[ruby-core:63073] [ruby-trunk - Bug #9927] webrick does not unset content-length when responding to HEAD requests

Issue #9927 has been updated by Adrien Thebo.


I didn't make this very clear, but the `curl` invocation hangs until the webrick server is killed, and then prints `transfer closed with 23 bytes remaining to read` which indicates it was hanging.

----------------------------------------
Bug #9927: webrick does not unset content-length when responding to HEAD requests
https://bugs.ruby-lang.org/issues/9927#change-47150

* Author: Adrien Thebo
* Status: Open
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
* ruby -v: ruby 1.9.3p484 (2013-11-22 revision 43786) [x86_64-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
When Webrick responds to HEAD requests it omits the body (per RFC2616 -- 4.4 Message Length). However when setting up the response headers the content-length field is set to the length of the body, which means that the resulting response will have a content length that doesn't match the actual response. This means that some HTTP clients may hang when reading the response.

This is reproducible with the following:

```ruby
require 'webrick'

server = WEBrick::HTTPServer.new :Port => 8080, :BindAddress => '127.0.0.1'
server.mount_proc("/") do |req, res|
  res.body = "This will be ignored!\r\n"
end
trap('INT') do
  server.shutdown
end
server.start
```

Running this with curl results in the following:

~~~
└> ruby webrick-head.rb                 
[2014-06-10 12:07:28] INFO  WEBrick 1.3.1
[2014-06-10 12:07:28] INFO  ruby 1.9.3 (2013-11-22) [x86_64-linux]
[2014-06-10 12:07:28] INFO  WEBrick::HTTPServer#start: pid=24798 port=8080
localhost - - [10/Jun/2014:12:07:30 PDT] "HEAD / HTTP/1.1" 200 0
- -> /
^C[2014-06-10 12:07:36] INFO  going to shutdown ...
[2014-06-10 12:07:36] INFO  WEBrick::HTTPServer#start done.
~~~

~~~
└> curl -v -X HEAD http://localhost:8080
* Rebuilt URL to: http://localhost:8080/
* Hostname was NOT found in DNS cache
*   Trying 127.0.0.1...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed

  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0* Connected to localhost (127.0.0.1) port 8080 (#0)
> HEAD / HTTP/1.1
> User-Agent: curl/7.37.0
> Host: localhost:8080
> Accept: */*
> 
< HTTP/1.1 200 OK 
* Server WEBrick/1.3.1 (Ruby/1.9.3/2013-11-22) is not blacklisted
< Server: WEBrick/1.3.1 (Ruby/1.9.3/2013-11-22)
< Date: Tue, 10 Jun 2014 19:07:30 GMT
< Content-Length: 23
< Connection: Keep-Alive
< 

  0    23    0     0    0     0      0      0 --:--:--  0:00:01 --:--:--     0
  0    23    0     0    0     0      0      0 --:--:--  0:00:02 --:--:--     0
  0    23    0     0    0     0      0      0 --:--:--  0:00:03 --:--:--     0
  0    23    0     0    0     0      0      0 --:--:--  0:00:04 --:--:--     0
  0    23    0     0    0     0      0      0 --:--:--  0:00:05 --:--:--     0
[Ctrl-C sent to server]
  0    23    0     0    0     0      0      0 --:--:--  0:00:06 --:--:--     0{ [data not shown]
* transfer closed with 23 bytes remaining to read

  0    23    0     0    0     0      0      0 --:--:--  0:00:06 --:--:--     0
* Closing connection 0
curl: (18) transfer closed with 23 bytes remaining to read
~~~

This is reasonably straightforward to fix; when the headers are being created and the code is checking to see if the body should be ignored for HTTP 204 and 304, we can check to see if we're responding to a HEAD request and behave accordingly. I've attached patches to this effect

---Files--------------------------------
0001-lib-webrick-httpresponse.rb-unset-content-length-hea.patch (1.54 KB)


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