fix: browser API chrome.downloads.download 代码及Mock修正

packages/chrome-extension-mock/downloads.ts

@@ -1,20 +1,293 @@
+import EventEmitter from "eventemitter3";
+
+type DownloadChangedListener = (downloadDelta: chrome.downloads.DownloadDelta) => void;
+type DetermineFilenameListener = (
+  downloadItem: chrome.downloads.DownloadItem,
+  suggest: (suggestion?: chrome.downloads.FilenameSuggestion) => void
+) => void | boolean;
+
+type Callback<T> = (value: T) => void;
+type DownloadItem = chrome.downloads.DownloadItem & {
+  conflictAction?: `${chrome.downloads.FilenameConflictAction}`;
+};
+
 export default class Downloads {
-  onChangedCallback: ((downloadDelta: chrome.downloads.DownloadDelta) => void) | null = null;
+  downloadIdAccum: number = 0;
+  hook = new EventEmitter<string, any>();
+  items = new Map<number, DownloadItem>();
+  autoComplete = true;
+  autoCompleteDelay = 1;
 
   onChanged = {
-    addListener: (callback: (downloadDelta: chrome.downloads.DownloadDelta) => void) => {
-      this.onChangedCallback = callback;
+    addListener: (callback: DownloadChangedListener) => {
+      this.hook.addListener("onChanged", callback);
+    },
+    removeListener: (callback: DownloadChangedListener) => {
+      this.hook.removeListener("onChanged", callback);
+    },
+    hasListener: (callback: DownloadChangedListener) => this.hook.listeners("onChanged").includes(callback),
+    hasListeners: () => this.hook.listenerCount("onChanged") > 0,
+  };
+
+  onDeterminingFilename = {
+    addListener: (callback: DetermineFilenameListener) => {
+      this.hook.addListener("onDeterminingFilename", callback);
     },
-    removeListener: (_callback: (downloadDelta: chrome.downloads.DownloadDelta) => void) => {
-      this.onChangedCallback = null;
+    removeListener: (callback: DetermineFilenameListener) => {
+      this.hook.removeListener("onDeterminingFilename", callback);
     },
+    hasListener: (callback: DetermineFilenameListener) =>
+      this.hook.listeners("onDeterminingFilename").includes(callback),
+    hasListeners: () => this.hook.listenerCount("onDeterminingFilename") > 0,
   };
 
