gandung/promise

Promise A+ Implementation In PHP

v1.0.2 2017-09-25 18:04 UTC

Requires

• php: >=5.6.0 || >=7.1.0
• gandung/task-queue: ^1.0

Requires (Dev)

• phpunit/phpunit: ~4.0

BSD-3-Clause

• Paulus Gandung Prakosa

README

This is a Promises/A+ implementation in PHP. This handles promise chaining immutably until all context handler is all gone from execution context.

Features

• Promises/A+ implementation.
• Promise resolution and chaining is handled iteratively.

API

Deferred

Quick Start

use Gandung\Promise\Deferred;

$deferred = new Deferred();

$deferred->resolve('success.');

$deferred->promise()->then(
	function($d) {
		echo sprintf("%s" . PHP_EOL, $d);
	},
	function($e) {
		echo sprintf("%s" . PHP_EOL, $e);
	}
);

It will print "success." because the promise state is fulfilled.

use Gandung\Promise\Deferred;

$deferred = new Deferred();

$deferred->reject('fail.');

$deferred->promise()->then(
	function($d) {
		echo sprintf("%s" . PHP_EOL, $d);
	},
	function($e) {
		echo sprintf("%s" . PHP_EOL, $e);
	}
);

It will print "fail." because the promise state is rejected.

Deferred Method

• promise()

Description

Ability to return immutable promise object when current is null.

Return Value

Returns the promise of the deferred.

• resolve($value)

Description

Resolves the promise return by method promise(). All consumers are notified by having $onFulfilled (which they registered via $promise->then()) called with $value.

Return Value

None.

• reject($reason)

Description

Rejects the promise returned by promise(), signalling that the deferred's computation failed. All consumers are notified by having $onRejected (which they registered via $promise->then()) called with $reason.

Return Value

None.

Promise

Quick Start

use Gandung\Promise\Promise;

$promise = new Promise();

$promise->then(
	function($d) {
		echo sprintf("%s" . PHP_EOL, $d);
	},
	function($e) {
		throw new \Exception($e);
	}
);

Promise Method

• then(callable $onFulfilled, callable $onRejected)

Description

Appends fulfillment and rejection handlers to the promise, and returns an immutable new promise resolving to the return value of the called handler.

Return Value

An immutable new promise.

• resolve($value)

Description

Fulfills the promise with the given '$value'

Return Value

None.

• reject($reason)

Description

Rejects the promise with the given '$reason'

Return Value

None.

• currentState()

Description

Returns the state of the promise. List of promise state can be found in 'PromiseInterface' class.

Return Value

Either STATE_PENDING, STATE_FULFILLED, OR STATE_REJECTED

• wait()

Description

Synchronously wait on the current promise to complete it's unfulfilled tasks.

Return Value

Returning the most current resolved promise value.

• cancel()

Description

Possible to cancel the most current active promise and it's ancestors which not yet been resolved and leave the current active promise state to rejected. It means the most current active promise is unable to be used.

Return Value

Return the most current cancelled promise value. It can be throwing an exception.

• setWaitCallback(\Closure $callback = null)

Description

Set the wait callback handler.

Return Value

None.

• setCancelCallback(\Closure $callback = null)

Description

Set the cancellation callback handler.

Return Value

None.

FulfilledPromise same as Promise

Quick Start

use Gandung\Promise\FulfilledPromise;

$promise = new FulfilledPromise('the quick dirty brown fox.');

$promise->then(function($d) {
	echo sprintf("%s" . PHP_EOL, $d);
});

RejectedPromise same as Promise

Quick Start

use Gandung\Promise\RejectedPromise;

$promise = new RejectedPromise('the quick dirty brown fox.');

$promise->then(null, function($e) {
	throw new \Exception($e);
});

Contributors

• Paulus Gandung Prakosa

License

BSD 3-Clause License

Copyright (c) 2017, Paulus Gandung Prakosa All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

• Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.