How to reduce duplication in your GitHub Actions workflows

Recently ReactJS v18 was released. I started to look into its improvements, and checked which of my projects could benefit from them.The main react-based project I maintain at the moment of writing this article is <a target="_blank" rel="noopener noreferrer" href="https://github.com/shlinkio/shlink-web-client">shlink-web-client</a>, so I naturally created a new branch and started the process.The update was quite smooth, as most of the other dependencies I was using from the react ecosystem were already updated to support v18. All but one, <a target="_blank" rel="noopener noreferrer" href="https://enzymejs.github.io/enzyme/">enzyme</a>, the testing framework I was using to unit-test react components.To be precise, I was able to continue running my tests, but some of them (those using <code>mount</code> instead of <code>shallow</code>) were still rendering components with the &quot;old&quot; React v17 approach, causing them to behave as in that version and a warning being printed in the console.<h3>First fix attempt</h3>The way enzyme integrates with the react version you are using is through an adapter library. The last official one supports only React v16, but someone released an <a target="_blank" rel="noopener noreferrer" href="https://github.com/wojtekmaj/enzyme-adapter-react-17">unofficial adapter for v17</a> which, with close to 650k weekly downloads, quickly became the way to go.I checked if there was one for React 18, but sadly there wasn&#x27;t.Also, the author of the adapter for v17 posted an article indicating <a target="_blank" rel="noopener noreferrer" href="https://dev.to/wojtekmaj/enzyme-is-dead-now-what-ekl">enzyme is dead</a>, he was not going to release one for v18, and publishing one for v17 was a mistake.With those facts in mind, I started to face what was probably going to be the moment to migrate to <a target="_blank" rel="noopener noreferrer" href="https://testing-library.com/docs/react-testing-library/intro">react testing library</a>.<h3>Migration strategy</h3>I decided to follow a migration strategy similar to the one suggested in the article above, but with a couple of modifications:<ul><li>I update to React 18 anyway, as tests still pass.</li><li>Migrate right away all tests using <code>mount</code>, as those are the ones behaving differently.</li><li>New tests should be written directly with react testing library (RTL from now on).</li><li>When an existing test needs to be changed, consider migrating it to RTL, and do it if there&#x27;s time.</li><li>Introduce some PR from time to time just migrating a handful of tests.</li><li>Once everything is migrated, get rid of everything related with enzyme.</li></ul><h3>First contact and impressions</h3>I was a bit sceptical with RTL, as it was focused more on integration tests, instead of unit tests, which meant I had to completely change the mindset to write tests.It also didn&#x27;t support shallow rendering, meaning that you will end up sometimes rendering a bigger component tree when testing container-like components, potentially causing side effects that could affect your test.On the other hand there&#x27;s more and more people stating that <a target="_blank" rel="noopener noreferrer" href="https://kentcdodds.com/blog/why-i-never-use-shallow-rendering">shallow rendering is an anti-pattern</a>, and that&#x27;s probably the reason of enzyme getting &quot;discontinued&quot;.Also, RTL has become the <a target="_blank" rel="noopener noreferrer" href="https://reactjs.org/docs/testing.html#tools">officially recommended framework</a> to test react components, it has become very popular, and it has even joined a wider group of testing libraries under the <a target="_blank" rel="noopener noreferrer" href="https://testing-library.com/"><code>@testing-library</code></a> organization.The thing is that I started to use it, and I was quickly surprised with how it felt to work with it, and all the benefits it was bringing to my tests.<h3>Benefits I have experienced</h3>Once I started migrating the first tests I noticed some benefits:<ul><li>Changing my mindset was actually easier than I thought. The docs are very well written, so it&#x27;s relatively easy to start using RTL.</li><li>My tests got simpler, and required less of those nasty global mocks that jest allows (I&#x27;m looking at you, <a target="_blank" rel="noopener noreferrer" href="https://jestjs.io/es-ES/docs/mock-functions#mocking-modules"><code>jest.mock</code></a>).</li><li>Tests were way less coupled with implementation details. I moved from testing the component props, to test what the user would see on the screen.</li><li>Related with previous point, I started to write my tests by looking at the screen instead of the component&#x27;s implementation.</li><li>Changes in source code led to fewer tests requiring to be changed.</li><li>A progressive migration was possible, where some tests still use enzyme and others are already using RTL.</li></ul>And overall, it felt good and I have already dedicated a couple of PRs just to migrate more tests.<h3>Challenges I faced</h3>But of course, migrating to a new tool always comes with its own challenges, and this was not an exception. I&#x27;ll explain the main ones I have faced so far and how I tackled them:<ul><li>RTL lets you do some things in a couple of different ways, and the docs may not be super clear about what&#x27;s the recommended option.For this I recommend reading <a target="_blank" rel="noopener noreferrer" href="https://acel.me/DCMb1">this article</a> from Kent C. Dodds, RTL&#x27;s author, which explains some common mistakes when using the library.</li><li>At first, I struggled a bit with asynchronous side effects and state changes in components, which can easily end up printing a warning like <code>Warning: An update to MyComponent inside a test was not wrapped in act</code>.The warning also explains how you are supposed to solve this by wrapping your code in <code>act()</code>, but this warning comes from React, not RTL, and what it is not telling you is that RTL already wraps all needed operations in <code>act()</code>.What this error usually mean is that you are not waiting for something to happen. <a target="_blank" rel="noopener noreferrer" href="https://acel.me/jnUdT">This other article</a>, also from Kent C. Dodds, explains everything you need to know about the things that can lead to this warning, and how to solve them.</li><li>Since you start testing from the user point of view, some use cases can be challenging to test without coupling with implementation details. For example, when you have a component which dynamically renders different images or icons, I used to directly check the component properties.For this I found the best solution was to use <a target="_blank" rel="noopener noreferrer" href="https://jestjs.io/docs/snapshot-testing">jest snapshots</a>. I didn&#x27;t want to manually check which SVG was being rendered in the DOM, just that different ones were being used in every case.<pre><pre><code class="language-tsx">// I went from this...
test(&#x27;...&#x27;, () =&gt; {
 const wrapper = shallow(&lt;MyComp dynamicValue=&quot;foo&quot; /&gt;);
 expect(wrapper.find(FontAwesomeIcon).prop(&#x27;icon&#x27;)).toEqual(someIcon);
})

