Implementation:MarketSquare Robotframework browser Evaluation Grpc Handlers

Knowledge Sources	MarketSquare_Robotframework_browser
Domains	Browser Automation, gRPC Handlers
Last Updated	2026-02-12 05:40 GMT

Overview

Implements element location, JavaScript evaluation, element state waiting, selector recording, element highlighting, and file download operations via gRPC handlers in the Node.js Playwright wrapper.

Description

evaluation.ts is a core gRPC handler module in the Node.js layer of the Browser library. It provides the bridge between Robot Framework Python keywords and Playwright browser operations for evaluation and element resolution tasks. The module handles:

• Element resolution: getElement and getElements resolve CSS/XPath selectors to Playwright Locator objects, storing UUID references in global state for the element=<uuid> syntax in RF keywords.
• Strategy-based element finding: getByX implements Playwright's getByAltText, getByLabel, getByPlaceholder, getByRole, getByTestId, getByText, and getByTitle strategies with support for RegExp patterns, strict mode, and frame selectors.
• JavaScript evaluation: evaluateJavascript executes arbitrary JavaScript on the page or on specific elements, supporting both page-level and element-scoped evaluation with optional arguments. It uses tryToTransformStringToFunction to convert string scripts into callable functions.
• State waiting: waitForElementState waits for elements to reach specific DOM states (attached, detached, hidden, visible, or custom states via elementHandle).
• Function waiting: waitForFunction waits for a JavaScript predicate to become truthy, optionally scoped to a specific element.
• Selector recording: recordSelector injects the interactive selector-finder UI into the browser page, allowing users to visually pick CSS selectors. It exposes setRecordedSelector, getRecordedSelectors, and highlightPWSelector functions on the page.
• Element highlighting: highlightElements and the internal highlightAll function create visual borders around matched elements with configurable duration, width, style, color, and mode (border/playwright/both).
• File download: download programmatically triggers file downloads using fetch and blob URLs, coordinating with the network module's _waitForDownload.

Usage

This module is invoked by the Python-side gRPC client when Robot Framework keywords such as Get Element, Evaluate JavaScript, Wait For Elements State, Wait For Function, Record Selector, Highlight Elements, Add Style Tag, and Download are called. It is not used directly by end users.

Code Reference

Source Location

• Repository: MarketSquare_Robotframework_browser
• File: node/playwright-wrapper/evaluation.ts
• Lines: 1-561

Signature

export async function getElement(
    request: Request.ElementSelector,
    state: PlaywrightState
): Promise<Response.String>

export async function getElements(
    request: Request.ElementSelector,
    state: PlaywrightState
): Promise<Response.Json>

export async function getByX(
    request: Request.GetByOptions,
    state: PlaywrightState
): Promise<Response.Json>

export async function evaluateJavascript(
    request: Request.EvaluateAll,
    state: PlaywrightState,
    page: Page
): Promise<Response.JavascriptExecutionResult>

export async function waitForElementState(
    request: Request.ElementSelectorWithOptions,
    pwState: PlaywrightState
): Promise<Response.Empty>

export async function waitForFunction(
    request: Request.WaitForFunctionOptions,
    state: PlaywrightState,
    page: Page
): Promise<Response.Json>

export async function addStyleTag(
    request: Request.StyleTag,
    page: Page
): Promise<Response.Empty>

export async function recordSelector(
    request: Request.Label,
    state: PlaywrightState
): Promise<Response.JavascriptExecutionResult>

export async function highlightElements(
    request: Request.ElementSelectorWithDuration,
    state: PlaywrightState
): Promise<Response.Empty>

export async function download(
    request: Request.DownloadOptions,
    state: PlaywrightState
): Promise<Response.Json>

Import

import { PlaywrightState } from './playwright-state';
import { Request, Response } from './generated/playwright_pb';
import { findLocator } from './playwright-invoke';
import { _waitForDownload } from './network';

I/O Contract

Inputs

Name	Type	Required	Description
request.selector	string	Yes	CSS, XPath, or element=uuid selector string
request.strict	boolean	No	Enable strict mode (fail if selector matches multiple elements)
request.script	string	Conditional	JavaScript code to evaluate (for evaluateJavascript, waitForFunction)
request.arg	string (JSON)	No	Serialized argument to pass to the JavaScript function
request.allElements	boolean	No	If true, evaluate against all matching elements
request.options	string (JSON)	No	JSON-serialized options (state, timeout, etc.)
request.strategy	string	Conditional	Selection strategy: AltText, Label, Placeholder, Role, TestId, Text, Title
request.duration	number	No	Highlight duration in milliseconds
request.width	string	No	Highlight border width (e.g. "3px")
request.style	string	No	Highlight border style (e.g. "dotted")
request.color	string	No	Highlight border color (e.g. "blue")
request.mode	string	No	Highlight mode: "border", "playwright", or "both"
state	PlaywrightState	Yes	Current Playwright state holding active browser/context/page

Outputs

Name	Type	Description
Response.String	gRPC Response	Single string result (element selector, evaluated value)
Response.Json	gRPC Response	JSON-serialized result (element arrays, function results, bounding boxes)
Response.JavascriptExecutionResult	gRPC Response	Result of JavaScript evaluation or selector recording
Response.Empty	gRPC Response	Confirmation with log message for void operations

Usage Examples

*** Test Cases ***
Get Element Example
    ${element}=    Get Element    css=h1#title
    Log    Found element: ${element}

Evaluate JavaScript Example
    ${result}=    Evaluate JavaScript    None
    ...    () => document.title
    Should Be Equal    ${result}    My Page Title

Wait For Elements State Example
    Wait For Elements State    id=loading-spinner    hidden    timeout=10s

Record Selector Example
    # Opens interactive selector picker in the browser
    ${selector}=    Record Selector    my_label

Highlight Elements Example
    Highlight Elements    css=.error-field    duration=3s

Download Example
    ${download_info}=    Download    https://example.com/file.pdf

Related Pages

• Environment:MarketSquare_Robotframework_browser_Node_Runtime