SymfonyCon Vienna 2025: Twig, still relevant in 2025?

Transcript

1. Twig: Still relevant in 2025? Fabien Potencier
2. Twig turned 15!
3. Twig is "still" widely used
4. The SPA Pendulum Swing The return of server-side rendering
5. </> htmx <button hx-post="/clicked" hx-swap="outerHTML"> Click Me </button> Supported in Symfony since 2.0 preview release 5 - Dec 8, 2010 https://github.com/symfony/symfony/commit/e8672740 https://jolicode.com/blog/making-a-single-page-application-with-htmx-and-symfony
6. </> htmx #[Route('/messages', name: 'messages')] public function messages(MessageRepository $messageRepo): Response { return $this->render('messages.html.twig', [ 'messages' => $messageRepo->findAll(), // many more variables ]); } {% extends 'base.html.twig' %} {% block body %} <ul id="messages"> {% for message in messages %} <li>{{ message.content }}</li> {% endfor %} </ul> <a href="{{ path('messages') }}">Refresh</a> {% endblock %}
7. #[Route('/messages/refresh', name: 'refresh_messages')] #[Template('messages/messages.html.twig', block: 'messages')] public function messages(MessageRepository $messageRepository): array { return ['messages' => $messageRepository->findAll()]; } {% extends 'base.html.twig' %} {% block body %} <ul id="messages"> {% block messages %} ... {% endblock %} </ul> <button hx-post="{{ path('refresh_messages') }}" hx-target="#messages"> Refresh </button> {% endblock %} "block" attribute added in Symfony 7.2 https://github.com/symfony/symfony/pull/58028 Twig ❤ </> htmx
8. Twig Sandbox User-contributed templates with security https://twig.symfony.com/doc/3.x/sandbox.html {{ include('not_trusted.html.twig', sandboxed: true) }}
9. Twig 3.9+ Twig evolved a lot in the last 6 months Template cache hot reload Operator precedence fixes Arrows everywhere Named arguments (macros, ...) Twig callable arguments as snake-case or camelCase Colon as argument separator Yielding instead of echo-ing Inline comments ChainCache Argument unpacking Static Analyzer support{% types %} Compile time checks {% guard %} Functions: enum, html_cva, enum_cases Filters: find, singular, plural, shuffle Tests: sequence, mapping Tons of internal changes/refactoring to make the code more robust (no more global functions!)
10. Template cache hot reload https://github.com/twigphp/Twig/pull/4338 Use cases: * Long-running processes - Messenger worker * Modern PHP app servers - FrankenPHP * User templates - stored in a DB * ...
11. Template cache hot reload https://github.com/twigphp/Twig/pull/4338 $twig = new Twig\Environment($loader, [ 'auto_reload' => false, 'cache' => __DIR__.'/cache', ]); // prime the cache echo $twig->load('index.twig')->render([]); // update the template file_put_contents(__DIR__.'/index.twig', file_get_contents(__DIR__.'/index.twig').'foo'); // still use the cached version echo $twig->load('index.twig')->render([]); // remove the cache for this template $twig->removeCache('index.twig'); // refresh the cache with the updated template echo $twig->load('index.twig')->render([]);
12. Template cache hot reload https://github.com/twigphp/Twig/pull/4338 In memory cache only (read-only cache)
13. ChainCache ReadOnlyFilesystemCache https://github.com/twigphp/Twig/pull/4171 https://github.com/symfony/symfony/pull/54384
14. Operator Precedence 2015 2019 2020 2022 2013 2014 2017
15. Operators Precedence {{ '42' ~ 1 + 41 }} ? {{ '42' ~ (1 + 41) }} {{ ('42' ~ 1) + 41 }} Probably not what you would expect Probably what you would expect
16. 4242 462 How to NOT break BC? Twig 3 Twig 4 {{ '42' ~ (1 + 41) }} {{ ('42' ~ 1) + 41 }} {{ '42' ~ 1 + 41 }} https://github.com/twigphp/Twig/pull/4363
17. A framework to automate these changes Since twig/twig 3.15: Add explicit parentheses around the "??" binary operator to avoid behavior change in the next major version as its precedence will change in "index.twig" at line 4.
