A couple of weeks ago I migrated a React project using redux to <a target="_blank" rel="noopener noreferrer" href="https://redux-toolkit.js.org/">Redux Toolkit</a>.
Redux has always been my preferred state management tool for React (which doesn&#x27;t mean I &quot;love&quot; it), but one of its main problems is the amount of boilerplate code it requires.
Because of that I had a couple of helper functions, but there was still some things not properly handled, like proper type inference on reducers and actions (I use TypeScript).
A bit by accident (I think it was on Twitter), I found out about Redux Toolkit (RTK from now on), an official library from the redux team, which provides some opinionated helpers to reduce the amount of boilerplate, and I decided to give it a chance.
These are my impressions.
<h3>TL;DR</h3>
I first started to use it in a proof of concept, and I quickly loved it.
RTK does not &quot;replace&quot; any of the redux principles, so you can progressively adopt it, by replacing small bits of code. My plan was to use it just for some reducers, but I liked it so much that I ended up migrating the whole project in a series of consecutive pull requests.
<h3>A bit of context</h3>
Before the migration, I used to follow the <a target="_blank" rel="noopener noreferrer" href="https://github.com/erikras/ducks-modular-redux">ducks modular pattern</a>, which promotes putting all your action types, action creators and the reducer handling those actions on the same module.
This fits pretty well with RTK, as in most of the cases you will use <a target="_blank" rel="noopener noreferrer" href="https://redux-toolkit.js.org/api/createSlice">slices</a>, and end up exporting the reducer and action creators returned by it, from the same module.
If you use <a target="_blank" rel="noopener noreferrer" href="https://redux-toolkit.js.org/api/createAsyncThunk">async thunks</a>, they usually need to be used by that same slice, so it&#x27;s not a bad idea to export them also from there.
<h3>Why I love it</h3>
There are a couple of reasons for which I loved RTK right away. The main one is that they make an impressive work on making type inference in TypeScript work properly.
<ul>
<li>Slices detect the type of the initial state in order to know what is expected to be passed as <code>state</code> to reducers.</li>
<li>You can infer the type of your store from what is generated by <code>configureStore</code> or <code>combineReducers</code> functions, allowing you to also properly type the <code>dispatch</code> function.</li>
<li>Action creators are generated with the proper param types based on the reducers provided to <code>createSlice</code> or the callback provided to <code>createAsyncThunk</code>.</li>
<li><code>createSlice</code> can consume all the action creators generated by <code>createAsyncThunk</code>, and infer the proper payload for each one of them.</li>
</ul>
Thanks to this, the code is super predictable and potential bugs can be caught sooner.
<blockquote>
More details on how to use RTK with typescript https://redux-toolkit.js.org/usage/usage-with-typescript
</blockquote>
But this is not the only benefit. Other reasons that make it very nice to work with are:
<ul>
<li>It keeps the same concepts from Redux, but removing the boilerplate or your own helper functions if you have them (yes, I didn&#x27;t want to keep all those <code>switch</code> statements everywhere).</li>
<li>It is mostly transparent for the components dispatching the actions or consuming the state.</li>
<li>All the tests covering your reducers/actions/components should keep passing, as the outcome from RTK is the same as if you built everything manually.</li>
