Chapters

26 Chapters | 2:53:08 |

01

Events, Events & Events!

5:10
02

Hooking into Symfony with an Event Subscriber

5:54
03

index.php to HttpKernel::handle()

6:50
04

RequestEvent & RouterListener

6:26
05

Routing Secrets & Request Attributes

7:47
06

The Controller Resolver

7:03
07

Who Creates the Controller & Gives it the Container?

8:04
08

How does the Controller Access the Container?

4:14
09

The Argument Resolver

8:13
10

Argument Value Resolvers

5:32
11

How Service Autowiring Works in a Controller Method

7:36
12

Calling the Controller & View Event

5:20
13

kernel.response Event & Request Format

6:36
14

Finishing the Request

6:03
15

Exception Handling

9:29
16

The Critical kernel.exception Event Listeners

7:07
17

FlattenException & Error Status Codes

6:10
18

Serializer Error Renderer: JSON/XML Errors

5:40
19

How the HTML Error Page is Rendered

7:34
20

The Magic `_controller` Attribute

6:36
21

Custom Global Controller Arguments

5:37
22

How Entity Controller Arguments Work

4:54
23

Sub Requests

7:54
24

Sub Requests & Request Data

5:40
25

Manually Making a Sub Request

6:34
26

Sub Request Attributes

9:05

> Symfony 5 > Symfony 5 Deep Dive! The HttpKernel Request-Response Flow

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23.

Sub Requests

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8 Comments

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ThibautPalma 2 years ago edited

I'm trying to come up with the simplest method for caching a subrequest from twig but I feel like there must be a better way. Anyway, I came up with:

class AppExtension extends AbstractExtension
{
    public function __construct(
        private CacheInterface $cache, 
        private HttpKernelInterface $httpKernel
    ){}

    public function getFunctions(): array
    {
        return [
            new TwigFunction('cached_subrequest', [$this, 'getCachedSubrequest']),
        ];
    }

    public function getCachedSubrequest(string $key, string $controller, int $expiration = 86400)
    {
        return $this->cache->get($key, function (ItemInterface $item) use ($controller, $expiration) {
            $item->expiresAfter($expiration);

            $response = $this->httpKernel->handle($controller, HttpKernelInterface::SUB_REQUEST);
            return $response->getContent();
        });
    }
}

Any thoughts on how to simplify this? I haven't tested it btw so I don't even know if this actually works!

|

weaverryan SFCASTS ThibautPalma 2 years ago

Hey @ThibautPalma!

Have you seen render_esi()? https://symfony.com/doc/current/http_cache/esi.html

It's made for this exact situation. I find working with the HTTPCache system a bit more cumbersome than the normal Cache service, but render_esi() is the way to go. When using that, any variables you pass to render_esi() become part of the cache key.

Let me know if that helps!

Cheers!

1 |

ThibautPalma weaverryan 2 years ago

Awesome, thank you Ryan!

|

kbond SFCASTS 6 years ago

I was definitely in the "over use" camp at one point. Even with http caching (not vanish, just Symfony's PHP implementation) I experienced quite a speed boost once I removed all fragments and turned off http caching.

Obviously "your mileage may vary" but that was my experience.

|

Cristian T. kbond 6 years ago

So don't you recommend using subrequest?

Another question I have ... in each sub-request, does it open a new connection to the database?

Thanks a lot

|

kbond SFCASTS Cristian T. 6 years ago

In my app, I used an ESI to display a user toolbar while http caching the "outer" html. Every "page load" had to do a full request/response cycle for just the user toolbar. So I saved on the database queries/rendering of the outer html. Later, I wanted to have other areas of the "outer html" that were specific to the user so I had to create another ESI... and another... In the end, removing all the ESI and rendering the entire page on each page load as a single request/response was faster. It also made my app much less complex.

So I wouldn't say I don't recommend it but I consider it a premature optimization. I suggest waiting until you actually have performance issues with your site before reaching for it.

Regarding database connections, I think if the sub-request happens within the current request (not using ESI/HTTP caching), the sub-request would share the doctrine connection (but I'm not 100% sure on this).

|

weaverryan SFCASTS kbond 6 years ago edited

Thanks for sharing you real-world experience Kevin B.!

I'm also 99% sure that the database connection is shared in the sub-request. A sub-request is ultimately nothing fancy: it's just more work inside the same PHP process. There is a concept of "resetting the container" in Symfony, but that does not happen between sub-requests.

