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-rw-r--r--src/background/index.js19
-rw-r--r--src/background/message-router.js177
-rw-r--r--src/background/ollama-client.js194
-rw-r--r--src/background/settings-service.js82
-rw-r--r--src/background/translation-session.js76
5 files changed, 548 insertions, 0 deletions
diff --git a/src/background/index.js b/src/background/index.js
new file mode 100644
index 0000000..9c97c9d
--- /dev/null
+++ b/src/background/index.js
@@ -0,0 +1,19 @@
+/**
+ * Background entry point (Firefox MV3 event page, ES module).
+ *
+ * All event listeners are registered synchronously at the top level so the
+ * event page can be woken by any of them (MDN: background scripts).
+ */
+
+import { registerRuntimeMessageHandler, handleConnection } from './message-router.js';
+import { loadSettings, watchSettings } from './settings-service.js';
+
+// One-shot messages from popup / options.
+registerRuntimeMessageHandler();
+
+// Streaming connections from the content script.
+browser.runtime.onConnect.addListener(handleConnection);
+
+// Keep the validated settings cache in sync and load initial settings.
+watchSettings();
+void loadSettings(); \ No newline at end of file
diff --git a/src/background/message-router.js b/src/background/message-router.js
new file mode 100644
index 0000000..c93fc9d
--- /dev/null
+++ b/src/background/message-router.js
@@ -0,0 +1,177 @@
+/**
+ * Message router (background).
+ *
+ * - runtime.Port ('translation-stream'): translate / cancel requests from
+ * the content script, streaming started/chunk/completed/error back.
+ * - runtime.onMessage: one-shot listModels request for popup/options.
+ *
+ * All inbound messages are validated; invalid ones are discarded
+ * (Specifications.md SEC-06, Design.md §8.4).
+ */
+
+import {
+ CONTENT_TO_BG,
+ BG_TO_CONTENT,
+ RUNTIME_MESSAGES,
+ MAX_SELECTION_LENGTH,
+ ERROR_CODES
+} from '../shared/constants.js';
+import { isValidTranslateRequest, isValidCancelRequest, isTrustedSender } from '../shared/messages.js';
+import { getSettings } from './settings-service.js';
+import { TranslationSession } from './translation-session.js';
+import { chatStream, listModels } from './ollama-client.js';
+import { buildSystemPrompt } from '../shared/prompt.js';
+import { buildOptions, toApiThinking } from '../shared/settings-schema.js';
+
+const session = new TranslationSession();
+
+/** User-facing messages per error code (kept minimal; no stack traces). */
+const ERROR_MESSAGES = {
+ [ERROR_CODES.INVALID_REQUEST]: '要求が不正です。',
+ [ERROR_CODES.TEXT_EMPTY]: '選択文字列が空です。',
+ [ERROR_CODES.TEXT_TOO_LONG]: `選択文字列が長すぎます(上限 ${MAX_SELECTION_LENGTH} 文字)。`,
+ [ERROR_CODES.OLLAMA_UNAVAILABLE]: 'Ollamaに接続できません。Ollamaが起動しているか確認してください。',
+ [ERROR_CODES.MODEL_NOT_FOUND]: '指定されたモデルが見つかりません。',
+ [ERROR_CODES.INVALID_SETTINGS]: '設定値が不正です。設定画面を確認してください。',
+ [ERROR_CODES.REQUEST_ABORTED]: '翻訳を中断しました。',
+ [ERROR_CODES.STREAM_ERROR]: '翻訳中にエラーが発生しました。',
+ [ERROR_CODES.UNKNOWN_ERROR]: '不明なエラーが発生しました。'
+};
+
+/**
+ * Handle one content-script port connection.
+ * @param {object} port runtime.Port
+ */
+export function handleConnection(port) {
+ if (!port || port.name !== 'translation-stream') return;
+
+ port.onMessage.addListener((message) => {
+ if (!isTrustedSender(port.sender)) return;
+
+ if (isValidTranslateRequest(message)) {
+ void runTranslation(port, message.requestId, message.text);
+ return;
+ }
+ if (isValidCancelRequest(message)) {
+ if (session.isActive(message.requestId)) {
+ session.clear(message.requestId);
+ }
+ return;
+ }
+ // Invalid message: discard silently (do not echo details to the page).
