Meziantou.Framework

Playwright

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The Meziantou.Framework.WebPlatform.Playwright package is a Playwright server whose browser is this engine. The Playwright clients connect to it as to a server started with npx playwright run-server, and automate its pages with the API of Playwright: navigation, locators, actions, assertions, evaluation, screenshots, PDF, network interception, cookies, emulation, dialogs, popups and frames. No browser is installed or started: the pages run in the process of the server.

dotnet package add Meziantou.Framework.WebPlatform.Playwright
await using var server = new PlaywrightServer(); // no DocumentLoader: the pages use page.SetContentAsync() and the routes
await server.StartAsync();

using var playwright = await Microsoft.Playwright.Playwright.CreateAsync();
await using var browser = await playwright.Chromium.ConnectAsync(server.WsEndpoint.ToString());
var page = await browser.NewPageAsync();
await page.SetContentAsync("""
    <label for=name>Name</label><input id=name>
    <button onclick="document.querySelector('output').textContent = 'Hello ' + document.querySelector('input').value">Greet</button>
    <output></output>
    """);

await page.GetByLabel("Name").FillAsync("World");
await page.GetByRole(AriaRole.Button, new() { Name = "Greet" }).ClickAsync();
await Assertions.Expect(page.Locator("output")).ToHaveTextAsync("Hello World");
var screenshot = await page.ScreenshotAsync();

How it works

Each connection gets a browser, reported as chromium by default. Each browser context of Playwright runs its pages on its own thread, with its own script engine, cookies and storage; each page is a BrowsingContext, and each frame a nested browsing context. The selectors (GetByRole, GetByText...), the actionability checks and the assertions are evaluated by the scripts of Playwright, injected in the pages as Playwright does, so they behave as in the browsers.

The pages are rendered by this engine: the scripts run with the JavaScript engine, the screenshots with the Imaging backend and the PDF with the PDF printing.

Versions

The protocol of Playwright changes with each minor version: the clients must have the major and minor versions of PlaywrightServer.PlaywrightVersion. The server rejects the other clients with an HTTP 428 response, as the Playwright server does; PlaywrightServerOptions.AllowAnyClientVersion accepts them anyway.

Not supported

  • Video recording, tracing (the traces are empty), HAR recording and replay, and downloads.
  • The workers and the service workers of the protocol, the clock (page.clock), the locator handlers, toMatchAriaSnapshot(), the WebSocket routes and the CDP sessions.
  • The WebP screenshots, and the files given by path to SetInputFiles(): give their content instead (FilePayload).
  • Geolocation, the permissions, ignoreHTTPSErrors, proxy and bypassCSP are ignored: the network options belong to the DocumentLoader.

See also the limitations of the engine.

In this section

  • Hosting the server: start the server in your process or in ASP.NET Core, and let the pages use the network.
  • Command-line tool: run the server from the command line, for the clients of any language.