In a recent post to his site, Sergey Zhuk walks through the process for building a REST API with ReactPHP and MySQL and a bit of help from a simple routing package to handle the requests.

Today we will be looking at creating a RESTful API using ReactPHP, MySQL and nikic/FastRoute. Let’s look at the API we want to build and what it can do.

He then steps through the development of the REST API:

• showing the file structure of the resulting application
• installing dependencies
• the code to set up the HTTP server for handling requests (using React)
• building out the database with a user table

He then gets into the main part of the tutorial, showing the build out of each of the routes for the CRUD operations (Create, Read, Update, Delete). He provides both the code to make the endpoint work and examples of the requests they handle.

Sergey Zhuk has a post to his site covering concurrency including some of the basic concepts and how promises and coroutines come in to play.

What does concurrency mean? To put it simply, concurrency means the execution of multiple tasks over a period of time. PHP runs in a single thread, which means that at any given moment there is only one bit of PHP code that can be running. That may seem like a limitation, but it brings us a lot of freedom. We don’t have to deal with all this complexity that comes with parallel programming and threaded environment. But at the same time, we have a different set of problems. We have to deal with concurrency. We have to manage and to coordinate it.

He goes on to talk about parallel requests, cross-request needs and the requirement for coordination. He then covers the subject of promises, briefly defining it and giving an example of creating a basic promise in ReactPHP. Following this he talks about the other main topic of the article: using PHP generators along with parallel requests to only create the responses when yielded.

In a new post to his site Cees-Jan Kiewiet shares details about the latest version of the React/Cache component for the ReactPHP library. In the tutorial he covers the library, what this update brings with it and how he's making use of it.

Recently we, ReactPHP, released 0.5 of our cache package with TTL and other PSR-16 similarities. In this post we'll go over which packages I recently updated and how I am using them in my sites.

He breaks the post up into a few different sections showing the caching in use:

• JSON and msgpack
• Redis
• Fallback
• react/http session middleware
• react/http webroot preload middleware

For each item in the list there's a bit of code showing it in action and some explanation as to what it's doing and how it helps.

Sergey Zhuk has posted the third part of his series covering the use of ReactPHP to scrape content from another source on the web. In this third part of the series he improves on his scripts from before (scraping from the IMDB site) to add in a proxy server.

n the previous article, we have created a scraper to parse movies data from used a simple in-memory queue to avoid sending hundreds or thousands of concurrent requests and thus to avoid being blocked. But what if you are already blocked? The site that you are scraping has already added your IP to its blacklist and you don’t know whether it is a temporal block or a permanent one.

Such issued can be resolved with a proxy server. Using proxies and rotating IP addresses can prevent you from being detected as a scraper.

He then shows how to use the clue/reactphp-buzz package to write an asynchronous HTTP request to google.com making use of promises rather than normal synchronous request handling. He then installs the clue/reactphp-socks package to make the connection to the proxy server(s) and modifies the Buzz client to use that as a connection. After finding a proxy server to use, he updates the scraper code created previously with the new Buzz+Socks combination and shows it in action scraping data. The post finishes with a look at adding some error handling and how to handle when the proxy requests authentication before use.

Sergey Zhuk has a new tutorial posted on his site showing you how to use child processes in ReactPHP to send emails asynchronously using Swiftmailer.

In PHP the most of libraries and native functions are blocking and thus they block an event-loop. For example, each time we make a database query with PDO, or check a file with file_exists() our asynchronous application is being blocked and waits. Things often become challenging when we want to integrate some synchronous code in an asynchronous application. This problem can be solved in two ways: rewrite a blocking code using a new non-blocking one or fork this blocking code and let it execute in a child process, while the main program continues running asynchronously.

This first approach is not always available, asynchronous PHP ecosystem is still small and not all use-cases have asynchronous implementations. So, in this article, we will cover the second approach.

He starts by creating the main HTTP server handler running locally on port 8080. He adds in an exception handler to catch potential issues and provides example code of an exception being thrown. With that structure in place he starts on the Swiftmailer integration, adding it to the exception handler and pushing the details of the exception into the message body. This is then modified to use the react/child-process package to wrap a new PHP file inside of a child process loop. The tutorial ends with an example of how to pass data between the parent and child process. In this case it's the message from the exception.