+ });
+
+ port.onDisconnect.addListener(() => {
+ // If the tab goes away, abort the translation owned by this port.
+ if (session.hasActive() && session.active.port === port) {
+ const requestId = session.active.requestId;
+ session.clear(requestId);
+ }
+ });
+}
+
+/**
+ * Run one translation: settings -> prompt -> Ollama stream -> port messages.
+ * @param {object} port
+ * @param {string} requestId
+ * @param {string} text
+ */
+async function runTranslation(port, requestId, text) {
+ const settings = await getSettings();
+
+ if (!settings.enabled) {
+ postError(port, requestId, ERROR_CODES.INVALID_REQUEST, 'Translation is disabled');
+ return;
+ }
+ if (!settings.model) {
+ postError(port, requestId, ERROR_CODES.INVALID_SETTINGS, 'No model configured');
+ return;
+ }
+
+ const controller = session.start(requestId, port);
+
+ port.postMessage({ type: BG_TO_CONTENT.STARTED, requestId, model: settings.model });
+
+ try {
+ await chatStream({
+ host: settings.ollamaHost,
+ model: settings.model,
+ messages: [
+ { role: 'system', content: buildSystemPrompt(settings) },
+ { role: 'user', content: text }
+ ],
+ think: toApiThinking(settings),
+ options: buildOptions(settings),
+ signal: controller.signal,
+ onChunk: (content) => {
+ // Drop chunks if a newer request took over.
+ if (!session.isActive(requestId)) return;
+ port.postMessage({ type: BG_TO_CONTENT.CHUNK, requestId, text: content });
+ }
+ });
+ if (session.isActive(requestId)) {
+ port.postMessage({ type: BG_TO_CONTENT.COMPLETED, requestId });
+ }
+ } catch (error) {
+ const code = (error && error.code) || ERROR_CODES.UNKNOWN_ERROR;
+ // Aborted requests are reported by TranslationSession.abortActive();
+ // avoid a duplicate error for the same requestId.
+ if (code !== ERROR_CODES.REQUEST_ABORTED && session.isActive(requestId)) {
+ postError(port, requestId, code, error && error.message ? error.message : '');
+ }
+ } finally {
+ session.clear(requestId);
+ }
+}
+
+/**
+ * @param {object} port
+ * @param {string} requestId
+ * @param {string} code
+ * @param {string} message
+ */
+function postError(port, requestId, code, message) {
+ try {
+ port.postMessage({ type: BG_TO_CONTENT.ERROR, requestId, code, message: ERROR_MESSAGES[code] || ERROR_MESSAGES[ERROR_CODES.UNKNOWN_ERROR] });
+ } catch {
+ // port may be disconnected
+ }
+}
+
+/**
+ * Register one-shot message handling (popup / options).
+ * @param {object} browserApi injectable for tests
+ */
+export function registerRuntimeMessageHandler(browserApi) {
+ const b = browserApi || globalThis.browser;
+ b.runtime.onMessage.addListener((message, sender) => {
+ if (!isTrustedSender(sender)) return Promise.resolve({ ok: false, error: ERROR_CODES.INVALID_REQUEST });
+ if (message && message.type === RUNTIME_MESSAGES.LIST_MODELS) {
+ return (async () => {
+ try {
+ const settings = await getSettings(browserApi);
+ const models = await listModels(settings.ollamaHost);
+ return { ok: true, models };
+ } catch (error) {
+ return { ok: false, error: (error && error.code) || ERROR_CODES.OLLAMA_UNAVAILABLE, message: (error && error.message) || '' };
+ }
+ })();
+ }
+ return Promise.resolve({ ok: false, error: ERROR_CODES.INVALID_REQUEST });
+ });
+}
+
+/**
+ * Test-only hook: inject a browser API so the router can be exercised
+ * outside a real extension context. Not used at runtime.
