Amp is a non-blocking concurrency framework for PHP. It provides an event loop, promises and streams as a base for asynchronous programming. Promises in combination with generators are used to build coroutines, which allow writing asynchronous code just like synchronous code, without any callbacks. ## Motivation Traditionally, PHP has a synchronous execution flow, doing one thing at a time. If you query a database, you send the query and wait for the response from the database server in a blocking manner. Once you have the response, you can start doing the next thing. Instead of sitting there and doing nothing while waiting, we could already send the next database query, or do an HTTP call to an API. Making use of the time we usually spend on waiting for I/O can speed up the total execution time. The following diagram shows the execution flow with dependencies between the different tasks, once executed sequentially and once concurrently.  Amp allows such concurrent I/O operations while keeping the cognitive load low by avoiding callbacks. Instead, the results of asynchronous operations can be awaited using `yield` resulting in code which is structured like traditional blocking I/O code while the actual execution flow is handled by Amp. ## Installation This package can be installed as a [Composer](https://getcomposer.org/) dependency. ```bash composer require amphp/amp ``` This installs the basic building blocks for asynchronous applications in PHP. We offer a lot of repositories building on top of this repository, e.g. - [`amphp/byte-stream`](https://github.com/amphp/byte-stream) providing a stream abstraction - [`amphp/socket`](https://github.com/amphp/socket) providing a socket layer for UDP and TCP including TLS - [`amphp/parallel`](https://github.com/amphp/parallel) providing parallel processing to utilize multiple CPU cores and offload blocking operations - [`amphp/http-client`](https://github.com/amphp/http-client) providing an HTTP/1.1 and HTTP/2 client - [`amphp/http-server`](https://github.com/amphp/http-server) providing an HTTP/1.1 and HTTP/2 application server - [`amphp/mysql`](https://github.com/amphp/mysql) and [`amphp/postgres`](https://github.com/amphp/postgres) for non-blocking database access - and [many more packages](https://github.com/amphp?type=source) ## Documentation Documentation can be found on [amphp.org](https://amphp.org/) as well as in the [`./docs`](./docs) directory. Each package has its own `./docs` directory. ## Requirements This package requires PHP 7.0 or later. Many of the other packages raised their requirement to PHP 7.1. No extensions required! ##### Optional Extensions Extensions are only needed if your app necessitates a high number of concurrent socket connections, usually this limit is configured up to 1024 file descriptors. - [`ev`](https://pecl.php.net/package/ev) - [`event`](https://pecl.php.net/package/event) - [`uv`](https://github.com/bwoebi/php-uv) ## Examples Examples can be found in the [`./examples`](./examples) directory of this repository as well as in the `./examples` directory of [our other libraries](https://github.com/amphp?utf8=%E2%9C%93&q=&type=public&language=php). ## Versioning `amphp/amp` follows the [semver](http://semver.org/) semantic versioning specification like all other `amphp` packages. ##### 2.x Supported. We don't have plans to release v3, yet. ##### 1.x No longer supported. We stopped providing bug fixes 2017-12-31 and stopped providing security fixes 2018-12-31. ## Compatible Packages Compatible packages should use the [`amphp`](https://github.com/search?utf8=%E2%9C%93&q=topic%3Aamphp) topic on GitHub. ## Security If you discover any security related issues, please email [`me@kelunik.com`](mailto:me@kelunik.com) instead of using the issue tracker. ## License The MIT License (MIT). Please see [`LICENSE`](./LICENSE) for more information.