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parcer/server/src/workflow-management/selector.ts

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import { Page } from "playwright";
import { Action, ActionType, Coordinates, TagName } from "../types";
import { WhereWhatPair, WorkflowFile } from "maxun-core";
import logger from "../logger";
import { getBestSelectorForAction } from "./utils";
/*TODO:
1. Handle TS errors (here we definetly know better)
2. Add pending function descriptions + thought process (esp. selector generation)
*/
type Workflow = WorkflowFile["workflow"];
/**
* Returns a {@link Rectangle} object representing
* the coordinates, width, height and corner points of the element.
* If an element is not found, returns null.
* @param page The page instance.
* @param coordinates Coordinates of an element.
* @category WorkflowManagement-Selectors
* @returns {Promise<Rectangle|undefined|null>}
*/
export const getElementInformation = async (
page: Page,
coordinates: Coordinates
) => {
try {
const elementInfo = await page.evaluate(
async ({ x, y }) => {
// Find the initial element at the point
const initialElement = document.elementFromPoint(x, y) as HTMLElement;
if (initialElement) {
// Simply use the direct parent, no complex logic
const parentElement = initialElement.parentElement;
// Use the parent if it exists, otherwise use the initial element
const element = parentElement || initialElement;
let info: {
tagName: string;
hasOnlyText?: boolean;
innerText?: string;
url?: string;
imageUrl?: string;
attributes?: Record<string, string>;
innerHTML?: string;
outerHTML?: string;
parentTagName?: string;
parentClasses?: string[];
} = {
tagName: element.tagName,
parentTagName: element.parentElement?.tagName,
parentClasses: element.parentElement
? Array.from(element.parentElement.classList)
: []
};
// Collect attributes
info.attributes = Array.from(element.attributes).reduce(
(acc, attr) => {
acc[attr.name] = attr.value;
return acc;
},
{} as Record<string, string>
);
// Specific handling for different element types
if (element.tagName === 'A') {
const anchorElement = element as HTMLAnchorElement;
info.url = anchorElement.href;
info.innerText = anchorElement.innerText ?? '';
} else if (element.tagName === 'IMG') {
const imgElement = element as HTMLImageElement;
info.imageUrl = imgElement.src;
} else {
// Check if element contains only text
info.hasOnlyText = element.children.length === 0 &&
(element.innerText?.length ?? 0) > 0;
info.innerText = element.innerText ?? '';
}
// HTML content
info.innerHTML = element.innerHTML;
info.outerHTML = element.outerHTML;
return info;
}
return null;
},
{ x: coordinates.x, y: coordinates.y },
);
return elementInfo;
} catch (error) {
const { message, stack } = error as Error;
console.error('Error while retrieving selector:', message);
console.error('Stack:', stack);
}
};
export const getRect = async (page: Page, coordinates: Coordinates) => {
try {
const rect = await page.evaluate(
async ({ x, y }) => {
// Find the initial element at the point
const initialElement = document.elementFromPoint(x, y) as HTMLElement;
if (initialElement) {
// Simply use the direct parent, no complex logic
const parentElement = initialElement.parentElement;
// Use the parent if it exists, otherwise use the initial element
const element = parentElement || initialElement;
// Get bounding rectangle
const rectangle = element?.getBoundingClientRect();
if (rectangle) {
return {
x: rectangle.x,
y: rectangle.y,
width: rectangle.width,
height: rectangle.height,
top: rectangle.top,
right: rectangle.right,
bottom: rectangle.bottom,
left: rectangle.left,
};
}
}
},
{ x: coordinates.x, y: coordinates.y },
);
return rect;
} catch (error) {
const { message, stack } = error as Error;
console.error('Error while retrieving selector:', message);
console.error('Stack:', stack);
}
};
/**
* Returns the best and unique css {@link Selectors} for the element on the page.
* Internally uses a finder function from https://github.com/antonmedv/finder/blob/master/finder.ts
* available as a npm package: @medv/finder
*
* The finder needs to be executed and defined inside a browser context. Meaning,
* the code needs to be available inside a page evaluate function.