// To this
test(&#x27;...&#x27;, () =&gt; {
 const { container } = render(&lt;MyComp dynamicValue=&quot;foo&quot; /&gt;);
 expect(container.firstChild).toMatchSnapshot();
})
</code></pre></pre></li><li>Something very similar happens if you use some library that renders canvas. There&#x27;s no way to test that from a DOM point of view, which is what RTL does.In my case I was using <a target="_blank" rel="noopener noreferrer" href="https://www.chartjs.org/">Chart.js</a> to render some charts, so I used <a target="_blank" rel="noopener noreferrer" href="https://github.com/hustcc/jest-canvas-mock">jest-canvas-mock</a>, which exposes a method on the canvas to see which are all the events invoked from the library.Then I used snapshots again to verify they had the expected &quot;shape&quot;.<pre><pre><code class="language-tsx">// I went from this...
test(&#x27;...&#x27;, () =&gt; {
 const wrapper = shallow(&lt;MyCompWithCanvas /&gt;);
 expect(wrapper.find(Chart).prop(&#x27;data&#x27;).datasets).toEqual(...);
})

// To this
test(&#x27;...&#x27;, () =&gt; {
 const { container } = render(&lt;MyCompWithCanvas /&gt;);
 const events = container.querySelector(&#x27;canvas&#x27;)?.getContext(&#x27;2d&#x27;)?.__getEvents();

 expect(events).toBeTruthy();
 expect(events).toMatchSnapshot();
})
</code></pre></pre></li></ul><h3>Conclusion</h3>For better or worst, enzyme should no longer be considered an option. If you are starting a new project or are using it on small ones, consider migrating to RTL as soon as possible.If you are using it in bigger projects, following the process described in this article will probably help you.In any case, you will get surprised. React testing library is a great tool and provides many benefits over enzyme.Its main issue is that it&#x27;s not a drop-in replacement for enzyme, so you will have to change a bit your mindset.

My experience migrating from enzyme to react testing library

Capturing code coverage for a test suite is a very useful way to know which parts of your source code are actually getting executed by tests.This is useful not only to know if you need to add more tests to your project (in case the coverage is too low), but also, if you want to apply technics like mutation testing, having a properly generated code coverage report will dramatically speed up te execution and help you know if a non-killed mutant is relevant.<h3>Generating the code coverage</h3>Capturing code coverage is usually easy in the most common types of tests, like unit tests, where the source code is executed in the same process.Tools like <a target="_blank" rel="noopener noreferrer" href="https://phpunit.de/">PHPUnit</a>, one of the most extended PHP testing frameworks, ships with tools like <a target="_blank" rel="noopener noreferrer" href="https://github.com/sebastianbergmann/php-code-coverage">php-code-coverage</a>, designed to capture the code under execution, just by providing a couple of lines of configuration.However, generating a reliable code coverage report is not always that easy for other types of tests.In contexts like E2E tests, where you may spin-up an API on a different process, and make your tests just call this API via HTTP and assert on the responses, PHPUnit will not be able to capture the code coverage, because the source code is actually being loaded on a different process.<h3>Remote code coverage</h3>A couple of weeks ago, I faced the issue described above. I had a web service for which I had a decent API test suite, but I wanted to capture code coverage for two main reasons:<ul><li>Be able to merge this coverage with the one generated by other tests suites, to know what&#x27;s the &quot;total&quot; code coverage, regardless the test producing it.</li><li>Apply mutation testing to the API tests, as I was already doing that for the rest of the test suites in the project. For this, I also needed to know exactly what tests were covering every line of the source code.</li></ul>After some investigation, I couldn&#x27;t find a built-in feature, where PHPUnit itself was able to &quot;remotely&quot; capture te code under test, so I had to think on a way to manually use <code>php-code-coverage</code> by myself.<h3>Code coverage reports</h3>In order to be able to capture code coverage, I had to make sure the instances of the objects provided by <code>php-code-coverage</code> where &quot;spin-up&quot; with the server, and then, the code coverage report was dumped at the end.Also, you usually define the code to include/exclude from coverage in PHPUnit&#x27;s config, but since this time we are the ones creating the coverage objects, this was not possible.I tried a couple of different approaches (more on this at the end), but the most accurate one for me, was to define two routes in my server, that were dynamically configured only when running the server in the context of these tests, and were responsible for creating and dumping the code coverage.<pre><pre><code class="language-php">use PHPUnit\Runner\Version;
use SebastianBergmann\CodeCoverage\CodeCoverage;
use SebastianBergmann\CodeCoverage\Driver\Selector;
use SebastianBergmann\CodeCoverage\Filter;
use SebastianBergmann\CodeCoverage\Report\Html\Facade as Html;
use SebastianBergmann\CodeCoverage\Report\PHP;
use SebastianBergmann\CodeCoverage\Report\Xml\Facade as Xml;

// Define directories containing the code you want to cover
$filter = new Filter();
$filter-&gt;includeDirectory(...);
$filter-&gt;includeDirectory(...);
$coverage = new CodeCoverage((new Selector())-&gt;forLineCoverage($filter), $filter);

// This is &quot;pseudo-code&quot;. Defining the routes depends on the framework you use
$app-&gt;get(&#x27;/api-tests/start-coverage&#x27;, function () use (&amp;$coverage) {
 $coverage-&gt;start(&#x27;API tests&#x27;);
 return new EmptyResponse();
});
$app-&gt;get(&#x27;/api-tests/stop-coverage&#x27;, function () use (&amp;$coverage) {
 $basePath = &#x27;...&#x27;; // Wherever you want the reports to be dumped
 $coverage-&gt;stop();