<li>It introduces a couple of extra helpers, like <a target="_blank" rel="noopener noreferrer" href="https://redux-toolkit.js.org/rtk-query/overview">RTK query</a> or the <a target="_blank" rel="noopener noreferrer" href="https://redux-toolkit.js.org/api/createListenerMiddleware">listener middleware</a>, which is very useful to dispatch actions as a result of other actions being dispatched.</li>
</ul>
<h3>Challenges I found</h3>
Of course, adopting a new tool always comes with some challenges.
The main &quot;problem&quot; I found is that RTK is a bit opinionated, but that&#x27;s precisely how they manage to reduce boilerplate code, and it&#x27;s also &quot;advertised&quot; in their website, so not a big surprise.
I usually prefer to be in control of everything (configuration over convention), but that&#x27;s just a personal preference, and sometimes it&#x27;s ok to accept a bit of magic for the sake of simplicity.
This caused the next challenges for my particular case:
<ul>
<li>
RTK assumes your project follows a strict <a target="_blank" rel="noopener noreferrer" href="https://redux.js.org/tutorials/fundamentals/part-7-standard-patterns#flux-standard-actions">Flux pattern</a>, meaning your actions always have the properties <code>type</code>, <code>payload</code> and optionally <code>meta</code> and <code>error</code>.
I was not following this pattern (my actions had the payload &quot;mixed&quot; on the first object level), so I had to adapt all my actions first, fix the tests, then migrate the reducer to RTK and make sure the tests kept passing.
<div></div>
</li>
<li>
Immutability is no longer promoted in reducers. Instead, the library requires <a target="_blank" rel="noopener noreferrer" href="https://immerjs.github.io/immer/">immer</a> internally, and using proxies they automatically ensure immutability, even if you &quot;mutate&quot; the state.
This feels a bit counterintuitive at first, because redux always promoted an immutable approach, and the use of immer is not obvious.
However, they have <a target="_blank" rel="noopener noreferrer" href="https://redux-toolkit.js.org/usage/immer-reducers#why-immer-is-built-in">good reasons</a> to do it, and if your reducers return a state object, you can still use the immutable approach. It&#x27;s up to you.
<div></div>
</li>
<li>
Action creators resulting of <code>createAsyncThunk</code> can only have one argument.
This is because the async thunk callback receives a second argument containing the <code>dispatch</code> and <code>getState</code> functions, as well as a couple of other goodies, enforcing this convention to avoid human errors.
<div></div>
</li>
<li>
You cannot dispatch other actions after the callback passed to <code>createAsyncThunk</code>, because it has to return the payload and RTK dispatches the action for you.
However, this is probably something you usually should not be doing, and in my case, I resolved it with the <a target="_blank" rel="noopener noreferrer" href="https://redux-toolkit.js.org/api/createListenerMiddleware">listener middleware</a>, listening for the second action in order to dispatch the second one.
</li>
</ul>
<h3>Conclusion</h3>
My conclusion is that RTK is definitely worth it if you use redux.
It makes code simpler, more predictable and better typed. However, it still requires knowing how redux works internally and what are its patterns, in order to understand why the library exposes the helpers it exposes and why.
For existing redux projects, you can migrate progressively, addressing the challenges bit by bit and not all at once, which simplifies its adoption.
For new projects in which you want to use redux, I would recommend starting right away with RTK.

