(core) Export to Excel and Send to drive

Summary:
Implementing export to excel and send to Google Drive feature.

As part of this feature few things were implemented:
- Server side google authentication exposed on url: (docs, docs-s, or localhost:8080)/auth/google
- Exporting grist documents as an excel file (xlsx)
- Storing exported grist document (in excel format) in Google Drive as a spreadsheet document.

Server side google authentication requires one new environmental variables
- GOOGLE_CLIENT_SECRET (required) used by authentication handler

Test Plan: Browser tests for exporting to excel.

Reviewers: paulfitz, dsagal

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D2924

app/client/components/GristDoc.ts

@@ -601,6 +601,14 @@ export class GristDoc extends DisposableWithEvents {
     );
   }
 
+  public getXlsxLink() {
+    const params = {
+      ...this.docComm.getUrlParams(),
+      title: this.docPageModel.currentDocTitle.get(),
+    };
+    return this.docComm.docUrl(`gen_xlsx`) + '?' + encodeQueryParams(params);
+  }
+
   public getCsvLink() {
     const filters = this.viewModel.activeSection.peek().filteredFields.get().map(field=> ({
       colRef : field.colRef.peek(),
@@ -614,7 +622,7 @@ export class GristDoc extends DisposableWithEvents {
       activeSortSpec: JSON.stringify(this.viewModel.activeSection().activeSortSpec()),
       filters : JSON.stringify(filters),
     };
-    return this.docComm.docUrl('gen_csv') + '?' + encodeQueryParams(params);
+    return this.docComm.docUrl(`gen_csv`) + '?' + encodeQueryParams(params);
   }
 
   public hasGranularAccessRules(): boolean {

app/client/ui/ShareMenu.ts

@@ -3,6 +3,7 @@ import {AppModel, reportError} from 'app/client/models/AppModel';
 import {DocInfo, DocPageModel} from 'app/client/models/DocPageModel';
 import {docUrl, urlState} from 'app/client/models/gristUrlState';
 import {makeCopy, replaceTrunkWithFork} from 'app/client/ui/MakeCopyMenu';
+import {sendToDrive} from 'app/client/ui/sendToDrive';
 import {cssHoverCircle, cssTopBarBtn} from 'app/client/ui/TopBarCss';
 import {primaryButton} from 'app/client/ui2018/buttons';
 import {colors, mediaXSmall, testId} from 'app/client/ui2018/cssVars';
@@ -222,6 +223,10 @@ function menuExports(doc: Document, pageModel: DocPageModel) {
     ),
     menuItemLink({ href: gristDoc.getCsvLink(), target: '_blank', download: ''},
       menuIcon('Download'), 'Export CSV', testId('tb-share-option')),
+    menuItemLink({ href: gristDoc.getXlsxLink(), target: '_blank', download: ''},
+      menuIcon('Download'), 'Export XLSX', testId('tb-share-option')),
+    menuItem(() => sendToDrive(doc, pageModel),
+      menuIcon('Download'), 'Send to Google Drive', testId('tb-share-option')),
   ];
 }
 

app/client/ui/sendToDrive.ts

@@ -0,0 +1,106 @@
+import {get as getBrowserGlobals} from 'app/client/lib/browserGlobals';
+import {getHomeUrl} from 'app/client/models/AppModel';
+import {reportError} from 'app/client/models/errors';
+import {spinnerModal} from 'app/client/ui2018/modals';
+import type { DocPageModel } from 'app/client/models/DocPageModel';
+import type { Document } from 'app/common/UserAPI';
+import type { Disposable } from 'grainjs';
+
+const G = getBrowserGlobals('window');
+
+/**
+ * Generates Google Auth endpoint (exposed by Grist) url. For example:
+ * https://docs.getgrist.com/auth/google
+ * @param scope Requested access scope for Google Services
+ * https://developers.google.com/identity/protocols/oauth2/scopes
+ */
+function getGoogleAuthEndpoint(scope?: string) {
+  return new URL(`auth/google?scope=${scope || ''}`, getHomeUrl()).href;
+}
+
+/**
+ * Sends xlsx file to Google Drive. It first authenticates with Google to get encrypted access token,
+ * then it calls "send-to-drive" api endpoint to upload xlsx file to drive and finally it redirects
+ * to the created spreadsheet.
+ * Code that is received from Google contains encrypted access token, server is able to decrypt it
+ * using GOOGLE_CLIENT_SECRET key.
+ */
+export function sendToDrive(doc: Document, pageModel: DocPageModel) {
+  // Get current document - it will be used to remove popup listener.
+  const gristDoc = pageModel.gristDoc.get();
+  // Sanity check - gristDoc should be always present
+  if (!gristDoc) { throw new Error("Grist document is not present in Page Model"); }
+
+  // Create send to google drive handler (it will return a spreadsheet url).
+  const send = (code: string) =>
+    // Decorate it with a spinner
+    spinnerModal('Sending file to Google Drive',
+      pageModel.appModel.api.getDocAPI(doc.id)
+        .sendToDrive(code, pageModel.currentDocTitle.get())
+    );
+
+  // Compute google auth server endpoint (grist endpoint for server side google authentication).
+  // This endpoint will redirect user to Google Consent screen and after Google sends a response,
+  // it will render a page (/static/message.html) that will post a message containing message
+  // from Google. Message will be an object { code, error }. We will use the code to invoke
+  // "send-to-drive" api endpoint - that will actually send the xlsx file to Google Drive.
+  const authLink = getGoogleAuthEndpoint();
+  const authWindow = openPopup(authLink);
+  attachListener(gristDoc, authWindow, async (event: MessageEvent) => {
+    // For the first message (we expect only a single message) close the window.
+    authWindow.close();
+
+    // Check response from the popup
+    const response = (event.data || {}) as { code?: string, error?: string };
+    // - when user declined, do nothing,
+    if (response.error === "access_denied") { return; }
+    // - when there is no response code or error code is different from what we expected - report to user.
+    if (!response.code) { reportError(response.error || "Unrecognized or empty error code"); return; }
+
+    // Send file to Google Drive.
+    try {
+      const { url } = await send(response.code);
+      G.window.location.assign(url);
+    } catch (err) {
+      reportError(err);
+    }
+  });
+}
+
+// Helper function that attaches a handler to message event from a popup window.
+function attachListener(owner: Disposable, popup: Window, listener: (e: MessageEvent) => any) {
+  const wrapped = (e: MessageEvent) => {
+    // Listen to events only from our window.
+    if (e.source !== popup) { return; }
+    // In case when Grist was reloaded or user navigated away - do nothing.
+    if (owner.isDisposed()) { return; }
+    listener(e);
+  };
+  G.window.addEventListener('message', wrapped);
+  owner.onDispose(() => {
+    G.window.removeEventListener('message', wrapped);
+  });
+}
+
+function openPopup(url: string): Window {
+  // Center window on desktop
+  // https://stackoverflow.com/questions/16363474/window-open-on-a-multi-monitor-dual-monitor-system-where-does-window-pop-up
+  const width = 600;
+  const height = 650;
+  const left = window.screenX + (screen.width - width) / 2;
+  const top = (screen.height - height) / 4;
+  let windowFeatures = `top=${top},left=${left},menubar=no,location=no,` +
+    `resizable=yes,scrollbars=yes,status=yes,height=${height},width=${width}`;
+
+  // If window will be too large (for example on mobile) - open as a new tab
+  if (screen.width <= width || screen.height <= height) {
+    windowFeatures = '';
+  }
+
+  const authWindow = G.window.open(url, "GoogleAuthPopup", windowFeatures);
+  if (!authWindow) {
+    // This method should be invoked by an user action.
+    throw new Error("This method should be invoked synchronously");
+  }
+  return authWindow;
+}

app/common/UserAPI.ts

@@ -344,6 +344,13 @@ export interface DocAPI {
   // is HEAD, the result will contain a copy of any rows added or updated.
   compareVersion(leftHash: string, rightHash: string): Promise<DocStateComparison>;
   getDownloadUrl(template?: boolean): string;
+  /**
+   * Exports current document to the Google Drive as a spreadsheet file. To invoke this method, first
+   * acquire "code" via Google Auth Endpoint (see ShareMenu.ts for an example).
+   * @param code Authorization code returned from Google (requested via Grist's Google Auth Endpoint)
+   * @param title Name of the spreadsheet that will be created (should use a Grist document's title)
+   */
+  sendToDrive(code: string, title: string): Promise<{url: string}>;
 }
 
