Expressive 3!

Yesterday, we tagged and released Expressive 3!

Expressive 3 provides a middleware microframework.

Create a new Expressive application using Composer:

$ composer create-project zendframework/zend-expressive-skeleton

The installer will prompt you for your choice of:

  • Initial application architecture (minimal, flat, modular)
  • Which dependency injection container you would like to use.
  • Which routing library you would like to use.
  • Which templating library you would like to use, if any.
  • Which error handling library you would like to use, if any.

From there, it creates a new project for you, and allows you to get started developing immediately.

You can read more in our quick start, and may want to check out our command line tooling to see what we provide to make development even faster for you!

What are the features?

Expressive 3 embraces modern PHP, and requires PHP 7.1 or higher. Strong type-hinting, including return type hints, make both our job and your job easier and more predictable. The ability to use all modern PHP features helps us deliver a solid base for your application.

Expressive 3 provides full support for the PSR-15 (Middleware and Request Handlers) standard. We believe strongly in supporting standards, to the extent that this release also drops direct support for the "double-pass" middleware style we have supported since version 1.0

Expressive 3 massively refactors its internals as well. In fact, the majority of the code in the zend-expressive package was removed, moved to other existing packages where it had a better semantic affiliation1, or extracted to new packages2. This base package now mainly handles coordinating collaborators and providing a user-friendly interface to creating your application pipeline and routes.3

Expressive 3 provides more command line tooling and tooling improvements in order to make developing your application easier. We added a command for creating factories for existing classes (factory:create).4 The middleware:create command now creates a factory for the middleware generated. We added support for creating request handlers5, complete with factory generation and registration, as well as template support.6

Finally, we recognize that Expressive has changed massively between versions 1 and 3, while simultaneously keeping its primary API stable and unchanged. However, to help users find the information they need for the version they run, we have rolled out versioned documentation, with each version providing only information specific to its release cycle:

The most recent version will always be present in the primary navigation, with links to other versions present as well.

New components!

We have several new components that provide features for Expressive — or any PSR-15 framework you may be using! These include:

We have a number of other packages in the works around authentication, authorization, and data validation that we will be releasing in the coming weeks and months; stay tuned for announcements!

What about upgrading?

We have prepared a migration document that covers new features, removed features, and a list of all changes.

Additionally, we have provided migration tooling to aid you in your migration from version 2 to version 3. The tool will not necessarily give you a fully running application, but it will take care of the majority of the changes necessary to bump your application to version 3, including setting up appropriate dependencies, and updating your bootstrapping files to conform to the new skeleton application structure.

If you need assistance, you can find community help:

What's next?

We have been working on a number of API-related modules for Expressive (and any PSR-15 applications) since last summer, with a number of components already completed, and others close to completion. We plan to finalize these in the next few months.

Thank You!

We extend a hearty thank you to everyone who tested the various pre-releases and provided feedback. Additionally, we are singling out the following individuals who provided significant contributions to the Expressive 3 project:

  • Enrico Zimuel provided a ton of feedback and critique during the design phase, and was a driving force behind many of the API usability decisions.

  • Rob Allen did a workshop at SunshinePHP, right as we dropped our initial alpha releases, and provided feedback and testing for much of our tooling additions.

  • Frank Brückner provided ongoing feedback and review of pull requests, primarily around documentation; he is also responsible for a forthcoming rewrite of our documentation theme to make it more responsive and mobile-friendly.

  • Daniel Gimenes provided feedback and ideas as we refactored zend-stratigility; he is the one behind package-level utility functions such as Zend\Stratigility\doublePassMiddleware(), Zend\Stratigility\path(), and more.

  • Witold Wasiczko provided the majority of the rewrite of zend-stratigility for version 3. He can be celebrated for removing over half the code from that repository!

In addition to these people, I want to extend a personal thank you to the following people:

  • Geert Eltink has helped maintain Expressive v2, and particularly the various routers and template engines, making them ready for v3 and testing continually. As a maintainer, I was able to rely on him to take care of merges as we finalized the releases, and was pleasantly surprised to wake up to new releases several times when he fixed critical issues in our alpha and RC releases.

  • Michał Bundyra provided a constant stream of pull requests related to quality assurance (including ongoing work on our phpcs extension!), as well as critical review of incoming patches. He spearheaded important work in the refactoring process, including changes to how we handle response prototypes, and critical fixes in our routers to address issues with how we detect allowed methods for path route matches. We synced each and every single day, often arguing, but always coming to consensus and plowing on.

If you get a chance, reach out to these contributors and thank them for the release!


  • 0: The Expressive ecosystem makes use of many other standards as well, including PSR-7 HTTP Messages, PSR-11 Container, and PSR-13 HTTP Links.

  • 1: As an example, the routing, dispatch, and "implicit methods" middleware were all moved to the zend-expressive-router package, as they each work with the router and route results.

  • 2: Request generation, application dispatch, and response emission were all moved to a new package, zend-httphandlerrunner.

  • 3: These refactors led to a net removal of code across the board, vastly simplifying the internals. This will lead to ease of maintenance, greater stability, and, based on benchmarks we've been performing, 10% better performance and less system resource usage.

  • 4: factory:create uses PHP's Reflection API in order to determine what dependencies are in place in order to generate a factory class; it also registers the class and factory with the container!

  • 5: In previous Expressive versions, we referred to "actions", which were any middleware that returned a response instead of delegating to another layer of the application. PSR-15 calls such classes request handlers. Our tooling provides an action:create command, however, for those who prefer the "action" verbiage.

  • 6: The command creates a template named after the handler created; it uses the root namespace of the class to determine where to put it in the filesystem. Additionally, it alters the generated request handler to render the template into a zend-diactoros HtmlResponse!



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