Netty hangs when header too long

[tomas-langer]

Related to #2179

When a header is sent that is too big (such as 120 kb), the request hangs forever.
This is fixed in 2.0., but does not work in 1.4 (tested on latest 1.4.6-SNAPSHOT).

Also the first request with long header gets through and returns a response, the second one hangs.

Expected behaviour:

1. We should get a 400 response and appropriate message (header too big)
2. We should have a way to configure a bigger header (see Add Netty configuration options #2179) for cases where this is required.

This is a customer issue where the header is required to be bigger than 8Kb.

Reproducer:

class TestLongHeaders {
    @Test
    void testTooBigHeader() throws InterruptedException, ExecutionException, TimeoutException {
        WebServer ws = WebServer.builder(Routing.builder()
                                                 .get("/", (req, res) -> res.send("Hi"))
                                                 .register("/static", StaticContentSupport.create("/static"))
                                                 .build())
                .build()
                .start()
                .toCompletableFuture()
                .get(10, TimeUnit.SECONDS);

        Client client = ClientBuilder.newClient();
        String target = "http://localhost:" + ws.port();

        String headerValue = header(8000);
        String result = client.target(target)
                .request()
                .header("X_SHORT", headerValue)
                .get(String.class);

        assertThat(result, is("Hi"));

        headerValue = header(10000);
        result = client.target(target)
                .request()
                .header("X_LONG", headerValue)
                .get(String.class);
        assertThat(result, is("Hi"));

        result = client.target(target)
                .request()
                .header("X_LONG", headerValue)
                .get(String.class);
        assertThat(result, is("Hi"));
    }

    private String header(int size) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < size; i++) {
            sb.append("a");
        }
        return sb.toString();
    }
}

[tomas-langer]

Problem is now fixed in 1.x branch and new configuration options were added for server:

Configuration key	Default value	Java type	Description
max-header-size	8192	int	Maximal number of bytes of all header values combined. Returns 400 if headers are bigger
max-initial-line-length	4096	int	Maximal number of characters in the initial HTTP line. Returns 400 if line is longer
timeout-millis	no timeout	long	Server socket timeout.
receive-buffer-size	implementation default	int	Proposed value of the TCP receive window that is advertised to the remote peer on the server socket.
max-chunk-size	8192	int	Maximal size of a chunk to read from incoming requests
validate-headers	true	boolean	Whether to validate header names, if they contain illegal characters.
initial-buffer-size	128	int	Initial size of buffer used to parse HTTP line and headers