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Matt Sparks:
Building a PHP Framework: Part 7 – The Container
Jul 09, 2018 @ 12:33:16

Matt Sparks has posted the next tutorial in his "Building a PHP framework" series to his site today. In this latest article (part seven in the series) he focuses on building the container to handle dependencies.

Part 6 began our discussion of PHP containers. Today, I’ll be going into greater detail of the subject and, along with that, I’ll run down the work done so far on the Analyze container.

A huge debt of gratitude goes how to the folks behind the PHP League Container and others. I’ve learned a ton studying their code.

He then walks through the use of the container he created, Analyze/Container, to create and extract a Carbon instance. He then covers how the container is working behind the scenes to initialize the instance complete with dependencies (and optional arguments).

tagged: series part7 build framework container dependency tutorial

Link: https://developmentmatt.com/building-a-php-framework-part-7-the-container/

Rob Allen:
Dependency Injection with OpenWhisk PHP
Jun 20, 2018 @ 09:55:13

Rob Allen has continued his series of posts covering the use of PHP on the OpenWhisk platform. In his latest tutorial he shows how to use dependency injection for use in "non-trivial PHP applications".

Any non-trivial PHP applications use various components to do its work, from PDO though to classes from Packagist. It’s fairly common in a standard PHP application to use Dependency Injection to configure and load these classes when necessary. How do we do this in a serverless environment such as OpenWhisk?

This question comes up because we do not have a single entry point into our application, instead we have one entry point per action. If we’re using Serverless to write an API, then we probably

He uses a common connection type - PDO to a database - to illustrate a method for injecting dependencies in a serverless application. In his example, he starts with a simple script that returns a set of "todo" items from the database (with the PDO connection code embedded in it). Using dependency injection is a better way to manage that PDO connection so he shows how to update it to use the Pimple DI container and inject it via the constructor to make it available to the rest of the application.

tagged: dependency injection serverless openwhisk tutorial pdo database

Link: https://akrabat.com/di-with-openwhisk-php/

Tomas Vortuba:
Build Your First Symfony Console Application with Dependency Injection Under 4 Files
May 29, 2018 @ 10:16:01

Tomas Vortuba has continued his series looking at building command line tools with PHP and the Symfony Console component. In this latest post he shows how to create an application using dependency injection in just four files.

Series about PHP CLI Apps continues with 3rd part about writing Symfony Console Application with Dependency Injection in the first place. Not last, not second, but the first. Luckily, is easy to start using it.

He starts with a bit of information about how Symfony has evolved from the previous method of using controllers as services to create CLI tools. Now commands can be used as services and be pushed into/pulled from a dependency injection container. He then walks through the three steps to adding a command as a service:

  1. updating the services.yml file to include linking for the console application class.
  2. updating the Kernel to load the yml configuration.
  3. creating the bin file to execute the application.

With this structure in place, he then shows how to share functionality between services using a CompilerPass.

tagged: symfony console application dependency injection service command tutorial

Link: https://www.tomasvotruba.cz/blog/2018/05/28/build-your-first-symfony-console-application-with-dependency-injection-under-4-files/

Tomas Vortuba:
Why You Should Combine Symfony Console and Dependency Injection
May 09, 2018 @ 10:34:53

In a new post to his site, Tomas Votruba has a post sharing his thoughts about why you should combine Symfony Console and dependency injection and how it can help tp resolve issues with the overuse of static methods and functions.

I saw 2 links to SymfonyConsole in today's Week of Symfony (what a time reference, huh?). There are plenty of such posts out there, even in Pehapkari community blog: Best Practice for Symfony Console in Nette or Symfony Console from the Scratch. But nobody seems to write about the greatest bottleneck of Console applications - static cancer. Why is that?

He starts with some examples of the current status in PHP console applications including PHP_CodeSniffer, PHP CS Fixer and PHPStan. Each of these load commands to add functionality to the application which, as the application grows and changes, could be difficult to maintain in the future. Instead he recommends making use of dependency injection. He then talks about how containers are already a part of the console applications mentioned and finishes up focusing on the combination of the SymfonyConsole and SymfonyDependencyInjection components.

tagged: symfony console dependency injection combination tutorial container

Link: https://www.tomasvotruba.cz/blog/2018/05/07/why-you-should-combine-symfony-console-and-dependency-injection/

Tomas Votruba:
How to Slowly Turn your Symfony Project to Legacy with Action Injection
Apr 24, 2018 @ 09:55:49

Tomas Votruba has a new post to his site showing how to "turn your Symfony project to legacy" through the use of action injection for mapping controllers and methods to request handling.

The other day I saw the question on Reddit about Symfony's controller action dependency injection. More people around me are hyped about this new feature in Symfony 3.3 that allows to autowire services via action argument typehints. It's new, it's cool and no one has a bad experience with it. The ideal candidate for any code you write today.

Since Nette and Laravel introduced a similar feature in 2014, there are empirical data that we learn from.

Today I'll share the experience I have from consulting few Nette applications with dangerous overuse of this pattern and how this one thing turned the code to complete mess.

He starts off with some example code, asking where the issue is showing a call to a service handler to process the an argument. This would be used when a controller is registered as a service to help reduce the amount of work to define routes and add more "magic" for request handling. While the idea sounds good, he points out some of the issues with the approach including dependency injection problems and how, if it expands outside of controllers, it can lead to a poorly written application.

tagged: symfony injection action legacy nette dependency issue

Link: https://www.tomasvotruba.cz/blog/2018/04/23/how-to-slowly-turn-your-symfony-project-to-legacy-with-action-injection/

Andrew Embler:
Automated Dependency Injection Using Containers
Mar 13, 2018 @ 11:58:42

In a previous post to his site Andrew Embler provided a "concrete guide to dependency injection", a method to help make code easier to test and more flexible/maintainable. In this latest post he continues the series and moves to the next topic: dependency injection containers.

