http.request(method: HEAD) + server keep-alive = uncatchable "Parse error"

[avz]

In the HEAD-request if the server responded Connection: keep-alive then http.request() throws a Parse error, but a handler for error is not called.

server.js

var net = require('net')

var server = net.createServer(function (socket) {
    var headers = [
        'HTTP/1.1 200 OK',
        'Connection: keep-alive',
        'Content-Length: 1' // required
    ]

    socket.write(headers.join('\r\n') + '\r\n\r\n1')
    socket.end()
})

server.listen(8888, '127.0.0.1')

client.js

var http = require('http')

var options = {
    host: 'localhost',
    port: 8888,
    path: '/',
    method: 'HEAD' // GET-requests work properly
};

var req = http.request(options, function(res) {
    console.log('STATUS: ' + res.statusCode);
    console.log('HEADERS: ' + JSON.stringify(res.headers));

    res.on('data', function (chunk) {
        console.log('BODY: ' + chunk);
    });
});

req.on('error', function(e) {
  console.log('HANDLED: ' + e.message);
});

req.end();

process.on('uncaughtException', function(err) {
    console.log('UNHANDLED: ' + err.stack)
})

result:

# node client.js
STATUS: 200
HEADERS: {"connection":"keep-alive","content-length":"1"}
UNHANDLED: Error: Parse Error
    at Socket.ondata (http.js:1125:24)
    at TCP.onread (net.js:334:27)

System info

# uname -srm
FreeBSD 8.2-STABLE amd64
# node -v
v0.6.3

[koichik]

socket.write(headers.join('\r\n') + '\r\n\r\n1')

Because the response of HEAD method does NOT have a body, the last character ('1') is NOT a part of the response.
Is it intentional?

With Connection: keep-alive, the response is completed without an error after all headers are received, and socket is detached.
Then the illegal data ('1') is detected.
So... who should emit the error? Agent?

[avz]

I know that is illegal response, but I want to catch this error in req.on('error') handler, not process.on('uncaughtException')

[koichik]

Because the response is completed successfully, the req should not emit 'error' event.

If the second request exists, it emits 'error'.
example:

    res.on('data', function (chunk) {
        console.log('BODY: ' + chunk);
    });

    // append below
    res.on('end', function() {
        http.globalAgent.maxSockets = 1;
        var req2 = http.request(options, function(res2) {
        });
        req2.on('error', function(e) {
            console.log('HANDLED by REQ2: ' + e.message);
        });
        req.end();
    });

result:

STATUS: 200
HEADERS: {"connection":"keep-alive","content-length":"1"}
HANDLED by REQ2: Parse Error

Because illegal data ('1') is the first character of the second response (it should be 'H' of HTTP/1.1 200 ok).
But, in your case, the second request does not exist, no request can emit 'error'.

You can catch the error on the socket.
example:

req.on('error', function(e) {
    console.log('HANDLED by SOCKET: ' + e.message);
});

// append below
req.on('socket', function(socket) {
  socket.on('error', function(e) {
    console.log('SOCKET HANDLED: ' + e.message);
  });
});

result:

STATUS: 200
HEADERS: {"connection":"keep-alive","content-length":"1"}
HANDLED by SOCKET: Parse Error

[luk-]

resolved?

[bnoordhuis]

Yep, resolved as of 827b2a9.