('id', array_keys($newSensorData))->get();
foreach($sensors as $sensor) {
    //some calculations then save the new values
    $sensor->value = $newSensorData[$sensor->id]['value'];
    $sensor->observed_at = $newSensorData[$sensor->id]['observed_at'];
}
$sensors->update();

The resulting SQL statement (assuming that the old value for sensor#12 is 32):

UPDATE `sensors` SET
`value` = CASE 
    WHEN `id` = 13 THEN 33
    WHEN `id` = 16 THEN 30
ELSE `value` END,
`observed_at` = CASE
    WHEN `id` = 12 THEN  '2016-06-30 12:30:01'
    WHEN `id` = 13 THEN '2016-06-30 12:30:05'
    WHEN `id` = 16 THEN '2016-06-30 12:30:05'
ELSE `observed_at` END
WHERE id in (12, 13, 16)

To enable batch update feature (+ insert ignore) register \Halaei\Helpers\Eloquent\EloquentServiceProvider::class in the list of providers in config/app.php.

Redis-Based blocking mutual exclusive lock

The \Halaei\Helpers\Redis\Lock class provides Redis-Based mutual exclusive locks with auto-release timer. The implementation is based on rpoplpush and brpoplpush Redis commands.

A process that requires a lock should call the lock($name, $tr = 2) method in a loop until it returns true;
where $name is the name of the lock and $tr is the auto-release timer in seconds (with milliseconds resolution).
If the lock is on-hold, the lock method waits for at most $tr seconds, until the lock is released.

When a process is done it must immediately release the lock by calling the unlock($name) method, with the same $name parameter used for calling the lock method.
If the process holds a lock for more that $tr seconds, it will be regarded as a failed process and the lock will be automatically released.

Note: Callers to the lock may not be aware of the release of the lock, if the lock was auto-released after the call to the lock method. So they should call lock once more.

use \Halaei\Helpers\Redis\Lock;

$lock = app(Lock::class);

...
// 1. Wait for lock named 'critical_section'
while (! $lock->lock('critical_section', 0.1) {}
// 2. Do some critical job
//...
// 3. Release the lock
$lock->unlock('critical_section', 0.1);

Process

The Halaei\Helpers\Process\Process class is a simplified version of Symfony\Process that fixes
an infinite loop issue.
(Note: It wasn’t easy for me to deliver my fix to Symfony and guarantee it won’t break something else, so I fix the issue in this package.)
To summarize the bug, if the process doesn’t read all the input, Symfony\Process might fall into an infinite loop and
never find out that the process is not running anymore.

Currently, Halaei\Helpers\Process doesn’t have all the features of Symfony\Process. So in case you don’t pass a large input to your process,
or you are sure your process never terminates without reading the whole input, and if you want features like reading the process output while the
process is running, feel safe to use Symfony\Process instead.

You can create an instance of Halaei\Helpers\Process just like the way you create Symfony\Process\Process.
To run a process, you may call $process->run() which always return an instance of Halaei\Helpers\Process\ProcessResult
after the process exits, or call $process->mustRun() which only returns ProcessResult only if the process exits with zero,
but in case of timeout or non-zero exit code or failure in starting the process it throws a Halaei\Helpers\Process\ProcessException exception.

use Halaei\Helpers\Process\Process;
use \Halaei\Helpers\Process\ProcessException;

$input = "Some input string";
$timout = 10; // seconds
$p = new Process(['some', 'command', 'with', 'args'], null, null, $input, $timout);
try {
    dump($p->mustRun()->stdOut);
} catch (ProcessException $e) {
    dump ($e->getCode(), $e->result->stdErr, $e->result->stdOut, $e->result->exitCode);
}

Future plans

Running concurrent processes (async).

Clean-up DB transactions between handling queued jobs

In order to make sure there is nothing wrong with the default DB connection even after a messed-up handling of a queued job,
call Halaei\Helpers\Listeners\RefreshDBConnections::boot() in AppServiceProvider::boot() function.

Safely terminate long-running workers

Long-running workers may cause unexpected issues if you are not 100% careful.
To safely terminate long-running workers call Halaei\Helpers\Listeners\RandomWorkerTerminator::boot() in AppServiceProvider::boot().

Disabling blade @parent

@parent feature of Laravel framework is implemented with a minor security bug.
So you may need to disable the feature. If in your config/app.php file relplace \Illuminate\View\ViewServiceProvider::class with \Halaei\Helpers\View\ViewServiceProvider::class.

Number Encryption

If you need to obfuscate auto-increment numbers into random-looking strings, use the Numcrypt class:

use Halaei\Helpers\Crypt\NumCrypt;

$crypt = new NumCrypt();
echo $crypt->encrypt(36); // 53k7hx
echo $crypt->decrypt('53k7hx'); // 36

The NumCrypt constructor accepts charset for the accepted characters in the output and a key for encryption (uxing XOR).
By default, the charset is [a-z0-9], and the key is 308312529.

Note: NumCrypt is not meant to be cryptographically secure.

use Halaei\Helpers\Crypt\NumCrypt;

$crypt = new NumCrypt('9876543210abcdef', 0 /*dont XOR*/);
echo $crypt->encrypt(16, 0 /*no padding*/); // 89
echo $crypt->decrypt('999989'); // 36

License

This package is open-sourced software licensed under the MIT license