gristlabs_grist-core/app/client/components/WidgetFrame.ts

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import * as BaseView from 'app/client/components/BaseView';
import {GristDoc} from 'app/client/components/GristDoc';
import {get as getBrowserGlobals} from 'app/client/lib/browserGlobals';
import {ColumnRec, ViewSectionRec} from 'app/client/models/DocModel';
import {AccessLevel, isSatisfied} from 'app/common/CustomWidget';
import {DisposableWithEvents} from 'app/common/DisposableWithEvents';
import {BulkColValues, fromTableDataAction, RowRecord} from 'app/common/DocActions';
import {extractInfoFromColType, reencodeAsAny} from 'app/common/gristTypes';
import {CustomSectionAPI, GristDocAPI, GristView,
InteractionOptionsRequest, WidgetAPI, WidgetColumnMap} from 'app/plugin/grist-plugin-api';
import {MsgType, Rpc} from 'grain-rpc';
import {Computed, Disposable, dom, Observable} from 'grainjs';
import noop = require('lodash/noop');
import debounce = require('lodash/debounce');
import isEqual = require('lodash/isEqual');
import flatMap = require('lodash/flatMap');
/**
* This file contains a WidgetFrame and all its components.
*
* WidgetFrame embeds an external Custom Widget (external webpage) in an iframe. It is used on a CustomView,
* to display widget content, and on the configuration screen to display widget's configuration screen.
*
* Beside exposing widget content, it also exposes some of the API's that Grist offers via grist-rpc.
* API are defined in the core/app/plugin/grist-plugin-api.ts.
*/
const G = getBrowserGlobals('window');
/**
* Options for WidgetFrame
*/
export interface WidgetFrameOptions {
/**
* Url of external page. Iframe is rebuild each time the URL changes.
*/
url: string;
/**
* Assigned access level. Iframe is rebuild each time access level is changed.
*/
access: AccessLevel;
/**
* If document is in readonly mode.
*/
readonly: boolean;
/**
* Optional callback to configure exposed API.
*/
configure?: (frame: WidgetFrame) => void;
/**
* Optional handler to modify the iframe.
*/
onElem?: (iframe: HTMLIFrameElement) => void;
}
/**
* Iframe that embeds Custom Widget page and exposes Grist API.
*/
export class WidgetFrame extends DisposableWithEvents {
// A grist-rpc object, encapsulated to prevent direct access.
private _rpc: Rpc;
// Created iframe element, used to receive and post messages via Rpc
private _iframe: HTMLIFrameElement | null;
constructor(private _options: WidgetFrameOptions) {
super();
_options.access = _options.access || AccessLevel.none;
// Build RPC object and connect it to iframe.
this._rpc = new Rpc({});
// Register outgoing message handler.
this._rpc.setSendMessage(msg => this._iframe?.contentWindow!.postMessage(msg, '*'));
// Register incoming message handler.
const listener = this._onMessage.bind(this);
// 'message' is an event's name used by Rpc in window to iframe communication.
G.window.addEventListener('message', listener);
this.onDispose(() => {
// Stop listening for events from the iframe.
G.window.removeEventListener('message', listener);
// Stop sending messages to the iframe.
this._rpc.setSendMessage(noop);
});
// Call custom configuration handler.
_options.configure?.(this);
}
/**
* Attach an EventSource with desired access level.
*/
public useEvents(source: IEventSource, access: AccessChecker) {
// Wrap event handler with access check.
const handler = async (data: any) => {
if (access.check(this._options.access)) {
await this._rpc.postMessage(data);
}
};
this.listenTo(source, 'event', handler);
// Give EventSource a chance to attach to WidgetFrame events.
source.attach(this);
}
/**
* Exposes API for Custom Widget.
* TODO: add ts-interface support. Currently all APIs are written in typescript,
* so those checks are not that needed.
*/
public exposeAPI(name: string, api: any, access: AccessChecker) {
this._rpc.registerImpl(name, wrapObject(api, access, this._options.access));
this.onDispose(() => this._rpc.unregisterImpl(name));
}
/**
* Expose a method for Custom Widget.
*/
public exposeMethod(name: string, handler: (...args: any[]) => any, access: AccessChecker) {
this._rpc.registerFunc(name, (...args: any[]) => {
if (access.check(this._options.access, 'invoke')) {
return handler(...args);
} else {
throwError(this._options.access);
}
});
}
/**
* Make configure call to the widget. Widget should open some configuration screen or ignore it.
*/
public editOptions() {
return this.callRemote('editOptions');
}
/**
* Call remote function that is exposed by the widget.
