refactor(extension): extract target-neutral recorder host and platform layer #1998
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,68 @@ | ||
| // The recorder document (recorder.html) hosts capture, upload, device | ||
| // enumeration, the mic probe and the camera-preview relay. On Chrome it runs | ||
| // as an offscreen document; this module owns its lifecycle so the rest of the | ||
| // service worker never touches chrome.offscreen directly. | ||
| // | ||
| // On Firefox there is no offscreen document API; hasRecorderHost and | ||
| // ensureRecorderHost return early so the service worker can import this module | ||
| // on both targets without reaching Chrome-only APIs at runtime. | ||
| import { capabilities } from "../platform/capabilities"; | ||
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| export const RECORDER_URL = "recorder.html"; | ||
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| let recorderDocumentCreation: Promise<void> | null = null; | ||
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| const getRecorderContexts = async () => { | ||
| const recorderUrl = chrome.runtime.getURL(RECORDER_URL); | ||
| return new Promise<Array<{ documentUrl?: string }>>((resolve) => { | ||
| chrome.runtime.getContexts( | ||
| { | ||
| contextTypes: ["OFFSCREEN_DOCUMENT" as chrome.runtime.ContextType], | ||
| documentUrls: [recorderUrl], | ||
| }, | ||
| (contexts) => resolve(contexts), | ||
| ); | ||
| }); | ||
| }; | ||
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| export const hasRecorderHost = async () => { | ||
| if (!capabilities.supportsOffscreen) return false; | ||
| return (await getRecorderContexts()).length > 0; | ||
| }; | ||
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| const createOffscreenDocument = () => | ||
| new Promise<void>((resolve, reject) => { | ||
| chrome.offscreen.createDocument( | ||
| { | ||
| url: RECORDER_URL, | ||
| reasons: ["USER_MEDIA", "DISPLAY_MEDIA", "BLOBS", "AUDIO_PLAYBACK"], | ||
| justification: "Record and upload Cap videos from an extension page.", | ||
| }, | ||
| () => { | ||
| const error = chrome.runtime.lastError; | ||
| if (!error) { | ||
| resolve(); | ||
| return; | ||
| } | ||
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| const message = error.message ?? "Failed to create offscreen document"; | ||
| if (message.toLowerCase().includes("single offscreen document")) { | ||
| resolve(); | ||
| return; | ||
| } | ||
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| reject(new Error(message)); | ||
| }, | ||
| ); | ||
| }); | ||
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| export const ensureRecorderHost = async () => { | ||
| if (!capabilities.supportsOffscreen) return; | ||
| const contexts = await getRecorderContexts(); | ||
| if (contexts.length > 0) return; | ||
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| recorderDocumentCreation ??= createOffscreenDocument().finally(() => { | ||
| recorderDocumentCreation = null; | ||
| }); | ||
| await recorderDocumentCreation; | ||
| }; | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,14 @@ | ||
| import { TARGET } from "./target"; | ||
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| // Per-target feature availability. Firefox has no chrome.offscreen or | ||
| // chrome.tabCapture, its getDisplayMedia exposes no system audio or per-tab | ||
| // surface, MV3 host permissions are user-grantable rather than granted at | ||
| // install, and getDisplayMedia requires transient user activation so capture | ||
| // cannot start without a click inside the recorder document. | ||
| export const capabilities = { | ||
| supportsTabCapture: TARGET === "chrome", | ||
|
Contributor
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Prompt To Fix With AIThis is a comment left during a code review.
Path: apps/chrome-extension/src/platform/capabilities.ts
Line: 9
Comment:
**Tab Capture Unguarded**
`supportsTabCapture` is defined as false for Firefox, but the service worker tab-recording path still calls `chrome.tabCapture.getMediaStreamId` without checking it. When a Firefox build starts a tab-mode recording, that path can still dereference an API Firefox does not provide, so the recording flow fails before capture can start. This needs a separate guard or tab-mode disablement at the call path that uses the capability.
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For each issue above, determine whether it is valid and should be fixed. If so, fix it directly. |
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| supportsOffscreen: TARGET === "chrome", | ||
| supportsSystemAudioCapture: TARGET === "chrome", | ||
| hostPermissionsGrantedAtInstall: TARGET === "chrome", | ||
| recorderNeedsUserGesture: TARGET === "firefox", | ||
| } as const; | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,4 @@ | ||
| // "chrome-extension:" on Chromium, "moz-extension:" on Firefox. Sender checks | ||
| // must use this instead of a hardcoded literal or Firefox extension pages get | ||
| // misclassified as web pages. | ||
| export const EXTENSION_PROTOCOL = new URL(chrome.runtime.getURL("")).protocol; |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,10 @@ | ||
| // Injected by vite `define` per build target (e.g. `__TARGET__: "firefox"`). | ||
| // Under vitest there is no define; the fallback to "chrome" is intentional — | ||
| // tests run against Chrome APIs. Every production Vite build MUST inject this | ||
| // define so that Firefox builds never accidentally enable Chrome-only paths. | ||
| declare const __TARGET__: "chrome" | "firefox" | undefined; | ||
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| export type ExtensionTarget = "chrome" | "firefox"; | ||
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| export const TARGET: ExtensionTarget = | ||
| typeof __TARGET__ === "undefined" ? "chrome" : __TARGET__; | ||
|
Contributor
There was a problem hiding this comment.
Prompt To Fix With AIThis is a comment left during a code review.
Path: apps/chrome-extension/src/platform/target.ts
Line: 8
Comment:
**Missing Target Becomes Chrome**
`TARGET` defaults to `"chrome"` whenever `__TARGET__` is absent, but the changed Vite config does not define `__TARGET__`. A Firefox build that uses this config without an injected define will enable Chrome-only capabilities like offscreen and tab capture, sending the Firefox worker into unsupported APIs.
How can I resolve this? If you propose a fix, please make it concise. |
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chrome.runtime.getContextscan invoke the callback withcontextsundefined (or fail in older runtimes), which would makehasRecorderHost()throw on.length. Small hardening tweak: