More interactive samples: PuppeteerSharp

_{Photo by Killian Cartignies on Unsplash}

Following the notebook that demonstrates how to learn .Net, i'm posting here the sample to play with PuppeteerSharp.

External Reference download

First, let's declare eternal dependencies required, in a dedicated section of code.

#r "nuget:PuppeteerSharp, 4.0.0"

Global context initilization

Then, let's init variable that we will use through the notebook.
It will take some time as a dedicated version of chrome will be downloaded.

using PuppeteerSharp;

await new BrowserFetcher().DownloadAsync(BrowserFetcher.DefaultRevision);
var browser = await Puppeteer.LaunchAsync(new LaunchOptions
{
    Headless = true
});

We will have now a browser initialized.

Play with it

We can now do some basic tests or more complicated ones.

Take screenshot

var page = await browser.NewPageAsync();
await page.GoToAsync("http://www.google.com");
await page.ScreenshotAsync("./FirstTest.png");

Select content

var currentPage = await browser.NewPageAsync();
await currentPage.GoToAsync("http://www.google.com");
await currentPage.QuerySelectorAllHandleAsync("input[name=q]").EvaluateFunctionAsync("el => el.value = 'test'");
await currentPage.ScreenshotAsync("./screenshot.jpg");
var output = await currentPage.QuerySelectorAllHandleAsync("div[id='SIvCob']").EvaluateFunctionAsync<string[]>("el => el.map(a => a.text)");
display(output);

Note: display method is provided by dotnet interactive.

Iterating urls

using (var page = await browser.NewPageAsync())
{
    await page.GoToAsync("http://www.google.com");
    var jsSelectAllAnchors = @"Array.from(document.querySelectorAll('div')).map(a => a.innerText);";
    var urls = await page.EvaluateExpressionAsync<string[]>(jsSelectAllAnchors);
    foreach (string url in urls)
    {
        Console.WriteLine($"Url: {url}");
    }
}

Hope this helps !

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