 // Operations that are supported by a doc worker.
@@ -775,4 +782,11 @@ export class DocAPIImpl extends BaseAPI implements DocAPI {
   public getDownloadUrl(template: boolean = false) {
     return this._url + `/download?template=${Number(template)}`;
   }
+
+  public async sendToDrive(code: string, title: string): Promise<{url: string}> {
+    const url = new URL(`${this._url}/send-to-drive`);
+    url.searchParams.append('title', title);
+    url.searchParams.append('code', code);
+    return this.requestJson(url.href);
+  }
 }

app/common/gutil.ts

@@ -133,7 +133,7 @@ export function undef<T extends Array<any>>(...list: T): Undef<T> {
  */
 export function safeJsonParse(json: string, defaultVal: any): any {
   try {
-    return JSON.parse(json);
+    return json !== '' && json !== undefined ? JSON.parse(json) : defaultVal;
   } catch (e) {
     return defaultVal;
   }

app/gen-server/lib/DocApiForwarder.ts

@@ -42,6 +42,7 @@ export class DocApiForwarder {
     app.use('/api/docs/:docId/remove', withDoc);
     app.delete('/api/docs/:docId', withDoc);
     app.use('/api/docs/:docId/download', withDoc);
+    app.use('/api/docs/:docId/send-to-drive', withDoc);
     app.use('/api/docs/:docId/fork', withDoc);
     app.use('/api/docs/:docId/create-fork', withDoc);
     app.use('/api/docs/:docId/apply', withDoc);

app/server/lib/DocApi.ts

@@ -28,6 +28,8 @@ import * as contentDisposition from 'content-disposition';
 import { Application, NextFunction, Request, RequestHandler, Response } from "express";
 import fetch from 'node-fetch';
 import * as path from 'path';
+import { exportToDrive } from "app/server/lib/GoogleExport";
+import { googleAuthTokenMiddleware } from "app/server/lib/GoogleAuth";
 
 // Cap on the number of requests that can be outstanding on a single document via the
 // rest doc api.  When this limit is exceeded, incoming requests receive an immediate
@@ -92,6 +94,8 @@ export class DocWorkerApi {
     const canEditMaybeRemoved = expressWrap(this._assertAccess.bind(this, 'editors', true));
     // check document exists, don't check user access
     const docExists = expressWrap(this._assertAccess.bind(this, null, false));
+    // converts google code to access token and adds it to request object
+    const decodeGoogleToken = expressWrap(googleAuthTokenMiddleware.bind(null));
 
     // Middleware to limit number of outstanding requests per document.  Will also
     // handle errors like expressWrap would.
@@ -443,6 +447,8 @@ export class DocWorkerApi {
       res.json(result);
     }));
 
+    this._app.get('/api/docs/:docId/send-to-drive', canView, decodeGoogleToken, withDoc(exportToDrive));
+
     // Create a document.  When an upload is included, it is imported as the initial
     // state of the document.  Otherwise a fresh empty document is created.
     // A "timezone" option can be supplied.

app/server/lib/DocWorker.ts

@@ -13,7 +13,7 @@ import {IDocStorageManager} from 'app/server/lib/IDocStorageManager';
 import * as log from 'app/server/lib/log';
 import {integerParam, optStringParam, stringParam} from 'app/server/lib/requestUtils';
 import {OpenMode, quoteIdent, SQLiteDB} from 'app/server/lib/SQLiteDB';
-import {generateCSV} from 'app/server/serverMethods';
+import {generateCSV, generateXLSX} from 'app/server/serverMethods';
 import * as contentDisposition from 'content-disposition';
 import * as express from 'express';
 import * as fse from 'fs-extra';
@@ -34,6 +34,10 @@ export class DocWorker {
     await generateCSV(req, res, this._comm);
   }
 
+  public async getXLSX(req: express.Request, res: express.Response): Promise<void> {
+    await generateXLSX(req, res, this._comm);
+  }
+
   public async getAttachment(req: express.Request, res: express.Response): Promise<void> {
     try {
       const docSession = this._getDocSession(stringParam(req.query.clientId),

