How to use DomGetContentQuadsRequest class of PuppeteerSharp.Messaging package

Got it:
var localStorage = await page.EvaluateFunctionAsync<Dictionary<string, string>>("async () => Object.assign({}, window.localStorage)");

You are on the wrong direction. The referenced site has playlist api which returns json. you can get information from :

http://iloveradio.de/typo3conf/ext/ep_channel/Scripts/playlist.php

Edit: Chome Inspector is used to find out Playlist link

The answers lies in starting the Process with a ProcessStartInfo that has RedirectStandardInput, RedirectStandardOutput and/or RedirectStandardError properties set and then using the Process.StandardInput, Process.StandardOutput and/or Process.StandardError properties to access the pipes.

I found a solution: If the pages will be created in the same scope as their browser instance, then the pages will be created as expected, otherwise Task.Run() will be stuck due to NewPageAsync() method.

Bad behaviour:

Task[] Tasks = new Task[1];
Browser browser = await Puppeteer.LaunchAsync
(
    new LaunchOptions
    {
        Headless = true,
        ExecutablePath = "Chromium\\chrome.exe"
    }
);
for (int i = 0; i < Tasks.Length; i++)
{
    int ThreadNumber = i;
    Tasks[i] = Task.Run(async () =>
    {
       Page page = await browser.NewPageAsync(); //stucks
    });
}

Task.WaitAll(Tasks);

As expected:

Task[] Tasks = new Task[1];
for (int i = 0; i < Tasks.Length; i++)
{
    int ThreadNumber = i;
    Tasks[i] = Task.Run(async () =>
    {
       Browser browser = await Puppeteer.LaunchAsync
       (
           new LaunchOptions
           {
                Headless = true,
               ExecutablePath = "Chromium\\chrome.exe"
           }
       );
       Page page = await browser.NewPageAsync(); //creates as expected
    });
}

Task.WaitAll(Tasks);

Anyway this is not the best solution because I have to create browsers for async tasks rather than using one browser for all async tasks. Hope someone can explain that. Thanks everyone for helping!

Technically speaking this a missing feature on the Linq methods. It's not so simple to code Async Linq functions.

On the other side, I find this much more simple to implement straight in javascript. Why? because you can test your script in your browser and then just move it to your C# code.

For instance, this method will find all li elements, find the li with a span with the text fire and then click the input.

await page.EvaluateFunctionAsync(@"() => {
     Array.from(document.querySelectorAll('li'))
         .find(l => l.querySelector('span').innerText === 'fire').querySelector('INPUT').click();
}");

You need to mount them in container. https://flaviocopes.com/docker-access-files-outside-container/

In Puppeteer, the function that we provide to page.evaluate is executed in context of the page and so it has to be a JavaScript function.

Likewise, in the equivalent functions in puppeteer-sharp e.g. page.EvaluateFunctionAsync, the first argument is a string which is nothing but a JavaScript function. You should be able to use the fetch as it is, something like:

await page.EvaluateFunctionAsync(@"() => {
  return fetch('url', {method: 'POST', body: 'test' });
}");

I think EvaluateFunctionAsync is the most straight forward way to do this:

var type = await node.EvaluateFunctionAsync<string>("node => node.type");

For local path, need to use file protocol like below:

await page.GoToAsync("file://" + Path.Combine(context.FunctionAppDirectory, "www", "index.html"));