[Urgent] HTTP connection hangs when using HEAD method

[mtojek]

Description

The connection stays open because of missing response data (basically hangs).

curl -X HEAD http://localhost:1323

Working code to debug

package main

import (
    "net/http"
    "github.com/labstack/echo"
    "github.com/labstack/echo/engine/standard"
)

func main() {
    e := echo.New()
    e.GET("/", func(c echo.Context) error {
        return c.String(http.StatusOK, "Hello, World!")
    })
    e.Run(standard.New(":1323"))
}

Version/commit

latest

[mtojek]

9.4 HEAD
The HEAD method is identical to GET except that the server MUST NOT return a message-body in the response. The metainformation contained in the HTTP headers in response to a HEAD request SHOULD be identical to the information sent in response to a GET request. This method can be used for obtaining metainformation about the entity implied by the request without transferring the entity-body itself. This method is often used for testing hypertext links for validity, accessibility, and recent modification.

Source: https://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html

What we have here is generally a bug:

$ curl -v -X HEAD http://localhost:1323
* Adding handle: conn: 0x7fc8a3804000
* Adding handle: send: 0
* Adding handle: recv: 0
* Curl_addHandleToPipeline: length: 1
* - Conn 0 (0x7fc8a3804000) send_pipe: 1, recv_pipe: 0
* About to connect() to localhost port 1323 (#0)
*   Trying 127.0.0.1...
* Connected to localhost (127.0.0.1) port 1323 (#0)
> HEAD / HTTP/1.1
> User-Agent: curl/7.30.0
> Host: localhost:1323
> Accept: */*
> 
< HTTP/1.1 405 Method Not Allowed
< Content-Type: text/plain; charset=utf-8
< Date: Sat, 30 Jul 2016 16:22:31 GMT
< Content-Length: 18
<