Could not proxy request to hyper-express server

[josejooj]

How my problem started

Hello again! I had posted about this a time ago

The post was basically about me not being able to proxy a react site to the api in hyper-express

I ended up opting for a "stop-gap solution", instead of making a proxy for the api, I just used axios and set the baseUrl as the API url, so I could make requests to the API without proxy, but the problem of not accepting requests via proxy was still there, and I thought I would have no problem with that anymore

Now, some context of my actual problem

Now I bought a VM on Google Cloud and set up a whole environment complete with nginx, below is the nginx configuration

server {
    listen 443 ssl;
    server_name dev.mywebsite.com;

    ssl_certificate /etc/letsencrypt/live/dev.mywebsite.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/dev.mywebsite.com/privkey.pem;

    location / {
        proxy_pass http://127.0.0.1:5173;
    }
}

server {
    listen 443 ssl;
    server_name api.dev.mywebsite.com;

    ssl_certificate /etc/letsencrypt/live/api.dev.mywebsite.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/api.dev.mywebsite.com/privkey.pem;

    location / {
       proxy_pass http://127.0.0.1:63031;
    }
}

• Server 1 would be the proxy for react + vite development site port
• Server 2 would be the proxy for my API in Hyper-Express

So, what is the problem?

• When I access dev.mywebsite.com I get the expected response from the React development server

• When I access api.dev.mywebsite.com I get the 502 Bad Gateway page error from nginx, and when I open the nginx error logs I get this: 2023/07/23 02:20:45 [error] 115843#115843: *66 upstream prematurely closed connection while reading response header from upstream, client: 170.238.13.25, server: api.dev.mywebsite.com, request: "GET /status HTTP/1.1", upstream: "http://127.0.0.1:6 3031/status", host: "api.dev.mywebsite.com"

• But if i do a request to the API inside my VM, i get this:

  > curl http://127.0.0.1:63031/status
  > {"status":200,"message":{"status":"Working","memory":{"usage":75.82,"total":3907.81},"time_working":{"days":0,"hours":0,"minutes":13,"seconds":34.007}}}

• And if a do the request directly by ip i receive this:

So the api is running, but not receiving proxy requests... This is my API code:

import HyperExpress, { UserRouteHandler } from 'hyper-express';
import { SQLClient } from './util/Database';
import { Routes } from './Routes';
import { inspect } from 'util';
import crypto from 'crypto';
import cors from 'cors';

const server = new HyperExpress.Server({
    fast_buffers: true,
    ssl_prefer_low_memory_usage: true,
    trust_proxy: true
});

const methods: Array<"get" | "use" | "post" | "delete" | "patch"> = ["get", "use", "post", "delete", "patch"];
const port = 63031;

server.use(cors()); // @ts-ignore
server.options('/*', cors());

for (const route of Routes.api.filter(x => x.use)) route.pattern !== "*" ? server.use(route.pattern, route.use!) : server.use(route.use!)
for (const route of Routes.api.filter(x => !x.use)) {
    for (const method of methods) {
        if (route[method]) server[method](route.pattern, route[method] as UserRouteHandler)
    }
}

for (const route of Routes.websocket) {
    server.upgrade(route.pattern, route.upgrade)
    server.ws(route.pattern, route.handler)
}

server.set_error_handler(async (req, res, error) => {

    let genRandomId = () => crypto.randomUUID().split("-").join("");
    let id = genRandomId();

    while ((await SQLClient.query(`SELECT FROM errors WHERE id = $1`, [id])).rowCount) id = genRandomId()

    const toinsert = {
        id,
        request: inspect(req, { depth: Infinity, maxArrayLength: Infinity }),
        response: inspect(res, { depth: Infinity, maxArrayLength: Infinity }),
        error: inspect(error),
        body: inspect(await req.json()), // @ts-ignore
        handler: `${req.route.handler}`
    }

    await SQLClient.query(
        `INSERT INTO errors (${Object.keys(toinsert)}) VALUES (${Object.keys(toinsert).map((x, i) => `$${i + 1}`)})`,
        Object.values(toinsert)
    )

    res._send(500, `Aconteceu um erro interno no servidor. Contate o suporte com o ID de erro: ${id}`);

})

server.listen(port).then((x) => {

    const routes: Record<string, string> = {};
    const table: Record<string, string>[] = [];

    for (const [method, routeObject] of Object.entries(server.routes)) {
        for (const route of Object.values(routeObject)) {
            if (!routes[route.pattern]) routes[route.pattern] = method.toUpperCase();
            else routes[route.pattern] += `, ${method.toUpperCase()}`;
        }
    }

    for (const [route, methods] of Object.entries(routes)) {
        const tableRow: Record<string, string> = {};
        const methodArray = methods.split(', ');
        tableRow['Route'] = route;
        for (const method of methodArray) tableRow[method] = '✅';
        table.push(tableRow);
    }

    console.table(table);
    console.log(`[API] - Estou online na porta ${port}`)

}).catch(e => console.log(`[API] - Ocorreu o seguinte erro ao abrir na porta ${port}`, e));

So, i want to know... What can i do to solve this? I like so much to work with hyper-express, i don't want to change to another module only for this...

• OBS - My website URL isn't mywebsite.com, i only don't want to share the url now, but i made the edits correctly and I think it will not affect the understanding of the question

[kartikk221]

Hello, so the below error seems to be uWebsockets.js aka. hyper-express closing the connection forcefully before the request has properly been received.

*66 upstream prematurely closed connection while reading response header from upstream, client: 170.238.13.25, server: api.dev.mywebsite.com, request: "GET /status HTTP/1.1", upstream: "http://127.0.0.1:6 3031/status", host: "api.dev.mywebsite.com"

This can only occur in the following scenarios:

• You have fast_abort set to true when you constructed the Server instance and a request with a too large content length is received.
• You or a middleware you use calls response.close() somewhere in your code before the request's body has been retrieved.

I would take the below steps to try and debug this problem further:

• Add a not found handler with Server.set_not_found_handler so that every request receives a proper response regardless of its path. You can simply return a 404 status code with whatever response body you wish or if any.
• Comment out the usage of the cors() middleware for now. I see that you are using the middleware twice. Once with a use() and then with a wildcard on options(). This would lead to the middleware running twice as use() covers all methods automatically. But just to be on the safe side, comment out both, then gradually add each one back to see If the middleware is causing the issue.

Also, can you provide to me the HTTP method, headers and body of the request you are sending to the API which gets prematurely closed by the server?

[masfahru]

Hopefully this help : https://github.com/uNetworking/uWebSockets.js/discussions/835#discussioncomment-5369383

[kartikk221]

Ohh I see. That makes perfect sense. I also use http 1.1 in my own NGINX configurations for upstream with hyper-express hence never encountered this problem. That should solve it.