Publication guard

phil/accessibility-check

Workflow\PublicationGuard is a listener of the guard events of symfony/workflow: it holds back a transition — a publication — while the content of its subject is not accessible. The guard asks the application for that content through Contract\SubjectContent, checks it, and blocks the transition when a finding is the blocking severity or graver, or when the checker refuses the content.

The content of a subject

The application knows where the content of a subject is. For a content of phil/content-bundle, the subject of workflow.phil_content.guard.publish is the localized draft row, whose body holds the HTML of the draft:

use Phil\AccessibilityCheck\Contract\SubjectContent;
use Phil\ContentBundle\Domain\Capability\BodyCapable;
use Phil\Ujo\Document;

final class DraftBody implements SubjectContent
{
    public function contentOf(object $subject): string|Document|null
    {
        return $subject instanceof BodyCapable ? $subject->getBody()?->html : null;
    }
}

null leaves the subject alone: a row without body, a subject of another kind.

Registering the guard

services:
    App\Accessibility\DraftBody: ~

    Phil\AccessibilityCheck\Workflow\PublicationGuard:
        arguments:
            $checker: '@Phil\AccessibilityCheck\AccessibilityChecker'
            $content: '@App\Accessibility\DraftBody'
            $blockAt: !php/enum Phil\AccessibilityCheck\Severity::Error
            $locale: 'fr'
        tags:
            - { name: kernel.event_listener, event: workflow.phil_content.guard.publish }

PublicationGuard::CONTENT_PUBLISH names that event. Any other guard event — workflow.<name>.guard.<transition> — works the same.

Argument	Default	Means
`checker`		the checker, with the application's policy
`content`		the application's `SubjectContent`
`blockAt`	`Severity::Error`	the severity from which a finding blocks; `null` never blocks
`locale`	`en`	the locale of the blocker's message
`language`	`null`	the language of a content that does not say its own; the policy's when `null`

The blocker

A transition held back for its findings carries a TransitionBlocker of code PublicationGuard::BLOCKED, whose message — key report.blocked — gives the number of blocking findings and the first one, and whose parameters hold the whole report, for the screen that tells the author what to fix:

use Phil\AccessibilityCheck\Report;
use Phil\AccessibilityCheck\Workflow\PublicationGuard;

foreach ($workflow->buildTransitionBlockerList($row, 'publish') as $blocker) {
    if (PublicationGuard::BLOCKED === $blocker->getCode()) {
        $report = $blocker->getParameters()['report'];   // a Report
    }
}

A content the checker refuses blocks with the code PublicationGuard::REFUSED and the reason as message. A blocked guard makes the transition not enabled: with phil/content-bundle, publish() throws TransitionRefused.