app/server/lib/ExcelFormatter.ts

@@ -0,0 +1,257 @@
+import {CellValue} from 'app/common/DocActions';
+import {GristType} from 'app/common/gristTypes';
+import * as gutil from 'app/common/gutil';
+import * as gristTypes from 'app/common/gristTypes';
+import {NumberFormatOptions} from 'app/common/NumberFormat';
+import {formatUnknown, IsRightTypeFunc} from 'app/common/ValueFormatter';
+import {decodeObject} from 'app/plugin/objtypes';
+import {Style} from 'exceljs';
+import * as moment from 'moment-timezone';
+
+interface WidgetOptions extends NumberFormatOptions {
+  textColor?: 'string';
+  fillColor?: 'string';
+  alignment?: 'left' | 'center' | 'right';
+  dateFormat?: string;
+  timeFormat?: string;
+}
+class BaseFormatter {
+  protected isRightType: IsRightTypeFunc;
+  protected widgetOptions: WidgetOptions = {};
+
+  constructor(public type: string, public opts: object) {
+    this.isRightType = gristTypes.isRightType(gristTypes.extractTypeFromColType(type)) ||
+      gristTypes.isRightType('Any')!;
+    this.widgetOptions = opts;
+  }
+
+  /**
+   * Formats a value that matches the type of this formatter. This should be overridden by derived
+   * classes to handle values in formatter-specific ways.
+   */
+  public format(value: any): any {
+    return value;
+  }
+
+  public style(): Partial<Style> {
+    const argb = (hex: string) => `FF${hex.substr(1)}`;
+    const style: Partial<Style> = {};
+    if (this.widgetOptions.fillColor) {
+      style.fill = {
+        type: 'pattern',
+        pattern: 'solid',
+        fgColor: { argb: argb(this.widgetOptions.fillColor) }
+      };
+    }
+    if (this.widgetOptions.textColor) {
+      style.font = {
+        color: { argb: argb(this.widgetOptions.textColor) }
+      };
+    }
+    if (this.widgetOptions.alignment) {
+      style.alignment = {
+        horizontal: this.widgetOptions.alignment
+      };
+    }
+    if (this.widgetOptions.dateFormat) {
+      style.numFmt = excelDateFormat(this.widgetOptions.dateFormat, 'yyyy-mm-dd');
+    }
+    if (this.widgetOptions.timeFormat) {
+      style.numFmt = excelDateFormat(this.widgetOptions.dateFormat!, 'yyyy-mm-dd') + ' ' +
+        excelDateFormat(this.widgetOptions.timeFormat, 'h:mm am/pm');
+    }
+    // For number formats - we will support default excel formatting only,
+    // those formats strings are the defaults that LibreOffice Calc is using.
+    if (this.widgetOptions.numMode) {
+      if (this.widgetOptions.numMode === 'currency') {
+        style.numFmt = '[$$-409]#,##0.00';
+      } else if (this.widgetOptions.numMode === 'percent') {
+        style.numFmt = '0.00%';
+      } else if (this.widgetOptions.numMode === 'decimal') {
+        style.numFmt = '0.00';
+      } else if (this.widgetOptions.numMode === 'scientific') {
+        style.numFmt = '0.00E+00';
+      }
+    }
+    return style;
+  }
+
+  /**
+   * Formats using this.format() if a value is of the right type for this formatter, or using
+   * formatUnknown (like AnyFormatter) otherwise, resulting in a string representation.
+   */
+  public formatAny(value: any): any {
+    return this.isRightType(value) ? this.format(value) : formatUnknown(value);
+  }
+}
+
+class AnyFormatter extends BaseFormatter {
+  public format(value: any): any {
+    return formatUnknown(value);
+  }
+}
+
+class ChoiceListFormatter extends BaseFormatter {
+  public format(value: any): any {
+    const obj = decodeObject(value);
+    if (Array.isArray(obj)) {
+      return obj.join("; ");
+    }
+    return formatUnknown(value);
+  }
+}
+
+class UnsupportedFormatter extends BaseFormatter {
+  public format(value: any): any {
+    return '';
+  }
+}
+
+class NumberFormatter extends BaseFormatter {
+  public format(value: any): any {
+    return Number.isFinite(value) ? value : '';
+  }
+}
+
+class DateFormatter extends BaseFormatter {
+  private _timezone: string;
+
+  constructor(type: string, opts: WidgetOptions, timezone: string = 'UTC') {
+    opts.dateFormat = opts.dateFormat || 'YYYY-MM-DD';
+    super(type, opts);
+    this._timezone = timezone || 'UTC';
+    // For native conversion - booleans are not a right type.
+    this.isRightType = (value: CellValue) => typeof value === 'number';
+  }
+
+  public format(value: any): any {
+    if (value === null) { return ''; }
+    // convert time to correct timezone
+    const time = moment(value * 1000).tz(this._timezone);
+    // in case moment is not able to interpret this as a valid date
+    // fallback to formatUnknown, for example for 0, NaN, Infinity
+    if (!time) {
+      return formatUnknown(value);
+    }
+    // make it look like a local time
+    time.utc(true).local();
+    // moment objects are mutable so we can just return original object.
+    return time.toDate();
+  }
+}
+
+class DateTimeFormatter extends DateFormatter {
+  constructor(type: string, opts: WidgetOptions) {
+    const timezone = gutil.removePrefix(type, "DateTime:") || '';
+    opts.timeFormat = opts.timeFormat === undefined ? 'h:mma' : opts.timeFormat;
+    super(type, opts, timezone);
+  }
+}
+
+const formatters: Partial<Record<GristType, typeof BaseFormatter>> = {
+  // for numbers - return javascript number
+  Numeric: NumberFormatter,
+  Int: NumberFormatter,
+  // for booleans - return javascript booleans
+  Bool: BaseFormatter,
+  // for dates - return javascript Date object
+  Date: DateFormatter,
+  DateTime: DateTimeFormatter,
+  ChoiceList: ChoiceListFormatter,
+  // for attachments - return blank cell
+  Attachments: UnsupportedFormatter,
+  // for anything else - return string (use default AnyFormatter)
+};
+
+/**
+ * Takes column type and widget options and returns a constructor with a format function that can
+ * properly convert a value passed to it into the right javascript object for that column.
+ * Exceljs library is using javascript primitives to specify correct excel type.
+ */
+export function createExcelFormatter(type: string, opts: object): BaseFormatter {
+  const ctor = formatters[gristTypes.extractTypeFromColType(type) as GristType] || AnyFormatter;
+  return new ctor(type, opts);
+}
+
+// ----------------------------------------------------------------------
+// Helper functions
+// ----------------------------------------------------------------------
+
+// Mapping from moment-js basic date format tokens to excel numFmt basic tokens.
+// We will convert all our predefined format to excel ones, and try to do our
+// best on converting custom formats. If we fail on custom formats we will fall
+// back to default ones.
+// More on formats can be found:
+// https://docs.microsoft.com/en-us/dotnet/api/documentformat.openxml.spreadsheet.numberingformats?view=openxml-2.8.1
+// http://officeopenxml.com/WPdateTimeFieldSwitches.php
+const mapping = new Map<string, string>();
+mapping.set('YYYY', 'yyyy');
+mapping.set('YY', 'yy');
+mapping.set('M', 'm');
+mapping.set('MM', 'mm');
+mapping.set('MMM', 'mmm');
+mapping.set('MMMM', 'mmmm');
+mapping.set('D', 'd');
+mapping.set('DD', 'dd');
+mapping.set('DDD', 'ddd');
+mapping.set('DDDD', 'dddd');
+mapping.set('Do', 'dd'); // no direct match
+mapping.set('L', 'yyyy-mm-dd');
+mapping.set('LL', 'mmmmm d yyyy');
+mapping.set('LLL', 'mmmmm d yyyy h:mm am/pm');
+mapping.set('LLLL', 'ddd, mmmmm d yyyy h:mm am/pm');
+mapping.set('h', 'h');
+mapping.set('HH', 'hh');
+// Minutes formats are the same as month's ones, but when they are after hour format
+// they are treated as minutes.
+mapping.set('m', 'm');
+mapping.set('mm', 'mm');
+mapping.set('mma', 'mm am/pm');
+mapping.set('ss', 'ss');
+mapping.set('s', 's');
+mapping.set('a', 'am/pm');
+mapping.set('A', 'am/pm');
+mapping.set('S', '0');
+mapping.set('SS', '00');
+mapping.set('SSS', '000');
+mapping.set('SSSS', '0000');
+mapping.set('SSSSS', '00000');
+mapping.set('SSSSSS', '000000');
+// We will omit timezone formats
+mapping.set('z', '');
+mapping.set('zz', '');
+mapping.set('Z', '');
+mapping.set('ZZ', '');
+
+/**
+ * Converts Moment js format string to excel numFormat
+ * @param format Moment js format string
+ * @param def Default excel format string
+ */
+function excelDateFormat(format: string, def: string) {
+  // split format to chunks by common separator
+  const chunks = format.split(/([\s:.,-/]+)/);
+
+  // try to map chunks
+  for (let i = 0; i < chunks.length; i += 2) {
+    const chunk = chunks[i];
+    if (mapping.has(chunk)) {
+      chunks[i] = mapping.get(chunk)!;
+    } else {
+      // fail on first mismatch
+      return def;
+    }
+  }
+  // fix the separators - they need to be prefixed by backslash
+  for (let i = 1; i < chunks.length; i += 2) {
+    const sep = chunks[i];
+    if (sep === '-') {
+      chunks[i] = '\\-';
+    }
+    if (sep.trim() === '') {
+      chunks[i] = '\\' + sep;
+    }
+  }
+
+  return chunks.join('');
+}