*/
public callRemote(name: string, ...args: any[]) {
return this._rpc.callRemoteFunc(name, ...args);
}
public buildDom() {
// Append access level to query string.
const urlWithAccess = (url: string) => {
if (!url) {
return url;
}
const urlObj = new URL(url);
urlObj.searchParams.append('access', this._options.access);
urlObj.searchParams.append('readonly', String(this._options.readonly));
return urlObj.href;
};
const fullUrl = urlWithAccess(this._options.url);
const onElem = this._options.onElem ?? ((el: HTMLIFrameElement) => el);
return onElem(
(this._iframe = dom('iframe', dom.cls('clipboard_focus'), dom.cls('custom_view'), {
src: fullUrl,
}))
);
}
private _onMessage(event: MessageEvent) {
if (this._iframe && event.source === this._iframe.contentWindow && !this.isDisposed()) {
// Previously, we forwarded messages targeted at "grist" to the back-end.
// Now, we process them immediately in the context of the client for access
// control purposes. To do that, any message that comes in with mdest of
// "grist" will have that destination wiped, and we provide a local
// implementation of the interface.
// It feels like it should be possible to deal with the mdest more cleanly,
// with a rpc.registerForwarder('grist', { ... }), but it seems somehow hard
// to call a locally registered interface of an rpc object?
if (event.data.mdest === 'grist') {
event.data.mdest = '';
}
if (event.data.mtype === MsgType.Ready) {
this.trigger('ready', this);
}
this._rpc.receiveMessage(event.data);
}
}
}
const throwError = (access: AccessLevel) => {
throw new Error('Access not granted. Current access level ' + access);
};
/**
* Wraps an object to check access level before it is called.
* TODO: grain-rpc exposes callWrapper which could be used for this purpose,
* but currently it doesn't have access to the incoming message.
*/
function wrapObject<T extends object>(impl: T, accessChecker: AccessChecker, access: AccessLevel): T {
return new Proxy(impl, {
// This proxies all the calls to methods on the API.
get(target: any, methodName: string) {
return function () {
if (methodName === 'then') {
// Making a proxy for then invocation is not a good idea.
return undefined;
}
if (accessChecker.check(access, methodName)) {
return target[methodName](...arguments);
} else {
throwError(access);
}
};
},
});
}
/**
* Interface for custom access rules.
*/
export interface AccessChecker {
/**
* Checks if the incoming call can be served on current access level.
* @param access Current access level
* @param method Method called on the interface, can use * or undefined to match all methods.
*/
check(access: AccessLevel, method?: string): boolean;
}
/**
* Checks if current access level is enough.
*/
export class MinimumLevel implements AccessChecker {
constructor(private _minimum: AccessLevel) {}
public check(access: AccessLevel): boolean {
return isSatisfied(access, this._minimum);
}
}
type MethodMatcher<T> = keyof T | '*';
/**
* Helper object that allows assigning access level to a particular method in the interface.
*
* Example:
*
* 1. Expose two methods, all other will be denied (even in full access mode)
* new ApiGranularAccess<GristDocAPI>()
* .require("read_table", "method1") // for method1 we need at least read_table
* .require("none", "method2") // for method2 no access level is needed
*
* 2. Expose two methods, all other will require full access (effectively the same as ex. 1)
* new ApiGranularAccess<GristDocAPI>()
* .require("read_table", "method1") // for method1 we need at least read_table
* .require("none", "method2") // for method2 no access level is needed
* .require("full", "*") // for any other, require full
*
* 3. Expose all methods on read_table access, but one can have none
* new ApiGranularAccess<GristDocAPI>()
* .require("none", "method2") // for method2 we are ok with none access
* .require("read_table", "*") // for any other, require read_table
*/
export class MethodAccess<T> implements AccessChecker {
private _accessMap: Map<MethodMatcher<T>, AccessLevel> = new Map();
constructor() {}
public require(level: AccessLevel, method: MethodMatcher<T> = '*') {
this._accessMap.set(method, level);
return this;
}
public check(access: AccessLevel, method?: string): boolean {
if (!method) {
throw new Error('Method name is required for MethodAccess check');
}
// Check if the iface was registered.
if (this._accessMap.has(method as MethodMatcher<T>)) {
// If it was, check that minimum access level is granted.
const minimum = this._accessMap.get(method as MethodMatcher<T>)!;
return isSatisfied(access, minimum);
} else if (this._accessMap.has('*')) {
// If there is a default rule, check if it permits the access.
const minimum = this._accessMap.get('*')!;
return isSatisfied(access, minimum);
} else {
// By default, don't allow anything on this interface.
return false;
}
}
}
/***********************
* Exposed APIs for Custom Widgets.
*
* Currently we expose 3 APIs
* - GristDocAPI - full access to document.
* - ViewAPI - access to current table.
* - WidgetAPI - access to widget configuration.
