Photo Directory: render the photo description as plain text - #860
Photo Directory: render the photo description as plain text#860mcliwanow wants to merge 7 commits into
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The description submitted with a photo is its alternative text, and the submit form sanitizes it as plain text on the way in. On output it was still run through the regular post content filters, so text that looks like markup was interpreted instead of displayed. Escape it before those filters run, keeping paragraphs and the visible text as submitted. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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Included review availability: Your plan provides up to 8 included reviews per hour; 7 remain after this review. 📝 WalkthroughWalkthroughPhoto content is converted to escaped plain text. Shortcode brackets and URL protocol delimiters are neutralized. Embed callbacks are no longer removed, tracked, or restored. ChangesPhoto content rendering
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The diagnosis is right and the shape of the fix is right: the description is plain text on the way in, and wp:post-content was handing it to the whole the_content stack on the way out. Escaping at PHP_INT_MIN so that do_blocks, do_shortcode and run_shortcode only ever see text is the correct layer, and [ covers both do_shortcode() at 11 and WP_Embed::run_shortcode() at 8.
I checked the surrounding claims against a real WordPress checkout. Two of the three hold. One does not.
wpautop() does not prevent auto-embedding. It creates the exact shape that triggers it.
WP_Embed::autoembed() makes two passes (class-wp-embed.php:446-451):
// Find URLs on their own line.
$content = preg_replace_callback( '|^(\s*)(https?://[^\s<>"]+)(\s*)$|im', ... );
// Find URLs in their own paragraph.
$content = preg_replace_callback( '|(<p(?: [^>]*)?>\s*)(https?://[^\s<>"]+)(\s*</p>)|i', ... );Wrapping first defeats the first pass and walks straight into the second. I ran core's wpautop() standalone over esc_html( 'https://youtu.be/abc123' ) and it returns <p>https://youtu.be/abc123</p>\n, which matches the second pattern with $2 === 'https://youtu.be/abc123'. So a description that is a single URL still reaches WP_Embed::shortcode() after this change, exactly as it does on trunk.
That the testing did not catch it is easy to explain: autoembed_callback() sets linkifunknown = false, so a URL with no oEmbed provider comes back byte-identical and the output looks untouched. A provider URL (YouTube, WordPress.tv, Twitter) does not.
It is worth fixing rather than deferring, because the consequences are not only cosmetic. On a front-end view $this->usecache is true but the cache starts empty, so WP_Embed::shortcode() falls through to wp_oembed_get(), which is an outbound HTTP request during page render, and then update_post_meta( $post_id, '_oembed_' . md5( ... ), $html ) writes to the photo post (class-wp-embed.php:307-316). A write and a remote fetch on a public GET, driven by submitted text. This is pre-existing rather than introduced here, but the PR is presented as closing it and does not.
Options, roughly in order of how much I like them:
- Unhook the embed filters for photo requests, for example
remove_filter( 'the_content', array( $GLOBALS['wp_embed'], 'autoembed' ), 8 )and the matchingrun_shortcodeat 8, guarded the same way the escape is. Explicit about what is being turned off, and no longer relies on out-guessing a regex. - Make the follow-up you describe (
wp:post-contentto a plain-text block inwporg-photos-2024) part of this change rather than optional. If the content never goes throughthe_contentfor the single view, the whole class of problem goes away, and thethe_contentfilter is left as defence for REST, feeds and excerpts. - At minimum, correct the comment.
// Wrap paragraphs now, so a URL on a line of its own is not auto-embedded.will send the next reader in the wrong direction.
The two claims that do hold:
wpautop()is idempotent over this output, so core's ownwpautopat priority 10 running a second time does not produce nested<p>. I ran it twice over the escaped forms of your test strings and got identical results, including<p>line1<br />\nline2</p>for a soft break.- The global-post check is sound for the paths named in the description.
WP_REST_Posts_Controller::prepare_item_for_response()assigns$GLOBALS['post']and callssetup_postdata()before it renderscontent.rendered(class-wp-rest-posts-controller.php:1889-1891), andwp_trim_excerpt()and the feed both run inside the loop, soget_post_type()sees the photo in all three.
Smaller notes:
- Keying on
get_post_type()with no argument keys on the global post, not on the content being filtered. Anyapply_filters( 'the_content', $something_else )that runs while a photo is the global post gets escaped too. On this site that is unlikely to bite, and the existingUploadsfilters are on a page rather than a photo, so they are unaffected. Mentioning it only so the constraint is written down somewhere. plain_text_to_html()has no caller butrender_content_as_plain_text().privateunless you have a second use in mind.- Excerpts get
strip_shortcodes()applied to the raw content bywp_trim_excerpt()before anythe_contentcallback runs, so a bracketed word still vanishes from the excerpt even after this change. Pre-existing, out of scope, but it means the excerpt and the body will not agree.
…escription WP_Embed::autoembed() also matches a URL that is alone inside a paragraph, so wrapping the escaped text first did not keep a URL-only description from being embedded, and the oEmbed lookup writes cache meta to the photo on a public request. Remove run_shortcode and autoembed for the photo and hook them back once its content has been filtered. Drop the pre-wrap and make the escaping helper private. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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Inline comments:
In `@wordpress.org/public_html/wp-content/plugins/photo-directory/inc/posts.php`:
- Line 293: Update Posts::render_content_as_plain_text() and its
remove_embed_filters/restore_embed_filters flow so WP_Embed callbacks remain
available during nested non-photo the_content processing, while still
suppressing them only for the active photo rendering invocation; preserve
correct restoration afterward. Add a regression test covering URL-only non-photo
content processed recursively through the_content and verifying embedding still
occurs.