 // I generated coverage reports in a couple of different formats
 (new PHP())-&gt;process($coverage, $basePath . &#x27;/coverage.cov&#x27;);
 (new Xml(Version::getVersionString()))-&gt;process($coverage, $basePath . &#x27;/coverage-xml&#x27;);
 (new Html())-&gt;process($coverage, $basePath . &#x27;/coverage-html&#x27;);

 return new EmptyResponse();
});
</code></pre></pre>Then, I added the next snippet to my PHPUnit <code>bootstrap.php</code> file, to make sure the endpoints configured above are invoked at the proper times:<pre><pre><code class="language-php">// when starting up the test suite, call the endpoint to start collecting coverage
$httpClient-&gt;request(&#x27;GET&#x27;, &#x27;http://localhost:8080/api-tests/start-coverage&#x27;);

// When the tests process shuts down, call the endpoint to stop the coverage
register_shutdown_function(function () use ($httpClient): void {
 $httpClient-&gt;request(&#x27;GET&#x27;, &#x27;http://localhost:8080/api-tests/stop-coverage&#x27;);
});
</code></pre></pre><blockquote>Learn more about how to configure PHPUnit&#x27;s <a target="_blank" rel="noopener noreferrer" href="https://phpunit.readthedocs.io/en/9.5/configuration.html#the-bootstrap-attribute">bootstrap script</a>.</blockquote>This was fine from a pure code coverage point of view, but if you try it yourself, you will notice the report says all the code has been covered by <code>API tests</code>, which is what we provide when calling <code>$coverage-&gt;start(&#x27;API tests&#x27;);</code><img src="/assets/img/remote-coverage/invalid-api-coverage.png" alt="Invalid API coverage"/>To properly do mutation testing we need to know which are the exact tests that cover every part of the code. That requirement took me to the next approach.<h3>Supporting mutation testing</h3>To be more precise with the generated reports, I needed some way to notify the server about the specific test performing the request.One way to do this is by sending a custom header when performing a request from your tests, and registering some event handler or middleware which starts the coverage for that request with the value coming from that header.With that, I evolved the configuration above, and added a middleware handler (the framework I use is <a target="_blank" rel="noopener noreferrer" href="https://www.php-fig.org/psr/psr-15/">PSR-15</a> based, but the framework of your choice will probably have a way to do this).<pre><pre><code class="language-php">use ...

$coverage = new CodeCoverage();

// This ensures the coverage is started and stopped on every request, using the &quot;x-coverage-id&quot; header as the ID.
$app-&gt;middleware(function (ServerRequestInterface $req, RequestHandlerInterface $handler) use (&amp;$coverage) {
$coverage?-&gt;start(&#x27;API Tests&#x27;);
 $coverage-&gt;start($req-&gt;getHeaderLine(&#x27;x-coverage-id&#x27;));

 try {
 return $handler-&gt;handle($req);
 } finally {
 $coverage-&gt;stop();
 }
});

// This route is no longer needed. You can also remove the request from your bootstrap script
// $app-&gt;get(&#x27;/api-tests/start-coverage&#x27;, ...);
$app-&gt;get(&#x27;/api-tests/stop-coverage&#x27;, ...);
</code></pre></pre>Then, inside your test you can do something like this:<pre><pre><code class="language-php">use PHPUnit\Framework\TestCase;

class MyApiTest extends TestCase
{
 private ClientInterface $httpClient;

 public function setUp(): void
 {
 $this-&gt;httpClient = ...;
 }

 public function testMyEndpoint(): void
 {
 $resp = $this-&gt;httpClient-&gt;request(&#x27;POST&#x27;, &#x27;...&#x27;, [
 &#x27;headers&#x27; =&gt; [
 &#x27;x-coverage-id&#x27; =&gt; static::class,
 ],
 ])

 // Asserts go here...
 }
}
</code></pre></pre>After this, the code coverage reports will properly show the actual tests covering them.<img src="/assets/img/remote-coverage/valid-api-coverage.png" alt="Valid API coverage"/><h3>Alternative approach</h3>The approach explained here is functional, but it&#x27;s a bit hacky. I had to do it like this because of limitations with how I serve the API with <a target="_blank" rel="noopener noreferrer" href="https://openswoole.com">openswoole</a>.However, instead of defining routes that need to be actively called to start/stop the code coverage (or just to dump the report, as in the second approach), you could try to register the shutdown function directly in the server side.If that works for you, it&#x27;s much more straightforward, and you won&#x27;t need to bother changing your tests bootstrap script.<h3>Conclusion</h3>Even though there&#x27;s room for improvement, this allows to generate code coverage reports for code that&#x27;s running on a different process.I plan to apply something similar for E2E tests for a command line app, so maybe I extend this article at some point.Also, I decided to write this article, because at the moment of having to implement this myself, I didn&#x27;t find too much useful information out there.I hope this helped you, and now you can collect code coverage reports on your API tests.

Capturing remote code coverage in API tests with PHPUnit

In the last couple of days I have been playing around with the idea of combining GitHub Actions and GitHub Pages to be able to dynamically build preview environments every time a pull request is opened against a repository hosting a client-side web app.The idea is that you can quickly preview the changes made by some contributor, without having to clone their branch and running everything locally, something specially useful for open source projects.In this article I will explain how to set everything up, and what are some considerations and problems you may face during the process.<h3>Enable github pages</h3>The first thing you need to do is enable your project to publish pages on some branch. I recommend creating a new branch for this, let&#x27;s say <code>preview-env</code>, and then enabling publishing on it.In order to do that go to your repository and then Settings -&gt; Pages, look for the Source section, and you should see something like this:<img src="/assets/img/preview-envs/github-pages-before-enabling.png" alt="GitHub pages before enabling"/>Click in the dropdown and select your new branch, <code>preview-env</code>. Then click Save.<img src="/assets/img/preview-envs/github-pages-after-enabling.png" alt="GitHub pages after enabling"/>After saving you will see a message at the top of this section telling you what&#x27;s the URL in which the pages are published. It always follows the same pattern. If your organization is <code>my-org</code> and your repository is <code>my-repo</code>, the url will be <code>https://my-org.github.io/my-repo/</code>.<h3>Configure the workflow</h3>Now we need to configure a workflow that will &quot;deploy&quot; the preview environment for the branch every time a new pull request is created or updated:Let&#x27;s imagine we have a React web app that is built with node.js. The configuration could look like this.<pre><pre><code class="language-yml"># .github/workflows/deploy-preview.yml
name: Deploy preview