app/server/lib/Export.ts

@@ -0,0 +1,299 @@
+import {buildColFilter} from 'app/common/ColumnFilterFunc';
+import {RowRecord} from 'app/common/DocActions';
+import {DocData} from 'app/common/DocData';
+import * as gristTypes from 'app/common/gristTypes';
+import * as gutil from 'app/common/gutil';
+import {buildRowFilter} from 'app/common/RowFilterFunc';
+import {SchemaTypes} from 'app/common/schema';
+import {SortFunc} from 'app/common/SortFunc';
+import {TableData} from 'app/common/TableData';
+import {ActiveDoc} from 'app/server/lib/ActiveDoc';
+import {RequestWithLogin} from 'app/server/lib/Authorizer';
+import {docSessionFromRequest} from 'app/server/lib/DocSession';
+import {ServerColumnGetters} from 'app/server/lib/ServerColumnGetters';
+import * as express from 'express';
+import * as _ from 'underscore';
+
+// Helper type for Cell Accessor
+type Access = (row: number) => any;
+
+// Helper interface with information about the column
+interface ExportColumn {
+  id: number;
+  colId: string;
+  label: string;
+  type: string;
+  widgetOptions: any;
+  parentPos: number;
+}
+// helper for empty column
+const emptyCol: ExportColumn = {
+  id: 0,
+  colId: '',
+  label: '',
+  type: '',
+  widgetOptions: null,
+  parentPos: 0
+};
+/**
+ * Bare data that is exported - used to convert to various formats.
+ */
+export interface ExportData {
+  /**
+   * Table name or table id.
+   */
+  tableName: string;
+  /**
+   * Document name.
+   */
+  docName: string;
+  /**
+   * Row ids (filtered and sorted).
+   */
+  rowIds: number[];
+  /**
+   * Accessor for value in a column.
+   */
+  access: Access[];
+  /**
+   * Columns information (primary used for formatting).
+   */
+  columns: ExportColumn[];
+}
+
+/**
+ * Export parameters that identifies a section, filters, sort order.
+ */
+export interface ExportParameters {
+  tableId: string;
+  viewSectionId: number;
+  sortOrder: number[];
+  filters: Filter[]
+}
+
+/**
+ * Gets export parameters from a request.
+ */
+export function parseExportParameters(req: express.Request): ExportParameters {
+  const tableId = req.query.tableId;
+  const viewSectionId = parseInt(req.query.viewSection, 10);
+  const sortOrder = gutil.safeJsonParse(req.query.activeSortSpec, null) as number[];
+  const filters: Filter[] = gutil.safeJsonParse(req.query.filters, []) || [];
+
+  return {
+    tableId,
+    viewSectionId,
+    sortOrder,
+    filters
+  };
+}
+
+/**
+ * Calculates the file name (without an extension) for exported table.
+ * @param activeDoc ActiveDoc
+ * @param req Request (with export params)
+ */
+export function parseExportFileName(activeDoc: ActiveDoc, req: express.Request) {
+  const title = req.query.title;
+  const tableId = req.query.tableId;
+  const docName = title || activeDoc.docName;
+  const name = docName +
+    (tableId === docName ? '' : '-' + tableId);
+  return name;
+}
+
+// Makes assertion that value does exists or throws an error
+function safe<T>(value: T, msg: string) {
+  if (!value) { throw new Error(msg); }
+  return value as NonNullable<T>;
+}
+
+// Helper to for getting table from docData.
+const safeTable = (docData: DocData, name: keyof SchemaTypes) => safe(docData.getTable(name),
+  `No table '${name}' in document with id ${docData}`);
+
+// Helper for getting record safe
+const safeRecord = (table: TableData, id: number) => safe(table.getRecord(id),
+  `No record ${id} in table ${table.tableId}`);
+
+/**
+ * Builds export for all raw tables that are in doc.
+ * @param activeDoc Active document
+ * @param req Request
+ */
+export async function exportDoc(
+  activeDoc: ActiveDoc,
+  req: express.Request) {
+  const docData = safe(activeDoc.docData, "No docData in active document");
+  const tables = safeTable(docData, '_grist_Tables');
+  // select raw tables
+  const tableIds = tables.filterRowIds({ summarySourceTable: 0 });
+  const tableExports = await Promise.all(
+    tableIds
+      .map(tId => exportTable(activeDoc, tId, req))
+  );
+  return tableExports;
+}
+
+/**
+ * Builds export data for section that can be used to produce files in various formats (csv, xlsx).
+ */
+export async function exportTable(
+  activeDoc: ActiveDoc,
+  tableId: number,
+  req: express.Request): Promise<ExportData> {
+  const docData = safe(activeDoc.docData, "No docData in active document");
+  const tables = safeTable(docData, '_grist_Tables');
+  const table = safeRecord(tables, tableId) as GristTables;
+  const tableColumns = (safeTable(docData, '_grist_Tables_column')
+    .getRecords() as GristTablesColumn[])
+    // remove manual sort column
+    .filter(col => col.colId !== gristTypes.MANUALSORT);
+  // Produce a column description matching what user will see / expect to export
+  const tableColsById = _.indexBy(tableColumns, 'id');
+  const columns = tableColumns.map(tc => {
+    // remove all columns that don't belong to this table
+    if (tc.parentId !== tableId) {
+      return emptyCol;
+    }
+    // remove all helpers
+    if (gristTypes.isHiddenCol(tc.colId)) {
+      return emptyCol;
+    }
+    // for reference columns, return display column, and copy settings from visible column
+    const displayCol = tableColsById[tc.displayCol || tc.id];
+    const colOptions = gutil.safeJsonParse(tc.widgetOptions, {});
+    const displayOptions = gutil.safeJsonParse(displayCol.widgetOptions, {});
+    const widgetOptions = Object.assign(displayOptions, colOptions);
+    return {
+      id: displayCol.id,
+      colId: displayCol.colId,
+      label: tc.label,
+      type: displayCol.type,
+      widgetOptions,
+      parentPos: tc.parentPos
+    };
+  }).filter(tc => tc !== emptyCol);
+
+  // fetch actual data
+  const data = await activeDoc.fetchTable(docSessionFromRequest(req as RequestWithLogin), table.tableId, true);
+  const rowIds = data[2];
+  const dataByColId = data[3];
+  // sort rows
+  const getters = new ServerColumnGetters(rowIds, dataByColId, columns);
+  // create cell accessors
+  const access = columns.map(col => getters.getColGetter(col.id)!);
+
+  let tableName = table.tableId;
+  // since tables ids are not very friendly, borrow name from a primary view
+  if (table.primaryViewId) {
+    const viewId = table.primaryViewId;
+    const views = safeTable(docData, '_grist_Views');
+    const view = safeRecord(views, viewId) as GristView;
+    tableName = view.name;
+  }
+
+  return {
+    tableName,
+    docName: activeDoc.docName,
+    rowIds,
+    access,
+    columns
+  };
+}
+
+/**
+ * Builds export data for section that can be used to produce files in various formats (csv, xlsx).
+ */
+export async function exportSection(
+  activeDoc: ActiveDoc,
+  viewSectionId: number,
+  sortOrder: number[] | null,
+  filters: Filter[] | null,
+  req: express.Request): Promise<ExportData> {
+
+  const docData = safe(activeDoc.docData, "No docData in active document");
+  const viewSections = safeTable(docData, '_grist_Views_section');
+  const viewSection = safeRecord(viewSections, viewSectionId) as GristViewsSection;
+  const tables = safeTable(docData, '_grist_Tables');
+  const table = safeRecord(tables, viewSection.tableRef) as GristTables;
+  const columns = safeTable(docData, '_grist_Tables_column')
+    .filterRecords({ parentId: table.id }) as GristTablesColumn[];
+  const viewSectionFields = safeTable(docData, '_grist_Views_section_field');
+  const fields = viewSectionFields.filterRecords({ parentId: viewSection.id }) as GristViewsSectionField[];
+
+  const tableColsById = _.indexBy(columns, 'id');
+
+  // Produce a column description matching what user will see / expect to export
+  const viewify = (col: GristTablesColumn, field: GristViewsSectionField) => {
+    field = field || {};
+    const displayCol = tableColsById[field.displayCol || col.displayCol || col.id];
+    const colWidgetOptions = gutil.safeJsonParse(col.widgetOptions, {});
+    const fieldWidgetOptions = gutil.safeJsonParse(field.widgetOptions, {});
+    const filterString = (filters || []).find(x => x.colRef === field.colRef)?.filter || field.filter;
+    const filterFunc = buildColFilter(filterString, col.type);
+    return {
+      id: displayCol.id,
+      colId: displayCol.colId,
+      label: col.label,
+      type: col.type,
+      parentPos: col.parentPos,
+      filterFunc,
+      widgetOptions: Object.assign(colWidgetOptions, fieldWidgetOptions)
+    };
+  };
+  const viewColumns = _.sortBy(fields, 'parentPos').map(
+    (field) => viewify(tableColsById[field.colRef], field));
+
+  // The columns named in sort order need to now become display columns
+  sortOrder = sortOrder || gutil.safeJsonParse(viewSection.sortColRefs, []);
+  const fieldsByColRef = _.indexBy(fields, 'colRef');
+  sortOrder = sortOrder!.map((directionalColRef) => {
+    const colRef = Math.abs(directionalColRef);
+    const col = tableColsById[colRef];
+    if (!col) {
+      return 0;
+    }
+    const effectiveColRef = viewify(col, fieldsByColRef[colRef]).id;
+    return directionalColRef > 0 ? effectiveColRef : -effectiveColRef;
+  });
+
+  // fetch actual data
+  const data = await activeDoc.fetchTable(docSessionFromRequest(req as RequestWithLogin), table.tableId, true);
+  let rowIds = data[2];
+  const dataByColId = data[3];
+  // sort rows
+  const getters = new ServerColumnGetters(rowIds, dataByColId, columns);
+  const sorter = new SortFunc(getters);
+  sorter.updateSpec(sortOrder);
+  rowIds.sort((a, b) => sorter.compare(a, b));
+  // create cell accessors
+  const access = viewColumns.map(col => getters.getColGetter(col.id)!);
+  // create row filter based on all columns filter
+  const rowFilter = viewColumns
+    .map((col, c) => buildRowFilter(access[c], col.filterFunc))
+    .reduce((prevFilter, curFilter) => (id) => prevFilter(id) && curFilter(id), () => true);
+  // filter rows numbers
+  rowIds = rowIds.filter(rowFilter);
+
+  return {
+    tableName: table.tableId,
+    docName: activeDoc.docName,
+    rowIds,
+    access,
+    columns: viewColumns
+  };
+}
+
+// Type helpers for types used in this export
+type RowModel<TName extends keyof SchemaTypes> = RowRecord & {
+  [ColId in keyof SchemaTypes[TName]]: SchemaTypes[TName][ColId];
+};
+type GristViewsSection = RowModel<'_grist_Views_section'>
+type GristTables = RowModel<'_grist_Tables'>
+type GristViewsSectionField = RowModel<'_grist_Views_section_field'>
+type GristTablesColumn = RowModel<'_grist_Tables_column'>
+type GristView = RowModel<'_grist_Views'>
+
+// Type for filters passed from the client
+export interface Filter { colRef: number, filter: string }

