node.js create object from raw http request string

Question

I have a raw HTTP request string from which I need to create an object representation.

Instead of reinvent the wheel I was thinking about use the internal http parser to get an instance of http.IncomingMessage

Is it possible?

I think so because string is not so different from a complete stream.

How to do it?

I had a look on source code and they get a request parser as follow

var HTTPParser = process.binding('http_parser').HTTPParser;
var parser = new HTTPParser(HTTPParser.REQUEST)

Edit

Some progress from a node.js test

var request = Buffer(raw);
var parser = new HTTPParser(HTTPParser.REQUEST);

parser.execute(request, 0, request.length);

Edit 2

Some eventHandlers were missing (all of them)

parser.onHeadersComplete = function(res) {
    console.log('onHeadersComplete');
    console.log(res);
};

parser.onBody = function(body) {
    console.log('body done');
    console.log(body.toString());
}

parser.onMessageComplete = function(res) {
    console.log('done');
};

Thanks

I updated my question. I have a "GET / HTTP/1.1\nHost: localhost\n\n" string, which I need to parse to create an object. The resulting object must be instance of http.IncomingMessage — PauloASilva
– PauloASilva, Commented Oct 3, 2014 at 14:52
Why don't you use the http module? require('http').createServer(function(req,res){ ... }) The function gets called each time there is a request. req is already an instance of http.IncomingMessage — stewe
– stewe, Commented Oct 3, 2014 at 21:19
I don't need an HTTP server to serve requests. I just beed a parser for HTTP messages. — PauloASilva
– PauloASilva, Commented Oct 4, 2014 at 18:57

KT. · Accepted Answer · 2015-12-02 16:04:12Z

3

Apparently, the http_parser module is a low-level callback-based parser. It will send whatever parts of the string it can parse to you via those callbacks, and it is up to you to make an IncomingMessage or whatever else you need from them.

I believe something like that might be what you are looking for:

var HTTPParser = process.binding('http_parser').HTTPParser;

function parseMessage(request) {
    var _message = {};
    var _parser = new HTTPParser(HTTPParser.REQUEST);

    _parser.onHeadersComplete = function(headers) { 
        _message = headers; 
    }

    _parser.onBody = function(body, start, len) {
        _message.data = body.slice(start, start+len);
    }

    var _result = _parser.execute(request, 0, request.length);

    if (_result != request.length) { 
        _message.error = _result; 
    }
    else {
        _message.error = false;
    }
    return _message;
}

var request = Buffer("GET / HTTP/1.1\nHost: localhost\nContent-Length: 2\n\nHi\n\n");
result = parseMessage(request);

Note that the particular IncomingMessage class is parameterized with a socket and generally built around the idea of it being used within a server. The code for parsing it is somewhat messy to be reused as-is (to my taste).

answered Dec 2, 2015 at 16:04

KT.

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Fr0sT Over a year ago

Recent Node versions changed interface, now callbacks are assigned like parser[HTTPParser.kOnHeaders] = function() {...}

loadaverage · Accepted Answer · 2016-02-12 04:13:23Z

Old topic, but I'll say something.

Exporting HTTPParser in own stuff (module or app) is not as simple, 'cause http library uses many internal local functions and constructors. Besides, HTTPParser itself is binded from C library and some helpers.

As I know http.parsers was removed from Node > 4, so the only way is to import all necessary stuff from http library.

For node 0.x there are easy way to import:

var parser = require("http").parsers.alloc();

parser.onIncoming = function(response) {
  console.log(response);
};

function parse(data) {
    var buffer = new Buffer(data);
    parser.execute(buffer, 0, buffer.length);
}
/**
 * tests
 */
parse("DELETE / HTTP/1.1\r\n");
parse("user-agent: curl\r\n");
parse("x-pingback:");
parse("12023\r\n");
parse("\r\n");

//response
{ _readableState: 
   { highWaterMark: 16384,
     buffer: [],
     length: 0,
     pipes: null,
     pipesCount: 0,
     flowing: false,
     ended: false,
     endEmitted: false,
     reading: false,
     calledRead: false,
     sync: true,
     needReadable: false,
     emittedReadable: false,
     readableListening: false,
     objectMode: false,
     defaultEncoding: 'utf8',
     ranOut: false,
     awaitDrain: 0,
     readingMore: false,
     decoder: null,
     encoding: null },
  readable: true,
  domain: null,
  _events: {},
  _maxListeners: 10,
  socket: undefined,
  connection: undefined,
  httpVersion: '1.1',
  complete: false,
  headers: { 'user-agent': 'curl', 'x-pingback': '12023' },
  trailers: {},
  _pendings: [],
  _pendingIndex: 0,
  url: '/',
  method: 'DELETE',
  statusCode: null,
  client: undefined,
  _consuming: false,
  _dumped: false,
  httpVersionMajor: 1,
  httpVersionMinor: 1,
  upgrade: false }

More info here

Also, thanks to @KT for elegant solution

Is there a solution for a newer node versions, like current LTS (v16)? require("http").parsers is undefined.

Iceberg · Accepted Answer · 2022-01-11 03:57:26Z

How about parsing it manually? The following is a sample of parsing http request from buffer. Need to convert the string to buffer firstly.

const data = Buffer.from([80, 79, 83, 84, 32, 104, 116, 116, 112, 58, 47, 47, 108, 111, 99, 97, 108, 104, 111, 115, 116, 58, 49, 50, 51, 52, 47, 104, 101, 108, 108, 111, 32, 72, 84, 84, 80, 47, 49, 46, 49, 13, 10, 72, 111, 115, 116, 58, 32, 108, 111, 99, 97, 108, 104, 111, 115, 116, 58, 49, 50, 51, 52, 13, 10, 85, 115, 101, 114, 45, 65, 103, 101, 110, 116, 58, 32, 99, 117, 114, 108, 47, 55, 46, 55, 56, 46, 48, 13, 10, 65, 99, 99, 101, 112, 116, 58, 32, 42, 47, 42, 13, 10, 80, 114, 111, 120, 121, 45, 67, 111, 110, 110, 101, 99, 116, 105, 111, 110, 58, 32, 75, 101, 101, 112, 45, 65, 108, 105, 118, 101, 13, 10, 67, 111, 110, 116, 101, 110, 116, 45, 76, 101, 110, 103, 116, 104, 58, 32, 55, 13, 10, 67, 111, 110, 116, 101, 110, 116, 45, 84, 121, 112, 101, 58, 32, 97, 112, 112, 108, 105, 99, 97, 116, 105, 111, 110, 47, 120, 45, 119, 119, 119, 45, 102, 111, 114, 109, 45, 117, 114, 108, 101, 110, 99, 111, 100, 101, 100, 13,10, 13, 10, 97, 61, 49, 38, 98, 61, 50]);


const delimIndex = data.indexOf('\r\n\r\n');
const lines = data.slice(0, delimIndex).toString('utf8').split('\r\n');
const startLine = lines[0];
const headers = lines.slice(1);
const body=data.slice(delimIndex + 4);

console.log(`${startLine}\n\n${headers.join('\n')}\n\n${body}`);

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