on:
 pull_request: null

jobs:
 deploy:
 runs-on: ubuntu-20.04
 continue-on-error: true
 steps:
 - name: Checkout code
 uses: actions/checkout@v2
 - name: Use node.js 14.15
 uses: actions/setup-node@v1
 with:
 node-version: 14.15
 - name: Generate slug
 id: generate_slug
 run: echo &quot;##[set-output name=slug;]$(echo ${GITHUB_HEAD_REF#refs/heads/} | sed -r &#x27;s/[~\^]+//g&#x27; | sed -r &#x27;s/[^a-zA-Z0-9]+/-/g&#x27; | sed -r &#x27;s/^-+\|-+$//g&#x27; | tr A-Z a-z)&quot;
 - name: Build
 run: npm ci &amp;&amp; npm run build
 - name: Deploy
 uses: JamesIves/github-pages-deploy-action@4.1.1
 with:
 branch: preview-env
 folder: build
 target-folder: ${{ steps.generate_slug.outputs.slug }}
 - name: Publish env
 uses: marocchino/sticky-pull-request-comment@v2
 with:
 header: Preview environment
 message: |
 ## Preview environment
 https://my-org.github.io/my-repo/${{ steps.generate_slug.outputs.slug }}/
</code></pre></pre><blockquote>If you are not familiar with GitHub Actions yet, take a look at the <a target="_blank" rel="noopener noreferrer" href="https://docs.github.com/en/actions">official documentation</a>.</blockquote>This workflow will follow the next steps:<ul><li>Checkout the code from the repository.</li><li>Set-up node.js 14.15</li><li>Based on the branch name, generate a slug that we will use to have separated deployment folders for every pull request we receive. The slug is exposed to next steps as an output.</li><li>Build the project. This step will obviously depend on the needs of your project.</li><li>Using <a target="_blank" rel="noopener noreferrer" href="https://github.com/JamesIves/github-pages-deploy-action">JamesIves/github-pages-deploy-action</a>, deploy the contents we previously built in the GitHub page, under a sub-folder matching the slug we generated a few steps above, and under the branch <code>preview-env</code> (remember we enabled GitHub pages for this branch).</li><li>Finally, using <a target="_blank" rel="noopener noreferrer" href="https://github.com/marocchino/sticky-pull-request-comment">marocchino/sticky-pull-request-comment</a>, post a comment in the pull request with a link to the preview environment, so that you can just click on it and see the deployment.</li></ul>The steps may change depending on your needs and how you build your project. For example, I have an extra step to update a property in the <code>package.json</code> that is then used to allow serving the app in a sub-path instead of the root of the domain.You may also not build your site with node.js, as you could be using any of the multiple existing static site generators out there, but you get the idea.Finally, you have probably noticed the config includes <code>continue-on-error: true</code>. This will allow the pull request to be merged even if this process fails for some reason.<h3>Considerations when using forks</h3>While the configuration above will work perfectly when creating pull requests inside the same repository, there are some limitations when the pull request comes from a fork (which is the usual in OSS projects).For security reasons, the <code>GITHUB_TOKEN</code> injected in those cases doesn&#x27;t have write permissions, which will make the &quot;deploy&quot; step fail.Also, you cannot define your own token with more permissions and inject it as a secret, as the secrets are not exposed to workflows running on forks.However, with a couple small config changes, we can work around these limitations:<h4>Change event</h4>The first thing we need to do is use the <code>pull_request_target</code> event instead of the <code>pull_request</code> one.<pre><pre><code class="language-diff">on:
- pull_request: null
+ pull_request_target: null
</code></pre></pre>According to the documentation, this is equivalent to the <code>pull_request</code> event, but it runs in the scope of the base repository.Thanks to this, the <code>GITHUB_TOKEN</code> will come with write permissions, and we will have access to secrets if needed.<h4>Checkout the fork</h4>The second thing we are going to change is that we now need to specify the repository to checkout.In order to do that, we need to add two inputs to the &quot;Checkout code&quot; step, like this:<pre><pre><code class="language-diff"> steps:
 - name: Checkout code
 uses: actions/checkout@v2
+ with:
+ repository: ${{ github.event.pull_request.head.repo.full_name }}
+ ref: ${{ github.event.pull_request.head.ref }}
</code></pre></pre>This will ensure we checkout from the fork repository, instead of the base one, which is the default, as it&#x27;s the one where the <code>pull_request_target</code> event is scoped to.And that&#x27;s it. With these two changes you can now deploy preview environments for pull requests coming from forks.<blockquote>IMPORTANT! The limitations of the <code>pull_request</code> event are there for a reason. People could potentially get access to your secrets or manipulate your code. Proceed at your own risk.</blockquote><h3>Other considerations</h3>Other than the limitations for forks, there are a few other minor things to take into consideration.<ul><li>Changes in GitHub Pages do not reflect immediately. It may take up to a couple of minutes for the deployment to be available, but considering you will usually not review a PR right after it has been created, this should not be a big issue.</li><li>As you have seen, every time a pull request is created, the deployment will generate a new folder in your GitHub Pages branch. This may result in a lot of old folders to pile-up, so you may want to set up some way to clean them up periodically or after the pull request has been merged.</li><li>Due to the fact that GitHub Pages only allows static pages to be served, this process cannot be used with apps that require some kind of back-end or server-side logic.</li><li>If your project is already using GitHub Pages for something else (serve the project&#x27;s website or docs), that may conflict with this, preventing you from having this kind of preview envs.</li></ul>