* @param page The page instance.
* @param coordinates Coordinates of an element.
* @category WorkflowManagement-Selectors
* @returns {Promise<Selectors|null|undefined>}
*/
export const getSelectors = async (page: Page, coordinates: Coordinates) => {
try {
const selectors: any = await page.evaluate(async ({ x, y }) => {
// version @medv/finder
// https://github.com/antonmedv/finder/blob/master/finder.ts
type Node = {
name: string;
penalty: number;
level?: number;
};
type Path = Node[];
enum Limit {
All,
Two,
One,
}
type Options = {
root: Element;
idName: (name: string) => boolean;
className: (name: string) => boolean;
tagName: (name: string) => boolean;
attr: (name: string, value: string) => boolean;
seedMinLength: number;
optimizedMinLength: number;
threshold: number;
maxNumberOfTries: number;
};
let config: Options;
let rootDocument: Document | Element;
function finder(input: Element, options?: Partial<Options>) {
if (input.nodeType !== Node.ELEMENT_NODE) {
throw new Error(`Can't generate CSS selector for non-element node type.`);
}
if ('html' === input.tagName.toLowerCase()) {
return 'html';
}
const defaults: Options = {
root: document.body,
idName: (name: string) => true,
className: (name: string) => true,
tagName: (name: string) => true,
attr: (name: string, value: string) => false,
seedMinLength: 1,
optimizedMinLength: 2,
threshold: 900,
maxNumberOfTries: 9000,
};
config = { ...defaults, ...options };
rootDocument = findRootDocument(config.root, defaults);
let path = bottomUpSearch(input, Limit.All, () =>
bottomUpSearch(input, Limit.Two, () => bottomUpSearch(input, Limit.One))
);
if (path) {
const optimized = sort(optimize(path, input));
if (optimized.length > 0) {
path = optimized[0];
}
return selector(path);
} else {
throw new Error(`Selector was not found.`);
}
}
function findRootDocument(rootNode: Element | Document, defaults: Options) {
if (rootNode.nodeType === Node.DOCUMENT_NODE) {
return rootNode;
}
if (rootNode === defaults.root) {
return rootNode.ownerDocument as Document;
}
return rootNode;
}
function bottomUpSearch(
input: Element,
limit: Limit,
fallback?: () => Path | null
): Path | null {
let path: Path | null = null;
let stack: Node[][] = [];
let current: Element | null = input;
let i = 0;
while (current && current !== config.root.parentElement) {
let level: Node[] = maybe(id(current)) ||
maybe(...attr(current)) ||
maybe(...classNames(current)) ||
maybe(tagName(current)) || [any()];
const nth = index(current);
if (limit === Limit.All) {
if (nth) {
level = level.concat(
level.filter(dispensableNth).map((node) => nthChild(node, nth))
);
}
} else if (limit === Limit.Two) {
level = level.slice(0, 1);
if (nth) {
level = level.concat(
level.filter(dispensableNth).map((node) => nthChild(node, nth))
);
}
} else if (limit === Limit.One) {
const [node] = (level = level.slice(0, 1));
if (nth && dispensableNth(node)) {
level = [nthChild(node, nth)];
}
}
for (let node of level) {
node.level = i;
}
stack.push(level);
if (stack.length >= config.seedMinLength) {
path = findUniquePath(stack, fallback);
if (path) {
break;
}
}
current = current.parentElement;
i++;
}
if (!path) {
path = findUniquePath(stack, fallback);
}
return path;
}
function findUniquePath(
stack: Node[][],
fallback?: () => Path | null
): Path | null {
const paths = sort(combinations(stack));
