DwarfNinja Posts - Answer Overflow

DwarfNinja

•Created by DwarfNinja on 2/19/2025 in #workers-help

Receiving webhook in a worker and sending it to the frontend?

Hey dear Cloudflare dev's, I receive a webhook from Mollie and want to forward its data to my frontend. As I understand, since workers are stateless, I can't share variables between functions eg. a global let webhook-data variable. My current approach stores the data in Cloudflare KV and then polls it to send via websockets or server-sent events, which feels overly complex and has it's own pitfalls. While Durable Objects offer in-memory state, I’m trying to keep costs low and it seems a large solution for what feels to be a small problem. Are there any suggestions how to best solve this? Thanks in advance! See the snippit below for an example of the above case:

/// server
app.post('/mollie-webhook', async (context) => {
    const payload = await context.req.text()
    console.log('Received webhook data:', payload)
    
    await context.env.recurify.put('latest-payment', payload)
    return context.text('Webhook received')
})

app.get('/mollie-payment-sse', async (c) => {
    c.header('Content-Encoding', 'Identity');

    return streamSSE(c, async (stream: SSEStreamingApi) => {
        let lastEventId: string | null = null;

        while (true) {
            await stream.sleep(1000);

            const storedEvent = await c.env.recurify.get('latest-payment');
            if (storedEvent) {
                const eventObj = JSON.parse(storedEvent);
                if (eventObj.id !== lastEventId) {
                    lastEventId = eventObj.id;
                    await stream.writeSSE({
                        event: 'new-payment-update',
                        data: eventObj.data,
                        id: eventObj.id,
                    });
                }
            }
        }
    });
});

/// server
app.post('/mollie-webhook', async (context) => {
    const payload = await context.req.text()
    console.log('Received webhook data:', payload)
    
    await context.env.recurify.put('latest-payment', payload)
    return context.text('Webhook received')
})

app.get('/mollie-payment-sse', async (c) => {
    c.header('Content-Encoding', 'Identity');

    return streamSSE(c, async (stream: SSEStreamingApi) => {
        let lastEventId: string | null = null;

        while (true) {
            await stream.sleep(1000);

            const storedEvent = await c.env.recurify.get('latest-payment');
            if (storedEvent) {
                const eventObj = JSON.parse(storedEvent);
                if (eventObj.id !== lastEventId) {
                    lastEventId = eventObj.id;
                    await stream.writeSSE({
                        event: 'new-payment-update',
                        data: eventObj.data,
                        id: eventObj.id,
                    });
                }
            }
        }
    });
});

9 replies

Gaming

Programming