GPAL Fluent: High-level fluent C# API

//Every method is async and takes a session id last. Passing null uses the session the browser is on, which is what a workflow wants unless it is driving a specific tab, window or iframe it got the id for itself. GetAwaiter().GetResult() is how a synchronous GPAL workflow calls them; an async workflow awaits instead. SendCommand is the general case: the DevTools method, that method's parameters as an anonymous object, and the session. The parameter names are the CDP protocol's own, so width, height, deviceScaleFactor and mobile are what Emulation.setDeviceMetricsOverride documents, not names GPAL invented. It answers the raw CDP result, so read it the way the protocol describes it rather than expecting a GPAL shape. Calls differ in what they identify an element by. Some take a css selector, as GetCssAttributes does. Others take a backend node id, which is CDP's own handle for a node and is what a GPALElement carries, so those are for code that already has an element rather than for finding one.

// every call takes a session id last, and null means the session the browser is on now

IBrowser browser = GPAL.Browser

.WithAutomationEngine(AutomationEngine.PuppeteerPort)

.GoTo("https://example.com")

.ToGPALObject();

PuppeteerCommunicator cdp = browser.PuppeteerCommunicator;

// 1. a method with its own parameters: a css selector and the session

int nodeId = cdp.QueryByCss("#main a.download", null).GetAwaiter().GetResult();

dynamic styles = cdp.GetCssAttributes(nodeId, null).GetAwaiter().GetResult();

dynamic answer = cdp.ExecuteJavaScript("document.title", null).GetAwaiter().GetResult();

// 2. optional parameters, named so the defaults in between are left alone. CheckNetworkIdle waits for

// the page to stop talking rather than for a fixed time

bool settled = cdp.CheckNetworkIdle(sessionId: null, maxConnections: 0, timeoutMs: 15000)

.GetAwaiter().GetResult();

// 3. a raw CDP command for a domain GPAL has no call for. SendCommand takes the method, an anonymous

// object of that method's own parameters, and the session

dynamic metrics = cdp.SendCommand(DevToolsMethods.PerformanceGetMetrics, new { }, null)

.GetAwaiter().GetResult();

dynamic emulated = cdp.SendCommand(DevToolsMethods.EmulationSetDeviceMetricsOverride,

new { width = 1280, height = 800, deviceScaleFactor = 2, mobile = false }, null)

.GetAwaiter().GetResult();