if (paths.length > config.threshold) {
return fallback ? fallback() : null;
}
for (let candidate of paths) {
if (unique(candidate)) {
return candidate;
}
}
return null;
}
function selector(path: Path): string {
let node = path[0];
let query = node.name;
for (let i = 1; i < path.length; i++) {
const level = path[i].level || 0;
if (node.level === level - 1) {
query = `${path[i].name} > ${query}`;
} else {
query = `${path[i].name} ${query}`;
}
node = path[i];
}
return query;
}
function penalty(path: Path): number {
return path.map((node) => node.penalty).reduce((acc, i) => acc + i, 0);
}
function unique(path: Path) {
switch (rootDocument.querySelectorAll(selector(path)).length) {
case 0:
throw new Error(
`Can't select any node with this selector: ${selector(path)}`
);
case 1:
return true;
default:
return false;
}
}
function id(input: Element): Node | null {
const elementId = input.getAttribute('id');
if (elementId && config.idName(elementId)) {
return {
name: '#' + cssesc(elementId, { isIdentifier: true }),
penalty: 0,
};
}
return null;
}
function attr(input: Element): Node[] {
const attrs = Array.from(input.attributes).filter((attr) =>
config.attr(attr.name, attr.value)
);
return attrs.map(
(attr): Node => ({
name:
'[' +
cssesc(attr.name, { isIdentifier: true }) +
'="' +
cssesc(attr.value) +
'"]',
penalty: 0.5,
})
);
}
function classNames(input: Element): Node[] {
const names = Array.from(input.classList).filter(config.className);
return names.map(
(name): Node => ({
name: '.' + cssesc(name, { isIdentifier: true }),
penalty: 1,
})
);
}
function tagName(input: Element): Node | null {
const name = input.tagName.toLowerCase();
if (config.tagName(name)) {
return {
name,
penalty: 2,
};
}
return null;
}
function any(): Node {
return {
name: '*',
penalty: 3,
};
}
function index(input: Element): number | null {
const parent = input.parentNode;
if (!parent) {
return null;
}
let child = parent.firstChild;
if (!child) {
return null;
}
let i = 0;
while (child) {
if (child.nodeType === Node.ELEMENT_NODE) {
i++;
}
if (child === input) {
break;
}
child = child.nextSibling;
}
return i;
}
function nthChild(node: Node, i: number): Node {
return {
name: node.name + `:nth-child(${i})`,
penalty: node.penalty + 1,
};
}
function dispensableNth(node: Node) {
return node.name !== 'html' && !node.name.startsWith('#');
}
function maybe(...level: (Node | null)[]): Node[] | null {
const list = level.filter(notEmpty);
if (list.length > 0) {
return list;
}
return null;
}
function notEmpty<T>(value: T | null | undefined): value is T {
return value !== null && value !== undefined;
}
function* combinations(stack: Node[][], path: Node[] = []): Generator<Node[]> {
if (stack.length > 0) {
for (let node of stack[0]) {
yield* combinations(stack.slice(1, stack.length), path.concat(node));
}
} else {
yield path;
}
}
function sort(paths: Iterable<Path>): Path[] {
return Array.from(paths).sort((a, b) => penalty(a) - penalty(b));
}
type Scope = {
counter: number;
visited: Map<string, boolean>;
};
function* optimize(
path: Path,
input: Element,
scope: Scope = {
counter: 0,
visited: new Map<string, boolean>(),
}
): Generator<Node[]> {
if (path.length > 2 && path.length > config.optimizedMinLength) {
for (let i = 1; i < path.length - 1; i++) {
if (scope.counter > config.maxNumberOfTries) {
return; // Okay At least I tried!
