接入移动壳文本文件导出能力

Expo 移动壳通过文件系统写入缓存文本并调用系统分享保存面板

补充移动壳导出能力依赖、配置守卫和 HostBridge 单测

更新宿主壳能力协议、方案文档和共享决策记录

apps/mobile-shell/src/mobileHostBridge.test.ts

@@ -1,4 +1,5 @@
 import * as Linking from 'expo-linking';
+import * as Sharing from 'expo-sharing';
 import { Share } from 'react-native';
 import { afterEach, describe, expect, test, vi } from 'vitest';
 
@@ -19,6 +20,30 @@ vi.mock('expo-clipboard', () => ({
   setStringAsync: vi.fn(),
 }));
 
+const writtenFiles = vi.hoisted(
+  () => [] as { uri: string; content: string }[],
+);
+
+vi.mock('expo-file-system', () => ({
+  Paths: {
+    cache: 'file:///cache/',
+  },
+  File: class MockFile {
+    uri: string;
+
+    constructor(_base: string, fileName: string) {
+      this.uri = `file:///cache/${fileName}`;
+    }
+
+    write(content: string) {
+      writtenFiles.push({
+        uri: this.uri,
+        content,
+      });
+    }
+  },
+}));
+
 vi.mock('expo-haptics', () => ({
   ImpactFeedbackStyle: {
     Heavy: 'heavy',
@@ -32,6 +57,11 @@ vi.mock('expo-linking', () => ({
   openURL: vi.fn(),
 }));
 
+vi.mock('expo-sharing', () => ({
+  isAvailableAsync: vi.fn(async () => true),
+  shareAsync: vi.fn(),
+}));
+
 vi.mock('react-native', () => ({
   Platform: {
     OS: 'ios',
@@ -87,7 +117,11 @@ function expectFailed(response: HostBridgeResponse) {
 
 afterEach(() => {
   vi.mocked(Linking.openURL).mockReset();
+  vi.mocked(Sharing.isAvailableAsync).mockReset();
+  vi.mocked(Sharing.isAvailableAsync).mockResolvedValue(true);
+  vi.mocked(Sharing.shareAsync).mockReset();
   vi.mocked(Share.share).mockReset();
+  writtenFiles.length = 0;
   resetMobileHostBridgeForTest();
 });
 
@@ -104,6 +138,9 @@ describe('handleMobileHostBridgeMessage', () => {
     expect(
       (okResponse.result as { capabilities: string[] }).capabilities,
     ).toContain('navigation.openNativePage');
+    expect(
+      (okResponse.result as { capabilities: string[] }).capabilities,
+    ).toContain('file.exportText');
     expect(
       (okResponse.result as { capabilities: string[] }).capabilities,
     ).toEqual(
@@ -237,7 +274,41 @@ describe('handleMobileHostBridgeMessage', () => {
     expect(Share.share).not.toHaveBeenCalled();
   });
 
-  test('移动壳未接入真实导出能力时明确返回 unsupported', async () => {
+  test('file.exportText 写入缓存文件并调起系统分享', async () => {
+    const response = await send(
+      request('file.exportText', {
+        fileName: ' ../作品:记录?.txt ',
+        content: '暖灯猫街',
+        mimeType: 'text/markdown',
+      }),
+    );
+
+    const okResponse = expectOk(response);
+
+    expect(okResponse.result).toEqual({
+      action: 'saved',
+      fileName: '作品-记录-.txt',
+      bytes: 12,
+    });
+    expect(writtenFiles).toEqual([
+      {
+        uri: 'file:///cache/作品-记录-.txt',
+        content: '暖灯猫街',
+      },
+    ]);
+    expect(Sharing.shareAsync).toHaveBeenCalledWith(
+      'file:///cache/作品-记录-.txt',
+      {
+        mimeType: 'text/markdown',
+        UTI: 'public.plain-text',
+        dialogTitle: '作品-记录-.txt',
+      },
+    );
+  });
+
+  test('file.exportText 在系统分享不可用时明确返回 unsupported capability', async () => {
+    vi.mocked(Sharing.isAvailableAsync).mockResolvedValue(false);
+
     const response = await send(
       request('file.exportText', {
         fileName: '作品记录.txt',
@@ -247,6 +318,23 @@ describe('handleMobileHostBridgeMessage', () => {
 
     const failedResponse = expectFailed(response);
 
-    expect(failedResponse.error.code).toBe('unsupported_method');
+    expect(failedResponse.error.code).toBe('unsupported_capability');
+    expect(writtenFiles).toEqual([]);
+    expect(Sharing.shareAsync).not.toHaveBeenCalled();
+  });
+
+  test('file.exportText 拒绝超出上限的文本内容', async () => {
+    const response = await send(
+      request('file.exportText', {
+        fileName: '作品记录.txt',
+        content: 'a'.repeat(5 * 1024 * 1024 + 1),
+      }),
+    );
+
+    const failedResponse = expectFailed(response);
+
+    expect(failedResponse.error.code).toBe('invalid_request');
+    expect(writtenFiles).toEqual([]);
+    expect(Sharing.shareAsync).not.toHaveBeenCalled();
   });
 });