***********************/
/**
* GristDocApi implemented over active GristDoc.
*/
export class GristDocAPIImpl implements GristDocAPI {
public static readonly defaultAccess = new MethodAccess<GristDocAPI>()
.require(AccessLevel.read_table, 'getDocName')
.require(AccessLevel.full); // for any other, require full Access.
constructor(private _doc: GristDoc) {}
public async getDocName() {
return this._doc.docId();
}
public async listTables(): Promise<string[]> {
// Could perhaps read tableIds from this.gristDoc.docModel.allTableIds.all()?
const tables = await this._doc.docComm.fetchTable('_grist_Tables');
// Tables the user doesn't have access to are just blanked out.
return tables[3].tableId.filter(tableId => tableId !== '') as string[];
}
public async fetchTable(tableId: string) {
return fromTableDataAction(await this._doc.docComm.fetchTable(tableId));
}
public async applyUserActions(actions: any[][]) {
return this._doc.docComm.applyUserActions(actions, {desc: undefined});
}
}
/**
* GristViewAPI implemented over BaseView.
*/
export class GristViewImpl implements GristView {
constructor(private _baseView: BaseView) {}
public async fetchSelectedTable(): Promise<any> {
// If widget has a custom columns mapping, we will ignore hidden columns section.
// Hidden/Visible columns will eventually reflect what is available, but this operation
// is not instant - and widget can receive rows with fields that are not in the mapping.
const columns: ColumnRec[] = this._visibleColumns();
const rowIds: number[] = this._baseView.sortedRows.getKoArray().peek() as number[];
const data: BulkColValues = {};
for (const column of columns) {
// Use the colId of the displayCol, which may be different in case of Reference columns.
const colId: string = column.displayColModel.peek().colId.peek();
const getter = this._baseView.tableModel.tableData.getRowPropFunc(colId)!;
const typeInfo = extractInfoFromColType(column.type.peek());
data[column.colId.peek()] = rowIds.map(r => reencodeAsAny(getter(r)!, typeInfo));
}
data.id = rowIds;
return data;
}
public async fetchSelectedRecord(rowId: number): Promise<any> {
// Prepare an object containing the fields available to the view
// for the specified row. A RECORD()-generated rendering would be
// more useful. but the data engine needs to know what information
// the custom view depends on, so we shouldn't volunteer any untracked
// information here.
const columns: ColumnRec[] = this._visibleColumns();
const data: RowRecord = {id: rowId};
for (const column of columns) {
const colId: string = column.displayColModel.peek().colId.peek();
const typeInfo = extractInfoFromColType(column.type.peek());
data[column.colId.peek()] = reencodeAsAny(
this._baseView.tableModel.tableData.getValue(rowId, colId)!,
typeInfo
);
}
return data;
}
private _visibleColumns() {
const columns: ColumnRec[] = this._baseView.viewSection.columns.peek();
const hiddenCols = this._baseView.viewSection.hiddenColumns.peek().map(c => c.id.peek());
const mappings = this._baseView.viewSection.mappedColumns.peek();
const mappedColumns = new Set(flatMap(Object.values(mappings || {})));
const notHidden = (col: ColumnRec) => !hiddenCols.includes(col.id.peek());
const mapped = (col: ColumnRec) => mappings && mappedColumns.has(col.colId.peek());
// If columns are mapped, return only those that are mapped.
// Otherwise return all not hidden columns;
return mappings ? columns.filter(mapped) : columns.filter(notHidden);
}
}
/**
* WidgetAPI implemented over active section.
*/
export class WidgetAPIImpl implements WidgetAPI {
constructor(private _section: ViewSectionRec) {}
/**
* Stores options in viewSection.customDef.widgetDef json field.
* This way whenever widget is changed, options are removed and not shared
* between widgets by design.
*/
public async setOptions(options: object): Promise<void> {
if (options === null || options === undefined || typeof options !== 'object') {
throw new Error('options must be a valid JSON object');
}
this._section.activeCustomOptions(options);
}
public async getOptions(): Promise<Record<string, unknown> | null> {
return this._section.activeCustomOptions.peek() ?? null;
}
public async clearOptions(): Promise<void> {
this._section.activeCustomOptions(null);
}
public async setOption(key: string, value: any): Promise<void> {
const options = {...this._section.activeCustomOptions.peek()};
options[key] = value;
this._section.activeCustomOptions(options);
}
public getOption(key: string): Promise<unknown> {
const options = this._section.activeCustomOptions.peek();
return options?.[key];
}
}
/************************
* Events that are sent to the CustomWidget.
*
* Currently:
* - onRecord, implemented by RecordNotifier, sends a message each time active row is changed.