Sergey Zhuk has posted the second part of his "fast web scraping" series that makes use of the ReactPHP package to perform the requests. In part one he laid some of the groundwork for the scraper and made a few requests. In this second part he improves on this basic script and how to throttle the requests so as to not overload the end server.

t is very convenient to have a single HTTP client which can be used to send as many HTTP requests as you want concurrently. But at the same time, a bad scraper which performs hundreds of concurrent requests per second can impact the performance of the site being scraped. Since the scrapers don’t drive any human traffic on the site and just affect the performance, some sites don’t like them and try to block their access. The easiest way to prevent being blocked is to crawl nicely with auto throttling the scraping speed (limiting the number of concurrent requests). The faster you scrap, the worse it is for everybody. The scraper should look like a human and perform requests accordingly. A good solution for throttling requests is a simple queue.

He shows how to integrate the clue/mq-react package into the current scraper to interface with a RabbitMQ instance and handle the reading of and writing to the queue. He includes the code needed to update the ReactPHP client. The mq-react package makes the update simple with the HTTP client reading from the queue instance rather than the array of URLs. One the queue is integrated, he then shows how to create a "parser" that can read in the HTML and extract only the wanted data using the DomCrawler component.

Sergey Zhuk has a post on his site that covers using a Router with a ReactPHP component. This router lets you more easily direct the HTTP requests coming into the application to the correct piece of functionality.

Router defines the way your application responds to a client request to a specific endpoint which is defined by URI (or path) and a specific HTTP request method (GET, POST, etc.). With ReactPHP Http component we can create an asynchronous web server. But out of the box the component doesn’t provide any routing, so you should use third-party libraries in case you want to create a web-server with a routing system.

He starts with an example of manual routing, showing the code for a basic server and adding in handlers based on the path+HTTP verb to respond with different content. He expands this basic example out to a more "real world" situation of the usual CRUD handling for "tasks". The post then shows how to change things up and use the FastRoute routing package to remove the manual route definitions from the server and define them in the router instead. It can then dispatch these to the correct location more easily. The post finishes up showing an additional feature: how to use wildcards in these URL definitions.

Sergey Zhuk has posted another ReactPHP tutorial to his site, this time focusing on working with the filesystem from a ReactPHP application.

I/O operations in the filesystem are often very slow, compared with CPU calculations. In an asynchronous PHP application this means that every time we access the filesystem even with a simple fopen() call, the event loop is being blocked. All other operations cannot be executed while we are reading or writing on the disk.

[...] So, what is the solution? ReactPHP ecosystem already has a component that allows you to work asynchronously with a filesystem: reactphp/filesystem. This component provides a promise-based interface for the most commonly used operations within a filesystem.

He starts the code with a bit of setup, creating the initial event loop, the related Filesystem instance and a pointer to a "test.txt" file. He then walks through the basic filesystem operations and the code required: reading in the file contents, creating a new file and writing content back out to a file. The next section goes through the same functionality for directories. He ends the post with a look at symbolic link creation, read and delete operations.

In a new post to his site Cees-Jan Kiewiet covers a new library he discovered - Cigar - and how to use it for smoke testing a ReactPHP application. Smoke testing (or "sanity testing") is the evaluation of the major functionality of an application rather than individual pieces of code.

Last week I came across Cigar, a smoke testing tool by Matt Brunt. Which, to me, is great stepping stone for my personal projects/sites to integration tests. In this post we not only go into Cigar, but also how to start your HTTP ReactPHP application, run cigar against it, and shut it down again. (Note that it doesn't have to be a ReactPHP application it can also be a NodeJS app, or PHP's build in webserver you use for testing.)

He then walks through the process of installing Cigar and creating the initial configuration file of endpoints to test (along with expected statuses). He then shows how to automate things further and creates a bash script that starts the ReactPHP application, runs the tests then shuts the application down. It's a simple script but can help save a few keystrokes every time the tests are run.

Sergey Zhuk has a new ReactPHP-related post to his site today showing you how to use the library to scrape content from the web quickly, making use of the asynchronous abilities the package provides.

Almost every PHP developer has ever parsed some data from the Web. Often we need some data, which is available only on some website and we want to pull this data and save it somewhere. It looks like we open a browser, walk through the links and copy data that we need. But the same thing can be automated via script. In this tutorial, I will show you the way how you can increase the speed of you parser making requests asynchronously.

In his example he creates a scraper that goes to a movie's page on the IMDB website and extracts the title, description, release date and the list of genres it falls into. Instead of creating a single-threaded process that can only fetch a single page at a time, he uses ReactPHP to speed things up and provide it a list of pages to fetch all at the same time. He starts by walking through the setup of the package and the creation of the browser instance. He then includes the code to make the request and crawl the contents of the result for the data. The post ends with the full code for the client and a way to add in a timeout in case the request fails.