A couple of weeks ago I migrated a React project using redux to Redux Toolkit. Redux has always been my preferred state management tool for React (which doesn't mean I "love" it), but one of its main problems is the amount of boilerplate code it requires.

Because of that I had a couple of helper…

My experience migrating to Redux Toolkit (RTK)

In 2019, GitHub published their own solution to run automated workflows called GitHub Actions, which allowed those hosting their code in GitHub, to be able to define and run their CI/CD pipelines in the same platform. When it was released, one of the main pain points to use it was that defining…

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 class="language-tsx"><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>
</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 class="language-tsx"><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>
</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.

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 shlink-web-client, so I naturally created a new branch and started the process.

The…

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…

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 class="language-yml"><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>
<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 class="language-diff"><code class="language-diff">on:
- pull_request: null
+ pull_request_target: null
</code></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 class="language-diff"><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>
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>

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…

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

<a target="_blank" rel="noopener noreferrer" href="https://getcomposer.org/">Composer</a> is The Tool in any modern PHP project. Nowadays I can&#x27;t imagine to work without it.
It is much more powerful than some people think, easily solving the integration of third party components in our projects, but there are some advanced features that are less known.
I&#x27;m going to try to explain some of the best practices and mechanisms bundled with composer.
<blockquote>
If you are not familiar with composer, some time ago I wrote an introduction article that you should read before continuing with this one. <a href="/2014/07/19/dependency-management-and-autoloading-in-php-projects-with-composer/">Dependency management and autoloading in php projects with composer</a>.
</blockquote>
<h3>Globally installing composer</h3>
It is a good practice to have composer installed globally, instead of having a binary file per project.
After downloading the <code>composer.phar</code> file from the <a target="_blank" rel="noopener noreferrer" href="https://getcomposer.org/download/">composer</a> website, you can start using it by running <code>php composer.phar [...]</code>. Instead, we are going to place it in a global location so that we can run the command <code>composer [...]</code> from this moment on.
In UNIX systems, just make the file executable and move it to a folder that&#x27;s already in the path.
<pre class="language-bash"><code class="language-bash">sudo chmod +x composer.phar
sudo mv composer.phar /usr/local/bin/composer
</code></pre>
Under Windows systems, there is an installer that will make the work for you. Download it <a target="_blank" rel="noopener noreferrer" href="https://getcomposer.org/doc/00-intro.md#installation-windows">here</a>.
Now, go to any location and run <code>composer</code>. You should see composer&#x27;s help.
<h3>Create the composer.json file</h3>
The first thing you should do when starting a new PHP project is to create the composer.json file. It is the main configuration file, where metadata, dependencies and autoloading are defined.
You probably don&#x27;t remember the main parts of this file, and end up copying the file from othe projects. There is no need to do that, just run <code>composer init</code> and the Composer config generator will be executed, guiding you over the process of creating the file.
<h3>Add dependencies to an existing composer.json file</h3>
In the documentation of many libraries, they tell you to manually edit your composer.json file to add new dependencies. That can be problematic, because you could have a syntax error, forget to add a trailing comma, etc.
The best practice to add dependencies to your composer.json file is to run the command <code>composer require vendor-name/library-name ~3.0</code>. That will add the new dependency to your file (avoiding syntax errors) and then install it.
If you don&#x27;t include the version name, composer will try to find out what&#x27;s the best version to use, by following <a target="_blank" rel="noopener noreferrer" href="http://semver.org/">Semantic Versioning</a>. If it is not able to know which version to use, it will ask you to decide.
<h3>Production environments</h3>
The management of dependencies and new classes is not the same in our development environment and the production environment. In development we need new classes to be automatically autoloaded, and we want to have certain dependencies, like phpunit or php code sniffer that are not of any use in production.
In development we will usually install or update dependencies by running <code>composer install</code> or <code>composer update</code>. That will include all dependencies in require and require-dev blocks, and generate an autoloader by following different strategies. Some of those autoloading strategies imply the iteration of directories in order to find class files.