app/server/lib/ExportCSV.ts

@@ -0,0 +1,48 @@
+import {createFormatter} from 'app/common/ValueFormatter';
+import {ActiveDoc} from 'app/server/lib/ActiveDoc';
+import {ExportData, exportSection, Filter} from 'app/server/lib/Export';
+import * as bluebird from 'bluebird';
+import * as csv from 'csv';
+import * as express from 'express';
+
+// promisify csv
+bluebird.promisifyAll(csv);
+
+/**
+ * Returns a csv stream that can be transformed or parsed.  See https://github.com/wdavidw/node-csv
+ * for API details.
+ *
+ * @param {Object} activeDoc - the activeDoc that the table being converted belongs to.
+ * @param {Integer} viewSectionId - id of the viewsection to export.
+ * @param {Integer[]} activeSortOrder (optional) - overriding sort order.
+ * @param {Filter[]} filters (optional) - filters defined from ui.
+ * @return {Promise<string>} Promise for the resulting CSV.
+ */
+export async function makeCSV(
+  activeDoc: ActiveDoc,
+  viewSectionId: number,
+  sortOrder: number[],
+  filters: Filter[],
+  req: express.Request) {
+
+  const data = await exportSection(activeDoc, viewSectionId, sortOrder, filters, req);
+  const file = convertToCsv(data);
+  return file;
+}
+
+function convertToCsv({
+  rowIds,
+  access,
+  columns: viewColumns
+}: ExportData) {
+
+  // create formatters for columns
+  const formatters = viewColumns.map(col => createFormatter(col.type, col.widgetOptions));
+  // Arrange the data into a row-indexed matrix, starting with column headers.
+  const csvMatrix = [viewColumns.map(col => col.label)];
+  // populate all the rows with values as strings
+  rowIds.forEach(row => {
+    csvMatrix.push(access.map((getter, c) => formatters[c].formatAny(getter(row))));
+  });
+  return csv.stringifyAsync(csvMatrix);
+}

app/server/lib/ExportXLSX.ts

@@ -0,0 +1,91 @@
+import {ActiveDoc} from 'app/server/lib/ActiveDoc';
+import {createExcelFormatter} from 'app/server/lib/ExcelFormatter';
+import {ExportData, exportDoc} from 'app/server/lib/Export';
+import {Alignment, Border, Fill, Workbook} from 'exceljs';
+import * as express from 'express';
+
+/**
+ * Creates excel document with all tables from an active Grist document.
+ */
+export async function makeXLSX(
+  activeDoc: ActiveDoc,
+  req: express.Request): Promise<ArrayBuffer> {
+  const content = await exportDoc(activeDoc, req);
+  const data = await convertToExcel(content, req.host === 'localhost');
+  return data;
+}
+
+/**
+ * Converts export data to an excel file.
+ */
+async function convertToExcel(tables: ExportData[], testDates: boolean) {
+  // Create workbook and add single sheet to it.
+  const wb = new Workbook();
+  if (testDates) {
+    // HACK: for testing, we will keep static dates
+    const date = new Date(Date.UTC(2018, 11, 1, 0, 0, 0));
+    wb.modified = date;
+    wb.created = date;
+    wb.lastPrinted = date;
+    wb.creator = 'test';
+    wb.lastModifiedBy = 'test';
+  }
+  // Prepare border - some of the cells can have background colors, in that case border will
+  // not be visible
+  const borderStyle: Border = {
+    color: { argb: 'FFE2E2E3' }, // dark gray - default border color for gdrive
+    style: 'thin'
+  };
+  const borders = {
+    left: borderStyle,
+    right: borderStyle,
+    top: borderStyle,
+    bottom: borderStyle
+  };
+  const headerBackground: Fill = {
+    type: 'pattern',
+    pattern: 'solid',
+    fgColor: { argb: 'FFEEEEEE' } // gray
+  };
+  const headerFontColor = {
+    color: {
+      argb: 'FF000000' // black
+    }
+  };
+  const centerAlignment: Partial<Alignment> = {
+    horizontal: 'center'
+  };
+  for (const table of tables) {
+    const { columns, rowIds, access, tableName } = table;
+    const ws = wb.addWorksheet(tableName);
+    // Build excel formatters.
+    const formatters = columns.map(col => createExcelFormatter(col.type, col.widgetOptions));
+    // Generate headers for all columns with correct styles for whole column.
+    // Actual header style for a first row will be overwritten later.
+    ws.columns = columns.map((col, c) => ({ header: col.label, style: formatters[c].style() }));
+    // Populate excel file with data
+    rowIds.forEach(row => {
+      ws.addRow(access.map((getter, c) => formatters[c].formatAny(getter(row))));
+    });
+    // style up the header row
+    for (let i = 1; i <= columns.length; i++) {
+      // apply to all rows (including header)
+      ws.getColumn(i).border = borders;
+      // apply only to header
+      const header = ws.getCell(1, i);
+      header.fill = headerBackground;
+      header.font = headerFontColor;
+      header.alignment = centerAlignment;
+    }
+    // Make each column a little wider.
+    ws.columns.forEach(column => {
+      if (!column.header) {
+        return;
+      }
+      // 14 points is about 100 pixels in a default font (point is around 7.5 pixels)
+      column.width = column.header.length < 14 ? 14 : column.header.length;
+    });
+  }
+
+  return await wb.xlsx.writeBuffer();
+}

app/server/lib/FlexServer.ts

@@ -45,7 +45,7 @@ import {addPluginEndpoints, limitToPlugins} from 'app/server/lib/PluginEndpoint'
 import {PluginManager} from 'app/server/lib/PluginManager';
 import {adaptServerUrl, addOrgToPath, addPermit, getScope, optStringParam, RequestWithGristInfo, stringParam,
         TEST_HTTPS_OFFSET, trustOrigin} from 'app/server/lib/requestUtils';
-import {ISendAppPageOptions, makeGristConfig, makeSendAppPage} from 'app/server/lib/sendAppPage';
+import {ISendAppPageOptions, makeGristConfig, makeMessagePage, makeSendAppPage} from 'app/server/lib/sendAppPage';
 import {getDatabaseUrl} from 'app/server/lib/serverUtils';
 import {Sessions} from 'app/server/lib/Sessions';
 import * as shutdown from 'app/server/lib/shutdown';
@@ -64,6 +64,7 @@ import {AddressInfo} from 'net';
 import fetch from 'node-fetch';
 import * as path from 'path';
 import * as serveStatic from "serve-static";
+import { addGoogleAuthEndpoint } from "app/server/lib/GoogleAuth";
 
 // Health checks are a little noisy in the logs, so we don't show them all.
 // We show the first N health checks:
@@ -1229,6 +1230,12 @@ export class FlexServer implements GristServer {
     }
   }
 
+  public addGoogleAuthEndpoint() {
+    if (this._check('google-auth')) { return; }
+    const messagePage = makeMessagePage(this, getAppPathTo(this.appRoot, 'static'));
+    addGoogleAuthEndpoint(this.app, messagePage);
+  }
+
   // Adds endpoints that support imports and exports.
   private _addSupportPaths(docAccessMiddleware: express.RequestHandler[]) {
     if (!this._docWorker) { throw new Error("need DocWorker"); }
@@ -1252,6 +1259,10 @@ export class FlexServer implements GristServer {
       return this._docWorker.getCSV(req, res);
     }));
 
