PRC Print Engine

Canonical docs: docs/plugins/prc-print-engine/

Standalone WordPress plugin that serves a print-styled document for posts and generates server-side PDFs via a Firebase headless Chromium Cloud Function.

Features

• /print URL endpoint for logged-in users (path interception; legacy ?pdf=true redirects to /print)
• Cover sheet, About page, static TOC, and article/report body
• Paged.js client pagination for print preview
• Server-side PDF generation on prc_platform_async_on_publish / prc_platform_async_on_update (Action Scheduler → Firebase generatePdf → WP media attachment)
• Editor Print Engine sidebar for ad-hoc PDF regeneration
• REST: POST /prc-print-engine/v1/posts/{id}/generate-pdf, GET …/pdf, POST /prc-print-engine/v1/screenshot
• Block callback registry (prc_print_engine_register_block_callbacks) for print markup and styles
• Editor Block Visibility controls for hide-on-print / display-on-print
• Chart-builder integration emits static PNG figures when available

Soft dependencies

Guarded at call sites — plugin boots without them:

• prc-firebase — OIDC token minting for Cloud Function calls
• prc-report-package — multi-chapter report assembly
• prc-staff-bylines — cover bylines
• prc-schema-seo — cover media contact resolver
• prc-chart-builder — chart print callbacks
• Action Scheduler — async PDF jobs (via post-publish-pipeline)

Requires

• prc-scripts

Firebase render functions

Deploy from firebase/:

./bin/deploy-render-functions.sh staging /path/to/firebase-service-account-staging.json
./bin/deploy-render-functions.sh production /path/to/firebase-service-account-prod.json

WordPress resolves URLs via client-mu-plugins/firebase-render.php (prc_platform_firebase_render_endpoints).

Stored PDF meta on the post:

• _print_engine_pdf_attachment_id
• _print_engine_pdf_url
• _print_engine_content_hash
• _print_engine_pdf_generated_at

Development

npx turbo build --filter=@prc/print-engine
php plugins/prc-print-engine/tests/test-block-print-registry.php
php plugins/prc-print-engine/tests/test-visibility-helpers.php

Playwright (VIP dev-env required):

npx playwright test tests/prc-print-engine/

Registry

add_action( 'prc_print_engine_register_block_callbacks', function () {
    \PRC\Platform\Print_Engine\Block_Print_Registry::register(
        'my-plugin/my-block',
        function ( string $content, array $block, \WP_Post $post ): string {
            return $content;
        }
    );
} );

Access model

Staff-beta: browser /print and print discovery / report-materials links require a logged-in WordPress user. Anonymous /print requests 404 (no login redirect) so WordPress cannot 404-guess a print-* post. Server-side PDF generation continues without a WP session by minting a short-lived, post-bound machine-fetch ticket on the /print URL Firebase fetches.

Content eligibility is unchanged and separate from audience access: published posts/pages with prc-print-engine support may be printable; password-protected posts require a valid password cookie (or read_post); drafts require capability or a valid preview nonce. Automatic PDF generation still runs only for publicly published, non-password-protected posts.