Setting-up a preview environment for your client-side apps with GitHub Actions and GitHub Pages

I remember many years ago, when I released my first open source project, that every time I had a new release ready, I was never sure what should be the new version number.Versioning software is not as straightforward as it might look when you don&#x27;t have a lot of experience.In this article I&#x27;ll try to explain the <a target="_blank" rel="noopener noreferrer" href="https://semver.org/">SemVer</a> approach to version software, and some things you might want to take into account on top of that.<h3>Semantic Versioning</h3>The first thing you need is a solid set of rules that help you decide which should your next version be.I remember thinking &quot;is this version big enough as to jump from 1.0 to 2.0?&quot; or &quot;I have seen projects using three numbers for the version, X.Y.Z, should I do the same?&quot;Those questions are easier to answer if you stick to some standard that tells you what to do, and that will help others more easily understand your intention.My recommendation is to use <a target="_blank" rel="noopener noreferrer" href="https://semver.org/">Semantic Versioning</a>, as it defines a solid starting point, and it&#x27;s quite adopted by the community.Semantic Versioning states that you should use three numbers to identify versions, <code>MAJOR.MINOR.PATCH</code>, and follow these rules in order to decide which one to increase:<ul><li><code>PATCH</code>: the new release includes only bug fixes. People are encouraged to update to this release and no changes are needed in their code bases.</li><li><code>MINOR</code>: the new release includes new backwards-compatible features. People can update to this version without changing their code bases, and make use of the new features afterwards if they wish.</li><li><code>MAJOR</code>: the new release includes <a target="_blank" rel="noopener noreferrer" href="https://en.wikipedia.org/wiki/Backward_compatibility">backward compatibility</a> breaks. Changes in the code base will be needed when updating to this version.</li></ul><blockquote>These rules are easier to apply to libraries and frameworks than it is for apps and services. More about this later.</blockquote><h3>Try to keep backwards-compatibility</h3>Ok, we have some rules now. However, I have seen very frequently people mistaking what can be done with what should be done.Yes, if you introduce a breaking change, you can update the major version and that&#x27;s it. However, if you do it too frequently, people won&#x27;t be happy, and you will end up with a fragmented user base, that stop updating to newer versions.I remember using a library to deploy stuff that had a new major version every couple of months, changing things like &quot;The <code>host</code> function is now called <code>server</code>&quot;. Yes, ok, but why do I have to change my stuff so frequently.It&#x27;s usually better to try to implement things in a backwards-compatible way, and keep track of the things you want to change and do it all at a time.You can also deprecate things, and document the way you want those things to be done moving forward. That way you give people the chance to start changing their code and simplify a hypothetical upcoming major release.<h3>Provide clear upgrade paths</h3>As mentioned above, too frequent major version changes are not desirable, but sooner or later you will want to release a new major version for different reasons.<ul><li>Getting rid of that feature which is hard to maintain, introduces lots of bugs, and provides little value.</li><li>Supporting something new which is very hard to implement without breaking backwards compatibility.</li><li>Removing all those deprecated methods you have been dragging for months.</li><li>Fix design issues, where something was architected in the wrong way, and only spotted after some time.</li></ul>At the time this happens you will want your users to upgrade to the newer version, as you don&#x27;t want people to report bugs that only affect older versions, or to expect you to backport fixes to older versions because they haven&#x27;t updated to the new one.The best way to achieve this is to provide clear and simple upgrade paths:<ul><li>Prepare your releases for the things to come: If you want to introduce new ways of doing things, do it before the major release, and deprecate the older ones. For example, you can have a new method that gets called by an older one, while you mark the old one as deprecated.People will be more willing to update and change their code afterwards. By the time the major release is published, their code will be ready to upgrade.</li><li>Include a CHANGELOG file in your project, explaining the changes introduced in every version. A very good way to document a change log is the <a target="_blank" rel="noopener noreferrer" href="https://keepachangelog.com/">Keep a changelog</a> initiative.You can also use some other platform to document the change log, like GitHub releases.</li><li>Include documentation on how to upgrade to a major release: This is probably the most important one. Document all the steps that need to be followed and all the required changes to update from a release to the next major one.A good way to do this is by including an UPGRADE file in your project. You can see <a target="_blank" rel="noopener noreferrer" href="https://github.com/acmailer/acmailer/blob/main/UPGRADE.md">this example</a>.</li></ul><h3>Versioning libraries vs apps</h3>Semantic Versioning is a good standard to version software, but it plays much better with libraries and frameworks that are installed using some kind of package manager, than it does with apps and services that are not directly depended on.For example, how do you identify a backward compatibility break on a web user interface?With this kind of software there are more grey areas, and you will end up using your intuition.For example, not long ago I released a <a href="/2020/12/24/released-shlink-web-client-v3-0-0/">new major version</a> for a web app I maintain, and it was completely compatible with the previous one. However, it introduced a larger amount of features than usual, and big UI changes, so I decided it was worth the bump.Because of this there are projects that use different approaches to version apps. For example:<ul><li>Firefox and Chrome have 6-week cycles, and after each one of them they release a new major version no matter what.</li><li>Jetbrains publishes a few releases of their IDEs every year (I think 3) which always start with the year they were released on, like <code>2020.3.0</code>, and they increase the patch number for bugfixes.</li><li>Ubuntu releases 2 versions every year, one in April and one in October, and they are always identified by the year and month they were released on, like <code>19.04</code> or <code>20.10</code>.</li></ul><h3>Special versions</h3>There&#x27;s also a set of special versions that can be used to publish the so-called pre-release versions. These <a target="_blank" rel="noopener noreferrer" href="https://semver.org/#spec-item-9">are covered</a> by Semantic Versioning, but sometimes they are not so easy to understand.It is also very likely that you never have to use these, as only relatively big projects will need this level of granularity, but it&#x27;s still good to know what&#x27;s their purpose and what do they imply.<h4>0.x.y</h4>It is possible to release a version of your software where the major number is <code>0</code>. When this happens, it means your software is still in its early stages.It does not mean it&#x27;s necessarily unstable, but it means you are still introducing frequent changes on it, and therefore, it might be a bit more fragile than a version starting with a number greater than <code>0</code>.<h4>Alpha</h4>The intention of an alpha release is that a subset of people con test some new functionality, but you don&#x27;t want people to use it in productionAlpha versions are on their very early stages. Their public API is very likely to change, and they probably contain bugs.Semantic Versioning states that alpha versions are identified by this pattern: <code>MAJOR.MINOR.PATCH-alpha.NUMBER</code>, for example <code>2.0.0-alpha.1</code>.<h4>Beta</h4>Similar to alpha versions, beta versions are also prone to contain bugs, but their API will in theory not change. That means that you could potentially adapt your software to start using a beta version, and when the corresponding stable release is published, you shouldn&#x27;t need that many changes.Semantic Versioning defines a pattern similar to the one for alpha versions: <code>MAJOR.MINOR.PATCH-beta.NUMBER</code>, for example <code>2.0.0-beta.1</code>.<h4>Release candidate</h4>Release candidates (RC) are pre-release versions that you will want to publish for the general user-base to test an upcoming release. You want to publish a RC so that it&#x27;s battle tested by as many people as possible, in order to find possible bugs and edge cases.They should not contain many bugs, but some could be found. The public API should not change anymore.According to Semantic Versioning, the pattern to identify a RC is <code>MAJOR.MINOR.PATCH-rc.NUMBER</code>, for example <code>2.0.0-rc.1</code>.<h3>Conclusion</h3>We have seen some approaches and considerations to properly version your software.Versioning is not so straightforward when you don&#x27;t have a lot of experience, but as you have seen, you just need to know a small set of rules and use a bit your intuition.With those tools, you will be able to properly version your software.