+    this.app.get('/gen_xlsx', ...docAccessMiddleware, expressWrap(async (req, res) => {
+      return this._docWorker.getXLSX(req, res);
+    }));
+
     this.app.get('/attachment', ...docAccessMiddleware,
       expressWrap(async (req, res) => this._docWorker.getAttachment(req, res)));
   }

app/server/lib/GoogleAuth.ts

@@ -0,0 +1,170 @@
+import {auth} from '@googleapis/oauth2';
+import {ApiError} from 'app/common/ApiError';
+import {parseSubdomain} from 'app/common/gristUrls';
+import {expressWrap} from 'app/server/lib/expressWrap';
+import * as log from 'app/server/lib/log';
+import * as express from 'express';
+import {URL} from 'url';
+
+/**
+ * Google Auth Endpoint for performing server side authentication. More information can be found
+ * at https://developers.google.com/identity/protocols/oauth2/web-server.
+ *
+ * Environmental variables used:
+ * - GOOGLE_CLIENT_ID :     key obtained from a Google Project, not secret can be shared publicly,
+ *                          the same client id is used in Google Drive Plugin
+ * - GOOGLE_CLIENT_SECRET:  secret key for Google Project, can't be shared - it is used to (d)encrypt
+ *                          data that we obtain from Google Auth Service (all done in the api)
+ *
+ * High level description:
+ *
+ * Each API endpoint that wants to talk to Google Api needs an access_token that identifies our application
+ * and permits us to access some of the user data or work with the API on the user's behalf (examples for that are
+ * Google Drive plugin and Google Export endpoint, [Send to Google Drive] feature on the UI).)
+ * To obtain this token on the server-side, the application needs to redirect the user to a
+ * Google Consent Screen - where the user can log into his account and give consent for the permissions
+ * we need. Permissions are defined by SCOPES - that exactly describes what we are allowed to do.
+ * More on scopes can be read on https://developers.google.com/identity/protocols/oauth2/scopes.
+ * When we are redirecting the user to a Google Consent Screen, we are also sending a static URL for an endpoint
+ * where Google will redirect the user after he gives us permissions or declines our request. For that, we are exposing
+ * static URL http://docs.getgrist.com/auth/google (on prod) or http://localhost:8080/auth/google (dev).
+ *
+ * NOTE: Actually, we are exposing only auth/google endpoint that can be accessed in various ways, including any
+ * subdomain, but Google will always redirect to the configured endpoint (example: http://docs.getgrist.com/auth/google)
+ *
+ * This endpoint will render a simple page (see /static/message.html) that will immediately post
+ * a message to the parent window with a response from Google in the form of { code? : string, error?: string }.
+ * Code returned from Google will be an encrypted access_token that the client-side code should use to invoke
+ * the server-side API endpoint that wishes to call one of the Google API endpoints. A server-side endpoint can use
+ * "googleAuthTokenMiddleware" middleware to convert code to access_token (by making a separate call to Google
+ * for exchanging code for an access_token).
+ * This access_token could be stored in the user's session for further use, but since we are making only a single call
+ * very rarely, and access_token will expire eventually; it is better to acquire access_token every time.
+ * More on storing access_token offline can be read on:
+ * https://developers.google.com/identity/protocols/oauth2/web-server#obtainingaccesstokens
+ *
+ * How to use:
+ *
+ * To call server-side endpoint that expects access_token, first decorate it with "googleAuthTokenMiddleware"
+ * middleware, then perform "server-side" authentication with Google on the client-side to acquire an encrypted token.
+ * Client code should open up a popup window with an URL to Grist's Google Auth endpoint (/auth/google) and wait
+ * for a message from a popup window containing an encrypted token.
+ * Having encrypted token ("code"), a client can call the server-side endpoint by adding to the query string the code
+ * acquired from the popup window. Server endpoint (decorated by "googleAuthTokenMiddleware") will get access_token
+ * in a query string.
+ */
+
+
+// Path for the auth endpoint.
+const authHandlerPath = "/auth/google";
+
+// "View and manage Google Drive files and folders that you have opened or created with this app.""
+export const DRIVE_SCOPE = 'https://www.googleapis.com/auth/drive.file';
+
+// Redirect host after the Google Auth login form is completed. This reuses the same domain name
+// as for Cognito login.
+const AUTH_SUBDOMAIN = process.env.GRIST_ID_PREFIX ? `docs-${process.env.GRIST_ID_PREFIX}` : 'docs';
+
+/**
+ * Return a full url for Google Auth handler. Examples are:
+ *
+ * http://localhost:8080/auth/google in dev
+ * https://docs-s.getgrist.com in staging
+ * https://docs.getgrist.com in prod
+ */
+function getFullAuthEndpointUrl(): string {
+  const homeUrl = process.env.APP_HOME_URL;
+  // if homeUrl is localhost - (in dev environment) - use the development url
+  if (homeUrl && new URL(homeUrl).hostname === "localhost") {
+    return `${homeUrl}${authHandlerPath}`;
+  }
+  const homeBaseDomain = homeUrl && parseSubdomain(new URL(homeUrl).host).base;
+  const baseDomain = homeBaseDomain || '.getgrist.com';
+  return `https://${AUTH_SUBDOMAIN}${baseDomain}${authHandlerPath}`;
+}
+
+/**
+ * Middleware for obtaining access_token from Google Auth Service.
+ * It expects code query parameter (provided by frontend code) add adds to access_token to query parameters.
+ */
+export async function googleAuthTokenMiddleware(
+  req: express.Request,
+  res: express.Response,
+  next: express.NextFunction) {
+  // If access token is in place, proceed
+  if (!req.query.code) {
+    throw new ApiError("Google Auth endpoint requires a code parameter in the query string", 400);
+  } else {
+    try {
+      const oAuth2Client = _googleAuthClient();
+      // Decrypt code that was send back from Google Auth service. Uses GOOGLE_CLIENT_SECRET key.
+      const tokenResponse = await oAuth2Client.getToken(req.query.code);
+      // Get the access token (access token will be present in a default request configuration).
+      const access_token = tokenResponse.tokens.access_token!;
+      req.query.access_token = access_token;
+      next();
+    } catch (err) {
+      log.error("GoogleAuth - Error", err);
+      throw err;
+    }
+  }
+}
+
+/**
+ * Adds a static Google Auth endpoint. This will be used by Google Auth Service to redirect back, after the user
+ * finishes a signing and a consent flow. Google will pass 2 arguments in a query string:
+ * - code: encrypted access token when user gave permissions
+ * - error: error code when user declined our request.
+ */
+export function addGoogleAuthEndpoint(
+  expressApp: express.Application,
+  messagePage: (req: express.Request, res: express.Response, message: any) => any
+) {
+  if (!process.env.GOOGLE_CLIENT_SECRET) {
+    log.error("Failed to create GoogleAuth endpoint: GOOGLE_CLIENT_SECRET is not defined");
+    expressApp.get(authHandlerPath, expressWrap(async (req: express.Request, res: express.Response) => {
+      throw new Error("Send to Google Drive is not configured.");
+    }));
+    return;
+  }
+  log.info(`GoogleAuth - auth handler at ${getFullAuthEndpointUrl()}`);
+
+  expressApp.get(authHandlerPath, expressWrap(async (req: express.Request, res: express.Response) => {
+    // Test if the code is in a query string. Google sends it back after user has given a concent for
+    // our request. It is encrypted (with CLIENT_SECRET) and signed with redirect url.
+    if (req.query.code) {
+      log.debug("GoogleAuth - response from Google with valid code");
+      messagePage(req, res, { code: req.query.code });
+    } else if (req.query.error) {
+      log.debug("GoogleAuth - response from Google with error code", req.query.error);
+      if (req.query.error === "access_denied") {
+        messagePage(req, res, { error: req.query.error });
+      } else {
+        // This should not happen, either code or error is a mandatory query parameter.
+        throw new ApiError("Error authenticating with Google", 500);
+      }
+    } else {
+      const oAuth2Client = _googleAuthClient();
+      const scope = req.query.scope || DRIVE_SCOPE;
+      const authUrl = oAuth2Client.generateAuthUrl({
+        scope,
+        prompt: 'select_account'
+      });
+      log.debug(`GoogleAuth - redirecting to Google consent screen`, {
+        authUrl,
+        scope
+      });
+      res.redirect(authUrl);
+    }
+  }));
+}
+
+/**
+ * Builds the OAuth2 Google client.
+ */
+function _googleAuthClient() {
+  const CLIENT_ID = process.env.GOOGLE_CLIENT_ID;
+  const CLIENT_SECRET = process.env.GOOGLE_CLIENT_SECRET;
+  const oAuth2Client = new auth.OAuth2(CLIENT_ID, CLIENT_SECRET, getFullAuthEndpointUrl());
+  return oAuth2Client;
+}