That is ok for development, but in production we need something more efficient than that, and also, we don&#x27;t want require-dev dependencies to be installed.
To get this done, in a deployment process, we should run this command instead.
<pre class="language-bash"><code class="language-bash">composer install --no-dev --optimize-autoloader --prefer-dist --no-interaction
</code></pre>
This is what each flag makes:
<ul>
<li><code>--no-dev</code>: prevents dependencies defined in the requre-dev block to be installed.</li>
<li><code>--optimize-autoloader</code>: generates a classmap autoloader, that will map each class with the file that contains it, preventing unnecessary directory iterations.</li>
<li><code>--prefer-dist</code>: installs distributable versions of the libraries, instead of source code, when possible.</li>
<li><code>--no-interaction</code>: will always try to make the proper decission in case any &quot;conflict&quot; is produced, so that the process is completly unatended.</li>
</ul>
This is the command you should use when deploying a project, just after clonning a clean repository.
<h3>Private repositories</h3>
This is probably one of the most powerful features while working on many private projects that depend on each other.
By default, composer fetches dependencies from a single repository, <a target="_blank" rel="noopener noreferrer" href="https://packagist.org/">Packagist</a>, which needs to have access to a public repository (usually github). But what happens if my code is private, and I don&#x27;t want to (or can&#x27;t) open source it? May I use composer to install private dependencies? The answer is yes.
The composer.json file can include a repositories block, where we define other repositories (either public or private) where composer will try to find dependencies.
There are several repository types supported by composer, from a VCS repository to a plain local directory containing zip files.
<pre class="language-javascript"><code class="language-javascript">{
 &quot;repositories&quot;: [
 {
 &quot;type&quot;: &quot;vcs&quot;,
 &quot;url&quot;: &quot;https://my-repos.com/something-private&quot;
 },
 {
 &quot;type&quot;: &quot;pear&quot;,
 &quot;url&quot;: &quot;http://pear2.php.net&quot;
 },
 {
 &quot;type&quot;: &quot;artifact&quot;,
 &quot;url&quot;: &quot;path/to/directory/with/zips/&quot;
 }
 ]
}
</code></pre>
Composer will look for dependencies on each defined repository in order, and Packagist as a last resource.
Defining repositories is very flexible and a little bit complex in some cases, so I recommend you to read the <a target="_blank" rel="noopener noreferrer" href="https://getcomposer.org/doc/05-repositories.md">documentation</a>.
<h3>CLI scripts</h3>
Sometimes a library includes some command line interface scripts that the user can use to automate configuring some stuff.
If you want to include your own CLI scripts and allow any user to find them when installing your library as a dependency, you will want to define them in the bin block.
<pre class="language-javascript"><code class="language-javascript">{
 &quot;bin&quot;: [
 &quot;scripts/generate-foo&quot;,
 &quot;scripts/create-bar&quot;,
 &quot;scripts/do-something&quot;
 ]
}
</code></pre>
It is just a list of script paths that composer will &quot;copy&quot; to the <code>vendor/bin</code> directory after installation (it doesn&#x27;t really copy them, it creates symlinks in UNIX systems and generates bat files under Windows).
This makes all the CLI scripts of all dependencies to be &quot;placed&quot; in the same location, so it is easier to find them.
This makes sense only in non-root projects (those that will be installed as dependencies of other projects and are not base applications).
<h3>Events</h3>
Composer will trigger some events during the process of installing dependencies, generating autoloaders and such. You can define some scripts or code snippets that will be automatically executed when those events are triggered.
These event listeners are defined in the scripts block. They can be either CLI commands or static class methods.
<pre class="language-javascript"><code class="language-javascript">{
 &quot;scripts&quot;: {
 &quot;post-package-install&quot;: &quot;Acelaya\\MyClass::postPkgInstall&quot;,
 &quot;post-install-cmd&quot;: [
 &quot;Acelaya\\MyClass::postInstall&quot;,
 &quot;phpunit -c app/&quot;
 ]
 }
}
</code></pre>
The complete list of events can be found in composer&#x27;s <a target="_blank" rel="noopener noreferrer" href="https://getcomposer.org/doc/articles/scripts.md#event-names">documentation</a>. Take a look at them and see if you can optimize your workflow.
<h3>Applications installation</h3>
At this point we all know that we can use composer to install libraries at project level, but what happens with applications, known as root projects in composer&#x27;s terms.
We can also use composer to distribute complete applications, allowing them to be easily installed by using this command.
<pre class="language-bash"><code class="language-bash">composer create-project vendor-name/app-name
</code></pre>
This will download the application (as if we would have cloned the repository) and then install its dependencies. We could even take advantage of composer&#x27;s events, and initialize a database or create some non-tracked directories.
<h3>Conclusion</h3>
And that&#x27;s pretty much all.
Use composer, it will improve your PHP projects.

