How do I properly use puppeteer-sharp with server-side Blazor / SignalR?

Question

I can get puppeteer-sharp (with headless both true and false) to obtain server-side-rendered Blazor pages, but it looks like I'm only getting the server pre-render and NOT any client-side initiated events (e.g., for instance the second OnInitialized, or any OnAfterRender, OnAfterRenderAsync).

My best guess is that Signal R is not working properly using puppeteer-sharp.

I do this:

        using var browserFetcher = new BrowserFetcher();
        await browserFetcher.DownloadAsync();
        await using var browser = await Puppeteer.LaunchAsync(new LaunchOptions { 
            Headless = true
        });
        await using var page = await browser.NewPageAsync();
        await page.SetJavaScriptEnabledAsync(true);
        await page.GoToAsync("<<mypage>>, 
                     new NavigationOptions { 
                              WaitUntil = new WaitUntilNavigation[] { 
                                  WaitUntilNavigation.Load 
                              }  
                     }
        );
        string sContent = await page.GetContentAsync();

Is there any way to get ALL of the Blazor events to fire properly, or any good discussion of this on the web somewhere?

Thanks in advance!

Do you have any way to test this on a public URL? – hardkoded May 23 '22 at 19:22 — hardkoded, May 23 '22 at 19:22

score 1 · Answer 1 · answered May 26 '22 at 03:39

The answer here was that puppeteer-sharp is actually working just fine with SignalR in all cases.

I really had a separate, more general problem with my authorization settings where the fallback was improperly set. In that case, pages that supposedly did not require authorization were really only providing a single server-prerender (and no later SignalR-enabled onParameterSet, etc.). This incorrect behavior was the same in both a manual browser windows and puppeteer.

How do I properly use puppeteer-sharp with server-side Blazor / SignalR?

1 Answers1