+ * @param {object} browserApi
+ * @visibleForTesting
+ */
+export function __setBrowserApiForTests(browserApi) {
+ testBrowserApi = browserApi;
+ browserApi.runtime.onConnect.addListener(handleConnection);
+ registerRuntimeMessageHandler(browserApi);
+}
+
+/** @type {object|null} test-injected browser api */
+let testBrowserApi = null; \ No newline at end of file
diff --git a/src/background/ollama-client.js b/src/background/ollama-client.js
new file mode 100644
index 0000000..0286230
--- /dev/null
+++ b/src/background/ollama-client.js
@@ -0,0 +1,194 @@
+/**
+ * Ollama REST API client (background only).
+ *
+ * Uses the browser Fetch API directly against the Ollama REST API.
+ * - GET {host}/api/tags : list installed models
+ * - POST {host}/api/chat : streaming chat completion (NDJSON)
+ *
+ * Security rules implemented here (Security.md §4):
+ * - the host is re-validated immediately before each request;
+ * - NDJSON is parsed with a buffering line reader that tolerates chunk
+ * boundaries falling inside a JSON object;
+ * - requests can be aborted via AbortController.
+ */
+
+import { isValidOllamaHost } from '../shared/settings-schema.js';
+import { ERROR_CODES } from '../shared/constants.js';
+
+/**
+ * Translate a fetch/HTTP failure into a stable error code.
+ * @param {Response|undefined} response
+ * @returns {string} error code
+ */
+function statusCodeToError(status) {
+ if (status === 404) return ERROR_CODES.MODEL_NOT_FOUND;
+ if (status === 400 || status === 403) return ERROR_CODES.INVALID_SETTINGS;
+ if (status >= 500) return ERROR_CODES.STREAM_ERROR;
+ return ERROR_CODES.STREAM_ERROR;
+}
+
+/**
+ * Assert that the host is allowed. Throws Error with code attached.
+ * @param {string} host
+ */
+function assertAllowedHost(host) {
+ if (!isValidOllamaHost(host)) {
+ const error = new Error('Invalid Ollama host');
+ error.code = ERROR_CODES.INVALID_SETTINGS;
+ throw error;
+ }
+}
+
+/**
+ * Normalize an error thrown by fetch into an extension error code.
+ * @param {*} error
+ * @param {{aborted?: boolean, code?: string}} [options]
+ * @returns {Error}
+ */
+export function toExtensionError(error, { aborted = false, code = ERROR_CODES.OLLAMA_UNAVAILABLE } = {}) {
+ if (error && error.name === 'AbortError') {
+ const e = new Error('Request aborted');
+ e.code = ERROR_CODES.REQUEST_ABORTED;
+ return e;
+ }
+ if (error && error.code) return error;
+ // fetch() rejects on network failures (Ollama not running etc.)
+ const e = new Error(error instanceof Error ? error.message : 'Unknown Ollama error');
+ e.code = aborted ? ERROR_CODES.REQUEST_ABORTED : code;
+ return e;
+}
+
+/**
+ * List models installed in Ollama.
+ * @param {string} host validated host
+ * @param {AbortSignal} [signal]
+ * @returns {Promise<string[]>} model names
+ */
+export async function listModels(host, signal) {
+ assertAllowedHost(host);
+ let response;
+ try {
+ response = await fetch(`${host}/api/tags`, { method: 'GET', signal });
+ } catch (error) {
+ throw toExtensionError(error);
+ }
+ if (!response.ok) {
+ const e = new Error(`Ollama /api/tags failed: ${response.status}`);
+ e.code = response.status === 404 ? ERROR_CODES.MODEL_NOT_FOUND : ERROR_CODES.STREAM_ERROR;
+ throw e;
+ }
+ const data = await response.json();
+ if (!data || !Array.isArray(data.models)) return [];
+ return data.models.map((m) => (m && typeof m.name === 'string' ? m.name : '')).filter((name) => name.length > 0);
+}
+
+/**
+ * Stream a chat completion. Calls handlers for each incremental text chunk.
