Congrats + body parser

[orefalo]

This library performs better than turbo-http under high load, congrats.

Now I am a little confused about the api, how would you implement a body parser?

I am trying to stitch it to an Apollo GraphQL instance

Thanks!

[ghost]

/* Simple examples of getting JSON from a POST */

const uWS = require('../dist/uws.js');
const port = 9001;

const app = uWS./*SSL*/App({
  key_file_name: 'misc/key.pem',
  cert_file_name: 'misc/cert.pem',
  passphrase: '1234'
}).post('/*', (res, req) => {

  /* Note that you cannot read from req after returning from here */
  let url = req.getUrl();

  /* Read the body until done or error */
  readJson(res, (obj) => {
    console.log('Posted to ' + url + ': ');
    console.log(obj);

    res.end('Thanks for this json!');
  }, () => {
    /* Request was prematurely aborted, stop reading */
    console.log('Ugh!');
  });

}).listen(port, (token) => {
  if (token) {
    console.log('Listening to port ' + port);
  } else {
    console.log('Failed to listen to port ' + port);
  }
});

/* Helper function for reading a posted JSON body */
function readJson(res, cb, err) {
  let buffer;
  /* Register data cb */
  res.onData((ab, isLast) => {
    let chunk = Buffer.from(ab);
    if (isLast) {
      if (buffer) {
        cb(JSON.parse(Buffer.concat([buffer, chunk])));
      } else {
        cb(JSON.parse(chunk));
      }
    } else {
      if (buffer) {
        buffer = Buffer.concat([buffer, chunk]);
      } else {
        buffer = Buffer.concat([chunk]);
      }
    }
  });

  /* Register error cb */
  res.onAborted(err);
}

You mean like getting json from a post or something?

[iamsimakov]

hello, thanks for project. Can anybody say how to check empty or no empty data?

[ghost]

I guess onData has to be called with isLast set immediately if there was no data otherwise we hang the connection forever

[iamsimakov]

@alexhultman Yes, that is why I was need to check empty data, or there is another way to check and immediately close the connection. thanks

[ghost]

Yeah it is a bug - onData needs to return false/true or immediately call the callback with isLast. Something like that. I guess the most automatically compatible way is to call with isLast immediately

[ghost]

Okay this is fixed now. You can see the JsonPost example. It tells you when there is no data and when there is

[orefalo]

Thank you!

[orefalo]

You mean like getting json from a post or something?

Yes - json body parsing. graphql body parsing to be exact.

[yamiteru]

type TPromiseObjectNull = Promise<{ [key: string]: any } | null>;

export default (res): TPromiseObjectNull => new Promise((resolve, reject) => {
    let buffer;

    res.onData((ab, isLast) => {
        const chunk = Buffer.from(ab);

        if (isLast) {
            const toParse = buffer
                ? Buffer.concat([buffer, chunk])
                : chunk;
            const resolveValue = JSON.parse(toParse as unknown as string);

            resolve(resolveValue);
        }

        else {
            const concatValue = buffer
                ? [buffer, chunk]
                : [chunk];

            buffer = Buffer.concat(concatValue);
        }
    });

    res.onAborted(_ => reject(null));
});

[Wilson-Emmanuel]

I edited @yamiteru response. this is working for me.

const parseBody = (res: uWS.HttpResponse): Promise<{ [key: string]: any } | null> => {
    return new Promise((resolve, reject) => {
        let buffer: Buffer = Buffer.alloc(0);
        let totalSize = 0;

        res.onData((ab, isLast) => {
            try {
                if (res.aborted) {
                    reject(new Error('Request aborted'));
                    return;
                }


                if(ab.byteLength > 0) { // I found some non-last onData with 0 byte length
                    const copy = copyArrayBuffer(ab); // Immediately copy the ArrayBuffer into a Buffer, every return of onData neuters the ArrayBuffer
                    totalSize += copy.byteLength;
                    buffer = Buffer.concat([buffer, Buffer.from(copy)]);
                }

                if (totalSize > MAX_BODY_SIZE) { // define your allowed max size if it applies to you
                    reject(new Error('Request body too large: max 4MB allowed'));
                    return;
                }

                if (isLast) {
                    // If this is the last chunk, process the final buffer
                    // Convert the buffer to a string and parse it as JSON
                    // this will fail if the buffer doesn't contain a valid JSON (e.g. length = 0)
                    const resolveValue = JSON.parse(buffer.toString());
                    resolve(resolveValue);
                }
            } catch (err: any) {
                reject(new Error(`Failed to parse JSON: ${err.message}`));
            }
        });
    });
};

[dragonlobster]

this solution works good, just to add the copyArrayBuffer function:

const copyArrayBuffer = (src: ArrayBuffer) => {
    var dst = new ArrayBuffer(src.byteLength);
    new Uint8Array(dst).set(new Uint8Array(src));
    return dst;
}

Is there a way to set res.body to the body; similar to express.json() setting req.body to the JSON object