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Improve Blazor reconnection experience. #13015

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Merged
merged 1 commit into from
Aug 14, 2019
Merged

Improve Blazor reconnection experience. #13015

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4 changes: 2 additions & 2 deletions src/Components/Web.JS/dist/Release/blazor.server.js
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7 changes: 6 additions & 1 deletion src/Components/Web.JS/src/Boot.Server.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -37,8 +37,13 @@ async function boot(userOptions?: Partial<BlazorOptions>): Promise<void> {
}

const reconnection = existingConnection || await initializeConnection(options, logger);
if (reconnection.state !== signalR.HubConnectionState.Connected) {
logger.log(LogLevel.Information, 'Reconnection attempt failed. Unable to connect to the server.');
return false;
}

if (!(await circuit.reconnect(reconnection))) {
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SignalR throws if you attempt to reconnect like this while the connection is not connected. This prevented the reconnect display from properly handling scenarios where the server went away.

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@NTaylorMullen NTaylorMullen Aug 14, 2019 •
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Actually, can't remove this entirely. It breaks the expectation of calling code, i.e. in DefaultReconnectionHandler it expects:

        // reconnectCallback will asynchronously return:
        // - true to mean success
        // - false to mean we reached the server, but it rejected the connection (e.g., unknown circuit ID)
        // - exception to mean we didn't reach the server (this can be sync or async)

In a way it makes sense. Basically, we need to have 3 different return values and instead of having an enum the previous design utilized exceptions. I'll revert this change in my next change for this experience but enable the reconnect display to handle exceptions so the UI doesn't die.

logger.log(LogLevel.Information, 'Reconnection attempt failed.');
logger.log(LogLevel.Information, 'Reconnection attempt to the circuit failed.');
return false;
}

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14 changes: 10 additions & 4 deletions src/Components/Web.JS/src/Platform/Circuits/DefaultReconnectDisplay.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -31,12 +31,18 @@ export class DefaultReconnectDisplay implements ReconnectDisplay {
];

this.modal.style.cssText = modalStyles.join(';');
this.modal.innerHTML = '<h5 style="margin-top: 20px"></h5><button style="margin:5px auto 5px">Retry?</button><p>Alternatively, <a href>reload</a></p>';
this.modal.innerHTML = '<h5 style="margin-top: 20px"></h5><button style="margin:5px auto 5px">Retry</button><p>Alternatively, <a href>reload</a></p>';
this.message = this.modal.querySelector('h5')!;
this.button = this.modal.querySelector('button')!;
this.reloadParagraph = this.modal.querySelector('p')!;

this.button.addEventListener('click', () => window['Blazor'].reconnect());
this.button.addEventListener('click', async () => {
this.show();
const successful = await window['Blazor'].reconnect();
if (!successful) {
this.failed();
}
});
this.reloadParagraph.querySelector('a')!.addEventListener('click', () => location.reload());
}

Expand All @@ -57,7 +63,7 @@ export class DefaultReconnectDisplay implements ReconnectDisplay {

failed(): void {
this.button.style.display = 'block';
this.reloadParagraph.style.display = 'block';
this.message.textContent = 'Failed to reconnect to the server.';
this.reloadParagraph.style.display = 'none';
this.message.innerHTML = 'Reconnection failed. Try <a href>reloading</a> the page if you\'re unable to reconnect.';
}
}
2 changes: 1 addition & 1 deletion src/Components/Web.JS/tests/DefaultReconnectDisplay.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,7 @@ describe('DefaultReconnectDisplay', () => {
display.failed();

expect(display.modal.style.display).toBe('block');
expect(display.message.textContent).toBe('Failed to reconnect to the server.');
expect(display.message.innerHTML).toBe('Reconnection failed. Try <a href=\"\">reloading</a> the page if you\'re unable to reconnect.');
expect(display.button.style.display).toBe('block');
});

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