Composer is The Tool in any modern PHP project. Nowadays I can't imagine to work without it. It is much more powerful than some people think, easily solving the integration of third party components in our projects, but there are some advanced features that are less known.

I'm going to try to…

Composer advanced concepts

One of the common problems we have to confront when starting a new PHP project is how to handle the different dependencies we are going to have.
One could think the easier solution is to download all the libraries we are going to need, put them in a <code>lib</code> directory and add them to the version control of the project, but this could be problematic. Let&#x27;s see why.
The main problems of using this practice are this.
<ul>
<li>Dependencies of dependencies: Our dependencies may have their own dependencies that we will also need to download.</li>
<li>Updates: What happens if we need a new feature in the last version of one dependendency? We are going to have to update it manually, and that can be a hard task. Baybe even the new version has new dependencies of its own that we will need to download.</li>
<li>Autoloading: How do we deal with autoloading the classes in the dependencies? Some of them may have its own autoloading system, but anyway, we are going to need to <code>include</code> all the autoloaders of each dependency.</li>
</ul>
How do we solve all of this? The answer is <a target="_blank" rel="noopener noreferrer" href="http://getcomposer.org">Composer</a>.
<h3>Starting with composer</h3>
Composer has become the dependency manager in the main PHP projects. It uses its own library repository (<a target="_blank" rel="noopener noreferrer" href="https://packagist.org/">packagist</a>) to handle dependencies, but you can setup private repositories too.
It uses a small configuration file, the <code>composer.json</code>, to know which are our dependencies, and it will download their dependencies recursively without us having to do anything special.
We can define an autoloading strategy in that file too, and forget about that task for our project and our dependencies.
This are some examples of famous PHP project&#x27;s <code>composer.json</code> files:
<ul>
<li><a target="_blank" rel="noopener noreferrer" href="https://github.com/zendframework/zf2/blob/master/composer.json">Zend Framework</a></li>
<li><a target="_blank" rel="noopener noreferrer" href="https://github.com/symfony/symfony/blob/master/composer.json">Symfony</a></li>
<li><a target="_blank" rel="noopener noreferrer" href="https://github.com/doctrine/doctrine2/blob/master/composer.json">Doctrine</a></li>
<li><a target="_blank" rel="noopener noreferrer" href="https://github.com/aws/aws-sdk-php/blob/master/composer.json">AWS PHP SDK</a></li>
<li><a target="_blank" rel="noopener noreferrer" href="https://github.com/Seldaek/monolog/blob/master/composer.json">Monolog</a></li>
<li><a target="_blank" rel="noopener noreferrer" href="https://github.com/thephpleague/flysystem/blob/master/composer.json">Flysystem</a></li>
</ul>
Now lets see a simpler composer file:
<pre class="language-json"><code class="language-json">{
 &quot;name&quot; : &quot;acelaya/zf2-acmailer&quot;,
 &quot;description&quot; : &quot;Mail sending module for Zend Framework 2&quot;,
 &quot;type&quot; : &quot;library&quot;,
 &quot;authors&quot; : [
 {
 &quot;name&quot; : &quot;Alejandro Celaya Alastrué&quot;,
 &quot;email&quot; : &quot;alejandro@alejandrocelaya.com&quot;,
 &quot;homepage&quot; : &quot;http://www.alejandrocelaya.com&quot;,
 &quot;role&quot; : &quot;Developer&quot;
 }
 ],
 &quot;keywords&quot; : [
 &quot;mail&quot;,
 &quot;zend&quot;,
 &quot;php&quot;
 ],
 &quot;homepage&quot; : &quot;https://github.com/acelaya/ZF2-AcMailer&quot;,
 &quot;license&quot; : [
 &quot;BSD&quot;
 ],
 &quot;require&quot; : {
 &quot;php&quot; : &quot;&gt;=5.3.0&quot;,
 &quot;zendframework/zendframework&quot;: &quot;&gt;=2.2.2&quot;
 },
 &quot;require-dev&quot;: {
 &quot;phpunit/phpunit&quot;: &quot;&gt;=3.7&quot;,
 &quot;squizlabs/php_codesniffer&quot;: &quot;1.*&quot;,
 &quot;phploc/phploc&quot;: &quot;*&quot;,
 &quot;pdepend/pdepend&quot; : &quot;1.1.0&quot;,
 &quot;phpmd/phpmd&quot; : &quot;1.4.*&quot;,
 &quot;sebastian/phpcpd&quot;: &quot;*&quot;,
 &quot;theseer/phpdox&quot;: &quot;0.6.5&quot;
 },
 &quot;autoload&quot; : {
 &quot;psr-0&quot; : {
 &quot;AcMailer&quot; : &quot;src/&quot;
 },
 &quot;classmap&quot; : [
 &quot;./Module.php&quot;
 ]
 }
}
</code></pre>