Cheers!

|

sadikoff kbond 6 years ago edited

Hey Kevin B.

Thanks for sharing your experience with us, I hope this will help to many others!

Cheers!

|

This tutorial also works well for Symfony 6!

Symfony 5

What PHP libraries does this tutorial use?

// composer.json
{
    "require": {
        "php": ">=8.2",
        "ext-iconv": "*",
        "antishov/doctrine-extensions-bundle": "^1.4", // v1.4.3
        "aws/aws-sdk-php": "^3.87", // 3.133.20
        "composer/package-versions-deprecated": "^1.11", // 1.11.99
        "doctrine/annotations": "^1.0", // 1.12.1
        "doctrine/doctrine-bundle": "^2.0", // 2.2.3
        "doctrine/doctrine-migrations-bundle": "^1.3|^2.0", // 2.2.2
        "doctrine/orm": "^2.5.11", // 2.8.2
        "easycorp/easy-log-handler": "^1.0", // v1.0.9
        "http-interop/http-factory-guzzle": "^1.0", // 1.0.0
        "knplabs/knp-markdown-bundle": "^1.7", // 1.9.0
        "knplabs/knp-paginator-bundle": "^5.0", // v5.4.2
        "knplabs/knp-snappy-bundle": "^1.6", // v1.7.1
        "knplabs/knp-time-bundle": "^1.8", // v1.16.0
        "league/flysystem-aws-s3-v3": "^1.0", // 1.0.24
        "league/flysystem-cached-adapter": "^1.0", // 1.0.9
        "league/html-to-markdown": "^4.8", // 4.9.1
        "liip/imagine-bundle": "^2.1", // 2.5.0
        "oneup/flysystem-bundle": "^3.0", // 3.7.0
        "php-http/guzzle6-adapter": "^2.0", // v2.0.2
        "phpdocumentor/reflection-docblock": "^5.2", // 5.2.2
        "sensio/framework-extra-bundle": "^5.1", // v5.6.1
        "symfony/asset": "5.0.*", // v5.0.11
        "symfony/console": "5.0.*", // v5.0.11
        "symfony/dotenv": "5.0.*", // v5.0.11
        "symfony/flex": "^1.9", // v1.21.6
        "symfony/form": "5.0.*", // v5.0.11
        "symfony/framework-bundle": "5.0.*", // v5.0.11
        "symfony/mailer": "5.0.*", // v5.0.11
        "symfony/messenger": "5.0.*", // v5.0.11
        "symfony/monolog-bundle": "^3.5", // v3.6.0
        "symfony/property-access": "5.0.*|| 5.1.*", // v5.1.11
        "symfony/property-info": "5.0.*|| 5.1.*", // v5.1.10
        "symfony/routing": "5.1.*", // v5.1.11
        "symfony/security-bundle": "5.0.*", // v5.0.11
        "symfony/sendgrid-mailer": "5.0.*", // v5.0.11
        "symfony/serializer": "5.0.*|| 5.1.*", // v5.1.10
        "symfony/twig-bundle": "5.0.*", // v5.0.11
        "symfony/validator": "5.0.*", // v5.0.11
        "symfony/webpack-encore-bundle": "^1.4", // v1.11.1
        "symfony/yaml": "5.0.*", // v5.0.11
        "twig/cssinliner-extra": "^2.12", // v2.14.3
        "twig/extensions": "^1.5", // v1.5.4
        "twig/extra-bundle": "^2.12|^3.0", // v3.3.0
        "twig/inky-extra": "^2.12", // v2.14.3
        "twig/twig": "^2.12|^3.0" // v2.14.4
    },
    "require-dev": {
        "doctrine/doctrine-fixtures-bundle": "^3.0", // 3.4.0
        "fakerphp/faker": "^1.13", // v1.13.0
        "symfony/browser-kit": "5.0.*", // v5.0.11
        "symfony/debug-bundle": "5.0.*", // v5.0.11
        "symfony/maker-bundle": "^1.0", // v1.29.1
        "symfony/phpunit-bridge": "5.0.*", // v5.0.11
        "symfony/stopwatch": "^5.1", // v5.1.11
        "symfony/var-dumper": "5.0.*", // v5.0.11
        "symfony/web-profiler-bundle": "^5.0" // v5.0.11
    }
}

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