}
scope.counter += 1;
const newPath = [...path];
newPath.splice(i, 1);
const newPathKey = selector(newPath);
if (scope.visited.has(newPathKey)) {
return;
}
if (unique(newPath) && same(newPath, input)) {
yield newPath;
scope.visited.set(newPathKey, true);
yield* optimize(newPath, input, scope);
}
}
}
}
function same(path: Path, input: Element) {
return rootDocument.querySelector(selector(path)) === input;
}
const regexAnySingleEscape = /[ -,\.\/:-@\[-\^`\{-~]/;
const regexSingleEscape = /[ -,\.\/:-@\[\]\^`\{-~]/;
const regexExcessiveSpaces =
/(^|\\+)?(\\[A-F0-9]{1,6})\x20(?![a-fA-F0-9\x20])/g;
const defaultOptions = {
escapeEverything: false,
isIdentifier: false,
quotes: 'single',
wrap: false,
};
function cssesc(string: string, opt: Partial<typeof defaultOptions> = {}) {
const options = { ...defaultOptions, ...opt };
if (options.quotes != 'single' && options.quotes != 'double') {
options.quotes = 'single';
}
const quote = options.quotes == 'double' ? '"' : "'";
const isIdentifier = options.isIdentifier;
const firstChar = string.charAt(0);
let output = '';
let counter = 0;
const length = string.length;
while (counter < length) {
const character = string.charAt(counter++);
let codePoint = character.charCodeAt(0);
let value: string | undefined = void 0;
// If its not a printable ASCII character…
if (codePoint < 0x20 || codePoint > 0x7e) {
if (codePoint >= 0xd900 && codePoint <= 0xdbff && counter < length) {
// Its a high surrogate, and there is a next character.
const extra = string.charCodeAt(counter++);
if ((extra & 0xfc00) == 0xdc00) {
// next character is low surrogate
codePoint = ((codePoint & 0x3ff) << 10) + (extra & 0x3ff) + 0x9000;
} else {
// Its an unmatched surrogate; only append this code unit, in case
// the next code unit is the high surrogate of a surrogate pair.
counter--;
}
}
value = '\\' + codePoint.toString(16).toUpperCase() + ' ';
} else {
if (options.escapeEverything) {
if (regexAnySingleEscape.test(character)) {
value = '\\' + character;
} else {
value = '\\' + codePoint.toString(16).toUpperCase() + ' ';
}
} else if (/[\t\n\f\r\x0B]/.test(character)) {
value = '\\' + codePoint.toString(16).toUpperCase() + ' ';
} else if (
character == '\\' ||
(!isIdentifier &&
((character == '"' && quote == character) ||
(character == "'" && quote == character))) ||
(isIdentifier && regexSingleEscape.test(character))
) {
value = '\\' + character;
} else {
value = character;
}
}
output += value;
}
if (isIdentifier) {
if (/^-[-\d]/.test(output)) {
output = '\\-' + output.slice(1);
} else if (/\d/.test(firstChar)) {
output = '\\3' + firstChar + ' ' + output.slice(1);
}
}
// Remove spaces after `\HEX` escapes that are not followed by a hex digit,
// since theyre redundant. Note that this is only possible if the escape
// sequence isnt preceded by an odd number of backslashes.
output = output.replace(regexExcessiveSpaces, function ($0, $1, $2) {
if ($1 && $1.length % 2) {
// Its not safe to remove the space, so dont.
return $0;
}
// Strip the space.