app/server/lib/GoogleExport.ts

@@ -0,0 +1,83 @@
+import {drive} from '@googleapis/drive';
+import {ActiveDoc} from 'app/server/lib/ActiveDoc';
+import {RequestWithLogin} from 'app/server/lib/Authorizer';
+import {makeXLSX} from 'app/server/lib/ExportXLSX';
+import * as log from 'app/server/lib/log';
+import {Request, Response} from 'express';
+import {PassThrough} from 'stream';
+
+/**
+ * Endpoint logic for sending grist document to Google Drive. Grist document is first exported as an
+ * excel file and then pushed to Google Drive as a Google Spreadsheet.
+ */
+export async function exportToDrive(
+  activeDoc: ActiveDoc,
+  req: Request,
+  res: Response
+) {
+  // Token should come from auth middleware
+  const access_token = req.query.access_token;
+  if (!access_token) {
+    throw new Error("No access token - Can't send file to Google Drive");
+  }
+
+  const meta = {
+    docId : activeDoc.docName,
+    userId : (req as RequestWithLogin).userId
+  };
+  // Prepare file for exporting.
+  log.debug(`Export to drive - Preparing file for export`, meta);
+  const { name, data } = await prepareFile(activeDoc, req);
+  try {
+    // Send file to GDrive and get the url for a preview.
+    const url = await sendFileToDrive(name, data, access_token);
+    log.debug(`Export to drive - File exported, redirecting to Google Spreadsheet ${url}`, meta);
+    res.json({ url });
+  } catch (err) {
+    log.error("Export to drive - Error while sending file to GDrive", meta, err);
+    // Test if google returned a valid error message.
+    if (err.errors && err.errors.length) {
+      throw new Error(err.errors[0].message);
+    } else {
+      throw err;
+    }
+  }
+}
+
+// Creates spreadsheet file in a Google drive, by sending an excel and requesting for conversion.
+async function sendFileToDrive(fileNameNoExt: string, data: ArrayBuffer, oauth_token: string): Promise<string> {
+  // Here we are asking google drive to convert excel file to a google spreadsheet
+  const requestBody = {
+    // name of the spreadsheet to create
+    name: fileNameNoExt,
+    // mime type of the google spreadsheet
+    mimeType: 'application/vnd.google-apps.spreadsheet'
+  };
+  // wrap buffer into a stream
+  const stream = new PassThrough();
+  stream.end(data);
+  // Define what gets send - excel file
+  const media = {
+    mimeType: 'application/vnd.ms-excel',
+    body: stream
+  };
+  const googleDrive = drive("v3");
+  const fileRes = await googleDrive.files.create({
+    requestBody, // what to do with file - convert to spreadsheet
+    oauth_token, // access token
+    media, // file
+    fields: "webViewLink" // return webViewLink after creating file
+  });
+  const url = fileRes.data.webViewLink;
+  if (!url) {
+    throw new Error("Google Api has not returned valid response");
+  }
+  return url;
+}
+
+// Makes excel file the same way as export to excel works.
+async function prepareFile(doc: ActiveDoc, req: Request) {
+  const data = await makeXLSX(doc, req);
+  const name = (req.query.title || doc.docName);
+  return { name, data };
+}

app/server/lib/sendAppPage.ts

@@ -46,6 +46,22 @@ export function makeGristConfig(homeUrl: string|null, extra: Partial<GristLoadCo
   };
 }
 
+/**
+ * Creates a method that will send html page that will immediately post a message to a parent window.
+ * Primary used for Google Auth Grist's endpoint, but can be used in future in any other server side
+ * authentication flow.
+ */
+export function makeMessagePage(server: GristServer, staticDir: string) {
+  return async (req: express.Request, resp: express.Response, message: any) => {
+    const config = server.getGristConfig();
+    const fileContent = await fse.readFile(path.join(staticDir, "message.html"), 'utf8');
+    const content = fileContent
+      .replace("<!-- INSERT CONFIG -->", `<script>window.gristConfig = ${JSON.stringify(config)};</script>`)
+      .replace("<!-- INSERT MESSAGE -->", `<script>window.message = ${JSON.stringify(message)};</script>`);
+    resp.status(200).type('html').send(content);
+  };
+}
+
 /**
  * Send a simple template page, read from file at pagePath (relative to static/), with certain
  * placeholders replaced.

app/server/mergedServerMain.ts

@@ -121,6 +121,7 @@ export async function main(port: number, serverTypes: ServerType[],
     server.addBillingPages();
     server.addWelcomePaths();
     server.addLogEndpoint();
+    server.addGoogleAuthEndpoint();
   }
 
   if (includeDocs) {

app/server/serverMethods.ts

@@ -1,54 +1,34 @@
-import * as gutil from 'app/common/gutil';
-import { SortFunc } from "app/common/SortFunc";
-import { docSessionFromRequest } from "app/server/lib/DocSession";
-import * as bluebird from "bluebird";
-import * as contentDisposition from "content-disposition";
-import * as csv from "csv";
-import * as log from "./lib/log";
-import { ServerColumnGetters } from "./lib/ServerColumnGetters";
-import * as _ from "underscore";
-import * as express from "express";
 import * as Comm from 'app/server/lib/Comm';
-import { ActiveDoc } from "app/server/lib/ActiveDoc";
-import { createFormatter } from "app/common/ValueFormatter";
-import { SchemaTypes } from "app/common/schema";
-import { RequestWithLogin } from "app/server/lib/Authorizer";
-import { RowRecord } from "app/common/DocActions";
-import { buildColFilter } from "app/common/ColumnFilterFunc";
-import { buildRowFilter } from "app/common/RowFilterFunc";
-
-// promisify csv
-bluebird.promisifyAll(csv);
+import {parseExportFileName, parseExportParameters} from 'app/server/lib/Export';
+import {makeCSV} from 'app/server/lib/ExportCSV';
+import {makeXLSX} from 'app/server/lib/ExportXLSX';
+import * as log from 'app/server/lib/log';
+import * as contentDisposition from 'content-disposition';
+import * as express from 'express';
 
 export async function generateCSV(req: express.Request, res: express.Response, comm: Comm) {
-
   log.info('Generating .csv file...');
-  // Get the current table id
-  const tableId = req.param('tableId');
-  const viewSectionId = parseInt(req.param('viewSection'), 10);
-  const activeSortOrder = gutil.safeJsonParse(req.param('activeSortSpec'), null);
-  const filters: Filter[] = gutil.safeJsonParse(req.param("filters"), []) || [];
+  const {
+    viewSectionId,
+    filters,
+    sortOrder
+  } = parseExportParameters(req);
 
-  // Get the active doc
-  const clientId = req.param('clientId');
-  const docFD = parseInt(req.param('docFD'), 10);
+  const clientId = req.query.clientId;
+  const docFD = parseInt(req.query.docFD, 10);
   const client = comm.getClient(clientId);
   const docSession = client.getDocSession(docFD);
   const activeDoc = docSession.activeDoc;
 
   // Generate a decent name for the exported file.
-  const docName = req.query.title || activeDoc.docName;
-  const name = docName +
-    (tableId === docName ? '' : '-' + tableId) + '.csv';
-
+  const name = parseExportFileName(activeDoc, req);
   try {
-    const data = await makeCSV(activeDoc, viewSectionId, activeSortOrder, filters, req);
+    const data = await makeCSV(activeDoc, viewSectionId, sortOrder, filters, req);
     res.set('Content-Type', 'text/csv');
-    res.setHeader('Content-Disposition', contentDisposition(name));
+    res.setHeader('Content-Disposition', contentDisposition(name + '.csv'));
     res.send(data);
   } catch (err) {
     log.error("Exporting to CSV has failed. Request url: %s", req.url, err);
-    // send a generic information to client
     const errHtml =
       `<!doctype html>
 <html>
@@ -59,151 +39,28 @@ export async function generateCSV(req: express.Request, res: express.Response, c
   }
 }
 
