Return the product thumbnail in the mobile API, and allow a local HTTPS protocol

[gianfrancopiana]

What

Two fixes, both found while capturing App Store screenshots for the mobile app (antiwork/gumroad-mobile#358).

1. Product thumbnails were missing from the mobile Products tab. thumbnail_url came back nil for every product, so each row rendered a placeholder.
2. Local WebViews rendered blank over HTTPS. PROTOCOL had no override, so pointing the mobile app at a local backend broke every embedded page.

Why

The thumbnail was read with the wrong key type

Api::Mobile::ProductsController#product_json read props.dig("thumbnail", "url"). Every other key in that hash is a string, so this reads naturally — but Thumbnail#as_json returns symbol keys:

def as_json(*)
  { url:,
    guid:
  }
end

The outer lookup succeeds, the inner one misses, and the result is always nil.

This is not environment-specific. The web dashboard reads the same hash, but only after Inertia serializes it to JSON, where symbol keys become strings — so only the mobile API, which dereferences it in Ruby, is affected.

No test caught it. The controller spec asserted name, permalink, status, can_edit and can_destroy but never thumbnail_url, and the product schema declares the field as ["string", "null"], so nil validated.

PROTOCOL could not be overridden

CUSTOM_DOMAIN already exists to point a local backend at a registrable hostname, and the mobile app's dev config expects https://gumroad.dev. But CUSTOM_DOMAIN only changes the host — development stays on http, so Rails emits asset URLs like http://app.localhost:3000/vite-dev/entrypoints/base.ts.

Inside the app's HTTPS WebView those are unreachable. Every embedded page — sign-in, create product, settings — renders blank, with no error in the app and none in the Rails log. The page returns 200; only its assets fail.

This adds a CUSTOM_PROTOCOL override next to the existing CUSTOM_DOMAIN and ASSET_DOMAIN ones. Unset, PROTOCOL resolves exactly as before.

A third bug, surfaced by review

Review suggested ENV["CUSTOM_PROTOCOL"].presence. That cannot be used here: bin/vite requires config/domain.rb before Rails boots, so ActiveSupport is not loaded and presence raises NoMethodError.

Line 108 already called ENV["BRANCH_DEPLOYMENT"].present?, which means bin/vite has been crashing whenever CUSTOM_DOMAIN is set — the exact configuration this override pairs with:

$ CUSTOM_DOMAIN=gumroad.dev ruby -e '... require_relative "config/domain"'
NoMethodError: undefined method 'present?' for nil

Both checks are now plain Ruby, with a comment recording the constraint so it is not reintroduced.

Before / After

Not user-visible on the web. The mobile-side effect is in antiwork/gumroad-mobile#358: its frame 01 shows the Products tab with cover art, which required this fix — before it, every row showed a placeholder box.

Test Results

• bundle exec rspec spec/controllers/api/mobile/products_controller_spec.rb spec/config/domain_spec.rb — 18 examples, 0 failures
• bundle exec rubocop on all changed files — no offenses
• Every new example was checked against its bug by reverting the fix and confirming the failure:
  • reverting the key type fails "returns the thumbnail url"
  • reverting the blank guard fails the blank-CUSTOM_PROTOCOL example
  • restoring present? fails the pre-Rails example with NoMethodError
  • reverting strip fails the whitespace example

New coverage in spec/config/domain_spec.rb loads the file the way bin/vite does — bundler and vite_ruby, nothing else — because a bin/rails runner boots Rails and would hide the ActiveSupport constraint.

These assert the resolved constant, not the URLs built from it. Confirming a WebView loads assets over HTTPS end to end needs a running backend, so that stays manual.

QA steps

1. bundle exec rspec spec/controllers/api/mobile/products_controller_spec.rb spec/config/domain_spec.rb
2. Unset CUSTOM_PROTOCOL and confirm development still resolves http
3. For the WebView fix end to end: run this backend with CUSTOM_DOMAIN=gumroad.dev CUSTOM_PROTOCOL=https ASSET_DOMAIN=gumroad.dev, front it with an HTTPS proxy on 443, then open Products → New in the mobile app. The create-product page renders instead of coming up blank.

Note on CI

Compute relevant specs escalates here: bin/branch-specs cannot attribute specs to config/domain.rb, so it asks for the full suite. The run-all-specs label is applied for that reason.

I tried mapping config/domain.rb into CONFIG_SPEC_MAP to avoid the label, then reverted it. That mapping would drop the full-suite guard for every future change to the file, and its constants fan out widely — PROTOCOL alone is referenced in 37 files — while domain_spec.rb exercises no consumer specs (CSP, CORS, WebAuthn origins, URL generation). Escalating is correct here; the label is the intended mechanism.

---

🤖 Written with Claude Fable 5 (Claude Code).

The model investigated both bugs, wrote the fixes and specs, and verified each new example fails without its fix. Two of the three bugs were found by it while setting up a local backend to capture App Store screenshots; the whitespace and blank-value guards came from Greptile review feedback, which it evaluated before accepting. Its proposed .presence fix was rejected after testing showed it breaks bin/vite, and a self-inflicted change that would have weakened CI coverage was caught in review and reverted. All test results above were produced by real runs, not asserted.

[greptile-apps]

Greptile Summary

The PR restores thumbnail URLs in the mobile products response and adds a pre-Rails-safe protocol override for local HTTPS.

• Reads the symbol-keyed thumbnail URL from the presenter payload.
• Normalizes blank and whitespace-only protocol overrides to the environment default.
• Replaces an ActiveSupport-dependent environment check with plain Ruby.
• Adds focused controller and domain configuration coverage.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
app/controllers/api/mobile/products_controller.rb	Correctly reads the symbol-keyed thumbnail URL while preserving nil for products without thumbnails.
config/domain.rb	Adds a normalized protocol override and keeps pre-Rails loading independent of ActiveSupport.
spec/config/domain_spec.rb	Covers unset, blank, whitespace, HTTPS, and pre-Rails custom-domain configurations.
spec/controllers/api/mobile/products_controller_spec.rb	Verifies both present and absent thumbnail behavior in the mobile API response.

_{Reviews (3): Last reviewed commit: "Fall back when CUSTOM_PROTOCOL is only w..." | Re-trigger Greptile}

[gianfrancopiana]

@greptileai

[gianfrancopiana]

@greptileai