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Encode the characters later content filters key on instead of unhooking and rehooking them. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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Inline comments:
In `@wordpress.org/public_html/wp-content/plugins/photo-directory/inc/posts.php`:
- Line 282: Update the escaping at the content handling site around $content to
use an escaping path with double encoding enabled, preserving literal entity
text such as &copy;. Add a regression test covering already-encoded entities
and verify they remain literal after rendering.
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Good catch on
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Re-reviewed. The approach holds up: PHP_INT_MIN puts the escape ahead of WP_Embed::run_shortcode/autoembed (8), do_blocks (9), wptexturize/wpautop (10) and do_shortcode (11), and neutralising [ and :// closes the shortcode and autoembed paths. I could not construct markup through esc_html's double_encode = false behaviour: existing character references are preserved and the parser renders them as text.
Three things below, none blocking.
| * @return string | ||
| */ | ||
| public static function render_content_as_plain_text( $content ) { | ||
| if ( Registrations::get_post_type() !== get_post_type() ) { |
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The guard keys on the global post, not on the post whose content is being filtered.
get_post_type() with no argument reads $GLOBALS['post'], but the_content is routinely applied to a different post's content. Core's wp_trim_excerpt() is the clearest case: it resolves $post = get_post( $post ) and then calls apply_filters( 'the_content', $text ) on that post's content while leaving the global alone.
So get_the_excerpt( 24724 ) from outside the loop (a widget, a sidebar list, a page template) skips the escaping entirely and the legacy <a>/<p> markup goes through, which is the case this patch exists to prevent. wp_trim_words strips tags afterwards, so the practical damage is limited, but the guarantee has a hole in it rather than a documented tradeoff.
The docblock does own the other direction (a non-photo post filtered while a photo is the global post gets escaped and shows its markup as text). Worth noting WP_REST_Posts_Controller is safe here, it calls setup_postdata() first.
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Agreed, documented in the docblock now. Nothing in the plugin or the theme builds a photo excerpt outside the loop, so it's a known edge rather than a path anything uses.
| $content = esc_html( $content ); | ||
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| // Shortcode and URL syntax stay visible text: hide the characters shortcodes and embeds key on. | ||
| return str_replace( [ '[', '://' ], [ '[', '://' ], $content ); |
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esc_html() calls _wp_specialchars( $text, ENT_QUOTES, 'UTF-8', false ), and with $double_encode = false an already-valid entity passes through untouched. A description submitted as the literal nine characters &amp; survives sanitize_textarea_field intact and then renders as a single &, and [gallery] renders as [gallery].
Neither is exploitable, do_shortcode matches only a literal [, but it contradicts the stated contract that the submitted text is shown verbatim. htmlspecialchars( $content, ENT_QUOTES, 'UTF-8', true ) would be faithful.
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That's intentional. Intake goes through wp_filter_post_kses(), which stores a typed & as &, so the output has to leave existing entities alone or every ampersand ever submitted shows up as &. From the sandbox, including a real published row:
| add_action( 'post_updated', [ __CLASS__, 'sync_photo_post_to_photo_media_on_update' ], 5, 3 ); | ||
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| // Photo content is plain text (the alternative text), never post markup. | ||
| add_filter( 'the_content', [ __CLASS__, 'render_content_as_plain_text' ], PHP_INT_MIN ); |
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Knock-on effect one file down, at posts.php:407: the RSS alt attribute is now double-escaped.
add_photo_to_rss_feed() is on the_content_feed, which core feeds the output of the_content. It does strip_tags( $content ) and passes the result as [ 'alt' => $content ] to get_the_post_thumbnail(), and wp_get_attachment_image() runs every attribute through esc_attr().
Before this change, a description Fish & chips reached that point as raw text and esc_attr produced the correct alt="Fish & chips". Now esc_html has already produced Fish & chips, so the feed emits alt="Fish &amp; chips" and the entity is announced literally. Same for <, > and ".
The <figcaption> on the following line is unaffected, it is inserted as HTML.
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esc_attr() doesn't double encode. It uses the same _wp_specialchars() call as esc_html(), with double_encode off, so an & that is already there stays &. Checked the patched path on the sandbox:
Encoded once, same as before the change.
…lter docblock Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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Why
The description submitted with a photo is its alternative text. The submit form says "No HTML" and caps it at 350 characters, and since 9fc0f0a
Uploads::sanitize_submitted_description()stores it as plain text. On output it was still treated as post content, so text that looks like markup was interpreted instead of displayed.What changed
Posts::render_content_as_plain_text()runs first onthe_contentfor the photo post type and escapes the description, so every later callback sees text. Paragraphs and texturize still apply, other post types are untouched.Testing
Verified on wp-env against WordPress master with the plugin active: a description round-trips through intake unchanged, renders as text on the single photo page (through the template over HTTP, through
apply_filters( 'the_content' ), and in the excerpt), and a page with[gallery]still expands it.Of the existing photos, two published ones (24724, 28413) carry old
<a>/<p>markup from before the intake sanitizer and will show it as text. Their descriptions get edited to plain text alongside the deploy.🤖 Generated with Claude Code
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