Updated transistor renderer by 9larsons · Pull Request #26279 · TryGhost/Ghost

9larsons · 2026-02-05T18:56:26Z

ref https://linear.app/ghost/issue/NY-1005/

added dynamic replacement of {uuid} using the same mechanism as content-gating at the API level
updated renderer
added tests

This PR fully wires up the substitution of {uuid} in the outputted content (API response). The token is set within the rendered html content so that we don't need to re-render the content at request time for each member. This instead allows us to do it at the API, just like we do with content visibility, which is also leveraged by this functionality.

This handles the actual display on the frontend. This is difficult to test because you need the integration set up with an available domain - you can see the build on site 352618 on staging.

This does not change the email rendering pipeline.

The Editor > Post Preview > Web view is still broken - we have to follow up with changes to inject a valid uuid in order to be able to preview it there. That is tracked separately.

no ref - added dynamic replacement of {uuid} within the {{content}} block - updated renderer - added tests

coderabbitai · 2026-02-05T18:56:35Z

Walkthrough

The changes implement a deferred UUID substitution mechanism for embedded content. The transistor-renderer is modified to use a fixed {uuid} placeholder in URLs instead of requiring memberUuid at render time. Separately, post-gating.js adds logic to replace URL-encoded {uuid} placeholders (%7Buuid%7D) with actual member.uuid values during post-processing. This shifts UUID injection from render time to a later processing stage. Test coverage is added for both the post-gating substitution logic and transistor-renderer behavior across web and email rendering paths.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'Updated transistor renderer' directly relates to the main change in the PR, which updates the transistor renderer to use dynamic {uuid} replacement.
Description check	✅ Passed	The PR description clearly relates to the changeset, describing the dynamic {uuid} replacement mechanism, renderer updates, and test additions referenced in all modified files.

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9larsons · 2026-02-05T21:26:02Z

ghost/core/test/unit/server/services/koenig/node-renderers/transistor-renderer.test.js

@@ -0,0 +1,124 @@
+const assert = require('assert/strict');


I should've added these tests with the original renderer commit.

9larsons · 2026-02-05T21:26:57Z

ghost/core/core/server/services/koenig/node-renderers/transistor-renderer.js

    const iframe = document.createElement('iframe');
    iframe.setAttribute('width', '100%');
-    iframe.setAttribute('height', '400');
+    iframe.setAttribute('height', '325');


This matches the content height based on the embed. You can see this here with https://partner.transistor.fm/ghost/embed/7d75f320-d0ed-4e6a-9ef5-840163033dbd for the moment.

A little concerned that we have a fixed height and scrolling=no below. But that's probably an issue for another ticket.

9larsons · 2026-02-05T21:27:21Z

ghost/core/core/server/services/koenig/node-renderers/transistor-renderer.js

-
-    const embedUrl = new URL(`https://partner.transistor.fm/ghost/embed/${memberUuid}`);
+    // Use {uuid} placeholder - content.js will substitute with member UUID at request time
+    const embedUrl = new URL(`https://partner.transistor.fm/ghost/embed/{uuid}`);


We no longer get to null check here because it must get substituted at the API level.

9larsons · 2026-02-05T21:27:39Z

ghost/core/core/server/api/endpoints/utils/serializers/output/utils/post-gating.js

+    const member = frame.original.context.member;
+    if (member && member.uuid && attrs.html) {
+        attrs.html = attrs.html.replace(/%7Buuid%7D/gi, member.uuid);
+    }


It seemed best to handle this as encoded, though I'm ambivalent here.

EvanHahn

Some non-blocking comments.

I think the ref in the PR description is wrong. (Should it be NY-998?)

EvanHahn · 2026-02-05T21:43:21Z

ghost/core/test/unit/api/canary/utils/serializers/output/utils/post-gating.test.js

+
+                gating.forPost(attrs, frame);
+
+                // Non-encoded {uuid} should NOT be replaced


nit: I think this comment is unnecessary, based on the title of the test.

Suggested change

// Non-encoded {uuid} should NOT be replaced

EvanHahn · 2026-02-05T21:43:48Z

ghost/core/test/unit/server/services/koenig/node-renderers/transistor-renderer.test.js

+            const result = renderForWeb(getTestData());
+
+            assert.ok(result.html);
+            // URL constructor encodes {uuid} to %7Buuid%7D


nit: I think this comment is unnecessary.

Suggested change

// URL constructor encodes {uuid} to %7Buuid%7D

EvanHahn · 2026-02-05T21:45:21Z

ghost/core/test/unit/server/services/koenig/node-renderers/transistor-renderer.test.js

+        it('renders iframe with URL-encoded %7Buuid%7D placeholder', function () {
+            const result = renderForWeb(getTestData());
+
+            assert.ok(result.html);


nit: I think all of these assert.ok(result.html)s are unnecessary because you immediately check something about them later. I'd probably remove unless you're getting type errors.

EvanHahn · 2026-02-05T21:45:53Z

ghost/core/test/unit/server/services/koenig/node-renderers/transistor-renderer.test.js

+            const result = renderForEmail(getTestData({accentColor: null}));
+
+            assert.ok(result.html);
+            // Default is #15171A


nit: I think it's clear without this comment.

Suggested change

// Default is #15171A

EvanHahn · 2026-02-05T21:47:54Z

ghost/core/core/server/services/koenig/node-renderers/transistor-renderer.js

    const iframe = document.createElement('iframe');
    iframe.setAttribute('width', '100%');
-    iframe.setAttribute('height', '400');
+    iframe.setAttribute('height', '325');


A little concerned that we have a fixed height and scrolling=no below. But that's probably an issue for another ticket.

Updated transistor renderer

82dbd35

no ref - added dynamic replacement of {uuid} within the {{content}} block - updated renderer - added tests

9larsons added 2 commits February 5, 2026 13:29

Moved from content to post-gating

4467b42

Updated snapshot

102bd9b

9larsons requested a review from EvanHahn February 5, 2026 21:21

9larsons marked this pull request as ready for review February 5, 2026 21:21

Merge branch 'main' into upd-transistor-renderer

4e85ae8

9larsons commented Feb 5, 2026

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EvanHahn approved these changes Feb 5, 2026

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		gating.forPost(attrs, frame);

		// Non-encoded {uuid} should NOT be replaced

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9larsons commented Feb 5, 2026 •

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