I recently posted about dependency injection, a guide that I hope was easy to read and understand. It's a topic that's confusing, due in no small part to its name. As I mention there, the same term defines the simple process of externally providing instance variables to a class as it does to the Container object's magical auto-instantiation of object (which also "injects dependencies.")

I'd like to talk a bit more about that. Now that we understand the term "Dependency Injection" (which is simply providing classes to classes through a constructor or a setter), let's talk about how we might make this a little less onerous.

He starts with an example from the concrete5 project where a class would require three object instances each time it would be created. Fortunately the software includes a make command that does some of this work for you. It makes use of a dependency injection container behind the scenes to get the instances it needs. He then covers cascading dependencies, some special logic for class creation and how to "get fancy with it" by defining custom logic when an instance is created.

tagged: dependency injection container concrete5 instance tutorial

Link: http://andrewembler.com/2018/03/automated-dependency-injection-using-containers

Frank de Jonge:
Being in control of time in PHP
Mar 08, 2018 @ 10:49:18

Frank de Jonge has a new post to his site covering something that always seems to be a difficult topic in development: time. In his post he suggests that date and time handling in your application is a "dependency" that could be difficult test.

When developers talk about the infrastructural boundaries or external dependencies they often talk about databases and third-party integration. They're the first thing we'll put behind an interface so we can stub them out during our tests. This gives us some control over them. It's become relatively easy to spot these dependencies because we do it frequently. They're the usual suspects.

However, some "dependencies" are much harder to spot. They even live right inside the standard library of PHP and often manage to seep through the cracks. Date/Time handling is such a thing. So what's the problem and how do we fix it?

He goes on to talk about date/time handling programming languages in general and how its variance can can cause issues that might be out of our control. He suggests that when time "gets the best of you" you should opt to be more specific in your date/time handling (the cause is usually precision). He then gets into some code examples of how to "control time" by reducing the impact that direct date/time handling could have on your application. He also includes an example of testing this handling and finishes with the idea of "consuming time as a service".

tagged: datetime control test unittest example dependency

Link: https://blog.frankdejonge.nl/being-in-control-of-time-in-php/

Andrew Embler:
A Concrete Guide to Dependency Injection
Mar 05, 2018 @ 13:54:48

In a new post to his site Andrew Embler provides a concrete guide to dependency injection, a look at some of the foundational principles behind dependency injection, some problems and how they could be resolved.

As we develop concrete5, we are very conscious about keeping the code base modern, so that we don't have to go through a massive, painful rewrite like we did with version 5.7. This means that we're frequently deep in the weeds, applying new concepts and functionality to new and old code alike.

[...] Here, we're going to talk about Dependency Injection. There are numerous tutorials, blog posts and Stack Overflow questions, regarding Dependency Injection – but there's always room for some more.

He starts with a look at the "old days" where dependencies were created inside of the class methods as needed and not shared. He then covers some of the problems with this approach and how a move to dependency injection (DI) can help. In his example a database object instance is created inside of the method each time it's' needed. The move to DI helps to resolve those issues by passing in the database instance instead. He finishes the post trying to clear up some of the terminology confusions around DI and briefly mentions containers (dependency injection containers) and the role they play.

tagged: dependency injection tutorial introduction guide

Link: http://andrewembler.com/2018/03/concrete-guide-dependency-injection

Nikola Poša:
Factory as a Service
Feb 19, 2018 @ 10:53:16

In a post to his site Nikola Poša looks at a method that can be used to provide a slightly different object from a dependency injection container based on other criteria: making use of a factory as a service.

Dependency Injection Containers are a great invention - when used the right way, they allow us to keep our factories and assembly logic of services outside the core business logic of our application.

By default, a service created is shared, meaning that exactly the same instance will be returned whenever service is retrieved from a container. This is a desired behaviour in most of the cases. [...] Yet certain use cases may require services to be created conditionally during runtime, such as for example based on the value of a parameter resolved from the current request.

He first covers some of the anti-patterns that could be used to resolve this issue: a setter method on the returned object, using a service manager or creating a static factory instead. He offers a solution to the problem that makes use of a factory inside of the DI container. This factory then uses configuration values from the container to set up the object and return it.

tagged: factory service dependency injection tutorial database connection

Link: https://blog.nikolaposa.in.rs/2018/02/16/factory-as-a-service/

Joe Ferguson:
How to move a dependency to Composer while requiring an old version
Jan 17, 2018 @ 09:54:24

In a new post to his site Joe Ferguson shows you how to move a dependency over to Composer but still require the older version, possibly one that's already included in the codebase as a checked-in source.

A common problem I run into with older applications are dependencies that have been added and loaded from the application’s repository. You would often see a “libraries” folder with a “className.php” type file. If you’re lucky you’ll have the entire folder of the dependency including the release notes to be able to find out exactly what version you’re using.

[...] What if the author hasn’t tagged our older version? Maybe they converted the repository to git from subversion or some other system? You have to go digging into the commit history to find the commit you want to match your current version.

He includes the Composer configuration required for both examples (loading the older version and loading by commit ID) as well as the addition of the "minimum-stability" option. This option allows you to pull directly from the "master" branch if you need to - just be sure to define exact versions of other dependencies otherwise you'll get dev versions of them too.

tagged: composer dependency version old tutorial commit master

Link: https://www.joeferguson.me/how-to-move-a-dependency-to-composer-while-requiring-an-old-version/