+ *
+ * @param {object} params
+ * @param {string} params.host validated Ollama host
+ * @param {string} params.model
+ * @param {Array<{role: string, content: string}>} params.messages
+ * @param {boolean|string} [params.think] true | 'low' | 'medium' | 'high'; omit when off
+ * @param {object} params.options Ollama options object
+ * @param {(text: string, thinking: string) => void} params.onChunk
+ * @param {AbortSignal} [params.signal]
+ * @returns {Promise<void>} resolves when the stream completes
+ */
+export async function chatStream({ host, model, messages, think, options, onChunk, signal }) {
+ assertAllowedHost(host);
+
+ const body = { model, messages, stream: true };
+ if (think !== undefined) {
+ body.think = think;
+ }
+ if (options && Object.keys(options).length > 0) {
+ body.options = options;
+ }
+
+ let response;
+ try {
+ response = await fetch(`${host}/api/chat`, {
+ method: 'POST',
+ headers: { 'Content-Type': 'application/json' },
+ body: JSON.stringify(body),
+ signal
+ });
+ } catch (error) {
+ throw toExtensionError(error, { aborted: isAbortError(error) });
+ }
+
+ if (!response.ok) {
+ const e = new Error(`Ollama /api/chat failed: ${response.status}`);
+ e.code =
+ response.status === 404
+ ? ERROR_CODES.MODEL_NOT_FOUND
+ : response.status === 400 || response.status === 403
+ ? ERROR_CODES.INVALID_SETTINGS
+ : ERROR_CODES.STREAM_ERROR;
+ throw e;
+ }
+ if (!response.body) {
+ const e = new Error('Ollama response has no body');
+ e.code = ERROR_CODES.STREAM_ERROR;
+ throw e;
+ }
+
+ const reader = response.body.getReader();
+ const decoder = new TextDecoder();
+ let buffer = '';
+
+ const processLine = (line) => {
+ if (!line) return;
+ let parsed;
+ try {
+ parsed = JSON.parse(line);
+ } catch {
+ // Malformed line: skip it rather than crashing the stream.
+ return;
+ }
+ if (parsed === null || typeof parsed !== 'object') return;
+ if (parsed.error) {
+ const e = new Error(String(parsed.error));
+ e.code = typeof parsed.error === 'string' && /not found/i.test(parsed.error) ? ERROR_CODES.MODEL_NOT_FOUND : ERROR_CODES.STREAM_ERROR;
+ throw e;
+ }
+ const content = parsed.message && typeof parsed.message.content === 'string' ? parsed.message.content : '';
+ const thinking = parsed.message && typeof parsed.message.thinking === 'string' ? parsed.message.thinking : '';
+ if (content || thinking) {
+ onChunk(content, thinking);
+ }
+ };
+
+ try {
+ for (;;) {
+ const { done, value } = await reader.read();
+ if (done) break;
+ buffer += decoder.decode(value, { stream: true });
+ let newlineIndex;
+ while ((newlineIndex = buffer.indexOf('\n')) !== -1) {
+ const line = buffer.slice(0, newlineIndex).replace(/\r$/, '');
+ buffer = buffer.slice(newlineIndex + 1);
+ processLine(line);
+ }
+ }
+ // Flush any remaining buffered line.
+ const tail = buffer.replace(/\r$/, '');
+ if (tail) processLine(tail);
+ } catch (error) {
+ if (isAbortError(error)) {
+ const e = new Error('Request aborted');
+ e.code = ERROR_CODES.REQUEST_ABORTED;
+ throw e;
+ }
+ throw error && error.code ? error : toExtensionError(error, { code: ERROR_CODES.STREAM_ERROR });
+ }
+}
+
+/**
+ * @param {*} error
+ * @returns {boolean}
+ */
+function isAbortError(error) {
+ return Boolean(error && (error.name === 'AbortError' || error.code === ERROR_CODES.REQUEST_ABORTED));
+} \ No newline at end of file
diff --git a/src/background/settings-service.js b/src/background/settings-service.js
new file mode 100644
index 0000000..2687921
--- /dev/null
+++ b/src/background/settings-service.js
@@ -0,0 +1,82 @@
+/**
+ * Settings service (background): storage access with validation.
+ *
+ * Load flow (Design.md §17.2):
+ * 1. generate default settings
+ * 2. read storage
+ * 3. merge
+ * 4. validate
+ * 5. invalid values fall back to defaults
+ *
+ * The validated cache is refreshed on storage.onChanged.