What to take into account when versioning software

I&#x27;m sure you are familiar with those &quot;remember me&quot; checkboxes in login forms. They are a common way to allow a user to keep his/her session in a web application for an extended period of time when he is in a trusted computer.One could think that it is a small and easy-to-implement feature, but it has indeed a lot of considerations.I wasn&#x27;t able to properly implement it in the first projects I worked in, and I&#x27;m trying to explain everything I&#x27;ve learned about it in the last years.<blockquote>In this article I&#x27;m not going to show you how to implement a persistent login in one or another programming language, but what are the good practices that should be followed when you implement it in the way you want.</blockquote><h3>First thoughts.</h3>The first thing that one could try is to extend the lifetime of the system that persists the session and identifies the user between requests (usually a cookie). The problem is that many systems doesn&#x27;t allow to do that in an isolated way, you are forced to extend the lifetime of all sessions. Also, it is not always easy to change the session lifetime dynamically.So it&#x27;s not a good idea, because the user could be accessing your app from a public computer, and his session could be stolen if he forgets to logout. Because of this, the best way to do it is to have another element (another cookie) that keeps the persistent session and is used to transparently regenerate the regular session when it expires.<h3>How to implement it.</h3>When a user logs in and he has checked the &quot;remember me&quot; field, you will create a cookie with an extended lifetime (for example, 2 weeks).That cookie will contain a unique token that will identify a user. It should be backed in the database by creating a table that relates the token with a user. It could contain other metadata too, like the client&#x27;s IP address or a flag that says if the session is still valid.In consecutive requests, your system will keep checking if an authenticated user exists, but if not, instead of redirecting to a login or returning a 403 status, it should check for the persistent login cookie first.When that cookie exists, you will find the user it belongs to, and authenticate him. Then, you will invalidate the cookie and the session in the database, and generate a new one that will expire in the same date as the previous one. Finally, the new token should be returned in a new persistent login cookie that will replace the previous one by having the same name.When the user manually logs out, the persistent login cookie should be dropped too.<h3>Security considerations</h3>Now you have a basic idea on how to implement it, but there are some security considerations to take into account in order to avoid problems in the future.The first thing that we have to assume is that persistent sessions have their risks. There is no way to implement a completely secure persistent login, but following this instructions the system will be reasonably secure.<ul><li>Persistent login will be handled by a cookie in the client and a database in the server (or a similar persistence system).</li><li>Persistent sessions will have an expiration time, for example 2 weeks. During that time, any regular session will be regenerated by the persistent session. Once it has passed, the user will be prompted to provide his credentials when the regular session expires. The expiration time will be set both in the cookie and in the database.</li><li>Persistent login cookies will contain one-time tokens. Once a token has been used it will be invalidated and a new one will be generated.</li><li>In order to protect these tokens from <a target="_blank" rel="noopener noreferrer" href="https://en.wikipedia.org/wiki/Cross-site_scripting">XSS</a> attacks in the site, persistent login cookies should be <code>HttpOnly</code>, so that they cannot be read from the browser.</li><li>Multiple valid persistent sessions will be allowed.</li><li>When a user logs out, its current persistent session in the database and the persistent login cookie will be invalidated.</li><li>The user should be able to invalidate all the persistent sessions that are still valid.</li><li>Invalid persistent sessions won&#x27;t be deleted. This way, if the user tries to access with an invalid cookie, he will be notified of a possible stolen cookie, and immediately all the other persistent sessions will be invalidated.</li><li>When the user changes his/her password, all the persistent sessions should be invalidated.</li><li>The token needs to be unique. Just generate some hash including the date and some other field. It doesn&#x27;t need to be super secure, but make sure to not send critical information to the client (like usernames or passwords).</li><li>And finally, there should be some operations restricted to users whose regular session has been regenerated by a persistent session, like changing a password or performing some kind of payment. In those cases, the user should be prompted for his current password anyway.</li></ul>Of course, if your system manages critical data, you shouldn&#x27;t implement persistent login at all. I don&#x27;t think you have seen it at any bank application.In any other case, this should be a good way to go.