This is the composer file of my Zend Framework 2 module <a target="_blank" rel="noopener noreferrer" href="https://github.com/acelaya/ZF2-AcMailer">AcMailer</a>. Let&#x27;s explain it.
The properties name, description, type, authors, keywords, homepage and license are just metadata to provide useful information to other users and ease finding the project in <a target="_blank" rel="noopener noreferrer" href="https://packagist.org/">packagist</a>.
The require property is the place where we define our dependencies and the version we want to install. We can define here the minimum required PHP version and even the php modules we need (like <code>php-pdo</code>, <code>php-intl</code> and such).
The require-dev property allows us to define other dependencies that won&#x27;t be necessery in a production environment, like testing or documentation tools.
Finally the autoload property is where we define how our own classes are loaded. It is very easy to define a <code>psr-0</code> or <code>psr-4</code> autoloading strategy, but we can even define a <code>classmap</code> with a list of paths to files.
<blockquote>
You don&#x27;t have to remember the <code>composer.json</code> schema. You can interactively create it by running <code>php composer.phar init</code>.
</blockquote>
<h3>Installing dependencies</h3>
Once this is defined we just need the composer binary file (usually in phar format), that can be found <a target="_blank" rel="noopener noreferrer" href="https://getcomposer.org/download/">here</a>, and run <code>php composer.phar install</code>.
This will create a <code>vendor</code> folder in the root of our project, download our dependencies there, the dependencies of our dependencies, and set-up an autoloader that will be able to load all our dependencies and our own classes as well.
After this it&#x27;s enough with a single <code>include</code> statement to <code>vendor/autoload.php</code> to be able to access any class.
If later in the project we need to update an existing dependency, add new dependencies or change the autoloading, we just need to update the information in the <code>composer.json</code> file and run <code>php composer.phar update</code> to update dependencies and autoloader.
<blockquote>
It is recommended to include the composer binary in the PATH to be able to run <code>composer</code> instead of <code>php composer.phar</code>.
</blockquote>
<blockquote>
If you are using a VCS like <a target="_blank" rel="noopener noreferrer" href="https://git-scm.com/">git</a> in your project you will probably want to ignore your <code>vendor</code> folder.
</blockquote>
<h3>Advanced usages</h3>
This should be enough to start working with composer, but it is a much more powerful tool with more features. It is not a bad idea to take a quick read to its <a target="_blank" rel="noopener noreferrer" href="https://getcomposer.org/doc/">documentation</a>, but let&#x27;s see the main advanced features.
<ul>
<li>Classmap autoloader: By running <code>composer dumpautoload --optimize</code> we can generate a much faster autoloader which defines a class =&gt; file map array with all the classes handled by composer. This is the more suitable autoloader for production environments.</li>
<li>Production dependencies: If we include de modifier <code>--no-dev</code> while installing or updating dependencies, it will ignore (or remove) the require-dev dependencies. For example <code>composer update --no-dev</code></li>
<li>Private repositories: If you want to install dependencies from repositories other than <a target="_blank" rel="noopener noreferrer" href="https://packagist.org/">packagist</a>, you can do it by using the repositories property. It supports many types of repositories, from VCS to PEAR repositories. Complete documentation <a target="_blank" rel="noopener noreferrer" href="https://getcomposer.org/doc/05-repositories.md">here</a>.</li>
<li>Global packages: If you want to install dependencies globally, just add the <code>global</code> keyword before the <code>install</code> or <code>update</code>. That will install the dependencies in the <code>~/.composer/vendor</code> directory instead of installing them in the local <code>vendor</code> directory. For example <code>composer global update</code>.</li>
</ul>
And that&#x27;s all you need to know to start working with composer.
Update 2015-04-25: I&#x27;ve written an article addressing advanced concepts that is a good continuation to this one. <a href="/2015/04/25/composer-advanced-concepts/">Composer advanced concepts</a>.