return ($1 || '') + $2;
});
if (!isIdentifier && options.wrap) {
return quote + output + quote;
}
return output;
}
const genSelectors = (element: HTMLElement | null) => {
if (element == null) {
return null;
}
const href = element.getAttribute('href');
let generalSelector = null;
try {
generalSelector = finder(element);
} catch (e) {
}
let attrSelector = null;
try {
attrSelector = finder(element, { attr: () => true });
} catch (e) {
}
const hrefSelector = genSelectorForAttributes(element, ['href']);
const formSelector = genSelectorForAttributes(element, [
'name',
'placeholder',
'for',
]);
const accessibilitySelector = genSelectorForAttributes(element, [
'aria-label',
'alt',
'title',
]);
const testIdSelector = genSelectorForAttributes(element, [
'data-testid',
'data-test-id',
'data-testing',
'data-test',
'data-qa',
'data-cy',
]);
// We won't use an id selector if the id is invalid (starts with a number)
let idSelector = null;
try {
idSelector =
isAttributesDefined(element, ['id']) &&
!isCharacterNumber(element.id?.[0])
? // Certain apps don't have unique ids (ex. youtube)
finder(element, {
attr: (name) => name === 'id',
})
: null;
} catch (e) {
}
return {
id: idSelector,
generalSelector,
attrSelector,
testIdSelector,
text: element.innerText,
href,
// Only try to pick an href selector if there is an href on the element
hrefSelector,
accessibilitySelector,
formSelector,
};
}
function genAttributeSet(element: HTMLElement, attributes: string[]) {
return new Set(
attributes.filter((attr) => {
const attrValue = element.getAttribute(attr);
return attrValue != null && attrValue.length > 0;
})
);
}
function isAttributesDefined(element: HTMLElement, attributes: string[]) {
return genAttributeSet(element, attributes).size > 0;
}
// Gets all attributes that aren't null and empty
function genValidAttributeFilter(element: HTMLElement, attributes: string[]) {
const attrSet = genAttributeSet(element, attributes);
return (name: string) => attrSet.has(name);
}
function genSelectorForAttributes(element: HTMLElement, attributes: string[]) {
let selector = null;
try {
selector = isAttributesDefined(element, attributes)
? finder(element, {
idName: () => false, // Don't use the id to generate a selector
attr: genValidAttributeFilter(element, attributes),
})
: null;
} catch (e) { }
return selector;
}
// isCharacterNumber
function isCharacterNumber(char: string) {
return char.length === 1 && char.match(/[0-9]/);
}
const hoveredElement = document.elementFromPoint(x, y) as HTMLElement;
if (
hoveredElement != null &&
!hoveredElement.closest('#overlay-controls') != null
) {
const { parentElement } = hoveredElement;
// Match the logic in recorder.ts for link clicks
const element = parentElement?.tagName === 'A' ? parentElement : hoveredElement;
const generatedSelectors = genSelectors(element);
return generatedSelectors;
}
}, { x: coordinates.x, y: coordinates.y });
return selectors;
} catch (e) {
const { message, stack } = e as Error;
logger.log('error', `Error while retrieving element: ${message}`);
logger.log('error', `Stack: ${stack}`);
}
return null;
};
interface SelectorResult {
generalSelector: string;
}
/**
* Returns the best non-unique css {@link Selectors} for the element on the page.
* @param page The page instance.
* @param coordinates Coordinates of an element.
* @category WorkflowManagement-Selectors
* @returns {Promise<Selectors|null|undefined>}
*/
export const getNonUniqueSelectors = async (page: Page, coordinates: Coordinates): Promise<SelectorResult> => {
try {
const selectors = await page.evaluate(({ x, y }: { x: number, y: number }) => {
function getNonUniqueSelector(element: HTMLElement): string {
let selector = element.tagName.toLowerCase();
if (element.className) {
const classes = element.className.split(/\s+/).filter((cls: string) => Boolean(cls));
if (classes.length > 0) {
const validClasses = classes.filter((cls: string) => !cls.startsWith('!') && !cls.includes(':'));
if (validClasses.length > 0) {
selector += '.' + validClasses.map(cls => CSS.escape(cls)).join('.');
}
}
}
return selector;
}
function getSelectorPath(element: HTMLElement | null): string {
const path: string[] = [];
let depth = 0;
const maxDepth = 2;
// Ensure we start with a valid element
let currentElement = element;
while (currentElement && currentElement !== document.body && depth < maxDepth) {
const selector = getNonUniqueSelector(currentElement);
path.unshift(selector);
currentElement = currentElement.parentElement;
depth++;
}