How to properly implement persistent login

I have spoken many times at this blog about dependency injection, and how the ZF2 ServiceManager is one of the best tools to solve it.
You can read these related articles to know more:<ul><li><a href="/2014/07/03/how-to-properly-use-the-zend-framework-2-service-manager-as-a-dependency-injection-container/">How to properly use the Zend framework 2 service manager as a dependency injection container</a></li><li><a href="/2014/10/09/advanced-usage-of-service-manager-in-zend-framework-2/">Advanced usage of ServiceManager in Zend Framework 2</a></li><li><a href="/2015/02/06/managing-objects-creation-and-dependency-injection-with-zend-service-manager/">Managing objects creation and dependency injection with Zend\ServiceManager</a></li></ul>In this article I&#x27;m going to speak about another utility that comes with the <code>Zend\ServiceManager</code> package, the <code>AbstractPluginManager</code>.<h3>Injecting a service container</h3>Generally it is a very bad practice to inject a service container into any object, but there are some situations where it could be even good, when certain conditions are met. In one of the ZF2 mailing lists somebody asked which were these situations. I couldn&#x27;t find the email, but the answers said that you can do it when the service container manages resources of the same type, and your object virtually depends on all of them. For example, imagine you have a database connections pool. It is responsible of creating connection objects, and knowing which one should be returned. If you have another object that needs to perform database connections, you don&#x27;t want to inject all of the connection objects into it, you should rather inject the connection pool. That will reduce the number of dependencies of your object. In this situation, the connection pool is some kind of service container, but injecting it has more benefits than disadvantages.<h3>The AbstractPluginManager implementation</h3>Once we know the theory, we can see how to implement it. The AbstractPluginManager is a class that extends the ServiceManager, but includes an abstract method <code>validatePlugin</code> that implementors should use to validate objects when they are created. It just needs to throw an exception if it is not valid, for example because it doesn&#x27;t implement certain interface.This way we can be sure that all the services managed by it can be used for a specific task. In the connection pool example, all the managed objects should be capable of connecting to a database.<h3>A real example</h3>Imagine that we have a service that needs to connect to different social networks in order to generate social login URLs and get user information from them.
That service abstracts the concrete implementation for each social network, and to do it, it gets concrete social connectors injected.It could look like this:<pre><pre><code class="language-php">namespace Acelaya\Social;

use Acelaya\Social\Connector\FacebookConnector;
use Acelaya\Social\Connector\LinkedinConnector;
use Acelaya\Social\Connector\TwitterConnector;

class SocialUsers
{
 public function __construct(
 FacebookConnector $fConnector,
 TwitterConnector $tConnector,
 LinkedinConnector $lConnector
 ) {
 // [...]
 }
 
 /**
 * @return string
 */
 public function getLoginUrl($socialNetwork)
 {
 if ($socialNetwork === &#x27;facebook&#x27;) {
 return $this-&gt;fConnector-&gt;getLoginUrl();
 } elseif ($socialNetwork === &#x27;twitter&#x27;) {
 return $this-&gt;tConnector-&gt;getLoginUrl();
 } elseif ($socialNetwork === &#x27;linkedin&#x27;) {
 return $this-&gt;lConnector-&gt;getLoginUrl();
 }
 }
 
 /**
 * @return array
 */
 public function getUserData($socialNetwork, $authToken)
 {
 if ($socialNetwork === &#x27;facebook&#x27;) {
 return $this-&gt;fConnector-&gt;getUserData($authToken);
 } elseif ($socialNetwork === &#x27;twitter&#x27;) {
 return $this-&gt;tConnector-&gt;getUserData($authToken);
 } elseif ($socialNetwork === &#x27;linkedin&#x27;) {
 return $this-&gt;lConnector-&gt;getUserData($authToken);
 }
 }
}
</code></pre></pre>The service methods call to the proper connector based on the social network we specify. Apparently, it&#x27;s a simple implementation.But there is a problem. If the number of social networks we support grows too much, at some point this service is going to have too many dependencies, and that&#x27;s a code smell. Also, having a lot of <code>if</code> statements per method is not very clean either.The solution would be to create a <code>SocialPluginManager</code>, an object that extends <code>Zend\ServiceManager\AbstractPluginManager</code> and manages and creates each social connector transparently. Then, we just need to make the <code>SocialUsers</code> service to depend on the <code>SocialPluginManager</code>.Each social connector should implement an interface like this.<pre><pre><code class="language-php">namespace Acelaya\Social\Connector;

interface SocialConnectorInterface
{
 /**
 * @return string
 */
 public function getLoginUrl();
 
 /**
 * @return array
 */
 public function getUserData($authToken);
}
</code></pre></pre>Then the <code>SocialPluginManager</code> will just need to check if any created object implements it.<pre><pre><code class="language-php">namespace Acelaya\Social;

use Acelaya\Social\Connector\SocialConnectorInterface;
use Zend\ServiceManager\AbstractPluginManager;
use Zend\ServiceManager\Exception;

class SocialPluginManager extends AbstractPluginManager
{
 /**
 * Validate the plugin
 *
 * Checks that the filter loaded is either a valid callback or an instance
 * of FilterInterface.
 *
 * @param mixed $plugin
 * @return void
 * @throws Exception\RuntimeException if invalid
 */
 public function validatePlugin($plugin)
 {
 if ($plugin instanceof SocialConnectorInterface) {
 return;
 }
 
 throw new Exception\RuntimeException(sprintf(
 &#x27;Plugins managed by &quot;%s&quot; must implement &quot;%s&quot;. &quot;%s&quot; provided&#x27;,
 __CLASS__,
 SocialConnectorInterface::class,
 is_object($plugin) ? get_class($plugin) : gettype($plugin)
 ));
 }
}
</code></pre></pre>We now need to refactor the <code>SocialUsers</code> service so that it depends on the <code>SocialPluginManager</code>.<pre><pre><code class="language-php">namespace Acelaya\Social;

use Acelaya\Social\Connector\SocialConnectorInterface;
use Acelaya\Social\Exception\InvalidSocialNetworkException;

class SocialUsers
{
 public function __construct(SocialPluginManager $socialPlugins)
 {
 // [...]
 }
 
