Issue #5813 has been reported by Yui NARUSE.

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Bug #5813: net/http's EOFError and Keep-Alive
https://bugs.ruby-lang.org/issues/5813

Author: Yui NARUSE
Status: Assigned
Priority: Normal
Assignee: Yui NARUSE
Category: 
Target version: 
ruby -v: ruby 2.0.0dev (2011-12-21 trunk 34086) [x86_64-freebsd9.0]


[ruby-dev:39421] describes exceptions thrown by open-uri, and raise a question why net/http raises EOFError.

net/http sometimes raises EOFError.
I recently find it is because of Keep-Alive.
On HTTP/1.1, connections are Keep-Alive and a Keep-Alive connection has a timeout.
If a client of such connection doesn't send anything after some communication,
server closes the connection because of Keep-Alive timeout,
and the client's connection shall raise EOFError (sometimes it may be ECONNRESET).

HTTP/1.1 says a client should retry a request if the request is idempotent.
http://tools.ietf.org/html/rfc2616#section-8.1.4
http://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-17#section-6.1.5
http://www.studyinghttp.net/connections
So I attached a patch to such retry to net/http.

FYI, this timeout of Keep-Alive, KeepAliveTimeout, is:
Apache in FreeBSD ports or pkgsrc is 5 seconds,
the on in Debian Packages or RPM is 15 seconds.

diff --git a/lib/net/http.rb b/lib/net/http.rb
index 879cfe0..13bd1a7 100644
--- a/lib/net/http.rb
+++ b/lib/net/http.rb
@@ -1332,7 +1332,10 @@ module Net   #:nodoc:
       res
     end
 
+    IDEMPOTENT_METHODS_ = %w/GET HEAD PUT DELETE OPTIONS TRACE/ # :nodoc:
+
     def transport_request(req)
+      count = 0
       begin_transport req
       res = catch(:response) {
         req.exec @socket, @curr_http_version, edit_path(req.path)
@@ -1346,6 +1349,16 @@ module Net   #:nodoc:
       }
       end_transport req, res
       res
+    rescue EOFError, Errno::ECONNRESET => exception
+      if count == 0 && IDEMPOTENT_METHODS_.include?(req.method)
+        count += 1
+        @socket.close if @socket and not @socket.closed?
+        D "Conn close because of error #{exception}, and retry"
+        retry
+      end
+      D "Conn close because of error #{exception}"
+      @socket.close if @socket and not @socket.closed?
+      raise
     rescue => exception
       D "Conn close because of error #{exception}"
       @socket.close if @socket and not @socket.closed?
diff --git a/test/net/http/test_http.rb b/test/net/http/test_http.rb
index 1515854..2e7ab4e 100644
--- a/test/net/http/test_http.rb
+++ b/test/net/http/test_http.rb
@@ -564,3 +564,29 @@ class TestNetHTTPContinue < Test::Unit::TestCase
     assert_not_match(/HTTP\/1.1 100 continue/, @debug.string)
   end
 end
+
+class TestNetHTTPKeepAlive < Test::Unit::TestCase
+  CONFIG = {
+    'host' => '127.0.0.1',
+    'port' => 10081,
+    'proxy_host' => nil,
+    'proxy_port' => nil,
+    'RequestTimeout' => 0.1,
+  }
+
+  include TestNetHTTPUtils
+
+  def test_keep_alive_get
+    start {|http|
+      res = http.get('/')
+      assert_kind_of Net::HTTPResponse, res
+      assert_kind_of String, res.body
+      sleep 1
+      assert_nothing_raised {
+        res = http.get('/')
+      }
+      assert_kind_of Net::HTTPResponse, res
+      assert_kind_of String, res.body
+    }
+  end
+end
diff --git a/test/net/http/utils.rb b/test/net/http/utils.rb
index 50f616f..07e0b9f 100644
--- a/test/net/http/utils.rb
+++ b/test/net/http/utils.rb
@@ -51,6 +51,7 @@ module TestNetHTTPUtils
       :ServerType => Thread,
     }
     server_config[:OutputBufferSize] = 4 if config('chunked')
+    server_config[:RequestTimeout] = config('RequestTimeout') if config('RequestTimeout')
     if defined?(OpenSSL) and config('ssl_enable')
       server_config.update({
         :SSLEnable      => true,


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