* - onRecords, implemented by TableNotifier, sends a message each time table is changed
* - onOptions, implemented by ConfigNotifier, sends a message each time configuration is changed
*
* All of those events are also sent when CustomWidget sends its ready message.
************************/
/**
* EventSource should trigger event called "event" that will be send to the Custom Widget.
*/
export interface IEventSource extends DisposableWithEvents {
/**
* Called by WidgetFrame, allowing EventSource to attach to its ready event.
*/
attach(frame: WidgetFrame): void;
}
export class BaseEventSource extends DisposableWithEvents implements IEventSource {
// Attaches to WidgetFrame ready event.
public attach(frame: WidgetFrame): void {
this.listenTo(frame, 'ready', this._ready.bind(this));
}
protected _ready() {
// To override if needed to react on the ready event.
}
protected _notify(data: any) {
if (this.isDisposed()) {
return;
}
this.trigger('event', data);
}
}
/**
* Notifies about cursor position change. Exposed in the API as a onRecord handler.
*/
export class RecordNotifier extends BaseEventSource {
private _debounced: () => void; // debounced call to let the view know linked cursor changed.
constructor(private _baseView: BaseView) {
super();
this._debounced = debounce(() => this._update(), 0);
this.autoDispose(_baseView.cursor.rowIndex.subscribe(this._debounced));
}
private _update() {
if (this.isDisposed()) {
return;
}
const state = {
tableId: this._baseView.viewSection.table().tableId(),
rowId: this._baseView.cursor.getCursorPos().rowId || undefined,
dataChange: false,
};
this._notify(state);
}
}
/**
* Notifies about options position change. Exposed in the API as a onOptions handler.
*/
export class ConfigNotifier extends BaseEventSource {
private _currentConfig: Computed<any | null>;
private _debounced: () => void; // debounced call to let the view know linked cursor changed.
constructor(private _section: ViewSectionRec, private _accessLevel: AccessLevel) {
super();
this._currentConfig = Computed.create(this, use => {
const options = use(this._section.activeCustomOptions);
return options;
});
this._debounced = debounce(() => this._update(), 0);
const subscribe = (obs: Observable<any>) => {
this.autoDispose(
obs.addListener((cur, prev) => {
if (isEqual(prev, cur)) {
return;
}
this._debounced();
})
);
};
subscribe(this._currentConfig);
}
protected _ready() {
// On ready, send initial configuration.
this._debounced();
}
private _update() {
if (this.isDisposed()) {
return;
}
this._notify({
options: this._currentConfig.get(),
settings: {
accessLevel: this._accessLevel,
},
});
}
}
/**
* Notifies about cursor table data or structure change.
* Exposed in the API as a onRecords handler.
* This Notifier sends an initial event when subscribed
*/
export class TableNotifier extends BaseEventSource {
private _debounced: () => void;
private _updateMapping = true;
constructor(private _baseView: BaseView) {
super();
this._debounced = debounce(() => this._update(), 0);
this.autoDispose(_baseView.viewSection.viewFields().subscribe(this._debounced.bind(this)));
this.listenTo(_baseView.sortedRows, 'rowNotify', this._debounced.bind(this));
this.autoDispose(_baseView.sortedRows.getKoArray().subscribe(this._debounced.bind(this)));
this.autoDispose(_baseView.viewSection.mappedColumns
.subscribe(() => {
this._updateMapping = true;
this._debounced();
})
);
}
protected _ready() {
// On ready, send initial table information.
this._debounced();
}
private _update() {
if (this.isDisposed()) {
return;
}
const state = {
tableId: this._baseView.viewSection.table().tableId(),
rowId: this._baseView.cursor.getCursorPos().rowId || undefined,
dataChange: true,
mappingsChange: this._updateMapping
};
this._updateMapping = false;
this._notify(state);
}
}
export class CustomSectionAPIImpl extends Disposable implements CustomSectionAPI {
constructor(
private _section: ViewSectionRec,
private _currentAccess: AccessLevel,
private _promptCallback: (access: AccessLevel) => void
) {
super();
}
public async mappings(): Promise<WidgetColumnMap|null> {
return this._section.mappedColumns.peek();
}
/**
* Method called as part of ready message. Allows widget to request for particular features or inform about
* capabilities.
*/
public async configure(settings: InteractionOptionsRequest): Promise<void> {
if (settings.hasCustomOptions !== undefined) {
this._section.hasCustomOptions(settings.hasCustomOptions);
}
if (settings.requiredAccess && settings.requiredAccess !== this._currentAccess) {
this._promptCallback(settings.requiredAccess as AccessLevel);
}
if (settings.columns !== undefined) {
this._section.columnsToMap(settings.columns);
} else {
this._section.columnsToMap(null);
}
}
}