+ */
+
+import { sanitizeSettings, defaultSettings } from '../shared/settings-schema.js';
+
+const STORAGE_KEY = 'settings';
+
+/** @type {object|null} cached validated settings */
+let cache = null;
+
+/**
+ * @param {object} [browserApi] injectable browser API (defaults to globalThis.browser)
+ * @returns {object}
+ */
+function api(browserApi) {
+ return browserApi || globalThis.browser;
+}
+
+/**
+ * Load settings from storage.local, sanitize and cache them.
+ * @param {object} [browserApi]
+ * @returns {Promise<object>} validated settings
+ */
+export async function loadSettings(browserApi) {
+ const b = api(browserApi);
+ let stored = null;
+ try {
+ const result = await b.storage.local.get({ settings: null });
+ stored = result.settings;
+ } catch {
+ stored = null;
+ }
+ cache = sanitizeSettings(stored);
+ return cache;
+}
+
+/**
+ * Save settings. Values are sanitized before writing.
+ * @param {object} settings raw settings object from the UI
+ * @param {object} [browserApi]
+ * @returns {Promise<object>} the validated settings actually stored
+ */
+export async function saveSettings(settings, browserApi) {
+ const b = api(browserApi);
+ const validated = sanitizeSettings(settings);
+ await b.storage.local.set({ settings: validated });
+ cache = validated;
+ return validated;
+}
+
+/**
+ * @param {object} [browserApi]
+ * @returns {Promise<object>} current validated settings (cached when possible)
+ */
+export async function getSettings(browserApi) {
+ if (cache) return cache;
+ return loadSettings(browserApi);
+}
+
+/**
+ * Register the storage.onChanged listener that keeps the cache in sync.
+ * Must be called once from the background entry point.
+ * @param {object} [browserApi]
+ */
+export function watchSettings(browserApi) {
+ const b = api(browserApi);
+ b.storage.onChanged.addListener((changes, areaName) => {
+ if (areaName === 'local' && changes.settings) {
+ cache = sanitizeSettings(changes.settings.newValue);
+ }
+ });
+} \ No newline at end of file
diff --git a/src/background/translation-session.js b/src/background/translation-session.js
new file mode 100644
index 0000000..1d02974
--- /dev/null
+++ b/src/background/translation-session.js
@@ -0,0 +1,76 @@
+/**
+ * Translation session management (background).
+ *
+ * Only one translation may be active at a time (SEC-14 / Design.md §9).
+ * Starting a new request aborts the previous one. Chunks belonging to a
+ * stale requestId are discarded.
+ */
+
+import { ERROR_CODES } from '../shared/constants.js';
+
+export class TranslationSession {
+ constructor() {
+ /** @type {{requestId: string, controller: AbortController, port: object}|null} */
+ this.active = null;
+ }
+
+ /**
+ * @returns {boolean}
+ */
+ hasActive() {
+ return this.active !== null;
+ }
+
+ /**
+ * Abort the active request, if any. Notifies its port so the UI can reset.
+ * @returns {void}
+ */
+ abortActive() {
+ if (!this.active) return;
+ const { controller, port, requestId } = this.active;
+ this.active = null;
+ try {
+ controller.abort();
+ } catch {
+ // ignore abort errors
+ }
+ if (port) {
+ try {
+ port.postMessage({ type: 'error', requestId, code: ERROR_CODES.REQUEST_ABORTED, message: 'Superseded by a newer request' });
+ } catch {
+ // port may be gone
+ }
+ }
+ }
+
+ /**
+ * Register a new active request, aborting any previous one.
+ * @param {string} requestId
+ * @param {object} port runtime.Port owning the request
+ * @returns {AbortController} the controller for the new request
+ */
+ start(requestId, port) {
+ this.abortActive();
+ const controller = new AbortController();
+ this.active = { requestId, controller, port };
+ return controller;
+ }
+
+ /**
+ * @param {string} requestId
+ * @returns {boolean} true when the given id is the active request.
+ */
+ isActive(requestId) {
+ return this.active !== null && this.active.requestId === requestId;
+ }
+
+ /**
+ * Clear the active session when it matches the id.
+ * @param {string} requestId
+ */
+ clear(requestId) {
+ if (this.isActive(requestId)) {
+ this.active = null;
+ }
+ }
+} \ No newline at end of file