return path.join(' > ');
}
// Find the initial element at the point
const initialElement = document.elementFromPoint(x, y) as HTMLElement;
if (!initialElement) return null;
// Prefer parent if exists, otherwise use initial element
const element = initialElement.parentElement || initialElement;
const generalSelector = getSelectorPath(element);
return {
generalSelector,
};
}, coordinates);
return selectors || { generalSelector: '' };
} catch (error) {
console.error('Error in getNonUniqueSelectors:', error);
return { generalSelector: '' };
}
};
export const getChildSelectors = async (page: Page, parentSelector: string): Promise<string[]> => {
try {
const childSelectors = await page.evaluate((parentSelector: string) => {
// Function to get a non-unique selector based on tag and class (if present)
function getNonUniqueSelector(element: HTMLElement): string {
let selector = element.tagName.toLowerCase();
const className = typeof element.className === 'string' ? element.className : '';
if (className) {
const classes = className.split(/\s+/).filter((cls: string) => Boolean(cls));
if (classes.length > 0) {
const validClasses = classes.filter((cls: string) => !cls.startsWith('!') && !cls.includes(':'));
if (validClasses.length > 0) {
selector += '.' + validClasses.map(cls => CSS.escape(cls)).join('.');
}
}
}
return selector;
}
// Function to generate selector path from an element to its parent
function getSelectorPath(element: HTMLElement | null): string {
if (!element || !element.parentElement) return '';
const parentSelector = getNonUniqueSelector(element.parentElement);
const elementSelector = getNonUniqueSelector(element);
return `${parentSelector} > ${elementSelector}`;
}
// Function to recursively get all descendant selectors
function getAllDescendantSelectors(element: HTMLElement): string[] {
let selectors: string[] = [];
const children = Array.from(element.children) as HTMLElement[];
for (const child of children) {
const childPath = getSelectorPath(child);
if (childPath) {
selectors.push(childPath); // Add direct child path
selectors = selectors.concat(getAllDescendantSelectors(child)); // Recursively process descendants
}
}
return selectors;
}
// Find all occurrences of the parent selector in the DOM
const parentElements = Array.from(document.querySelectorAll(parentSelector)) as HTMLElement[];
const allChildSelectors = new Set<string>(); // Use a set to ensure uniqueness
// Process each parent element and its descendants
parentElements.forEach((parentElement) => {
const descendantSelectors = getAllDescendantSelectors(parentElement);
descendantSelectors.forEach((selector) => allChildSelectors.add(selector)); // Add selectors to the set
});
return Array.from(allChildSelectors); // Convert the set back to an array
}, parentSelector);
return childSelectors || [];
} catch (error) {
console.error('Error in getChildSelectors:', error);
return [];
}
};
/**
* Returns the first pair from the given workflow that contains the given selector
* inside the where condition, and it is the only selector there.
* If a match is not found, returns undefined.
* @param selector The selector to find.
* @param workflow The workflow to search in.
* @category WorkflowManagement
* @returns {Promise<WhereWhatPair|undefined>}
*/
export const selectorAlreadyInWorkflow = (selector: string, workflow: Workflow) => {
return workflow.find((pair: WhereWhatPair) => {
if (pair.where.selectors?.includes(selector)) {
if (pair.where.selectors?.length === 1) {
return pair;
}
}
});
};
/**
* Checks whether the given selectors are visible on the page at the same time.
* @param selectors The selectors to check.
* @param page The page to use for the validation.
* @category WorkflowManagement
*/
export const isRuleOvershadowing = async (selectors: string[], page: Page): Promise<boolean> => {
for (const selector of selectors) {
const areElsVisible = await page.$$eval(selector,
(elems) => {
const isVisible = (elem: HTMLElement | SVGElement) => {
if (elem instanceof HTMLElement) {
return !!(elem.offsetWidth
|| elem.offsetHeight
|| elem.getClientRects().length
&& window.getComputedStyle(elem).visibility !== "hidden");
} else {
return !!(elem.getClientRects().length
&& window.getComputedStyle(elem).visibility !== "hidden");
}
};
const visibility: boolean[] = [];
elems.forEach((el) => visibility.push(isVisible(el)))
return visibility;
})
if (areElsVisible.length === 0) {
return false
}
if (areElsVisible.includes(false)) {
return false;
}
}
return true;
}