feat: add helper process (#2753)

apps/electron/src/main/export/index.ts

@@ -0,0 +1,10 @@
+import type { NamespaceHandlers } from '../type';
+import { savePDFFileAs } from './pdf';
+
+export const exportHandlers = {
+  savePDFFileAs: async (_, title: string) => {
+    return savePDFFileAs(title);
+  },
+} satisfies NamespaceHandlers;
+
+export * from './pdf';

apps/electron/src/main/export/pdf.ts

@@ -0,0 +1,61 @@
+import { BrowserWindow, dialog, shell } from 'electron';
+import fs from 'fs-extra';
+
+import { logger } from '../logger';
+import type { ErrorMessage } from './utils';
+import { getFakedResult } from './utils';
+
+export interface SavePDFFileResult {
+  filePath?: string;
+  canceled?: boolean;
+  error?: ErrorMessage;
+}
+
+/**
+ * This function is called when the user clicks the "Export to PDF" button in the electron.
+ *
+ * It will just copy the file to the given path
+ */
+export async function savePDFFileAs(
+  pageTitle: string
+): Promise<SavePDFFileResult> {
+  try {
+    const ret =
+      getFakedResult() ??
+      (await dialog.showSaveDialog({
+        properties: ['showOverwriteConfirmation'],
+        title: 'Save PDF',
+        showsTagField: false,
+        buttonLabel: 'Save',
+        defaultPath: `${pageTitle}.pdf`,
+        message: 'Save Page as a PDF file',
+      }));
+    const filePath = ret.filePath;
+    if (ret.canceled || !filePath) {
+      return {
+        canceled: true,
+      };
+    }
+
+    await BrowserWindow.getFocusedWindow()
+      ?.webContents.printToPDF({
+        pageSize: 'A4',
+        printBackground: true,
+        landscape: false,
+      })
+      .then(data => {
+        fs.writeFile(filePath, data, error => {
+          if (error) throw error;
+          logger.log(`Wrote PDF successfully to ${filePath}`);
+        });
+      });
+
+    await shell.openPath(filePath);
+    return { filePath };
+  } catch (err) {
+    logger.error('savePDFFileAs', err);
+    return {
+      error: 'UNKNOWN_ERROR',
+    };
+  }
+}

apps/electron/src/main/export/utils.ts

@@ -0,0 +1,24 @@
+// provide a backdoor to set dialog path for testing in playwright
+interface FakeDialogResult {
+  canceled?: boolean;
+  filePath?: string;
+  filePaths?: string[];
+}
+// result will be used in the next call to showOpenDialog
+// if it is being read once, it will be reset to undefined
+let fakeDialogResult: FakeDialogResult | undefined = undefined;
+export function getFakedResult() {
+  const result = fakeDialogResult;
+  fakeDialogResult = undefined;
+  return result;
+}
+
+export function setFakeDialogResult(result: FakeDialogResult | undefined) {
+  fakeDialogResult = result;
+  // for convenience, we will fill filePaths with filePath if it is not set
+  if (result?.filePaths === undefined && result?.filePath !== undefined) {
+    result.filePaths = [result.filePath];
+  }
+}
+const ErrorMessages = ['FILE_ALREADY_EXISTS', 'UNKNOWN_ERROR'] as const;
+export type ErrorMessage = (typeof ErrorMessages)[number];