Why does Blazor Server have the browser call blazor.server.js multiple times?

Question

Hi all;

I watched a page load using F12 and blazor.server.js is loaded multiple times (see below). I understand the browser loading multiple times because of the ?id=... being different on each. But why does the Blazor code reloading the same Javascript file instead of reading it once and then referencing that loaded file?

thanks - dave

Answer 1

Hi @David Thielen,

It's a expected behavior for LongPolling protocol. If you don't want to use LongPolling, you can set it in your Program.cs Like below.

app.MapBlazorHub(options =>
{
    options.Transports = HttpTransportType.WebSockets;
});  

By default, we can use websocket protocol directly, if not works, please kindly check the websocket feature setting in azure portal .

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Jason