18. Other operator precedence changes 'not' => ['precedence' => 50, 'precedence_change' => new OperatorPrecedenceChange(70)] '??' => ['precedence' => 300, 'precedence_change' => new OperatorPrecedenceChange(5)] '~' => ['precedence' => 40, 'precedence_change' => new OperatorPrecedenceChange(27)]
19. PHP 8 has a similar change concatenation vs addition/substraction https://wiki.php.net/rfc/concatenation_precedence
20. Inline comments {{ # this is an inline comment "Hello World"|upper # this is an inline comment }} {{ { # this is an inline comment fruit: 'apple', # this is an inline comment color: 'red', # this is an inline comment }|join(', ') }} {{ "Hello World"|upper # this is an inline comment }} {{ "Hello World"|upper # this is an inline comment }} Nope Yep Yep Yep
21. Inline comments https://github.com/twigphp/Twig/pull/4349
22. Twig callables A Twig Filter is a Twig callable A Twig Function is a Twig callable A Twig Test is a Twig callable A Twig Tag is NOT a Twig callable 'needs_environment' => false, 'needs_context' => false, 'needs_charset' => false, 'is_variadic' => false, 'deprecation_info' => null, 'deprecated' => false, 'deprecating_package' => '', 'alternative' => null,
23. : vs = for named arguments https://github.com/twigphp/Twig/pull/4209 https://twig.symfony.com/doc/3.x/coding_standards.html
24. Named arguments everywhere https://github.com/twigphp/Twig/pull/4300 {# dot operator#} {{ html.generate_input(name: 'pwd', type: 'password') }} {# macro #} {{ html.generate(name: 'pwd', type: 'password') }} {# block function #} {{ block(name: "title", template: "common_blocks.twig") }}
25. Static analysis with {% types %} https://github.com/twigphp/Twig/pull/4235 https://twig.symfony.com/types {% types { is_correct: 'boolean', score?: 'number', } %} https://github.com/alisqi/TwigQI https://github.com/twigstan/twigstan
26. Compile-time checks with {% guard %} https://github.com/twigphp/Twig/pull/4304 https://twig.symfony.com/guard {% guard function importmap %} {{ importmap('app') }} {% else %} {# the importmap function doesn't exist, generate fallback code #} {% endguard %}
27. Arguments unpacking https://github.com/twigphp/Twig/pull/4300 {% set numbers = [1, 2, ...moreNumbers] %} {% set ratings = {'foo': 10, 'bar': 5, ...moreRatings} %} {{ 'Hello %s %s!'|format(...['Fabien', 'Potencier']) }} New
28. Twig callable args as camel or snake https://github.com/twigphp/Twig/pull/4318 public static function htmlCva(... $compoundVariants = [], ...): Cva {% set alert = html_cva( // ... compound_variants=[{ color: ['red'], size: ['md', 'lg'], class: 'font-bold' }] ) %} PHP likes camelCase Twig likes snake_case
29. Arrows everywhere https://github.com/twigphp/Twig/pull/4377 https://github.com/twigphp/Twig/pull/4378 {% set first_name_fn = (p) => p.first %} {{ _self.display_people(people, first_name_fn) }} {% macro display_people(people, fn) %} {{ people|map(fn)|join(', ') }} {% endmacro %}
30. Yielding output instead of ob_* output https://github.com/twigphp/Twig/pull/3950
31. for tag new implementation 4.x only
32. for improvements (4.x only) loop.last always available non-countable generators https://github.com/twigphp/Twig/pull/4134
33. for improvements (4.x only) loop.previous / loop.next {% for value in values %} {% if not loop.first and value > loop.previous %} The value just increased! {% endif %} {{ value }} {% if not loop.last and loop.next > value %} The value will increase even more! {% endif %} {% endfor %} https://github.com/twigphp/Twig/pull/4135 New
34. for improvements (4.x only) loop.changed {% for entry in entries %} {% if loop.changed(entry.category) %} <h2>{{ entry.category }}</h2> {% endif %} <p>{{ entry.message }}</p> {% endfor %} https://github.com/twigphp/Twig/pull/4135 New
35. for improvements (4.x only) loop.cycle {% for row in rows %} <li class="{{ loop.cycle('odd', 'even') }}">{{ row }}</li> {% endfor %} https://github.com/twigphp/Twig/pull/4135 New {{ cycle(['odd', 'even'], loop.index0) }}
36. for improvements (4.x only) recursive loops via loop() <ul class="sitemap"> {%- for item in sitemap %} <li>{{ item.title }} {%- if item.children -%} <ul class="submenu depth-{{ loop.depth }}"> {{ loop(item.children) }} </ul> {%- endif %} </li> {%- endfor %} </ul> New https://github.com/twigphp/Twig/pull/4153 New
37. for improvements (4.x only) if support is back! {% set stopOnFabien = false %} {% for user in users if not stopOnFabien %} - {{ user }} {% set stopOnFabien = user == 'Fabien' %} {% endfor %} https://github.com/twigphp/Twig/pull/4251 {% for user in users if loop.length != 5 %} - {{ user }} {% endfor %}
38. Welcome to the new world! 💪 + +
39. https://symfony.com/sponsor Sponsor Symfony Thank you!