One of the common problems we have to confront when starting a new PHP project is how to handle the different dependencies we are going to have. One could think the easier solution is to download all the libraries we are going to need, put them in a lib directory and add them to the version control…

Dependency management and autoloading in php projects with composer

Dependency management is very important in any kind of project. Any application will need to use third party libraries to avoid to reinvent the wheel.
The problem is that getting each one of them from a different place takes time, and it&#x27;s not easy to be sure we get the correct version.
To solve this in java projects we can use an automated dependency manager, like <a target="_blank" rel="noopener noreferrer" href="https://maven.apache.org/">Maven</a>, which is really a building system with dependcy management included. The problem with maven is that it could be hard to use, and not very intuitive.
Instead of Maven, I rather prefer to use <a target="_blank" rel="noopener noreferrer" href="https://ant.apache.org/ivy/">Ivy</a>. It is a more simple and agile dependency management system, designed to be used with <a target="_blank" rel="noopener noreferrer" href="https://ant.apache.org/">Ant</a>, but it takes dependencies from Maven repositories, like <a target="_blank" rel="noopener noreferrer" href="https://mvnrepository.com/">Maven central</a>.
<h3>Getting started</h3>
To use Ivy we need to create an <code>ivy.xml</code> file in the project root directory. It will be used to define which dependencies are needed by our project, and will need to be downloaded at building time.
This is the <a target="_blank" rel="noopener noreferrer" href="https://github.com/acelaya/subclient-subconnector">Subconnector</a> Ivy script.
<pre class="language-xml"><code class="language-xml">&lt;ivy-module version=&quot;2.0&quot;&gt;
 &lt;info organisation=&quot;net.subclient&quot; module=&quot;subconnector&quot; /&gt;

 &lt;dependencies&gt;
 &lt;dependency org=&quot;junit&quot; name=&quot;junit&quot; rev=&quot;4.10&quot; /&gt;
 &lt;dependency org=&quot;com.google.code.gson&quot; name=&quot;gson&quot; rev=&quot;2.2.2&quot; /&gt;
 &lt;dependency org=&quot;log4j&quot; name=&quot;log4j&quot; rev=&quot;1.2.17&quot; /&gt;
 &lt;dependency org=&quot;org.apache.commons&quot; name=&quot;commons-lang3&quot; rev=&quot;3.1&quot;/&gt;
 &lt;/dependencies&gt;
&lt;/ivy-module&gt;
</code></pre>
As you can see, it is very simple. We just defined an info element with the basic project information, and a dependencies element with nested information of each of the dependencies of the project.
For each one of them we have to know its organization, name and revision. With this we can be sure we will get the desired library and revision.
But how do we know what to put in <code>org</code>, <code>name</code> and <code>rev</code> attributes? The <a target="_blank" rel="noopener noreferrer" href="https://mvnrepository.com/">maven central repository</a> webpage will help us with this.
At the top search bar we can write the name of a library, for example gson. The first result corresponds to the gson artifacts in the maven central. By selecting the desired version we will get the dependency element for an Ivy script, as well as other dependency management systems, like Maven or <a target="_blank" rel="noopener noreferrer" href="https://gradle.org/">Gradle</a>.
<img src="/assets/img/dependency.jpg" alt="Maven dependency example"/>
We just need to copy and paste it. Nice and easy.
<h3>Automate retrieving dependencies</h3>
Once our Ivy script is ready, it is time to include retrieving dependencies in our building process. The easiest way to do it is to create an Ant target in our <code>build.xml</code> script, like this.
<pre class="language-xml"><code class="language-xml">&lt;target name=&quot;retrieve-dependencies&quot;
 description=&quot;Retrieve dependencies with Apache IVY&quot;&gt;

 &lt;ivy:retrieve type=&quot;jar&quot; /&gt;

&lt;/target&gt;
</code></pre>
This will look for the ivy.xml script and download dependencies defined on it in a lib folder, but only binary jar files. If <code>type=&quot;jar&quot;</code> is removed, all docs, sources and binaries will be retrieved.
Make sure to add Ivy binaries to Ant classpath to make it properly work. The <code>project</code> element in the build script will need also to look like this.
<pre class="language-xml"><code class="language-xml">&lt;project basedir=&quot;.&quot; default=&quot;build&quot; name=&quot;Subconnector&quot; xmlns:ivy=&quot;antlib:org.apache.ivy.ant&quot;&gt;

 ...

&lt;/project&gt;
</code></pre>
Notice the <code>xmlns:ivy</code> attribute.
Now we are ready to go.
For an advanced Ivy configuration take a look at its <a target="_blank" rel="noopener noreferrer" href="https://ant.apache.org/ivy/history/2.3.0/index.html">official documentation</a>. It explains how to use custom repositories, how to set up a proxy server, how to change default local lib folder, etc.

Dependency management is very important in any kind of project. Any application will need to use third party libraries to avoid to reinvent the wheel. The problem is that getting each one of them from a different place takes time, and it's not easy to be sure we get the correct version.

To solve…

Alejandro Celaya | Blog

Software development, agile methodologies and open source software.

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