 /**
 * @return string
 */
 public function getLoginUrl($socialNetwork)
 {
 return $this-&gt;getSocialConnector($socialNetwork)-&gt;getLoginUrl();
 }
 
 /**
 * @return array
 */
 public function getUserData($socialNetwork, $authToken)
 {
 return $this-&gt;getSocialConnector($socialNetwork)-&gt;getUserData($authToken);
 }
 
 /**
 * @return SocialConnectorInterface
 */
 protected function getSocialConnector($socialNetwork)
 {
 if (! $this-&gt;socialPlugins-&gt;has($socialNetwork)) {
 throw new InvalidSocialNetworkException($socialNetwork);
 }
 
 return $this-&gt;socialPlugins-&gt;get($socialNetwork);
 }
}
</code></pre></pre>The resulting code is much cleaner, and now we can add any new social network without having to change the <code>SocialUsers</code> service. We just need to create and register the new social connector.The last thing we have to do is defining the <code>SocialPluginManager</code> configuration. Since the <code>AbstractPluginManager</code> extends the <code>ServiceManager</code>, it is exactly the same as the one used for it. To make the previous code work, we have to use the social network name as the service name for each connector, so the configuration could look like this.<pre><pre><code class="language-php">use Acelaya\Social\Connector;

return [
 &#x27;factories&#x27; =&gt; [
 &#x27;facebook&#x27; =&gt; Connector\FacebookConnectorFactory::class,
 &#x27;twitter&#x27; =&gt; Connector\TwitterConnectorFactory::class,
 &#x27;linkedin&#x27; =&gt; Connector\LinkedinConnectorFactory::class,
 ]
];
</code></pre></pre>I have used factories as an example, but you can use any valid strategy you want.You can see a small example project <a target="_blank" rel="noopener noreferrer" href="https://github.com/acelaya-blog/di-with-plugin-manager">here</a>. The concrete social connector doesn&#x27;t do nothing, but you can see how they work.The plugin managers are widely used in <code>Zend\Mvc</code> for tasks like this. The controller plugins, view helpers, form elements and such can all be managed by its own plugin managers.

Improve dependency injection in PHP apps with Zend Framework plugin managers

It&#x27;s well known that using autoincrement identifiers for resources in a public API is not a very good idea, since you are exposing too much information about the size of your database and your business in general.The PHP community is recommending to better use UUIDs these days, because it hides that information and can be generated anywhere and still be unique.It has a number of advantages. The first one, as I already said, is the fact that it hides critical information of the system when you have to publicly share it, it is not easy to find out anything about the application business if you only have a UUID. But there are more:<ul><li>A UUID (Universally Unique IDentifier) is universally unique. That menas that it is not unique only in the scope of a table, like an autoincrement, but unique accross any system in the world.</li><li>Since it is globally unique, it can be generated before being stored in the database or even in client-side, and we can be sure (almost) it won&#x27;t be duplicated.</li><li>Allows to easily migrate and merge information from different tables and databases, by keeping their identifier, since it will still be unique.</li><li>Decouples your application with the persistence layer, since all the information is generated before being persisted. (Thanks to <a target="_blank" rel="noopener noreferrer" href="https://twitter.com/tomas2387/status/658237457117368320">@tomas2387</a> for mentioning this)</li></ul>I&#x27;m going to explain now, how to take advantage of UUIDs when working with databases in PHP applications by using Doctrine and the fantastic <a target="_blank" rel="noopener noreferrer" href="https://github.com/ramsey/uuid">ramsey/uuid</a> package, with the bridge library <a target="_blank" rel="noopener noreferrer" href="https://github.com/ramsey/uuid-doctrine">ramsey/uuid-doctrine</a>.<h3>Creating entities</h3>Entities will have an ID, but instead of setting them with an autoincrement strategy and an integer type, we are going to use the uuid doctrine type and typehint the ID as a <code>Ramsey\Uuid\UuidInterface</code>.We are also going to initialize the ID in the entity&#x27;s constructor. Once the entity is created, it will have an ID, generated outside the database, but unique, so we can safely persist the entity.<pre><pre><code class="language-php">namespace Acelaya\Blog\Entity;

use Ramsey\Uuid\Uuid;
use Ramsey\Uuid\UuidInterface;

/**
 * @Entity
 * @Table(name=&quot;user&quot;)
 */
class User
{
 /**
 * @var UuidInterface
 *
 * @Id
 * @Column(type=&quot;uuid&quot;)
 */
 protected $id;
 /**
 * @var string
 *
 * @Column(length=256)
 */
 protected $username;
 /**
 * @var string
 *
 * @Column(length=256)
 */
 protected $password;
 /**
 * @var string
 *
 * @Column(length=256)
 */
 protected $fullName;

 public function __construct()
 {
 $this-&gt;id = Uuid::uuid4();
 }

 // Getters and setters...
}
</code></pre></pre>As you can see, we don&#x27;t have to set the <code>@GeneratedValue</code> annotation in the <code>id</code> property, since the value is not generated in the database. Instead, it is initialized in the contructor.<h3>Registering the type</h3>The last example is very simple. We don&#x27;t have to do anything, and our <code>id</code> will be a <code>Ramsey\Uuid\Uuid</code> instance, so we can compare it with other UUIDs and serialize it in many ways, but Doctrine doesn&#x27;t know how to serialize and deserialize that field while exchanging data with the database. We need to register the uuid type.<pre><pre><code class="language-php">use Doctrine\DBAL\Types\Type;
use Ramsey\Uuid\Doctrine\UuidType;

// Some kind of bootstrapping...

Type::addType(&#x27;uuid&#x27;, UuidType::class);
</code></pre></pre>Once this is set, we can use the uuid doctrine type for any property and it will be properly serialized/unserialized. We just need to initialize those properties in our entities&#x27;s constructors with the desired UUID version.