-  download(_: any, callback: (downloadId: number) => void) {
-    callback && callback(1);
-    this.onChangedCallback?.({
-      id: 1,
-      state: { current: "complete" },
+  reset() {
+    this.downloadIdAccum = 0;
+    this.items.clear();
+    this.hook.removeAllListeners();
+    this.autoComplete = true;
+    this.autoCompleteDelay = 1;
+    this.clearLastError();
+  }
+
+  download(options: chrome.downloads.DownloadOptions, callback?: Callback<number>) {
+    this.clearLastError();
+    if (!options?.url) {
+      const error = new Error("The download url is required.");
+      if (callback) {
+        this.withLastError(error.message, () => callback(undefined as unknown as number));
+        return;
+      }
+      return Promise.reject(error);
+    }
+
+    const id = ++this.downloadIdAccum;
+    const item = this.createDownloadItem(id, options);
+    this.items.set(id, item);
+
+    // Chrome 会先把 id 返回给调用方，随后才进入文件名决定和状态变化事件。
+    const delayed = async () => {
+      await this.determineFilename(item);
+      if (this.autoComplete && item.state === "in_progress") {
+        this.complete(id);
+      }
+    };
+
+    if (callback) {
+      callback(id);
+      setTimeout(delayed, this.autoCompleteDelay);
+      return;
+    }
+    return new Promise<number>((resolve) => {
+      resolve(id);
+      setTimeout(delayed, this.autoCompleteDelay);
     });
   }
+
+  cancel(downloadId: number, callback?: () => void) {
+    this.clearLastError();
+    const item = this.items.get(downloadId);
+    if (!item) return this.maybeAsync(undefined, callback);
+    if (item.state === "in_progress") {
+      item.state = "interrupted";
+      item.error = "USER_CANCELED";
+      item.endTime = new Date().toISOString();
+      this.emitChanged({
+        id: downloadId,
+        state: { previous: "in_progress", current: "interrupted" },
+        error: { current: "USER_CANCELED" },
+      });
+    }
+    return this.maybeAsync(undefined, callback);
+  }
+
+  search(query: chrome.downloads.DownloadQuery, callback?: Callback<chrome.downloads.DownloadItem[]>) {
+    this.clearLastError();
+    const result = [...this.items.values()].filter((item) => this.matchQuery(item, query));
+    return this.maybeAsync(result, callback);
+  }
+
+  erase(query: chrome.downloads.DownloadQuery, callback?: Callback<number[]>) {
+    this.clearLastError();
+    const ids = [...this.items.values()].filter((item) => this.matchQuery(item, query)).map((item) => item.id);
+    ids.forEach((id) => this.items.delete(id));
+    return this.maybeAsync(ids, callback);
+  }
+
+  pause(downloadId: number, callback?: () => void) {
+    this.clearLastError();
+    const item = this.items.get(downloadId);
+    if (item && item.state === "in_progress" && !item.paused) {
+      item.paused = true;
+      this.emitChanged({
+        id: downloadId,
+        paused: { previous: false, current: true },
+      });
+    }
+    return this.maybeAsync(undefined, callback);
+  }
+
+  resume(downloadId: number, callback?: () => void) {
+    this.clearLastError();
+    const item = this.items.get(downloadId);
+    if (item && item.paused) {
+      item.paused = false;
+      this.emitChanged({
+        id: downloadId,
+        paused: { previous: true, current: false },
+      });
+    }
+    return this.maybeAsync(undefined, callback);
+  }
+
+  show(_downloadId: number) {
+    this.clearLastError();
+  }
+
+  showDefaultFolder() {
+    this.clearLastError();
+  }
+
+  open(_downloadId: number, callback?: () => void) {
+    this.clearLastError();
+    return this.maybeAsync(undefined, callback);
+  }
+
+  removeFile(_downloadId: number, callback?: () => void) {
+    this.clearLastError();
+    return this.maybeAsync(undefined, callback);
+  }
+
+  complete(downloadId: number) {
+    const item = this.items.get(downloadId);
+    if (!item || item.state !== "in_progress") return;
+    item.state = "complete";
+    item.bytesReceived = item.totalBytes >= 0 ? item.totalBytes : item.bytesReceived;
+    item.endTime = new Date().toISOString();
+    this.emitChanged({
+      id: downloadId,
+      state: { previous: "in_progress", current: "complete" },
+    });
+  }
+
+  interrupt(downloadId: number, error: `${chrome.downloads.InterruptReason}` = "NETWORK_FAILED") {
+    const item = this.items.get(downloadId);
+    if (!item || item.state !== "in_progress") return;
+    item.state = "interrupted";
+    item.error = error;
+    item.endTime = new Date().toISOString();
+    this.emitChanged({
+      id: downloadId,
+      state: { previous: "in_progress", current: "interrupted" },
+      error: { current: error },
+    });
+  }
+
+  private createDownloadItem(id: number, options: chrome.downloads.DownloadOptions): DownloadItem {
+    const filename = options.filename || this.inferFilename(options.url);
+    return {
+      id,
+      url: options.url,
+      finalUrl: options.url,
+      referrer: "",
+      filename,
+      danger: "safe",
+      mime: "",
+      startTime: new Date().toISOString(),
+      endTime: undefined,
+      estimatedEndTime: undefined,
+      state: "in_progress",
+      paused: false,
+      canResume: false,
+      error: undefined,
+      bytesReceived: 0,
+      totalBytes: -1,
+      fileSize: -1,
+      exists: true,
+      byExtensionId: globalThis.chrome?.runtime?.id,
+      byExtensionName: "ScriptCat Mock",
+      incognito: false,
+      conflictAction: options.conflictAction,
+    } as DownloadItem;
+  }
+
+  private inferFilename(url: string) {
+    try {
+      const pathname = new URL(url).pathname;
+      return decodeURIComponent(pathname.split("/").filter(Boolean).pop() || "download");
+    } catch {
+      return "download";
+    }
+  }
+
+  private async determineFilename(item: DownloadItem) {
+    const listeners = this.hook.listeners("onDeterminingFilename") as DetermineFilenameListener[];
+    if (listeners.length === 0) return;
+
+    const suggestion = await new Promise<chrome.downloads.FilenameSuggestion | undefined>((resolve) => {
+      let settled = false;
+      const suggest = (value?: chrome.downloads.FilenameSuggestion) => {
+        if (settled) return;
+        settled = true;
+        resolve(value);
+      };
+      listeners.forEach((listener) => listener({ ...item } as chrome.downloads.DownloadItem, suggest));
+      setTimeout(() => suggest(), 50);
+    });
+
+    if (suggestion?.filename) {
+      const previous = item.filename;
+      item.filename = suggestion.filename;
+      item.conflictAction = suggestion.conflictAction;
+      this.emitChanged({
+        id: item.id,
+        filename: { previous, current: suggestion.filename },
+      });
+    }
+  }
+
+  private matchQuery(item: DownloadItem, query: chrome.downloads.DownloadQuery) {
+    if (query.id !== undefined && item.id !== query.id) return false;
+    if (query.url && item.url !== query.url) return false;
+    if (query.filename && item.filename !== query.filename) return false;
+    if (query.state && item.state !== query.state) return false;
+    return true;
+  }
+
+  private emitChanged(delta: chrome.downloads.DownloadDelta) {
+    this.hook.emit("onChanged", delta);
+  }
+
+  private maybeAsync<T>(value: T, callback?: Callback<T>) {
+    if (callback) {
+      callback(value);
+      return;
+    }
+    return Promise.resolve(value);
+  }
+
+  private withLastError(message: string, fn: () => void) {
+    (
+      globalThis.chrome.runtime as typeof chrome.runtime & {
+        lastError?: chrome.runtime.LastError;
+      }
+    ).lastError = {
+      message,
+    };
+    try {
+      fn();
+    } finally {
+      this.clearLastError();
+    }
+  }
+
+  private clearLastError() {
+    if (globalThis.chrome?.runtime) {
+      delete (
+        globalThis.chrome.runtime as typeof chrome.runtime & {
+          lastError?: chrome.runtime.LastError;
+        }
+      ).lastError;
+    }
+  }
 }

packages/chrome-extension-mock/index.ts

@@ -26,7 +26,9 @@ const chromeMock = {
   extension: new Extension(),
   userScripts: new MockUserScripts(),
   action: new Action(),
-  init() {},
+  init() {
+    this.downloads.reset();
+  },
 };
 
 export default chromeMock;