-/**
- * Returns a csv stream that can be transformed or parsed.  See https://github.com/wdavidw/node-csv
- * for API details.
- *
- * @param {Object} activeDoc - the activeDoc that the table being converted belongs to.
- * @param {Integer} viewSectionId - id of the viewsection to export.
- * @param {Integer[]} activeSortOrder (optional) - overriding sort order.
- * @return {Promise<string>} Promise for the resulting CSV.
- */
-export async function makeCSV(
-  activeDoc: ActiveDoc,
-  viewSectionId: number,
-  sortOrder: number[],
-  filters: Filter[],
-  req: express.Request) {
-
-  const {
-    table,
-    viewSection,
-    tableColumns,
-    fields
-  } = explodeSafe(activeDoc, viewSectionId);
-
-  const tableColsById = _.indexBy(tableColumns, 'id');
-
-  // Produce a column description matching what user will see / expect to export
-  const viewify = (col: GristTablesColumn, field: GristViewsSectionField) => {
-    field = field || {};
-    const displayCol = tableColsById[field.displayCol || col.displayCol || col.id];
-    const colWidgetOptions = gutil.safeJsonParse(col.widgetOptions, {});
-    const fieldWidgetOptions = gutil.safeJsonParse(field.widgetOptions, {});
-    const filterFunc = buildColFilter(filters.find(x => x.colRef === field.colRef)?.filter, col.type);
-    return {
-      id: displayCol.id,
-      colId: displayCol.colId,
-      label: col.label,
-      colType: col.type,
-      filterFunc,
-      widgetOptions: Object.assign(colWidgetOptions, fieldWidgetOptions)
-    };
-  };
-  const viewColumns = _.sortBy(fields, 'parentPos').map(
-    (field) => viewify(tableColsById[field.colRef], field));
-
-  // The columns named in sort order need to now become display columns
-  sortOrder = sortOrder || gutil.safeJsonParse(viewSection.sortColRefs, []);
-  const fieldsByColRef = _.indexBy(fields, 'colRef');
-  sortOrder = sortOrder.map((directionalColRef) => {
-    const colRef = Math.abs(directionalColRef);
-    const col = tableColsById[colRef];
-    if (!col) {
-      return 0;
-    }
-    const effectiveColRef = viewify(col, fieldsByColRef[colRef]).id;
-    return directionalColRef > 0 ? effectiveColRef : -effectiveColRef;
-  });
-
-  const data = await activeDoc.fetchTable(docSessionFromRequest(req as RequestWithLogin), table.tableId, true);
-  const rowIds = data[2];
-  const dataByColId = data[3];
-  const getters = new ServerColumnGetters(rowIds, dataByColId, tableColumns);
-  const sorter = new SortFunc(getters);
-  sorter.updateSpec(sortOrder);
-  rowIds.sort((a, b) => sorter.compare(a, b));
-  const formatters = viewColumns.map(col =>
-    createFormatter(col.colType, col.widgetOptions));
-  // Arrange the data into a row-indexed matrix, starting with column headers.
-  const csvMatrix = [viewColumns.map(col => col.label)];
-  const access = viewColumns.map(col => getters.getColGetter(col.id));
-  // create row filter based on all columns filter
-  const rowFilter = viewColumns
-    .map((col, c) => buildRowFilter(access[c], col.filterFunc))
-    .reduce((prevFilter, curFilter) => (id) => prevFilter(id) && curFilter(id), () => true);
-  rowIds.forEach(row => {
-    if (!rowFilter(row)) {
-      return;
-    }
-    csvMatrix.push(access.map((getter, c) => formatters[c].formatAny(getter!(row))));
-  });
-
-  return csv.stringifyAsync(csvMatrix);
+export async function generateXLSX(req: express.Request, res: express.Response, comm: Comm) {
+  log.debug(`Generating .xlsx file`);
+  const clientId = req.query.clientId;
+  const docFD = parseInt(req.query.docFD, 10);
+  const client = comm.getClient(clientId);
+  const docSession = client.getDocSession(docFD);
+  const activeDoc = docSession.activeDoc;
+  try {
+    const data = await makeXLSX(activeDoc, req);
+    res.set('Content-Type', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
+    res.setHeader('Content-Disposition', contentDisposition((req.query.title || activeDoc.docName) + '.xlsx'));
+    res.send(data);
+    log.debug('XLSX file generated');
+  } catch (err) {
+    log.error("Exporting to XLSX has failed. Request url: %s", req.url, err);
+    // send a generic information to client
+    const errHtml =
+      `<!doctype html>
+<html>
+  <body>There was an unexpected error while generating a xlsx file.</body>
+</html>
+`;
+    res.status(400).send(errHtml);
+  }
 }
-
-
-// helper method that retrieves various parts about view section
-// from ActiveDoc
-function explodeSafe(activeDoc: ActiveDoc, viewSectionId: number) {
-  const docData = activeDoc.docData;
-
-  if (!docData) {
-    // Should not happen unless there's a logic error
-    // This method is exported (for testing) so it is possible
-    // to call it without loading active doc first
-    throw new Error("Document hasn't been loaded yet");
-  }
-
-  const viewSection = docData
-    .getTable('_grist_Views_section')
-    ?.getRecord(viewSectionId) as GristViewsSection | undefined;
-
-  if (!viewSection) {
-    throw new Error(`No table '_grist_Views_section' in document with id ${activeDoc.docName}`);
-  }
-
-  const table = docData
-    .getTable('_grist_Tables')
-    ?.getRecord(viewSection.tableRef) as GristTables | undefined;
-
-  if (!table) {
-    throw new Error(`No table '_grist_Tables' in document with id ${activeDoc.docName}`);
-  }
-
-  const fields = docData
-    .getTable('_grist_Views_section_field')
-    ?.filterRecords({ parentId: viewSection.id }) as GristViewsSectionField[] | undefined;
-
-  if (!fields) {
-    throw new Error(`No table '_grist_Views_section_field' in document with id ${activeDoc.docName}`);
-  }
-
-  const tableColumns = docData
-    .getTable('_grist_Tables_column')
-    ?.filterRecords({ parentId: table.id }) as GristTablesColumn[] | undefined;
-
-  if (!tableColumns) {
-    throw new Error(`No table '_grist_Tables_column' in document with id ${activeDoc.docName}`);
-  }
-
-  return {
-    table,
-    fields,
-    tableColumns,
-    viewSection
-  };
-}
-
-
-// Type helpers for types used in this export
-type RowModel<TName extends keyof SchemaTypes> = RowRecord & {
-  [ColId in keyof SchemaTypes[TName]]: SchemaTypes[TName][ColId];
-};
-type GristViewsSection = RowModel<'_grist_Views_section'>
-type GristTables = RowModel<'_grist_Tables'>
-type GristViewsSectionField = RowModel<'_grist_Views_section_field'>
-type GristTablesColumn = RowModel<'_grist_Tables_column'>
-
-// Type for filters passed from the client
-interface Filter { colRef: number, filter: string }

package.json

@@ -65,6 +65,8 @@
     "why-is-node-running": "2.0.3"
   },
   "dependencies": {
+    "@googleapis/drive": "0.3.1",
+    "@googleapis/oauth2": "0.2.0",
     "@gristlabs/connect-sqlite3": "0.9.11-grist.1",
     "@gristlabs/express-session": "1.17.0",
     "@gristlabs/pidusage": "2.0.17",
@@ -84,6 +86,7 @@
     "diff-match-patch": "1.0.5",
     "double-ended-queue": "2.1.0-0",
     "electron": "3.0.7",
+    "exceljs": "4.2.1",
     "express": "4.16.4",
     "file-type": "14.1.4",
     "fs-extra": "7.0.0",

static/message.html

@@ -0,0 +1,15 @@
+<!doctype html>
+<html>
+<head>
+  <meta charset="utf8">
+</head>
+<body>
+  <!-- INSERT CONFIG -->
+  <!-- INSERT MESSAGE -->
+  <script>
+    // Determine proper home url for origin parameter
+    const origin = gristConfig.pathOnly ? gristConfig.homeUrl : `https://${gristConfig.org}${gristConfig.baseDomain}`;
+    window.opener.postMessage(message, origin);
+  </script>
+</body>
+</html>